Fomite

Detecting whether medics have inadvertently transferred fluids to their clothing during a training sequence using simulated bodily fluids carrying an ultraviolet dye

For humans, common hospital fomites are skin cells, hair, clothing, and bedding.[5]

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.[6] It worries epidemiologists and hospital practitioners because of the growing selection of microbes resistant to disinfectants or antibiotics (so-called antimicrobial resistance phenomenon).

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.[7] Used syringes, if improperly handled, are particularly dangerous fomites.

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.[2][8]

Cold sores, hand–foot–mouth disease, and diarrhea are some examples of illnesses easily spread by contaminated fomites.[9] The risk of infection by these diseases and others through fomites can be greatly reduced by simply washing one's hands.[9] 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.[10]

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.[11] Nonetheless, fomites may include soiled clothes, towels, linens, handkerchiefs, and surgical dressings.[12][13]

SARS-CoV-2 was found to be viable on various surfaces from 4 to 72 hours under laboratory conditions. On porous surfaces, studies report inability to detect viable virus within minutes to hours; on non-porous surfaces, viable virus can be detected for days to weeks.[2][14] However, further research called into question the accuracy of such tests, instead finding fomite transmission of SARS-Cov-2 in real world settings is extremely rare if not impossible.[15][16][17][18]

Contact with aerosolized virus (large droplet spread) generated via talking, sneezing, coughing, or vomiting, or contact with airborne virus that settles after disturbance of a contaminated fomite (e.g. shaking a contaminated blanket). During the first 24 hours, the risk can be reduced by increasing ventilation and waiting as long as possible before entering the space (at least several hours, based on documented airborne transmission cases), and using personal protective equipment (including any protection needed for the cleaning and disinfection products) to reduce risk.[2][8]

The 2007 research showed that the influenza virus was still active on stainless steel 24 hours after contamination. Though on hands it survives only for five minutes, the constant contact with a fomite almost certainly means catching the infection.[19] Transfer efficiency depends not only on surface, but mainly on pathogen type. For example, avian influenza survives on both porous and non-porous materials for 144 hours.[11]

Contaminated needles are the most common fomite that transmits HIV.[20] Fomites from dirty needles also easily spread Hepatitis B.[21]