A fomite (/ˈfoʊmaɪt/) or fomes (/ˈfoʊmiːz/) is any inanimate object that, when contaminated with or exposed to infectious agents (such as pathogenic bacteria, viruses or fungi), can transfer disease to a new host.

A fomite is any inanimate object (also called passive vector) that, when contaminated with or exposed to infectious agents (such as pathogenic bacteria, viruses or fungi), can transfer disease to a new host. Contamination can occur when one of these objects comes into contact with bodily secretions, like nasal fluid, vomit or feces from toilet plume. Many common objects can sustain a pathogen until a person comes in contact with the pathogen, increasing the chance of infection. The likely objects are different in a hospital environment than at home or in a workplace. Fomites such as splinters, barbed wire or farmyard surfaces, including soil, feeding troughs or barn beams, have been implicated as sources of virus.

For humans, common hospital fomites are skin cells, hair, clothing, and bedding.

Fomites are associated particularly with hospital-acquired infections (HAIs), as they are possible routes to pass pathogens between patients. Stethoscopes and neckties are common fomites associated with health care providers. It worries epidemiologists and hospital practitioners because of the growing selection of microbes resistant to disinfectants or antibiotics (so-called antimicrobial resistance phenomenon).^{[citation needed]}

Basic hospital equipment, such as IV drip tubes, catheters, and life support equipment, can also be carriers, when the pathogens form biofilms on the surfaces. Careful sterilization of such objects prevents cross-infection. Used syringes, if improperly handled, are particularly dangerous fomites.^{[citation needed]}

In addition to objects in hospital settings, other common fomites for humans are cups, spoons, pencils, bath faucet handles, toilet flush levers, door knobs, light switches, handrails, elevator buttons, television remote controls, pens, touch screens, common-use phones, keyboards and computer mice, coffeepot handles, countertops, drinking fountains, and any other items that may be frequently touched by different people and infrequently cleaned.

Cold sores, hand–foot–mouth disease, and diarrhea are some examples of illnesses easily spread by contaminated fomites. The risk of infection by these diseases and others through fomites can be greatly reduced by simply washing one's hands. When two children in one household have influenza, more than 50% of shared items are contaminated with virus. In 40–90% cases, adults infected with rhinovirus have it on their hands.

Researchers have discovered that smooth (non-porous) surfaces like door knobs transmit bacteria and viruses better than porous materials like paper money because porous, especially fibrous, materials absorb and trap the contagion, making it harder to contract through simple touch. Nonetheless, fomites may include soiled clothes, towels, linens, handkerchiefs, and surgical dressings.