A fomite is any inanimate object (also called passive vector) that, when contaminated with or exposed to infectious agents (such as pathogenic bacteria, virusesorfungi), can transfer disease to a new host.[1][2] Contamination can occur when one of these objects comes into contact with bodily secretions, like nasal fluid, vomit, or feces. 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.[3] Fomites such as splinters, barbed wire or farmyard surfaces, including soil, feeding troughs or barn beams, have been implicated as sources of virus.[4]
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]
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.[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.[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]
Smallpox was long supposed to be transmitted either by direct contact or by fomites. However A. R. Rao’s careful researches in the 1960s, before smallpox was declared extinct, found little truth in the traditional belief that smallpox can be spread at a distance through infected clothing or bedding. He concluded that it normally invaded via the lungs.[20] Rao recognized that the virus can be detected on inanimate objects, and therefore might in some cases be transmitted by them, but he concluded that “smallpox is still an inhalation disease . . . the virus has to enter through the nose by inhalation.”[21]
Contaminated needles are the most common fomite that transmits HIV.[22] Fomites from dirty needles also easily spread Hepatitis B.[23]
The Italian scholar and physician Girolamo Fracastoro appears to have first used the Latin word fomes, meaning "tinder", in this sense in his essay on contagion, De Contagione et Contagiosis Morbis, published in 1546:[24] "By fomes I mean clothes, wooden objects, and things of that sort, which though not themselves corrupted can, nevertheless, preserve the original germs of the contagion and infect by means of these".[25]
English usage of fomes, pronounced /ˈfoʊmiːz/, is documented since 1658.[26] The English word fomite, which has been in use since 1859, is a back-formation from the plural fomites (originally borrowed from the Latin plural fōmĭtēs[ˈfoːmɪteːs]offōmĕs[ˈfoːmɛs]).[27][28] Over time, the English-language pronunciation of the plural fomites changed from /ˈfoʊmɪtiːz/) to /ˈfoʊmaɪts/, which led to the creation of a new singular fomite, pronounced /ˈfoʊmaɪt/.[28][29][30]
In Latin, fomes (genitive: fomitis, plural fomites, stem formit-) is a third-declension T-stem noun. Such nouns, like miles/militisorcomes/comitis, typically lose their T (thereby becoming a syllable shorter) in the nominative singular, but retain it in all other cases. In languages derived from Latin, the French fomite, Italian fomite, Spanish fómite and Portuguese fómite or fômite, retain the full stem.
^McGovern, B.; Doyle, E.; Fenelon, L. E.; et al. (1 June 2010). "The necktie as a potential vector of infection: are doctors happy to do without?". Journal of Hospital Infection. 75 (2): 138–139. doi:10.1016/j.jhin.2009.12.008. ISSN0195-6701. PMID20299125. [...] in any care activity that involves contact with patients, as [neckties] serve no beneficial function in patient care, are rarely laundered and have been shown to be colonised by pathogens. Coagulase-negative staphylococci (CoNS) were found on two of five neckties of doctors working in an intensive care unit, and Staphylococcus aureus was isolated from eight of 40 doctors' ties in a Scottish hospital.
^Sobolik, J. S.; Sajewski, E. T.; Jaykus, L. A.; Cooper, D. K.; Lopman, B. A.; Kraay, A. N.; Ryan, P. B.; Guest, J. L.; Webb-Girard, A.; Leon, J. S. (2021). "Low risk of SARS-CoV-2 transmission via fomite, even in cold-chain". medRxiv10.1101/2021.08.23.21262477.
^Nutton, Vivian (1990). "The Reception of Fracastoro's Theory of Contagion: The Seed That Fell among Thorns?". Osiris. 2nd Series, Vol. 6, Renaissance Medical Learning: Evolution of a Tradition. University of Chicago Press: 196–234. doi:10.1086/368701. JSTOR301787. PMID11612689. S2CID37260514.
^Fracastoro, Girolamo (1961). "Contagion, contagious diseases and their treatment (1546)". In Brock, Thomas D. (ed.). Milestones in Microbiology. Translated by Wright, Wilmer C. Prentice-Hall International. pp. 69–75. Retrieved 10 August 2013.
