Hubbry Logo
Epidemiology of HIV/AIDSEpidemiology of HIV/AIDSMain
Open search
Epidemiology of HIV/AIDS
Community hub
Epidemiology of HIV/AIDS
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Epidemiology of HIV/AIDS
Epidemiology of HIV/AIDS
Epidemiology of HIV/AIDS
View on Wikipedia
from Wikipedia

HIV/AIDS pandemic
A world map illustrating the proportion of population infected with HIV in 2023
DiseaseHIV/AIDS
Virus strainHIV
SourceNon-human primates[1]
LocationWorldwide
First outbreakJune 5, 1981[2]
Date1981–present
(44 years and 4 months)
Confirmed cases73.4 million – 116.4 million (2024)[3]
Deaths
44.1 million total deaths (2024)[3]

The global pandemic of HIV/AIDS (human immunodeficiency virus infection and acquired immunodeficiency syndrome) began in 1981, and is an ongoing worldwide public health issue.[4][5][6] According to the World Health Organization (WHO), by 2023, HIV/AIDS had killed approximately 40.4 million people, and approximately 39 million people were infected with HIV globally.[4] Of these, 29.8 million people (75%) are receiving antiretroviral treatment.[4] There were about 630,000 deaths from HIV/AIDS in 2022.[4] The 2015 Global Burden of Disease Study estimated that the global incidence of HIV infection peaked in 1997 at 3.3 million per year. Global incidence fell rapidly from 1997 to 2005, to about 2.6 million per year.[7] Incidence of HIV has continued to fall, decreasing by 23% from 2010 to 2020, with progress dominated by decreases in Eastern Africa and Southern Africa.[8] As of 2023, there are about 1.3 million new infections of HIV per year globally.[9]

HIV originated in nonhuman primates in Central Africa and jumped to humans several times in the late 19th or early 20th century.[10][11][12] One reconstruction of its genetic history suggests that HIV-1 group M, the strain most responsible for the global epidemic, may have originated in Kinshasa, the capital of the Democratic Republic of the Congo, around 1920.[13][14] AIDS was first recognized in 1981, and in 1983 HIV was discovered and identified as the cause of AIDS.[15][16][17]

In some countries, HIV disproportionately affects certain key populations (sex workers and their clients, men who have sex with men, people who inject drugs, and transgender people) and their sexual partners.[18] In Sub-Saharan Africa, 63% of new infections are women, with young women (aged 15 to 24 years) twice as likely as men of the same age to be living with HIV.[18] In Western Europe and North America, men who have sex with men account for almost two thirds of new HIV infections.[19]

In 2018, the prevalence of HIV in the Africa Region was estimated at 1.1 million people.[20] The African Region accounts for two thirds of the incidence of HIV around the world.[20] Sub-Saharan Africa is the region most affected by HIV. In 2020, more than two thirds of those living with HIV were living in Africa.[4] HIV rates have been decreasing in the region: From 2010 to 2020, new infections in eastern and southern Africa fell by 38%.[8] Still, South Africa has the largest population of people with HIV of any country in the world, at 8.45 million,[21] 13.9%[22] of the population as of 2022.

In Western Europe and North America, most people with HIV are able to access treatment and live long and healthy lives.[19] In 2020, 88% of people living with HIV in this region knew their HIV status, and 67% have suppressed viral loads.[19] In 2019, approximately 1.2 million people in the United States had HIV. 13% did not realize that they were infected.[23] In Canada in 2016, there were about 63,110 cases of HIV.[24][25] In 2020, 106,890 people were living with HIV in the UK and 614 died (99 of these from COVID-19 comorbidity).[26] In Australia, in 2020, there were about 29,090 cases.[27]

Global HIV data

[edit]

Since the first case of HIV/AIDS reported in 1981, this virus continues to be one of the most prevalent and deadliest pandemics worldwide. The Center for Disease Control mentions that the HIV disease continues to be a serious health issue for several parts of the world. Worldwide, there were about 1.7 million new cases of HIV reported in 2018. About 37.9 million people were living with HIV around the world in 2018, and 24.5 million of them were receiving medicines to treat HIV, called antiretroviral therapy (ART). Roughly an estimated 770,000 people died from AIDS-related illnesses in 2018.[28]

Although AIDS is a global disease, the CDC reports that Sub-Saharan Africa has the highest prevalence of HIV and AIDS worldwide, and accounts for approximately 61% of all new HIV infections. Other regions significantly affected by HIV and AIDS include Asia and the Pacific, Latin America and the Caribbean, Eastern Europe, and Central Asia.[28]

Worldwide there is a common stigma and discrimination surrounding HIV/AIDS. Respectively, infected patients are more subject to judgement, harassment, and acts of violence and come from marginalized areas where it is common to engage in illegal practices in exchange for money, drugs, or other exchangeable forms of currency.[29]

AVERT, an international HIV and AIDS charity created in 1986, makes continuous efforts to prioritize, normalize, and provide the latest information and education programs on HIV and AIDS for individuals and areas most affected by this disease worldwide. AVERT suggested that discrimination and other human rights violations may occur in health care settings, barring people from accessing health services or enjoying quality health care.[30]

Accessibility to tests have also played a significant role in the response and speed to which nations take action. Approximately 81% of people with HIV globally knew their HIV status in 2019. The remaining 19% (about 7.1 million people) still need access to HIV testing services. HIV testing is an essential gateway to HIV prevention, treatment, care and support services.[31]

It is crucial to have HIV tests available for individuals worldwide since it can help individuals detect the status of their disease from an early onset, seek help, and prevent further spread through the practice of suggestive safety precautions. Testing can be done for those between the ages of 13 and 64. The CDC recommends testing for HIV at least once for routine health care. HIV tests have a high accuracy and the tests come in the form of antibody tests, antigen/antibody tests, and NATS (nucleic acid test).[32]

There were approximately 38 million people across the globe with HIV/AIDS in 2019. Of these, 36.2 million were adults and 1.8 million were children under 15 years old.[33]

HIV/AIDS related deaths, HIV Incidence Rate, and HIV Prevalence Rate on a Global Scale
Year Deaths due to HIV/AIDS globally[34] HIV Infection Incidence Rate globally[35] HIV Infection Prevalence Rate Globally[35]
1990 336 387 2 100 000 8 500 000
1995 939 400 3 200 000 18 600 000
2000 1 560 000 2 900 000 26 000 000
2005 1 830 000 2 500 000 28 500 000
2010 1 370 000 2 200 000 30 800 000
2015 1 030 000 1 900 000 34 400 000
2021[36] 650 000 1 500 000 38 400 000
The prevalence, incidence, and death of HIV/AIDS, Worldwide, 1990-2019.[34]

Historical data for selected countries

[edit]

HIV/AIDS in World from 2001 to 2014 – adult prevalence  – data from CIA World Factbook[37]

By region

[edit]
See also: List of countries by HIV/AIDS adult prevalence rate

The global epidemic is not homogeneous within regions, with some countries more affected than others. Even at the country level, there are wide variations in infection levels between different areas and different population groups. New HIV infections are falling globally on average (a decrease of 23% from 2010 to 2020), but continue to rise in many parts of the world.[8] Sub-Saharan Africa is by far the worst-affected region, and targeted interventions in the region have decreased the spread of HIV.[19]

New infections fell in eastern and southern Africa by 38% from 2010 to 2020, but HIV in western and central Africa has not received the same attention, and as a result has made less progress.[19] HIV rates have declined slightly in Asia and the Pacific, with HIV decreasing in Mainland Southeast Asia, but increasing in the Philippines and Pakistan.[19] From 2010 to 2020, HIV infections increased by 21% in Latin America, 22% in the Middle East and North Africa, and 72% in Eastern Europe and central Asia.[8]

Most people in North America and western and central Europe with HIV are able to access treatment and live long and healthy lives.[19] Annual AIDS deaths have been continually declining since 2005 as antiretroviral therapy has become more widely available.[34]

2020/2021 HIV Regional data[18][35]
Region People living with HIV 2020 (adults and children) People living with HIV 2021 (adults and children)[35] Adult prevalence 2021 (%)[35]

Ages 15–49

New infections 2020 (per year) Adult HIV Incidence Rate 2021[35]

(per 1000 people)

AIDS-related deaths in 2020 AIDS-related deaths in 2021[35] People accessing treatment People receiving Antiretroviral Treatment (ART) 2021[35] Prevalence of those receiving ART 2021[35]
Eastern and southern Africa 20.6 million 20.6 million 6.2 670,000 2.39 310,000 280 000 16 million 16 200 000 78
Asia and the Pacific 5.7 million 6 million 0.2 280,000 0.10 140,000 140 000 3.6 million 4 000 000 66
Western and central Africa 4.7 million 5 million 1.3 200,000 0.46 150,000 140 000 3.5 million 3 900 000 78
Latin America 2.1 million 2.2 million 0.5 110,000 0.30 32,000 29 000 1.4 million 1 500 000 69
The Caribbean 330 000 330 000 1.2 13,000 0.57 6,000 5700 220,000 230 000 70
Middle East and north Africa 230 000 180 000 <0.1 16,000 0.06 7,900 5100 93,000 88 000 50
Eastern Europe and central Asia 1.6 million 1.8 million 1.1 140,000 1.00 35,000 44 000 870,000 930 000 51
Western and central Europe and North America 2.2 million 2.3 million 0.3 67,000 0.12 13,000 13 000 1.9 million 1 900 000 85
Global totals 37.6 million 38.4 million 0.7 1.5 million 0.31 690,000 650 000 27.4 million 28 700 000 75
Regional data 2010
World region[38] Estimated prevalence of HIV infection
(millions of adults and children) 		Estimated adult and child deaths during 2010 Adult prevalence (%)
Worldwide 31.6–35.2 1.6–1.9 million 0.8%
Sub-Saharan Africa 21.6–24.1 1.2 million 5.0%
South and South-East Asia 3.6–4.5 250,000 0.3%
Eastern Europe and Central Asia 1.3–1.7 90,000 0.9%
Latin America 1.2–1.7 67,000 0.4%
North America 1–1.9 20,000 0.6%
East Asia 0.58–1.1 56,000 0.1%
Western and Central Europe .77–.93 9,900 0.2%

Sub-Saharan Africa

[edit]
The estimated HIV infection rate in Africa in 2011
Graphs of life expectancy at birth for some sub-Saharan countries showing the fall in the 1990s primarily due to the AIDS pandemic[39]
Main article: HIV/AIDS in Africa

Sub-Saharan Africa remains the hardest-hit region. HIV infection is becoming endemic in sub-Saharan Africa, which is home to just over 12% of the world's population but two-thirds of all people infected with HIV.[38] As of 2022, it is estimated that the adult HIV prevalence rate is 6.2%, a 1.2% increase from data reported in the 2011 UNAIDS World Aids Day Report.[38][40] However, the actual prevalence varies between regions. The UNAIDS 2021 data estimates that about 58% of the HIV 4000 incidences per day are in Sub-Saharan Africa.[41]

Southern Africa is the hardest hit region, with adult prevalence rates exceeding 20% in most countries in the region, and 30% in Eswatini and Botswana. Analysis of prevalence across sub-Saharan Africa between 2000 and 2017 found high variation in prevalence at a subnational level, with some countries demonstrating a more than five-fold difference in prevalence between different districts.[42] Although Eastern and Southern Africa have a heavier burden of disease they have also shown much resilience in their response to HIV.[43]

Across Sub-Saharan Africa, more women are infected with HIV than men, with 13 women infected for every 10 infected men. This gender gap continues to grow. Throughout the region, women are being infected with HIV at earlier ages than men. The differences in infection levels between women and men are most pronounced among young people (aged 15–24 years). In this age group, there are 36 women infected with HIV for every 10 men. The widespread prevalence of sexually transmitted diseases, the promiscuous culture,[44] the practice of scarification, unsafe blood transfusions, and the poor state of hygiene and nutrition in some areas may all be facilitating factors in the transmission of HIV-1 (Bentwich et al., 1995).

It is important to work towards eliminating Mother-to-child transmission of HIV-1 in developing nations. Due to a lack of testing, a shortage in antenatal therapies and through the feeding of contaminated breast milk, 590,000 infants born in developing countries are infected with HIV-1 per year.[45] In 2000, the World Health Organization estimated that 25% of the units of blood transfused in Africa were not tested for HIV, and that 10% of HIV infections in Africa were transmitted via blood.[46]

Poor economic conditions (leading to the use of dirty needles in healthcare clinics) and lack of sex education contribute to high rates of infection. In some African countries, 25% or more of the working adult population is HIV-positive. Poor economic conditions caused by slow onset-emergencies, such as drought, or rapid onset natural disasters and conflict can result in young women and girls being forced into using sex as a survival strategy.[47] Worse still, research indicates that as emergencies, such as drought, take their toll and the number of potential 'clients' decreases, women are forced by clients to accept greater risks, such as not using contraceptives.[47]

AIDS-denialist policies have impeded the creation of effective programs for distribution of antiretroviral drugs. Denialist policies by former South African President Thabo Mbeki's administration led to several hundred thousand unnecessary deaths.[48][49] UNAIDS estimates that in 2005 there were 5.5 million people in South Africa infected with HIV — 12.4% of the population. According to a graph done by UNAIDS, there were 4 200 000 people living with HIV in South Africa in 2005. This was an increase of 400 000 people since 2003.[50]

In 2018, the prevalence of HIV in Eastern and Southern Africa combined was 1.8 million. This number only represents children and adolescents (Ages 0–19). As for those ages 15–24 in this region of Africa, the incidence rate (2018) was 290 000. About 203 000 of those infected were females.[50] The statistical release form the Republic of South Africa in 2020 states that the prevalence rate of HIV infections among adults ages 15–49 was 18.7% but the overall population in South Africa has a prevalence rate of 13%.[51] As of 2021, UNAIDS data from the eastern and southern countries in Africa showed the HIV prevalence rate to be 6.2% in adults ages 15–49.[35]

Females in Sub-Saharan Africa continue to be adversely affected by HIV with data that reveals women 15–24 years of age are two times as likely to contract HIV compared to their male counterparts.[52] However, it has been noted, that empowering women when it comes to education has an effect on lowering their risk of becoming infected with HIV.[52] Data from Sub-Saharan Africa also shows that women are more likely to get tested for HIV, therefore a higher percentage of women compared to men are aware that they have HIV.[52] There are also a higher percentage of women who are receiving treatment and women are more likely to continue with treatment once started.[52]

Although HIV infection rates are much lower in Nigeria than in other African countries, the size of Nigeria's population meant that by the end of 2003, there were an estimated 3.6 million people infected. On the other hand, Uganda, Zambia, Senegal, and most recently Botswana have begun intervention and educational measures to slow the spread of HIV, and Uganda has succeeded in actually reducing its HIV infection rate.[53]

During COVID-19, some countries in South and East Africa were able to set up treatment sites that provided 1.8 million individuals with a larger supply of antiretroviral (ART) medication that could sustain them for longer than the typical 3 months.[54] In the quarterly report following lockdown, they saw a 10% decrease in the number of individuals that experienced treatment interruptions from the quarter before lockdown.[54] South Africa also saw that those infected with HIV had a great risk of complications if they contracted the COVID-19 virus, and more so if they were not receiving ART.[54] The other issue seen before the COVID-19 pandemic arrived was the lack of health care workers. In a bar graph created by the World Health Organization (WHO) comparing regions and globally, Sub-Saharan Africa had the least number of health professionals per 10 000 people.[55]

Middle East and North Africa

[edit]

HIV/AIDS prevalence among the adult population (15-49) in the Middle East and North Africa (MENA) is estimated less than 0.1 between 1990 and 2018. This is the lowest prevalence rate compared to other regions in the world.[56]

In the MENA, roughly 230,000 people are living with HIV as of 2020,[57] a slight decrease from 240,000 in 2018 [35] where Iran accounted for approximately one-quarter (61,000) of the population with HIV followed by Sudan (59,000).[58] As well as, Sudan (5,200), Iran (4,400) and Egypt (3,600) took up more than 60% of the number of new infections themselves in the MENA (20,000). Roughly two-thirds of AIDS-related deaths in this region happened in these countries for the year 2018.[35]

Although the prevalence is low, concerns remain in this region. First, unlike the global downward trend in new HIV infections and AIDS-related deaths, the numbers have continuously increased in the MENA.[59] Second, compared to the global rate of antiretroviral therapy (62%),[60] the MENA region's rate is far below in 2020 (43%).[57][58] The low participation of antiretroviral therapy (ART) increases not only the number of AIDS-related deaths but the risk of mother-to-baby HIV infections, in which the MENA (24.7%) shows relatively high rates compared to other regions, for example, southern Africa (10%), Asia and the Pacific (17%).[56] It is estimated that only one in five individuals in need of ART will receive it, and even less than 10% in women and children.[61]

Key population at high risk in this region is identified as injection drug users, female sex workers and men who have sex with men.[56]

South and South-East Asia

[edit]
Main article: HIV/AIDS in Asia

The geographical size and human diversity of South and South-East Asia have resulted in HIV epidemics differing across the region.[citation needed]

In South and Southeast Asia, the HIV epidemic remains largely concentrated in injecting drug users (or people who inject drugs, PWID), men who have sex with men (MSM), sex workers, and clients of sex workers and their immediate sexual partners.[62] In the Philippines, in particular, sexual contact between males comprise the majority of new infections. An HIV surveillance study conducted by Dr. Louie Mar Gangcuangco and colleagues from the University of the Philippines-Philippine General Hospital showed that out of 406 MSM tested for HIV in Metro Manila, HIV prevalence was 11.8% (95% confidence interval: 8.7- 15.0).[63][64]

Migrants, in particular, are vulnerable and 67% of those infected in Bangladesh and 41% in Nepal are migrants returning from India.[62] This is in part due to human trafficking and exploitation, but also because even those migrants who willingly go to India in search of work are often afraid to access state health services due to concerns over their immigration status.[62]

Overall, integration of treatment and prevention programs has greatly increased in recent times since 2010. Condom programs have been most prevalent in the region and testing has increased disease HIV status awareness from 26 to 89% in the general region.[65] Antiretroviral therapy has been successful in Thailand in eliminating mother-to-child transmission of both HIV and syphilis.[65] Some countries have implemented needle and syringe exchange programs to combat PWID-related infections. In 2015, Bangladesh, India, Myanmar, Indonesia, Nepal, and Thailand all achieved the 200 needles distributed per PWID standard set by the World Health Organization (WHO) five years before the 2020 goal.[66] Throughout the region, countries have seen a decrease in AIDS-related deaths and new HIV infections from 2010 to 2015, with the exception of Indonesia.[65]

East Asia

[edit]
Main article: HIV/AIDS in Asia

The national HIV prevalence levels in East Asia is 0.1% in the adult (15–49) group. However, due to the large populations of many East Asian nations, this low national HIV prevalence still means that large numbers of people are infected with HIV. The picture in this region is dominated by China. Much of the current spread of HIV in China is through injecting drug use and paid sex. In China, UNAIDS estimated the number to be between 390,000 and 1.1 million, following a previous report that ranged from 430,000 to 1.5 million people.[67]

East Asia has an estimates 3.5 million people living with HIV, with prevalence low in the 15-49 age range. HIV/AIDS has remained somewhat stable with an approximated 3.5 million cases since 2005. Thailand is the only east Asian country with an over 1% HIV prevalence, which has declined from 1.7% in 2001 to 1.1% in 2015. No cases have been reported in the Democratic People's Republic of Korea.[68]

In the early 1990s, HIV spread in rural China through commercial plasma donations due to the lack of adequate infection prevention and control.[69] In Japan, just over half of HIV/AIDS cases are officially recorded as occurring amongst homosexual men, with the remainder occurring in heterosexual contact, injection drug use, and unknown means.[70]

In East Asia, men who have sex with men account for 18% of new HIV/AIDS cases and are therefore a key affected group along with sex workers and their clients who makeup 29% of new cases. This is also a noteworthy aspect because men who have sex with men had a prevalence of at least 5% or higher in countries in Asia and Pacific.[71]

Americas

[edit]

Caribbean

[edit]
Main article: HIV/AIDS in the Caribbean

The Caribbean is the second-most affected region in the world.[38][40] Among adults aged 15–44, AIDS has become the leading cause of death. However, there has been a significant decrease in the number of infections per year in the Caribbean.[72] There is a visible decrease in a graph presented by UNAIDS showing the number of new HIV infections from years 2015–2020.[72] There has also been a 50% decrease in the number of deaths due to AIDS since 2010.[72] The region's adult prevalence rate in 2011 was 0.9%.[38] As of 2021, the prevalence rate among adults ages 15–49 was 1.2% with 14 000 new HIV cases presenting in both adults and children which is a 28% decrease from 2010.[35][73]

HIV transmission occurs largely through heterosexual intercourse. A greater number of people who get infected with HIV/AIDS are heterosexuals.[74] with two-thirds of AIDS cases in this region attributed to this route. Sex between men is also a significant route of transmission, even though it is heavily stigmatized and illegal in many areas. HIV transmission through injecting drug use remains rare, except in Bermuda and Puerto Rico.[74]

Within the Caribbean, the country with the highest prevalence of HIV/AIDS is the Bahamas with a rate of 3.2% of adults with the disease. However, when comparing rates from 2004 to 2013, the number of newly diagnosed cases of HIV decreased by 4% over those years. Increased education and treatment drugs will help to decrease incidence levels even more.[75]

According to the UNAIDS Global AIDS Update 2022, there is a significant gap when it comes to children and adults alike receiving treatments which is playing a part in inhibiting the world from reaching its 2023 goal of 75% viral suppression among children.[76] This could be in part due to the high cost for treatment and services rounding to an estimated US$725 per person per year.[76]

Central and South America

[edit]
Main article: HIV/AIDS in Latin America

The populations of Central and South America have approximately 1.6 million people currently infected with HIV and this number has remained relatively unvarying with having a prevalence of approximately .4%. In Latin America, those infected with the disease have received help in the form of Antiretroviral treatment, with 75% of people with HIV receiving the treatment.[77]

In these regions of the American continent, only Guatemala and Honduras have national HIV prevalence of over 1%. In these countries, HIV-infected men outnumber HIV-infected women by roughly 3:1.[citation needed]

With HIV/AIDS incidence levels rising in Central America, education is the most important step in controlling the spread of this disease. In Central America, many people do not have access to treatment drugs. This results in 8–14% of people dying from AIDS in Honduras. To reduce the incidence levels of HIV/AIDS, education and drug access needs to improve.[78]

In a study of immigrants traveling to Europe, all asymptomatic persons were tested for a variety of infectious diseases. The prevalence of HIV among the 383 immigrants from Latin America was low, with only one person testing positive for a HIV infection. This data was collected from a group of immigrants with the majority from Bolivia, Ecuador and Colombia.[79]

United States

[edit]
Main article: HIV/AIDS in the United States

Since the epidemic began in the early 1980s, 1,216,917 people have been diagnosed with AIDS in the US. In 2016, 14% of the 1.1 million people over age 13 living with HIV were unaware of their infection.[80] The most recent CDC HIV Surveillance Report estimates that 38,281 new cases of HIV were diagnosed in the United States in 2017, a rate of 11.8 per 100,000 population.[81] Men who have sex with men accounted for approximately 8 out of 10 HIV diagnoses among males. Regionally, the population rates (per 100,000 people) of persons diagnosed with HIV infection in 2015 were highest in the South (16.8), followed by the Northeast (11.6), the West (9.8), and the Midwest (7.6).[82] Since 2015, HIV infections have decreased 8%, with 30,635 new cases reported in 2020. The highest incidence rates have continued to be measured in the South, with approximately 13% of the population unaware of their HIV status.[83]

The most frequent mode of transmission of HIV continues to be through male homosexual sexual relations. In general, recent studies have shown that 1 in 6 gay and bisexual men were infected with HIV.[84] As of 2014, in the United States, 83% of new HIV diagnoses among all males aged 13 and older and 67% of the total estimated new diagnoses were among homosexual and bisexual men. Those aged 13 to 24 also accounted for an estimated 92% of new HIV diagnoses among all men in their age group.[85]

A review of studies containing data regarding the prevalence of HIV in transgender women found that nearly 11.8% self-reported that they were infected with HIV.[86] Along with these findings, recent studies have also shown that transgender women are 34 times more likely to have HIV than other women.[84] A 2008 review of HIV studies among transgender women found that 28 percent tested positive for HIV.[87] In the National Transgender Discrimination Survey, 20.23% of black respondents reported being HIV-positive, with an additional 10% reporting that they were unaware of their status.[88]

AIDS is one of the top three causes of death for African American men aged 25–54 and for African American women aged 35–44 years in the United States of America. In the United States, African Americans make up about 48% of the total HIV-positive population and make up more than half of new HIV cases, despite making up only 12% of the population. The main route of transmission for women is through unprotected heterosexual sex. African American women are 19 times more likely to contract HIV than other women.[89]

By 2008, there was increased awareness that young African-American women in particular were at high risk for HIV infection.[90] In 2010, African Americans made up 10% of the population but about half of the HIV/AIDS cases nationwide.[91] This disparity is attributed in part to a lack of information about AIDS and a perception that they are not vulnerable, as well as to limited access to health-care resources and a higher likelihood of sexual contact with at-risk male sexual partners.[92]

Since 1985, the incidence of HIV infection among women had been steadily increasing. In 2005 it was estimated that at least 27% of new HIV infections were in women.[93] There has been increasing concern for the concurrency of violence surrounding women infected with HIV. In 2012, a meta-analysis showed that the rates of psychological trauma, including Intimate Partner Violence and PTSD in HIV positive women were more than five times and twice the national averages, respectively.[94] In 2013, the White House commissioned an Interagency Federal Working Group to address the intersection of violence and women infected with HIV.[95]

1996 would mark the first year since the beginning of the epidemic that the number of new HIV/AIDS cases would decline.[96] A significant 47% decline compared to the previous year would also be reported in 1997.[96]

There are also geographic disparities in AIDS prevalence in the United States, where it is most common in the large cities of California, esp. Los Angeles and San Francisco and the East Coast, ex. New York City and in urban cities of the Deep South.[97] Rates are lower in Utah, Texas, and Northern Florida.[97] Washington, D.C., the nation's capital, has the nation's highest rate of infection, at 3%. This rate is comparable to what is seen in west Africa, and is considered a severe epidemic.[98]

Canada

[edit]
Main article: HIV/AIDS in Canada

In 2016, there were approximately 63,100 people living with HIV/AIDS in Canada.[99] It was estimated that 9090 persons were living with undiagnosed HIV at the end of 2016.[99] Mortality has decreased due to medical advances against HIV/AIDS, especially highly active antiretroviral therapy (HAART). HIV/AIDS prevalence is increasing most rapidly amongst Indigenous Canadians, with 11.3% of new infections in 2016.[99] Canada aims to reach goals of the 90-90-90 strategy set by Join United Nations Programme on HIV/AIDS (UNAIDS) where 90% of those positive and living with HIV know their status, 90% of the diagnosed able to receive antiretroviral treatment, and 90% on treatment able to achieve viral suppression to eliminate the epidemic of AIDS by 2030.[100]

Eastern Europe and Central Asia

[edit]
Main article: HIV/AIDS in Eastern Europe and Central Asia

There is growing concern about a rapidly growing epidemic in Eastern Europe and Central Asia, where an estimated 1.23–3.7 million people were infected as of December 2011, though the adult (15–49) prevalence rate is low (1.1%). The rate of HIV infections began to grow rapidly from the mid-1990s, due to social and economic collapse, increased levels of intravenous drug use and increased numbers of sex workers. By 2010 the number of reported cases in Russia was over 450,000 according to the World Health Organization, up from 15,000 in 1995 and 190,000 in 2002. In June 2021, there are over 1.1 million people in Russia living with HIV.[101]

Ukraine and Estonia also have growing numbers of infected people, with estimates of 240,000 and 7,400 respectively in 2018. Also, transmission of HIV is increasing through sexual contact and drug use among the young (<30 years). In this region there were between 130,000 and 180,000 new HIV infections reported in 2021.[102]

Western Europe

[edit]
Main article: HIV/AIDS in Western Europe

In most countries of Western Europe, AIDS cases have fallen to levels not seen since the original outbreak; many attribute this trend to aggressive educational campaigns, screening of blood transfusions and increased use of condoms. Also, the death rate from AIDS in Western Europe has fallen sharply, as new AIDS therapies have proven to be an effective (though expensive) means of suppressing HIV.[103]

In this area, the routes of transmission of HIV is diverse, including paid sex, injecting drug use, mother to child, male with male sex and heterosexual sex.[103] However, many new infections in this region occur through contact with HIV-infected individuals from other regions. The adult (15–49) prevalence in this region is 0.3% with between 570,000 and 890,000 people currently infected with HIV. Due to the availability of antiretroviral therapy, AIDS deaths have stayed low since the lows of the late 1990s. However, in some countries, a large share of HIV infections remain undiagnosed and there is worrying evidence of antiretroviral drug resistance among some newly HIV-infected individuals in this region.[103]

Oceania

[edit]
Main articles: HIV/AIDS in Australia, HIV/AIDS in New Zealand, and HIV/AIDS in Papua New Guinea

There is a very large range of national situations regarding AIDS and HIV in this region. This is due in part to the large distances between the islands of Oceania. The wide range of development in the region also plays an important role. The prevalence is estimated at between 0.2% and 0.7%, with between 45,000 and 120,000 adults and children currently infected with HIV.[citation needed]

Papua New Guinea has one of the most serious AIDS epidemics in the region. According to UNAIDS, HIV cases in the country have been increasing at a rate of 30 percent annually since 1997, and the country's HIV prevalence rate in late 2006 was 1.3%.[104]

AIDS research and society

[edit]

In June 2001, the United Nations held a Special General Assembly to intensify international action to fight the HIV/AIDS pandemic as a global health issue, and to mobilize the resources needed towards this aim, labelling the situation a "global crisis".[105]

Regarding the social effects of the HIV/AIDS pandemic, some sociologists suggest that AIDS has caused a "profound re-medicalisation of sexuality".[106][107]

There has been extensive research done with HIV since 2001 in the United States, The National Institutes of Health (NIH) which is an agency funded by the U.S. department of Health and Human Services (HHS) has substantially improved the health, treatment, and lives of many individuals across the nation. The human immunodeficiency virus (HIV) is generally the precursor to AIDS. To this day, there is no cure for the virus; However, various treatments and education programs have been made available over time.[108][109][110]

NIH, is coordinated by the Office of AIDS Research (OAR) and this research carried out by nearly all the NIH Institutes and Centers, in both at NIH and at NIH-funded institutions worldwide. The NIH HIV/AIDS Research Program, represents the world's largest public investment in AIDS research.[111] Other agencies like the National Institute of Allergy and Infectious Diseases have also made substantial efforts to provide the latest and newest research and treatment available.[citation needed]

The NIH found that in certain areas of the world, the correlation in risky behaviors and the acquisition of HIV/AIDS is causational. Consistent drug usage and related risk behaviors, such as the exchange of sex for drugs or money, are linked to an increased risk of HIV acquisition in marginalized areas. NIAID and other NIH institutes work to develop and optimize harm reduction interventions that decrease the risk of drug use-associated and sexual transmission of HIV among injecting and non-injecting drug users.[112] Most organizations work collectively around the globe to understand, diagnose, treat, and battle the spread of this notorious disease, through the use of intervention and preventive programs the risk of acquiring HIV and the development of AIDS has dramatically dropped by 40% since its peak of cases back in 1998.[113]

Despite the advancements in scientific research and treatment, to this day there's no available cure for HIV/AIDS. Yet major efforts to contain the disease and improve the lives of many individuals through modernized anti-viral therapy have resulted in positive and promising results that may one day lead to a cure. The U.S. President's Emergency Plan for AIDS Relief (PEPFAR) is one of the largest U.S. Government's response to the global HIV/AIDS epidemic and represents the largest commitment by any nation to address a single disease in history. PEPFAR provided HIV testing services for 79.6 million people in Fiscal Year 2019 and, as of September 30, 2019, supported lifesaving anti-retroviral therapy for nearly 15.7 million men, women, and children.[31] As of the end of 2019, 25.4 million people with HIV (67%) were accessing antiretroviral therapy (ART) globally.

HIV treatment access is key to the global effort to end AIDS as a public health threat.[31] Because HIV is more prevalent in urban areas of the United States, individuals living in rural areas generally don't participate or receive HIV diagnosis. The CDC found huge disparities in HIV cases between Northern and Southern regions of the Nation. At a rate of 15.9 the Southern regions account for a large number of reports of HIV; subsequently, regions like the North and Midwest account for general rates between 9 and 7.2 making it significantly lower in case prevalence.[114] The development of an HIV vaccine has made little progress in the last forty years, but thanks to the development of mRNA technology used to quickly create COVID-19 vaccines for the SARS-CoV2 virus, creation of an HIV vaccine seems much more promising. The greatest challenge in applying the strategies of the COVID-19 vaccine is that HIV has a much greater number of variants that its vaccine needs to address.[115]

According to the CDC, populations affected and with most reported cases of HIV are generally found in gay, bisexual, and other men who reported male-to-male sexual contact. In 2018, gay and bisexual men accounted for 69% of the 37,968 new HIV diagnoses and 86% of diagnoses among males. HIV doesn't only affect individuals in this category, heterosexuals tend to be affected by HIV as well. In 2018, heterosexuals accounted for 24% of the 37,968 new HIV diagnoses in the United States.

  • Heterosexual men accounted for 8% of new HIV diagnoses.
  • Heterosexual women accounted for 16% of new HIV diagnoses.[116]

UNAIDS also suggested that the individuals who may also be at risk of acquiring this disease are generally:

  • 28 times higher among men who have sex with men.
  • 29 times higher among people who inject drugs.
  • 30 times higher for sex workers.
  • 13 times higher for transgender people.[117]

See also

[edit]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Epidemiology of HIV/AIDS

View on Grokipedia
from Grokipedia
The epidemiology of HIV/AIDS examines the distribution, determinants, and dynamics of human immunodeficiency virus (HIV) infection, which leads to acquired immunodeficiency syndrome (AIDS) in the absence of treatment, primarily transmitted through exchange of infected blood, semen, vaginal fluids, or breast milk during unprotected sexual intercourse, needle sharing among injecting drug users, or perinatal exposure. Globally, an estimated 39 million [36.0–44.8 million] people were living with HIV at the end of 2023, with 1.3 million [1.0–1.7 million] new infections and 630,000 [500,000–820,000] HIV-related deaths that year; approximately 30.7 million people were receiving antiretroviral therapy, marking substantial declines from peak levels due to widespread access, though progress has plateaued amid uneven regional implementation. HIV has claimed an estimated 40.4 million [33.6–48.4 million] lives since the start of the epidemic. Two-thirds of people living with HIV (25.9 million) are in the WHO African Region, where heterosexual transmission predominates, contrasting with higher male-to-male sexual transmission in Western countries. Key epidemiological features include concentrated epidemics among men who have sex with men and injecting drug users in low-prevalence settings, versus generalized epidemics fueled by concurrent sexual partnerships and low male circumcision rates in high-burden areas, with prevention challenges persisting despite proven interventions like pre-exposure prophylaxis and condom promotion.

Current Prevalence, Incidence, and Mortality

As of the end of 2023, an estimated 39 million [36.0–44.8 million] people were living with HIV globally. Approximately 30.7 million people were receiving antiretroviral therapy in 2023. Two thirds of people living with HIV (25.9 million) are in the WHO African Region. Sub-Saharan Africa accounted for the majority of cases, with about two-thirds of people living with HIV concentrated in that region. 1.3 million [1.0–1.7 million] people became newly infected with HIV in 2023, marking a stagnation in global prevention efforts despite treatment scale-up. Among children, around 712 new infections occurred daily, primarily through mother-to-child transmission in low-resource settings. 630 000 [500 000–820 000] people died from HIV-related causes in 2023, representing a 70% decline from the peak of over 2 million in 2004, attributable to expanded antiretroviral therapy access. HIV has claimed an estimated 40.4 million [33.6–48.4 million] lives since the start of the epidemic. However, one person died from HIV-related causes every minute, underscoring persistent gaps in diagnosis and treatment coverage. In the United States, 39,201 people received an HIV diagnosis in 2023, with men comprising the majority, particularly gay and bisexual men who accounted for over half of cases. Global new HIV infections have declined substantially over the past three decades, peaking at approximately 3.3 million in 1997 before falling to 1.3 million [1.0–1.7 million] in 2023, representing a 59% reduction from the peak but only a 40% drop since 2010 from 2.2 million [1.7–2.8 million]. The incidence rate among uninfected adults has similarly decreased from about 0.32 per 1,000 uninfected population in 2010 to 0.16 per 1,000 in recent years, driven initially by expanded antiretroviral therapy (ART) access and prevention efforts, though progress has plateaued since around 2015 due to insufficient scaling of behavioral and biomedical prevention in key populations. This stagnation is evident in the near-static annual new infections of roughly 1.3 million from 2023 onward, falling short of UNAIDS targets for a 75% reduction from 2010 levels by 2025, highlighting causal limitations in addressing high-risk transmission dynamics rather than relying solely on treatment expansion. AIDS-related mortality has followed a steeper trajectory downward, from 2.1 million deaths in 2004 and 1.4 million [1.1–1.7 million] in 2010 to 630,000 [500,000–820,000] in 2023, a 54% decline attributable primarily to ART scale-up, which has increased survival rates and reduced viral loads among treated individuals. Despite this, the persistent burden underscores that treatment alone cannot eradicate transmission, as undiagnosed cases—estimated at 5.3 million in recent years, with only 87% of people living with HIV aware of their status—continue to fuel chains of infection, particularly where testing and linkage to care lag. Projections to 2050 indicate a continued but moderated global burden, with models forecasting 43.4 million [38.7–55.0 million] people living with HIV under baseline scenarios assuming current trends in ART coverage and prevention efficacy persist, though optimistic pathways meeting aggressive UNAIDS targets (e.g., 95-95-95 diagnosis and treatment goals) could reduce this to around 29 million.00212-1/fulltext) These forecasts emphasize that without accelerated interventions targeting modifiable risk factors—such as condom use, partner reduction, and male circumcision in high-transmission contexts—the incidence plateau will endure, sustaining elevated prevalence in areas with entrenched epidemics and potentially reversing mortality gains if funding or access falters.00212-1/fulltext) Empirical modeling from the Global Burden of Disease study reinforces this, projecting stable or minimally declining incidence rates globally unless behavioral shifts outpace viral suppression efforts.00212-1/fulltext)

Historical Epidemiology

Origins and Zoonotic Emergence

HIV-1, the primary driver of the global AIDS pandemic, emerged through zoonotic spillover of simian immunodeficiency virus (SIVcpz) from central African chimpanzees (Pan troglodytes troglodytes), particularly in southeastern Cameroon, with phylogenetic estimates placing the initial cross-species transmission around the early 1900s, likely between 1880 and 1940. This event gave rise to HIV-1 group M, the most prevalent subtype, via exposure during bushmeat hunting and processing, where humans contracted the virus through cutaneous injuries or consumption of infected tissues. Genetic analyses reveal that SIVcpz strains from these chimpanzees are the closest relatives to HIV-1, with recombination events in the simian host preceding human adaptation, underscoring a natural evolutionary pathway without evidence of laboratory manipulation. In parallel, HIV-2 arose from multiple independent zoonotic transmissions of SIVsmm from sooty mangabeys (Cercocebus atys) in West Africa, primarily in regions like Guinea-Bissau, with spillovers dated to the mid-20th century or earlier based on phylogenetic divergence. Unlike HIV-1 group M, HIV-2 comprises nine subtypes from distinct mangabey lineages, reflecting repeated bushmeat-related exposures in forested areas endemic to the primate. These origins align with empirical virological data showing HIV-2's lower transmissibility and pathogenicity compared to HIV-1, consistent with incomplete adaptation from non-pathogenic simian reservoirs. The earliest molecularly confirmed human HIV-1 infection dates to a 1959 plasma sample from Kinshasa (then Léopoldville), Democratic Republic of the Congo, where viral RNA sequences were amplified and phylogenetically placed as an early divergent strain of group M. This predates widespread recognition of AIDS by decades and supports retrospective estimates of low-level circulation in Central African urban centers by the mid-20th century. Initial amplification beyond sporadic zoonoses was facilitated by colonial-era factors, including population density increases from urbanization and labor migration, alongside bushmeat trade intensification; unsanitary medical practices, such as needle reuse in vaccination campaigns, likely accelerated exponential growth in iatrogenic transmission networks, though debates persist on their relative contribution versus sexual routes. Phylogenetic reconstructions refute artificial origins, as HIV sequences nest within natural SIV clades with divergence times predating relevant human interventions, emphasizing ecological and behavioral drivers over contrived hypotheses.

Early Detection and Spread (1980s Onward)

![Deaths and new cases of HIV over time][float-right] The first official recognition of AIDS in the United States occurred on June 5, 1981, when the Centers for Disease Control and Prevention (CDC) reported five cases of Pneumocystis carinii pneumonia among previously healthy young men who have sex with men (MSM) in Los Angeles. These cases, characterized by severe immune deficiency, were soon followed by reports of Kaposi's sarcoma in similar demographics in New York and California, prompting surveillance that revealed clusters within dense MSM sexual networks. By December 1981, 337 cases of severe immune deficiency had been documented nationwide, underscoring the rapid dissemination facilitated by high-risk behaviors and limited awareness. Subsequent cases expanded beyond MSM to include Haitian immigrants, hemophiliacs receiving clotting factors, and heterosexual injection drug users, highlighting bloodborne transmission routes and leading to the initial "4-H" risk group classification (homosexuals, heroin users, Haitians, hemophiliacs). In the US, estimated annual HIV infections escalated exponentially from approximately 20,000 in 1981 to a peak of 130,400 in 1984–1985, driven by sustained transmission within these networks before preventive measures took hold. Parallel exponential growth occurred in Europe among MSM communities and in Haiti, where subtype B HIV had likely circulated since the late 1960s via sex tourism and migration links to the US, evading detection amid poor surveillance and behavioral denial. Global spread intensified in the mid-1980s, but recognition lagged in sub-Saharan Africa despite earlier viral presence; HIV was detected among African immigrants in Belgium by 1983, yet epidemic acknowledgment in most African nations occurred around 1984–1986, with initial reports from Uganda, Zambia, and Kenya revealing heterosexual transmission dominance overlooked due to institutional underfunding, stigma, and assumptions of it as a "Western" disease. This delay allowed unchecked proliferation in high-prevalence areas tied to urban migration and commercial sex. In contrast, a pivotal intervention was the 1985 rollout of HIV antibody screening for blood donations in the US and Europe, which reduced transfusion-related transmissions from thousands of cases pre-screening to near zero, as evidenced by post-1985 CDC data showing no further significant incidents from screened units. Delays in broader detection stemmed from behavioral factors like community stigma suppressing reporting and institutional hesitancy in prioritizing surveillance outside initial high-visibility groups.

Peak Epidemic Periods and Turning Points

In sub-Saharan Africa, the HIV epidemic peaked in the late 1990s, with annual new infections surpassing 3 million, primarily driven by heterosexual transmission networks reaching saturation in high-prevalence areas where adult prevalence exceeded 20% in countries like Zimbabwe and Botswana. This inflection point transitioned into a gradual decline by the early 2000s as AIDS-related mortality depleted susceptible populations and empirical evidence of behavior modification—such as reduced partner concurrency—emerged amid heightened awareness, independent of widespread antiretroviral access initially. In high-income settings, the United States experienced a mortality peak in 1995, followed by stabilization and sharp declines after the 1996 introduction of highly active antiretroviral therapy (HAART), which reduced AIDS deaths by about 70% through viral suppression and immune reconstitution. Similar patterns occurred in Western Europe, where HAART rollout correlated with infection rate drops of over 5% annually among men who have sex with men (MSM) from 1996 to 2000. Quantitative viral load testing, approved in the mid-1990s, served as a critical turning point by enabling real-time assessment of treatment efficacy and transmission risk, shifting management from symptomatic to virologic control. Post-HAART resurgences marked subsequent inflection points, particularly among MSM in Europe and Australia, where HIV notification rates rose 3.3% per year after 2000 despite improved treatment access, linked to prevention fatigue—manifesting as diminished adherence to condom use and testing amid treatment optimism reducing perceived risks. The late 1990s emergence of post-exposure prophylaxis (PEP), recommended by the CDC for non-occupational use by 1998, and pre-exposure prophylaxis (PrEP) from 2012 onward, provided biomedical turning points by averting infections in high-risk exposures, with PrEP demonstrating up to 99% efficacy in MSM trials and contributing to incidence plateaus rather than declines solely attributable to access barriers. These dynamics underscore behavioral saturation and lapses, rather than structural deficits alone, as causal drivers of epidemic curves in resourced contexts.

Transmission Dynamics

Primary Modes of Transmission

The primary modes of HIV transmission worldwide are sexual contact, injection drug use via contaminated needles or syringes, and mother-to-child transmission during pregnancy, labor, delivery, or breastfeeding. Sexual transmission accounts for more than 90% of new HIV infections globally. Injection drug use contributes approximately 8% of new infections, primarily through sharing contaminated equipment. Mother-to-child transmission represents about 9% of new pediatric infections, with an estimated 120,000 children under age five acquiring HIV in 2024 out of 1.3 million total new global infections. Transmission patterns vary regionally within these modes. In sub-Saharan Africa, where the epidemic is most concentrated, heterosexual contact drives the majority of sexual transmissions, with women and girls accounting for 63% of new adult infections. In Western countries, sexual transmission among men who have sex with men constitutes a larger share relative to population size compared to heterosexual routes. Bloodborne transmission via injection drug use is more prominent in regions like Eastern Europe and Central Asia, where it accounts for over 25% of new infections in some countries. Other routes are rare. Occupational exposures, such as needlestick injuries among healthcare workers, carry a transmission risk of approximately 0.3% per percutaneous incident involving HIV-positive blood. Historically, iatrogenic transmission through unscreened blood transfusions and blood products was significant before routine HIV screening was implemented in 1985, after which such risks declined dramatically due to donor testing and pathogen reduction measures.

Per-Act Transmission Risks and Empirical Estimates

A systematic review of prospective studies estimating per-act HIV transmission risks from untreated index partners identifies receptive anal intercourse as carrying the highest probability, at 138 infections per 10,000 exposures (1.38%). Insertive anal intercourse is substantially lower, at 11 per 10,000 (0.11%). For penile-vaginal intercourse, receptive (male-to-female) risk stands at 8 per 10,000 (0.08%), while insertive (female-to-male) is 4 per 10,000 (0.04%). Oral intercourse yields negligible risks, with estimates of 0 to 4 per 10,000 exposures across receptive fellatio, cunnilingus, and insertive acts.
Sexual ActEstimated Risk per 10,000 Exposures (Untreated Index Partner)
Receptive anal intercourse138
Insertive anal intercourse11
Receptive vaginal intercourse8
Insertive vaginal intercourse4
Oral intercourse (various)0–4
These figures derive from pooling data across partner studies, cohort analyses, and phylogenetic linkages, accounting for confirmed exposures without confounding by other routes. Empirical observations from serodiscordant couples, where the HIV-positive partner achieves viral suppression via antiretroviral therapy (ART), demonstrate near-absent transmission despite frequent condomless sex. The PARTNER study observed zero linked transmissions across 77,643 condomless anal intercourse acts in gay male couples and 14,594 acts in heterosexual couples, yielding an upper 95% confidence limit of 0.059 per 1,000 exposures for anal sex.30418-0/fulltext) A meta-analysis of such cohorts reports zero transmissions per 100 couple-years (95% CI: 0–0.103), reflecting thousands of acts under suppression. These data quantify the causal interruption of transmission by sustained viral load reduction below detectable thresholds, independent of act type or frequency within observed partnerships. While per-act probabilities remain low even untreated, cumulative risks escalate with repeated exposures in expansive sexual networks, where dozens to hundreds of acts can elevate infection odds from fractions to majorities over lifetimes.

Modifying Factors and Cofactors

High plasma HIV-1 RNA levels (>50,000 copies/mL) are associated with approximately a 10-fold increase in heterosexual transmission risk compared to lower viral loads, based on prospective cohort data from HIV-discordant couples where transmission probability rose exponentially with each log10 increment in viral load (roughly 2-3 fold per 10-fold viral load increase). During the acute phase of infection (typically the first 1-4 weeks post-exposure), viral loads peak at 106-107 copies/mL, rendering transmissibility 10-20 times higher than in the chronic phase due to elevated viremia and potential immune evasion before seroconversion. Sexually transmitted infections (STIs) act as biological cofactors by enhancing HIV susceptibility and infectivity through mucosal inflammation, ulceration, and increased viral shedding; for instance, herpes simplex virus type 2 (HSV-2) infection elevates HIV acquisition odds by 4.6-fold in women and 7-fold in men, while genital ulcers from various STIs double to quadruple transmission odds per coital act. Male circumcision reduces heterosexual HIV acquisition risk in men by 50-60%, as demonstrated in three randomized controlled trials (RCTs) involving over 10,000 uncircumcised men in South Africa, Kenya, and Uganda, where surgical removal of the foreskin decreased incidence through lowered susceptibility to penile micro-tears and reduced target cells for viral entry. Situational factors like acute alcohol or drug intoxication impair cognitive function and decision-making, leading to reduced condom adherence in intended preventive scenarios and thereby amplifying realized transmission efficiency; longitudinal studies link heavy substance use episodes to 20-50% lower consistent condom use rates during sex, independent of baseline viral load. These effects are behavioral rather than directly biological, with no causal evidence supporting non-biological psychosocial constructs like stigma as independent transmission multipliers beyond their indirect influence on testing and treatment uptake.

High-Risk Behaviors and Demographics

Sexual Behaviors and Orientation-Specific Risks

Men who have sex with men (MSM) bear a disproportionate burden of HIV transmission globally and in high-income settings, primarily due to higher per-act transmission risks associated with receptive anal intercourse and denser sexual networks that facilitate rapid spread. In the United States, MSM accounted for 67% of new HIV diagnoses in 2022, despite comprising an estimated 2-4% of the male population. The lifetime risk of HIV diagnosis among MSM is approximately 88 times higher than among heterosexual males, driven by biological factors such as the 18-fold greater infectivity of receptive anal intercourse (1.38% per-act risk) compared to receptive vaginal intercourse (0.08% per-act risk), compounded by behavioral patterns including higher partner concurrency and lower consistent condom use in some networks. Heterosexual transmission, while involving lower per-act risks (insertive vaginal intercourse at 0.04% and receptive at 0.08%), contributes substantially to epidemics in regions like sub-Saharan Africa through high volumes of partnerships, concurrency, and early sexual debut. In sub-Saharan Africa, over 80% of adult HIV infections occur via heterosexual contact, with women accounting for 55% of cases among adults, often linked to transactional sex and multiple concurrent partners that amplify exposure opportunities. Empirical studies highlight that partner concurrency—overlapping sexual relationships—accelerates transmission by increasing the likelihood of encountering an infected partner during the acute phase of infection, when viral loads are highest, though debates persist on its precise quantitative impact relative to serial monogamy with gaps. Condom use significantly mitigates sexual transmission risks across orientations, with meta-analyses estimating 80-96% effectiveness in preventing HIV in serodiscordant couples when used consistently and correctly, though real-world efficacy can dip to 60-70% due to inconsistent application or breakage. Serosorting—selecting partners of the same perceived HIV status—offers partial risk reduction by avoiding transmission to negatives but fails to eliminate dangers from undiagnosed infections, viral load variability, or misreported status, with studies showing no conclusive protective effect and potential for risk compensation via reduced condom use.

Injection Drug Use and Bloodborne Transmission

Injection drug use (IDU) contributes to approximately 10% of new HIV infections worldwide, with higher burdens in regions like Eastern Europe and Central Asia where unsafe injecting practices drive a significant portion of transmission. In these areas, HIV prevalence among people who inject drugs (PWID) reaches medians of 5% or more, often exceeding 20% in localized epidemics, fueled by heroin and synthetic opioid use. Transmission occurs primarily through sharing contaminated needles or syringes, which can retain viable HIV in residual blood even after injection. The per-sharing event risk of HIV transmission from an infected syringe is estimated at 0.63%, based on empirical data from percutaneous exposures adjusted for blood volume in shared equipment. This risk assumes untreated source plasma; viral load reductions via antiretroviral therapy lower it further, though not to zero without cessation of sharing. Multiple shares compound exposure, with studies indicating that frequent needle reuse in networks elevates incidence rates up to 69% of PWID-linked transmissions in high-prevalence settings. In the United States and Western Europe, IDU-associated HIV cases spiked in the 1980s and 1990s, coinciding with crack cocaine and heroin epidemics that increased injecting frequency and network density. By the early 1980s, seroprevalence among PWID in cities like New York exceeded 50%, with similar outbreaks in Edinburgh and other European hubs during the late 1980s. These "second-generation" epidemics followed initial zoonotic spread, amplified by polydrug use that impaired judgment and heightened syringe sharing. Needle exchange programs (NEPs), introduced in the late 1980s, correlate with 50% reductions in HIV incidence among participants in longitudinal studies, alongside decreased syringe sharing behaviors. However, outbreaks persist in clusters with low NEP coverage or high incarceration rates, where prison-based sharing—often involving polydrug withdrawal—drives secondary transmission upon release. Empirical evidence underscores that while harm reduction mitigates but does not eliminate risks, abstinence from injection remains the sole pathway to zero transmission probability in this mode.

Vertical and Other Transmission Routes

Vertical transmission of HIV from mother to child occurs during pregnancy, labor, delivery, or breastfeeding, with an untreated risk ranging from 15% to 45% depending on maternal viral load and breastfeeding duration. Antiretroviral therapy (ART) administered to the mother during pregnancy, combined with cesarean delivery and avoidance of breastfeeding where feasible, reduces this risk to less than 1% in settings with optimal access and adherence. Prevention of mother-to-child transmission (PMTCT) programs, scaled up globally since the early 2000s, have averted an estimated 2 million pediatric HIV infections through widespread ART provision. In 2024, approximately 712 children acquired HIV daily, primarily through vertical routes in regions with incomplete PMTCT coverage, while around 250 children died from AIDS-related causes each day, largely attributable to failures in antenatal testing, ART access, and follow-up care rather than inherent transmission risks. Empirical data from cohort studies confirm that early ART initiation before conception yields transmission rates below 0.5% in high-resource environments, underscoring the efficacy of viral suppression in preventing placental and peripartum transfer. Other transmission routes beyond sexual, injection drug use, and vertical pathways are exceedingly rare. Occupational exposures among healthcare workers have resulted in only 58 confirmed HIV infections in the United States since surveillance began in 1985, with most linked to percutaneous injuries from needlesticks involving known HIV-positive blood and just one case documented after 2000 due to improved post-exposure prophylaxis protocols. No evidence supports sustained HIV transmission through food or water, as the virus does not survive environmental conditions outside bodily fluids; isolated theoretical risks, such as pre-mastication of food by an HIV-positive caregiver with oral blood, have been documented in fewer than a handful of cases globally but do not constitute viable epidemic pathways.

Demographic Disparities by Age, Gender, and Socioeconomics

In 2024, women and girls accounted for approximately 45% of all new HIV infections globally across all ages, with among people living with HIV comprising 53% women and girls. This distribution reflects mode-specific risks: men experience disproportionate infections through male-to-male sexual contact, which has a higher per-act transmission probability due to biological efficiency, and injection drug use involving needle sharing. Women, conversely, predominate in heterosexual transmission cases, where female receptive vaginal intercourse carries an estimated 0.08% per-act risk compared to 0.04% for male insertive, compounded by factors such as cervical ectopy in younger women and behavioral patterns like serial monogamy with overlapping partners or unions with higher-risk males. Age-specific disparities show the bulk of new infections concentrated in the 15-49 age group, which aligns with peak reproductive and sexual activity years and accounts for over 90% of adult cases worldwide. Among adolescents and young adults aged 15-24, approximately 4,000 new infections occur weekly, driven by early sexual debut, higher rates of unprotected intercourse, and limited negotiation power in partnerships rather than age alone. Children under 15 represent a smaller fraction, with 1.4 million living with HIV in 2023 primarily from perinatal transmission during pregnancy, delivery, or breastfeeding, though incidence has declined due to reduced vertical efficiency with maternal viral suppression. Socioeconomic status correlates with higher HIV prevalence, yet evidence indicates behaviors as the primary mediator rather than economic deprivation per se; for instance, lower education levels associate with elevated infection rates through increased multiple partnering and lower condom adherence, persisting even in contexts with free testing availability. Poverty facilitates risk via enabling environments for injection drug use and transactional sex, but cross-sectional analyses reveal that adjusting for behavioral covariates like partner concurrency attenuates the direct socioeconomic effect, underscoring causal pathways rooted in individual choices and network dynamics over structural inequities alone. Among people with HIV in high-income settings, 35.6% live below the poverty line, linking to sustained high-risk practices post-diagnosis.

Regional and Country-Level Variations

Sub-Saharan Africa

Sub-Saharan Africa accounts for approximately 25.7 million people living with HIV as of 2022, representing about 67% of the global total, with adult prevalence estimated at 3.7% in eastern and southern Africa subregions. South Africa carries the largest national burden with over 7.5 million cases and an adult prevalence exceeding 12%, while Nigeria follows with around 1.9 million infections despite lower prevalence of about 1.4%. Heterosexual transmission dominates, with women and girls comprising 63% of new infections due to factors including age-disparate partnerships and biological vulnerabilities during intercourse. New HIV infections in the region declined from 1.7 million in 2010 to about 650,000 by 2023, yet progress stalls among key groups, with persistent mother-to-child transmissions contributing to roughly 90% of the 170,000 annual pediatric infections globally, predominantly in sub-Saharan Africa. Behavioral drivers amplify transmission: multiple concurrent sexual partnerships, prevalent in southern Africa, enable sustained viral circulation within networks, as evidenced by demographic and health surveys linking concurrency to higher incidence. Low male circumcision rates in non-circumcising ethnic groups—below 20% in some western African areas—exacerbate risks, with randomized controlled trials demonstrating 50-60% reduction in female-to-male acquisition among circumcised men. Antiretroviral therapy coverage reaches about 77% of diagnosed people living with HIV, supporting viral suppression in over 70% of those treated, though an estimated 19% remain undiagnosed, perpetuating onward transmission. Cultural practices such as polygyny and short partnership durations further sustain epidemics by increasing overlap in sexual networks, independent of socioeconomic confounders. Interventions targeting concurrency reduction and scaling voluntary medical male circumcision—aiming for 90% coverage in high-prevalence areas—have shown modeled impacts of up to 30% incidence drops, underscoring behavioral causality over generalized structural attributions.

Asia and Pacific Regions

In 2023, approximately 6.7 million people were living with HIV in Asia and the Pacific, representing the second-largest regional epidemic globally after sub-Saharan Africa, with adult prevalence remaining below 1% overall but concentrated in key populations such as men who have sex with men (MSM), female sex workers, and people who inject drugs (PWID). New infections totaled around 270,000 that year, driven primarily by sexual transmission within high-risk networks, with MSM accounting for over 40% of cases in urban settings across countries like India, Indonesia, and Thailand. Injection drug use remains a significant vector in Indonesia and parts of China, where sharing needles amplifies transmission efficiency in localized clusters, while heterosexual transmission linked to sex work contributes substantially in South and Southeast Asia. India and Indonesia bear the heaviest burdens, with India harboring an estimated 2.3 million people living with HIV as of 2023 and Indonesia reporting over 700,000 cases, including high vertical transmission rates that account for 23% and 26% of regional pediatric infections, respectively. In urban India, MSM prevalence exceeds 5% in sentinel surveillance, with rising infections tied to dense partner networks and limited condom use, while Indonesia's epidemics cluster around IDU in eastern provinces and sex work in Java. China's overall prevalence stays low at under 0.1%, but unreported MSM outbreaks in cities like Beijing and Guangzhou show infection rates up to 6-10% in community samples, fueled by stigma-driven under-testing and bridging to female partners. Pacific island nations exhibit heterogeneous patterns, with Papua New Guinea facing adult prevalence of 6-7% driven by sex work, mobility, and tribal practices like skin-cutting rituals that facilitate bloodborne spread, contrasting with lower rates under 1% in places like Fiji influenced by tourism-related risks. Prevention gaps persist, including inconsistent needle exchange for PWID and low PrEP uptake among MSM, leading to stalled declines; for instance, new infections among young MSM rose 20-30% annually in several East Asian hotspots from 2018-2023 due to app-facilitated partnering without risk reduction. Empirical data indicate per-act transmission risks in these networks are elevated by cofactors like STIs and methamphetamine use, underscoring the need for targeted interventions over generalized programs.

Americas

In the Americas, an estimated 4 million people were living with HIV as of 2023, with roughly 2.7 million in Latin America and the Caribbean and the remainder primarily in North America. New HIV infections totaled around 140,000 annually in recent years, reflecting regional variations in transmission dynamics and risk factors. While overall incidence has stabilized or declined in some areas due to targeted interventions, persistent disparities highlight the role of high-risk behaviors, particularly among men who have sex with men (MSM), alongside socioeconomic and migratory influences. In North America, the epidemic is heavily concentrated in the United States, where approximately 1.2 million people live with HIV, and new infections numbered 31,800 in 2022. MSM accounted for 67% of new diagnoses that year, underscoring the disproportionate impact of receptive anal intercourse and associated network effects in this demographic, despite comprising a small fraction of the population. Diagnoses in the southern U.S. states represented 52% of the national total, driven by factors including rural access barriers and higher prevalence among Black and Latino MSM. Latinos faced elevated rates, comprising 33% of new infections despite behavioral prevention options like pre-exposure prophylaxis (PrEP), which has shown efficacy in reducing incidence when targeted at high-risk groups. The Caribbean exhibits the highest adult HIV prevalence in the Americas at 1.2%, with about 15,000 new infections in 2023, often linked to heterosexual transmission, including through sex work and concurrent partnerships. Countries like Haiti and Jamaica drive much of the burden, with reductions in AIDS-related deaths (62% since 2010) attributed to expanded treatment access, though new infections remain slow to decline without intensified behavioral interventions. In Central America, prevalence is lower but elevated among migrants—often double the regional average—due to transit vulnerabilities such as transactional sex and disrupted care continuity along migration routes to North America. Latin America shows a mixed profile, with new infections rising 9% from 2010 to 2023, contrasting with global declines; transmission is more heterosexual-dominant in some countries like Brazil, though MSM prevalence reaches 9.5% median among key populations. Aggregate data reveal behavioral cofactors, including multiple partners and inconsistent condom use, as primary drivers, with evidence that focusing prevention on these—via PrEP and testing—yields measurable reductions, as seen in Brazil's early generic antiretroviral rollout stabilizing adult prevalence below 1%. Regional trends indicate overall stability but MSM-specific resurgences in urban centers, emphasizing the need for risk-act-based strategies over broad generalizations.

Europe and Central Asia

In Western Europe, HIV prevalence remains low at under 0.3% among adults aged 15-49, with new diagnoses in the EU/EEA stabilizing or declining to a rate of 5.3 per 100,000 population in 2023, a 15.9% decrease from 6.3 per 100,000 in 2014. Transmission is predominantly among men who have sex with men (MSM), accounting for about 40-50% of cases, alongside infections among migrants from high-prevalence regions. Pre-exposure prophylaxis (PrEP) uptake has contributed to reduced incidence among MSM, with models projecting further declines if testing and treatment adherence continue, as evidenced by a 24% drop in new infections across Western and Central Europe since 2010. In contrast, Eastern Europe and Central Asia face a rapidly expanding epidemic, with an estimated 1.7-2 million people living with HIV as of 2023, driven primarily by injection drug use (IDU) amid ongoing opioid crises. New infections reached 140,000 [120,000-160,000] in 2023, a 20% increase from prior years, with 93% concentrated in Russia and Ukraine where IDU accounts for 27-38% of transmissions. In Russia, annual new cases exceed 60,000, while Ukraine reports surges linked to conflict-disrupted harm reduction, with IDU prevalence amplifying bloodborne spread through shared needles. Policy environments restricting needle exchange and opioid substitution therapy—often due to punitive drug laws—causally exacerbate transmission by failing to interrupt IDU networks, as surveillance data link limited harm reduction coverage to sustained epidemics. Surveillance reveals stark disparities in testing and diagnosis: Western Europe achieves over 90% awareness among diagnosed cases through routine screening, enabling early intervention, whereas Eastern Europe and Central Asia lag with only 62% of people living with HIV aware of their status in 2022, leading to late diagnoses in 50-60% of cases. This gap underscores causal roles of infrastructural weaknesses and stigma in the East, where behavioral surveillance ties surges to unchecked IDU practices rather than solely structural factors. Overall, WHO European Region diagnoses totaled nearly 113,000 in 2023, with 69% in the eastern subregion, highlighting the need for targeted IDU interventions to curb trajectories diverging from Western containment.

Middle East and North Africa

The HIV epidemic in the Middle East and North Africa (MENA) region is characterized by low overall adult prevalence, estimated at under 0.2%, but with concentrated transmission in hidden high-risk networks such as people who inject drugs (PWID), men who have sex with men (MSM), and migrants. New infections rose by approximately 114% between 2010 and 2022, marking one of the fastest-growing epidemics globally, driven primarily by these key populations rather than generalized spread. Empirical seroprevalence surveys reveal stark disparities: among PWID, rates reach 9.3% in Iran and approximately 7% in Egypt, while MSM prevalence averages 12.6% regionally based on targeted testing. These figures underscore data limitations from underreporting, as surveillance often misses concealed behaviors due to criminalization and stigma. In Iran, injection drug use via needle-sharing has fueled spikes, with HIV prevalence among PWID climbing to 15% in some provinces by 2011 before partial declines through harm reduction, though annual incidence growth persists at 9.6%. Egypt shows similar patterns, with integrated behavioral and biological surveillance indicating 7.7% prevalence among IDU and 6.9% among MSM, linked to overlapping risks like polydrug use and commercial sex. Causal factors include not inherent regional immunity but behavioral networks amplified by socioeconomic vulnerabilities, such as poverty-driven drug markets and limited access to sterile equipment. Cultural and legal taboos against homosexuality and drug use delay detection, leading to late diagnoses and undercounted cases in official statistics. Emerging risks stem from migrant labor flows and conflict zones, where displaced populations face heightened exposure through disrupted healthcare, unhygienic conditions, and survival sex. In Gulf states, labor migrants from high-prevalence areas contribute to undetected transmission chains, while wars in Syria, Yemen, and Iraq exacerbate vulnerabilities via refugee camps' overcrowding and bloodborne exposures. Seroprevalence data from key population surveys in these settings highlight the need for targeted empirical monitoring, as generalized population testing yields near-zero rates masking concentrated epidemics. Ongoing underfunding and punitive policies hinder comprehensive surveillance, perpetuating data gaps that obscure true incidence trajectories.

Public Health Responses and Outcomes

Approximately 87% of the 39.9 million people living with HIV globally knew their status in 2024, leaving an estimated 5.3 million undiagnosed and contributing to persistent transmission chains. Regional disparities are pronounced, with awareness exceeding 90% in Western and Central Europe and North America—approaching near-universal levels in low-prevalence settings—compared to gaps in sub-Saharan Africa, where rates in Western and Central subregions hovered around 81% in 2023, driven by limited surveillance infrastructure and access barriers. These undiagnosed pools, estimated at 10-20% in high-burden African countries, sustain onward infections, as unaware individuals account for a disproportionate share of new cases. Surveillance has evolved from passive clinic-based reporting to active strategies incorporating molecular epidemiology and population surveys, improving detection accuracy since the early 2000s, though gaps persist in real-time tracking of undiagnosed cases. Post-2010, the rise of HIV self-testing (HIVST) kits—endorsed by WHO in 2012—has expanded reach, with global distribution surging from negligible levels to millions annually by the late 2010s, particularly in key populations facing stigma-related barriers to facility-based testing. Supervised and unsupervised HIVST models have demonstrated high acceptability, with uptake increases of 20-50% in hard-to-reach groups like men who have sex with men (MSM) and sex workers, linking to earlier diagnosis without relying solely on healthcare infrastructure. Diagnosis delays remain prevalent in high-risk groups, often attributable to behavioral avoidance rather than access alone; for instance, MSM and people who inject drugs (PWID) exhibit median delays of 2-3 years from infection to diagnosis, fueled by stigma, fear of disclosure, and distrust of services. In the U.S., approximately 15% of infections in 2015 involved a 3-year median delay among at-risk populations, with similar patterns in Europe where late diagnoses exceed 40% in some migrant and MSM subgroups. Empirical evidence links early diagnosis via expanded testing to 30-50% reductions in onward transmission, as undiagnosed or recently infected individuals drive a substantial portion of epidemics; however, avoidance in high-stigma contexts perpetuates these pools, underscoring the need for targeted, low-barrier interventions beyond access alone.

Antiretroviral Therapy Access and Viral Suppression

As of 2024, approximately 31.6 million people living with HIV globally were accessing antiretroviral therapy (ART), representing 77% coverage among an estimated 41 million people living with the virus. Among those on ART, 93% achieved viral suppression, defined as HIV RNA levels below detectable thresholds, enabling substantial reductions in transmission risk. Clinical trials such as HPTN 052 demonstrated that sustained viral suppression reduces the risk of sexual HIV transmission by 93% in serodiscordant heterosexual couples, with observational data from studies like PARTNER confirming zero linked transmissions in thousands of condomless sexual acts among suppressed individuals. These findings underpin the "undetectable equals untransmittable" (U=U) consensus, contributing to herd-level suppression effects where population-level ART scale-up correlates with declining new infections and AIDS-related deaths. Regional disparities in ART access persist, with coverage reaching over 95% in high-income Western countries like those in Western Europe and North America, compared to approximately 75% in sub-Saharan Africa, where the majority of cases occur. Empirical data link higher coverage and adherence to sharp mortality reductions; for instance, AIDS-related deaths fell by 69% globally since 2004, with steeper declines in regions achieving consistent suppression rates above 70%. In Eastern and Southern Africa, progress toward 95% suppression among treated individuals has driven localized epidemiological shifts, though gaps in rural access and monitoring hinder uniform outcomes. Causal factors undermining viral suppression include pretreatment and acquired drug resistance, which compromises regimen efficacy and elevates transmission risk despite ART initiation, alongside high treatment dropout rates averaging 26% in cohort studies, often tied to behavioral non-adherence such as inconsistent medication intake or loss to follow-up. While overall resistance prevalence has declined by 17% from 2018 to 2024 due to improved first-line regimens like dolutegravir-based therapy, persistent dropouts—exacerbated by socioeconomic barriers and risk-compensatory behaviors—prevent full realization of suppression's preventive potential, sustaining residual transmission chains. Adherence remains the primary determinant of sustained suppression, with lapses directly correlating to virologic failure and secondary infections in population models.

Prevention Interventions: Efficacy Data and Critiques

Pre-exposure prophylaxis (PrEP) using daily oral tenofovir disoproxil fumarate-emtricitabine has demonstrated high efficacy in randomized controlled trials (RCTs) among adherent users. In the iPrEx trial involving men who have sex with men (MSM) and transgender women, intention-to-treat analysis showed 44% overall efficacy, rising to over 90% among participants with detectable drug levels indicating adherence, with models estimating up to 99% protection for those taking four or more doses weekly. Similar results emerged from meta-analyses of MSM-focused RCTs, reporting 75-86% risk reduction overall, with efficacy nearing 100% under high adherence. Condoms, when used consistently and correctly, reduce heterosexual HIV transmission risk by 80-95% according to meta-analyses of observational and serodiscordant couple studies. Estimates vary from 60% in lower-quality usage scenarios to 96% under ideal conditions, though real-world effectiveness is often lower due to inconsistent application. Medical male circumcision provides approximately 60% risk reduction for heterosexual HIV acquisition in men, based on three RCTs conducted in South Africa, Kenya, and Uganda involving over 10,000 participants followed for up to 24 months, with efficacy ranging 38-66% across trials. These findings prompted World Health Organization recommendations for voluntary circumcision in high-prevalence heterosexual settings, though benefits are absent for MSM transmission dynamics. Despite these interventions' proven efficacies under controlled conditions, critiques highlight substantial gaps in real-world implementation, particularly adherence and behavioral factors. Among MSM, a key high-risk group targeted by PrEP, suboptimal adherence rates reach 33% globally per systematic reviews, undermining potential protection and contributing to breakthrough infections. Global HIV prevention funding exceeds $20 billion annually through mechanisms like the Global Fund and PEPFAR, yet new infections numbered 1.3 million in 2023—a 39% decline since 2010 but plateauing in MSM populations and insufficient relative to investment scale, suggesting overreliance on access expansion without commensurate emphasis on sustained behavior modification. From first-principles causal analysis, abstinence from sexual activity or strict mutual monogamy with regular HIV testing among uninfected partners yields near-zero risk of sexual transmission, empirically supported by serodiscordant couple studies and epidemiological models where partner reduction drove declines in Uganda's epidemic. These approaches, however, receive marginal policy prioritization compared to biomedical tools, despite evidence that behavioral strategies like partner limitation explain more variance in transmission rates than barrier or prophylactic methods alone in population-level data. Such de-emphasis may reflect institutional preferences for scalable interventions over those requiring individual agency, potentially limiting overall prevention impact.

Controversies and Empirical Debates

Behavioral Causality vs. Structural Explanations

Epidemiological analyses of HIV transmission emphasize behavioral causality, attributing infection risks primarily to modifiable individual actions such as the type of sexual act, number of partners, and condom non-use, rather than immutable structural conditions like poverty or discrimination. Per-act transmission probabilities demonstrate that receptive anal intercourse carries a risk of 1.38% (138 per 10,000 exposures), approximately 17 times higher than receptive penile-vaginal intercourse at 0.08% (8 per 10,000 exposures), underscoring how anatomical and frictional factors in specific behaviors elevate vulnerability independent of socioeconomic context. In the United States, men who have sex with men (MSM)—estimated at 2-4% of the male population—accounted for 67% of new HIV diagnoses (25,482 cases) in 2022, with a lifetime infection risk of 1 in 6, a disparity explained by the prevalence of high-risk anal practices across diverse income and education levels rather than uniform structural deprivation. In sub-Saharan Africa's generalized epidemics, behavioral patterns like sexual concurrency—overlapping partnerships that facilitate rapid partner-to-partner spread—emerge as key amplifiers in transmission models, outperforming explanations centered on gender inequality or economic marginalization. Peer-reviewed modeling shows concurrency drives heterosexual epidemics by increasing the effective reproduction number (R0), with empirical declines in concurrency (e.g., in eastern Zimbabwe from the 1990s onward) correlating directly with falling HIV prevalence, even amid persistent poverty.60779-4/fulltext) These findings align with causal mechanisms where behaviors create dense transmission networks, contrasting with structural narratives that often conflate correlation (e.g., higher rates in poor regions) with causation, overlooking variations in HIV burden across similarly impoverished African locales tied instead to partnering norms. Debates persist, with some academic perspectives—prevalent in institutions exhibiting systemic ideological biases toward collectivist framings—prioritizing structural determinants like stigma to highlight systemic inequities, potentially minimizing the role of personal agency in risk accumulation. However, risk-stratified data from cohort and surveillance studies reveal that behavioral factors explain the majority of variance in incidence disparities; for example, elevated MSM rates hold in high-resource, low-stigma settings where partner selection and act-specific risks dominate, indicating that modifiable choices offer the most direct leverage for causality over indirect structural proxies like discrimination, which fail to predict transmission once behaviors are accounted for. This empirical prioritization supports interventions rooted in behavioral realism, as structural attributions risk diverting focus from proximate, actionable drivers.

Policy and Intervention Failures

In the early 1980s, regulatory delays in screening blood products for HIV contamination caused thousands of infections among hemophiliacs reliant on clotting factors. In the United States, the Food and Drug Administration postponed widespread adoption of donor screening and heat treatment of blood products until March 1985, despite evidence of transmission risks emerging by 1982, leading to an estimated 6,000 to 10,000 hemophiliac infections. In France, government officials similarly deferred licensing of U.S.-developed HIV diagnostic tests until April 1985 to prioritize a French alternative, resulting in approximately 4,700 infections and over 300 deaths among recipients. These lapses stemmed from prioritizing national industry interests over immediate public health imperatives, amplifying iatrogenic spread before routine testing was enforced globally by 1987. Harm reduction interventions like needle and syringe programs (NSPs) have yielded mixed outcomes, reducing HIV transmission among people who inject drugs (PWID) but often without addressing underlying addiction drivers. A systematic review of 28 studies found NSPs associated with lower HIV seroconversion rates among PWID, with modeled estimates suggesting up to 18% reductions in new diagnoses following program openings. However, empirical data indicate NSPs may correlate with elevated opioid mortality, as one analysis of U.S. county-level data linked program expansions to higher overdose deaths, potentially by normalizing injection practices without commensurate declines in drug initiation or use prevalence. Policies favoring zero-tolerance enforcement or compulsory treatment, which prioritize cessation over accommodation, have received limited rigorous evaluation in HIV contexts, leaving causal trade-offs between infection control and dependency perpetuation underexplored. Antiretroviral therapy (ART) scale-up in sub-Saharan Africa, despite substantial donor funding, has been undermined by systemic corruption and logistical barriers, curtailing treatment access and viral suppression. Cases of ARV theft, procurement collusion, and bribery have precipitated drug stock-outs, with one study linking corruption indices to reduced ART coverage and higher perceived healthcare access difficulties across 36 countries. Globally, new HIV infections stagnated at 1.3 million [1.0–1.7 million] in 2023—39% above the 2025 UNAIDS target of fewer than 370,000—despite over $20 billion in annual funding, signaling inefficiencies in interventions that fail to disrupt core transmission behaviors like concurrent partnerships and inconsistent condom use. This plateau reflects over-allocation to expansion-focused programs amid persistent gaps in prevention efficacy, where empirical shortfalls in behavioral modification have not been offset by treatment-as-prevention alone.

Persistent Myths and Misattributions in Transmission

One persistent misconception involves the transmission of HIV through casual contact, such as sharing toilet seats, hugging, or exposure to saliva, sweat, or tears, despite epidemiological surveillance documenting no such cases since the epidemic's identification in 1981. Similarly, claims of vector-borne spread via mosquitoes or insects lack substantiation, as HIV cannot replicate in insect physiology and global incidence patterns do not correlate with insect vectors. Empirical data reveal stark disparities in transmission efficiency across sexual acts, contradicting narratives equating risks between heterosexual vaginal intercourse and receptive anal intercourse, which predominates in male-to-male transmission. Per-act probability estimates from meta-analyses indicate a 1.38% risk (138 per 10,000 exposures) for receptive anal intercourse with an untreated HIV-positive partner, compared to 0.04% (4 per 10,000) for insertive penile-vaginal intercourse, yielding an approximately 35-fold difference even before accounting for exposure frequency or biological cofactors like mucosal trauma. These gradients underscore behavioral specificity in causation, with cumulative risks amplifying in networks featuring higher-efficiency acts, as observed in early U.S. cohorts where male same-sex activity accounted for over 60% of cases despite comprising a small population fraction. The slogan "Undetectable equals Untransmittable" (U=U), derived from cohort studies like PARTNER showing zero linked transmissions in over 58,000 condomless acts among virally suppressed couples, holds under sustained adherence to antiretroviral therapy (ART) maintaining viral loads below 200 copies/mL. However, non-adherence risks viral rebound—typically within 2-3 weeks of interruption—restoring transmissibility to pre-treatment levels, a caveat evident in rebound rates exceeding 90% upon ART cessation in clinical trials. Policy-level denialism exemplifies misattribution of HIV causality away from viral etiology, as in South Africa's 2000-2005 era under President Thabo Mbeki, where resistance to ART rollout—favoring nutritional interventions over antiretrovirals—resulted in an estimated 330,000 excess deaths and 35,000 preventable mother-to-child transmissions, per modeling of observed versus counterfactual uptake aligned with WHO guidelines. Pre-intervention mother-to-child transmission rates, absent prophylaxis, ranged 15-45% across perinatal, intrapartum, and breastfeeding exposures, with biological transmission mechanistically driven by maternal viral load rather than extrinsic stigma alone, as reductions to under 5% post-PMTCT implementation demonstrate intervention efficacy over narrative reframing. Overreliance on stigma-reduction discourse has occasionally obscured agency in modifiable risks, such as partner selection or concurrency, which longitudinal serodiscordant studies link to 2-5-fold incidence elevations independent of socioeconomic confounders.

References

  1. https://www.who.int/news-room/fact-sheets/detail/hiv-aids
  2. https://www.ncbi.nlm.nih.gov/books/NBK534860/
  3. https://pmc.ncbi.nlm.nih.gov/articles/PMC3543106/
  4. https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370%2819%2930185-3/fulltext
  5. https://www.unaids.org/en/resources/fact-sheet
  6. https://data.unicef.org/topic/hivaids/global-regional-trends/
  7. https://www.cdc.gov/hiv-data/media/files/2025/04/hiv_surv_rep_tables_2023.xlsx
  8. https://www.unaids.org/sites/default/files/media_asset/UNAIDS_FactSheet_en.pdf
  9. https://www.unaids.org/en/resources/documents/2024/global-aids-update-2024
  10. https://data.who.int/indicators/i/49AC786/77D059C
  11. https://www.who.int/teams/global-hiv-hepatitis-and-stis-programmes/hiv/strategic-information/hiv-data-and-statistics
  12. https://crossroads.unaids.org/
  13. https://pmc.ncbi.nlm.nih.gov/articles/PMC3234451/
  14. https://royalsocietypublishing.org/doi/abs/10.1098/rstb.2010.0031
  15. https://pmc.ncbi.nlm.nih.gov/articles/PMC7098263/
  16. https://royalsocietypublishing.org/doi/10.1098/rstb.2001.0863
  17. https://www.pnas.org/doi/10.1073/pnas.0936469100
  18. https://academic.oup.com/book/41903/chapter/354760715
  19. https://pubmed.ncbi.nlm.nih.gov/9468138/
  20. https://www.science.org/content/article/oldest-surviving-hiv-virus-tells-all
  21. https://pmc.ncbi.nlm.nih.gov/articles/PMC6748459/
  22. https://www.tandfonline.com/doi/full/10.2217/fvl-2017-0042
  23. https://www.cdc.gov/mmwr/pdf/wk/mm5021.pdf
  24. https://www.cdc.gov/museum/online/story-of-cdc/aids/index.html
  25. https://circulatingnow.nlm.nih.gov/2021/06/04/june-5-1981-the-first-report-of-aids-in-the-u-s/
  26. https://www.cdc.gov/mmwr/volumes/70/wr/mm7022a1.htm
  27. https://www.pnas.org/doi/10.1073/pnas.0705329104
  28. https://pubmed.ncbi.nlm.nih.gov/27188298/
  29. https://www.cdc.gov/MMWr/preview/mmwrhtml/00040546.htm
  30. https://ashpublications.org/blood/article/112/7/2617/24725/The-hazards-of-blood-transfusion-in-historical
  31. https://ourworldindata.org/hiv-aids
  32. https://pmc.ncbi.nlm.nih.gov/articles/PMC6669088/
  33. https://www.acs.org/education/whatischemistry/landmarks/highly-active-antiretroviral-therapy-hiv.html
  34. https://www.sciencedirect.com/science/article/abs/pii/S1047279709000751
  35. https://www.researchgate.net/publication/319225065_HIV_Prevention_Fatigue_and_HIV_Treatment_Optimism_Among_Young_Men_Who_Have_Sex_With_Men
  36. https://www.ncbi.nlm.nih.gov/books/NBK562734/
  37. https://pmc.ncbi.nlm.nih.gov/articles/PMC6894479/
  38. https://www.unaids.org/sites/default/files/media_asset/02-hiv-human-rights-factsheet-people-who-use-drugs_en.pdf
  39. https://data.unicef.org/topic/hivaids/emtct/
  40. https://emedicine.medscape.com/article/784812-overview
  41. https://pmc.ncbi.nlm.nih.gov/articles/PMC9612039/
  42. https://www.sciencedirect.com/science/article/pii/S0033350624005043
  43. https://pmc.ncbi.nlm.nih.gov/articles/PMC4058443/
  44. https://stanfordhealthcare.org/medical-conditions/sexual-and-reproductive-health/hiv-aids/causes/risk-of-exposure.html
  45. https://pmc.ncbi.nlm.nih.gov/articles/PMC2614120/
  46. https://pmc.ncbi.nlm.nih.gov/articles/PMC6195215/
  47. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0001001
  48. https://pmc.ncbi.nlm.nih.gov/articles/PMC4233247/
  49. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020298
  50. https://pmc.ncbi.nlm.nih.gov/articles/PMC3784346/
  51. https://addictions.psych.ucla.edu/wp-content/uploads/sites/160/2018/01/The-association-between-alcohol-consumption-and-condom-use-Considering-correlates-of-HIV-risk-among-Black-men-who-have-sex-with-men.pdf
  52. https://pmc.ncbi.nlm.nih.gov/articles/PMC4112554/
  53. https://www.hiv.gov/hiv-basics/overview/data-and-trends/statistics
  54. https://pmc.ncbi.nlm.nih.gov/articles/PMC5524204/
  55. https://pmc.ncbi.nlm.nih.gov/articles/PMC1122131/
  56. https://www.prb.org/resources/young-women-in-sub-saharan-africa-face-a-high-risk-of-hiv-infection/
  57. https://www.guttmacher.org/journals/psrh/1999/11/effectiveness-condoms-reducing-heterosexual-transmission-hiv
  58. https://search.issuelab.org/resources/3136/3136.pdf
  59. https://pmc.ncbi.nlm.nih.gov/articles/PMC3947546/
  60. https://www.who.int/teams/global-hiv-hepatitis-and-stis-programmes/populations/people-who-inject-drugs
  61. https://pmc.ncbi.nlm.nih.gov/articles/PMC7088675/
  62. https://www.unaids.org/sites/default/files/media_asset/2024-unaids-global-aids-update-eeca_en.pdf
  63. https://www.cdc.gov/mmwr/preview/mmwrhtml/00054952.htm
  64. https://pmc.ncbi.nlm.nih.gov/articles/PMC10831193/
  65. https://pmc.ncbi.nlm.nih.gov/articles/PMC5069170/
  66. https://pmc.ncbi.nlm.nih.gov/articles/PMC4785082/
  67. https://pmc.ncbi.nlm.nih.gov/articles/PMC10150936/
  68. https://researchonline.gcu.ac.uk/files/39751648/A_Comparative_Analysis_of_Recent_HIV_Outbreaks_among_People_Who_Inject_Drugs_in_Europe_cleaneddon.pdf
  69. https://www.hiv.gov/federal-response/other-topics/syringe-services-programs
  70. https://pmc.ncbi.nlm.nih.gov/articles/PMC3456277/
  71. https://www.ncbi.nlm.nih.gov/books/NBK232343/
  72. https://ajph.aphapublications.org/doi/full/10.2105/AJPH.2004.060152
  73. https://www.aidsmap.com/about-hiv/how-likely-mother-child-transmission-hiv
  74. https://hivinfo.nih.gov/understanding-hiv/fact-sheets/preventing-perinatal-transmission-hiv-during-pregnancy-and-childbirth
  75. https://pmc.ncbi.nlm.nih.gov/articles/PMC9590322/
  76. https://clinicalinfo.hiv.gov/en/guidelines/perinatal/recommendations-arv-drugs-pregnancy-prevent-hiv-transmission-improve-health
  77. https://www.cdc.gov/hiv/causes/occupational-transmission.html
  78. https://www.cdc.gov/hiv/causes/index.html
  79. https://www.cfs.gov.hk/english/whatsnew/whatsnew_fst/whatsnew_fst_Can_HIV_AIDS_be_transmitted_by_food.html
  80. https://www.unaids.org/sites/default/files/media_asset/2024-unaids-global-aids-update-living-with-hiv_en.pdf
  81. https://www.who.int/data/gho/data/themes/hiv-aids
  82. https://www.hiv.gov/hiv-basics/overview/data-and-trends/global-statistics
  83. https://pmc.ncbi.nlm.nih.gov/articles/PMC12350184/
  84. https://www.apa.org/pi/ses/resources/publications/hiv-aids
  85. https://www.sciencedirect.com/science/article/pii/S2773065423000524
  86. https://www.sciencedirect.com/science/article/pii/S2772707622001035
  87. https://www.healthdata.org/news-events/newsroom/news-releases/sub-saharan-africa-leads-global-hiv-decline-progress-made-unaids
  88. https://pmc.ncbi.nlm.nih.gov/articles/PMC3819098/
  89. https://pmc.ncbi.nlm.nih.gov/articles/PMC3207867/
  90. https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-020-01635-5
  91. https://ccpr.ucla.edu/wp-content/uploads/2024/04/Polygyny-and-the-spread-of-HIV-in-Sub-Saharan-Africa_-A-case-of-benign-concurrency.pdf
  92. https://www.researchgate.net/publication/237217234_Why_is_HIV_Prevalence_so_Severe_in_Southern_Africa_The_role_of_multiple_concurrent_partnerships_and_lack_of_male_circumcision_Implications_for_AIDS_prevention
  93. https://documents1.worldbank.org/curated/en/588321527020162138/pdf/123333-WP-DEBATE4S-PUBLIC.pdf
  94. https://www.unaids.org/sites/default/files/media_asset/2024-unaids-global-aids-update-asia-pacific_en.pdf
  95. https://www.unaids.org/en/resources/documents/2024/2024-unaids-global-aids-update-asia-pacific
  96. https://www.aidsdatahub.org/resource/regional-profile-asia-and-pacific
  97. https://www.aidsdatahub.org/resource/unaids-data-2023
  98. https://www.paho.org/en/topics/hivaids
  99. https://www.paho.org/en/documents/hiv-epidemic-and-response-latin-america-and-caribbean-october-2023
  100. https://www.cdc.gov/hiv-data/nhss/estimated-hiv-incidence-and-prevalence.html
  101. https://www.cdc.gov/hiv/data-research/facts-stats/index.html
  102. https://www.cdc.gov/hiv/data-research/facts-stats/hispanic-latino-people.html
  103. https://thepath.unaids.org/wp-content/themes/unaids2023/assets/files/regional_fs_caribbean.pdf
  104. https://www.unaids.org/sites/default/files/media_asset/2024-unaids-global-aids-update-latin-america_en.pdf
  105. https://ajph.aphapublications.org/doi/full/10.2105/AJPH.2013.301770
  106. https://thepath.unaids.org/wp-content/themes/unaids2023/assets/files/regional_fs_latin_america.pdf
  107. https://www.ecdc.europa.eu/en/publications-data/hiv-aids-surveillance-europe-2024-2023-data
  108. https://www.ecdc.europa.eu/sites/default/files/documents/HIV_Surveillance_Report_2024.pdf
  109. https://www.unaids.org/sites/default/files/media_asset/2024-unaids-global-aids-update-western-central-europe-north-america_en.pdf
  110. https://www.thelancet.com/journals/lanhiv/article/PIIS2352-3018%2823%2900204-7/fulltext
  111. https://www.unaids.org/en/resources/documents/2024/2024-unaids-global-aids-update-eeca
  112. https://healthpolicy-watch.news/unaids-blames-punitive-laws-and-stigma-for-hiv-surge-in-eastern-europe-and-central-asia/
  113. https://www.npr.org/sections/goats-and-soda/2024/09/19/g-s1-20648/ukraine-hiv-aids-war
  114. https://www.theguardian.com/global-development/article/2024/aug/07/russian-influence-in-eastern-europe-is-aggravating-hiv-epidemic-aids
  115. https://pmc.ncbi.nlm.nih.gov/articles/PMC11255029/
  116. https://www.who.int/europe/news/item/28-11-2024-under--and-late-diagnosis-of-hiv-is-holding-back-progress-to-end-aids-in-the-european-region
  117. https://www.who.int/europe/news-room/fact-sheets/item/hiv-aids-in-the-who-european-region
  118. https://reliefweb.int/report/world/hivaids-surveillance-europe-2024-2023-data
  119. https://www.unaids.org/en/resources/documents/2023/global-aids-update-2023
  120. https://www.unaids.org/sites/default/files/media_asset/2024-unaids-global-aids-update-summary_en.pdf
  121. https://pmc.ncbi.nlm.nih.gov/articles/PMC9971956/
  122. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001414
  123. https://www.sciencedirect.com/science/article/pii/S2589537021003394
  124. https://bmjopen.bmj.com/content/13/12/e074005
  125. https://www.cdc.gov/mmwr/volumes/66/wr/mm6647e1.htm
  126. https://blogs.the-hospitalist.org/content/delayed-hiv-diagnoses-still-substantial-some-risk-groups
  127. https://academic.oup.com/cid/article/63/1/101/1745216
  128. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182335
  129. https://www.nejm.org/doi/full/10.1056/NEJMoa1600693
  130. https://www.sciencedirect.com/science/article/pii/S0140673619307019
  131. https://pubmed.ncbi.nlm.nih.gov/31652410/
  132. https://www.kff.org/global-health-policy/the-global-hiv-aids-epidemic/
  133. https://www.vox.com/future-perfect/363716/africa-hiv-aids-sub-saharan-progress
  134. https://pmc.ncbi.nlm.nih.gov/articles/PMC12185539/
  135. https://www.who.int/news-room/fact-sheets/detail/hiv-drug-resistance
  136. https://aidsrestherapy.biomedcentral.com/articles/10.1186/s12981-023-00512-4
  137. https://www.eatg.org/hiv-news/hiv-drug-resistance-is-declining-over-time/
  138. https://pmc.ncbi.nlm.nih.gov/articles/PMC12066365/
  139. https://pmc.ncbi.nlm.nih.gov/articles/PMC12343105/
  140. https://www.nejm.org/doi/full/10.1056/NEJMoa1011205
  141. https://pmc.ncbi.nlm.nih.gov/articles/PMC3721979/
  142. https://www.aidsmap.com/news/jul-2014/overall-prep-effectiveness-iprex-ole-study-50-100-those-taking-four-or-more-doses
  143. https://bmjopen.bmj.com/content/12/5/e048478
  144. https://pubmed.ncbi.nlm.nih.gov/8327927/
  145. https://pubmed.ncbi.nlm.nih.gov/19370585/
  146. https://www.who.int/teams/global-hiv-hepatitis-and-stis-programmes/hiv/prevention/voluntary-medical-male-circumcision
  147. https://pubmed.ncbi.nlm.nih.gov/39878582/
  148. https://journals.lww.com/jaids/fulltext/2025/05010/the_disparities_of_prep_adherence_among_men_who.1.aspx
  149. https://www.kff.org/hiv-aids/u-s-federal-funding-for-hivaids-trends-over-time/
  150. https://hivrisk.cdc.gov/can-decrease-hiv-risk/
  151. https://www.tandfonline.com/doi/full/10.1016/S0968-8080%252804%252923118-4
  152. https://www.guttmacher.org/pubs/compilations/agionabc.pdf
  153. https://hivinfo.nih.gov/understanding-hiv/fact-sheets/understanding-hiv-transmission
  154. https://www.gileadhiv.com/landscape/state-of-epidemic/
  155. https://pmc.ncbi.nlm.nih.gov/articles/PMC3520057/
  156. https://academic.oup.com/jid/article/210/suppl_2/S562/865894
  157. https://pmc.ncbi.nlm.nih.gov/articles/PMC3405825/
  158. https://www.cdc.gov/hiv/data-research/facts-stats/gay-bisexual-men.html
  159. https://www.cancernetwork.com/view/securing-international-blood-supply-against-hiv
  160. https://pubmed.ncbi.nlm.nih.gov/10761524/
  161. https://www.nature.com/articles/353781a0.pdf
  162. https://onlinelibrary.wiley.com/doi/10.1111/j.1423-0410.2007.00941.x
  163. https://pubmed.ncbi.nlm.nih.gov/24374889/
  164. https://www.sciencedirect.com/science/article/abs/pii/S0047272722001359
  165. https://pmc.ncbi.nlm.nih.gov/articles/PMC5892682/
  166. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220583
  167. https://pubmed.ncbi.nlm.nih.gov/30076604/
  168. https://www.unaids.org/en/resources/presscentre/pressreleaseandstatementarchive/2024/july/20240722_global-aids-update
  169. https://pmc.ncbi.nlm.nih.gov/articles/PMC5303549/
  170. https://www.unaids.org/en/frequently-asked-questions-about-hiv-and-aids
  171. https://hivrisk.cdc.gov/about-the-data/
  172. https://preventionaccess.org/wp-content/uploads/2021/04/JAMA-HIV-Viral-Load-and-Transmissibility-UU-Jan-10-2019.pdf
  173. https://pmc.ncbi.nlm.nih.gov/articles/PMC10284343/
  174. https://www.theguardian.com/world/2008/nov/27/south-africa-aids-mbeki
  175. https://pmc.ncbi.nlm.nih.gov/articles/PMC6305017/
  176. https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-022-07119-6
Add your contribution
Related Hubs
User Avatar
No comments yet.