Back in the early days of the pandemic, surfaces were the thing to worry about. The prevailing scientific wisdom was that the coronavirus spread mainly through large droplets that fell on surfaces, then touched them with our hands, and then touched our faces. (Masks, at the time, public health authorities said to be not necessary for the common people.) So we washed our hands until they became raw. We were twisting ourselves to avoid touching the doorknobs. We passed industrial loads of hand sanitizer, pressed elevator buttons with keys and pens, disinfected groceries, take out food and mail orders.
Then we knew we got it all back. The virus did not spread much through surfaces. spread in the air. We came to understand the gravity of indoor spaces, the importance of ventilation, and the difference between a cloth mask and an N95. In the meantime, we mostly stopped talking about hand washing. Soon gone are the days when you could hear people murmuring “Merry Christmas” in public restrooms. Packet scanning and lavish workplace disinfection protocols become a matter of survival Hygiene theater.
This entire episode has been among the most bizarre and most confusing transformations of the pandemic. Disinfection, that great bastion of public health, saved lives; Actually, no, it didn’t matter for COVID. On one level, this change should be seen as a sign of good scientific progress, but it also raises the question of the kinds of businesses that we briefly thought were the best defense available to us against the virus. If hand washing isn’t as important as we thought in March 2020, how important is it?
Any public health expert would be quick to tell you that, please, yes, you should still wash your hands. Emmanuel Goldman, a microbiologist at Rutgers New Jersey Medical School, considers this “common sense” to protect us from a range of viruses that spread through close contact and touch, such as gastrointestinal viruses. Also, let’s be honest: It’s gross to use the bathroom and then refuse to wash, whether or not you’re going to give someone a COVID.
However, the pandemic has accumulated evidence that transmission of the coronavirus through fomites – that is, inanimate contaminated objects or surfaces – plays a much smaller role, and that transmission of the virus through the air is a much larger role than we previously thought. The same likely applies to other respiratory pathogens, such as flu and coronaviruses that cause the common cold, Lynsey Marr, an environmental engineer and aerosol expert at Virginia Tech, tells me.
This realization is not entirely new: Study 1987 Researchers at the University of Wisconsin found that a group of men playing poker with “wet” cards contaminated with the rhinovirus did not become infected, while a group playing with other sick players did. Now Goldman intends to push that point even further. At a conference in December, he will present a paper arguing that, with rare exceptions, such as RSV, All Respiratory pathogens are mostly transmitted through the air. He told me that the reason we had long thought otherwise is because our understanding was founded on it wrong assumptions. In general, studies suggesting fomite-centric transmission theories have been virus survival studies, which measure how long a virus can live on a surface. Many of them either used unrealistically large amounts of the virus or only measured the presence of the virus’ genetic material, not whether it was still contagious. The “design” of these experiments, he said, “was not appropriate to be able to extrapolate to real-life conditions.”
The result, for Goldman, is that surface transmission of respiratory pathogens is “negligible,” possibly accounting for less than 0.01 percent of all infections. If this is true, then your chance of catching the flu or a cold by touching something in the course of everyday life is almost nil. Goldman acknowledged that there was a “spectrum of opinions” on the matter. Marr, for example, wouldn’t go that far: She’s confident that more than half the transmission of respiratory pathogens is airborne, though she said she wouldn’t be surprised if the percentage was much higher — the only number she’d rule over 100 percent.
For now, it’s important to avoid binary thinking about this, Saskia Popescu, an epidemiologist at George Mason University, tells me. Fomites, airborne droplets, smaller aerosol particles – all modes of transmission are possible. Sima Lakdua, an influenza transmission expert at Emory University, tells me that the relative breakdown will not be the same everywhere. Fomite transmission may be minimal in the grocery store, but that doesn’t mean it’s negligible in the nursery, where kids are constantly touching things, sneezing on things, and sticking things in their mouths. The corollary to this idea is that some infection prevention strategies have proven highly effective in one context but not in another. Sanitize the desk frequently in your own cubicle, even less.
Much of the obvious cleanup we did early in the pandemic was excessive, Popescu said, but she worries that we may have over-corrected a bit, putting some helpful behaviors — targeted disinfection, even hand washing in some cases — in the hygiene theater category. No matter where, the experts I spoke to all agreed that these behaviors remain important for dealing with non-respiratory pathogens. Recently, when several members of the Mar family contracted norovirus, a very annoying stomach bug that causes vomiting, diarrhea, and stomach cramps, she disinfected a number of high-touch surfaces around the house. Imagine that: one of the nation’s leading experts in air transport wiping doorknobs and light switches.
Marr wasn’t convinced that we over-corrected. Hand sanitizer is still prevalent, companies are still promoting surface cleaning protocols, and air quality is still there Relatively little attention. Recently, I saw someone use their shirt to open the visitor center door without touching the handle…and then go inside without a mask. She said there is nothing wrong with taking certain precautions to prevent transmission – not all of these measures should be dismissed en masse as cleanrooms – as long as they do not come at the expense of efforts to prevent airborne transmission. “If you’re washing your hands extra… you should also wear a good mask in crowded indoor environments,” said Marr. “If you care about cleaning surfaces, you should take care of cleaning the air.”
On Friday, as respiratory virus season approaches, CDC Director Rochelle Walinsky chirp From three tips for staying healthy: “Get your updated COVID-19 vaccine and get your annual flu shot,” “Stay home if you’re sick,” and — don’t forget — “Practice good hand hygiene.” She did not mention masks or ventilation.