What are ‘fomites’? Here’s why you should care
In the 2011 movie Contagion there’s a scene where Dr. Erin Mears, played by Kate Winslet, visits the Minnesota Department of Health to brief them on the emergence of a new virus.
“At this point we have to believe this is respiratory, maybe fomites too,” she says.
Fomites refers to the surfaces or objects that act as a transmission point for virus or bacteria. “The average person touches their face 2,000 to 3,000 times a day,” Dr. Mears explains. “Three to five times every waking minute. In between, we’re touching doorknobs, water fountains, elevator buttons, and each other. Those things become fomites.”
This movie, which was widely praised for its epidemiological literacy, began to make the rounds during the height of the COVID pandemic. It also freaked people out. Luckily, it turned out that fomites played a much, much smaller role in the transmission of COVID than scientists originally feared. Last April, the CDC concluded that the likelihood of contracting COVID from a surface was less than 1 in 10,000.
However, those odds aren’t the same for all viruses. Now that cold and flu season is upon us, here’s a few things you should know about fomites.
Why are they called ‘fomites’?
According to Thomas Brock’s Milestones of Microbiology, the term appears to have originated in the 1500’s in an essay on contagion by the Italian physician Girolamo Fracastoro. He used the word “fomes” which is Latin for “tinder” to refer to “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.”
Not all surfaces carry the same risk
Non-porous surfaces, like stainless steel, carry a higher risk of transmission than more porous surfaces like paper money. Some studies found that the influenza virus can survive on stainless steel for up to 24 hours but only on hands for a few minutes.
What seems to matter more than the type of surface, however, is a) proximity to an infected person and b) how often it is touched. The hand of a sick person (porous) may have a comparatively higher risk as a source of infection than the laundry room sink (non-porous). According to Nigel Cook’s 2013 book Viruses in Food and Water: Risks, Surveillance and Control, 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.
The most dangerous kind of fomite is a contaminated needle because it doesn’t require a secondary point of contact (i.e. you touching your nose, mouth, etc. after touching an infected surface), hence the need for careful handling.
The type of virus also matters
Certain types of disease have a higher likelihood of spread via fomites, including cold sores and hand-foot-mouth disease. While the standard flu virus can’t survive on most surfaces outside of lab settings for more than a few hours, other viruses, such as the avian flu, have been shown to survive on surfaces for as long as 144 hours — almost a week.
Different viruses also have different shedding patterns. With norovirus, a stomach bug that spreads during the winter, you can still be contagious after two weeks. Norovirus infections via fomite are more common than with the flu, where you are only contagious for about five days, and where the spread is more common through droplets or aerosols (i.e. breathing, coughing, sneezing, etc.)
Soap and water (or sanitizer) is basically magic
There is a reason hand hygiene is the single most consequential public health intervention of the last 200 years: properly sanitizing your hands or a surface brings the risk of contracting something from it down to almost zero.
Make sure you follow the CDC’s guide for proper hand washing, and use sanitizers when you can’t use soap and water. Disinfect high-traffic surfaces regularly with a quality disinfectant, and you’ll maximize your chances of fending off sickness this flu season.
At Ethisan, we’re answering your pandemic-related questions about vaccines, the virus, and hand hygiene. Our sanitizers are made from seven ingredients or fewer and are plant-based, eco-friendly and Canadian made. Browse our products to learn more.