Beth Kalb was concerned because of the pews. This summer, like many places, the century-old Catholic church she attends in a small town outside Minneapolis reopened its doors with new disinfection rituals. Kalb recognized the side effects easily. The varnish on the pews had started to wear, and the wood was always sticky with disinfectant, so the voluntary cleaners had begun to eliminate the tacky build-up by using soap and water. They had been in for weeks, and the cleaner had already washed up. Plus, after each use, all those chemicals could not be good for the individuals who were spritzing and wiping down the worship room. Kalb understood, as a nurse, the value of handwashing, but it all seemed a little bit like that. Surely it was too much for the wood.
For Erin Berman, these were books in Fremont, California. A federal initiative to help reopen libraries, named Realm, commissioned experiments in the spring to see how long the virus persists on items they borrow. Researchers borrowed materials from the Columbus, Ohio, library system and applied a virus inoculum to them in a nearby laboratory to see how long they could stay infectious. They began initially with books, calculating the amount of virus left after a day or two, but extended to magazines and DVDs and USB drives in subsequent months. A fourth round of tests in August answered the issue of putting books in stacks, rather than individually setting them out. Protected from light and drying air, after six days, the researchers were able to locate virus particles on them. On leather book covers, the virus lasted at least eight days in a fifth round of tests decided this month.
The organizers of the Realm stressed that none of what they reported was guidance; it was study intended to educate the employees of individual libraries who determined what to do in the homes of people with all those objects accumulating dust, and likely germs. They also noticed, however, that disinfecting every page of every book was not possible. Too many library employees were considering "book quarantines" that lasted a week or more after seeing the results.
Berman was aware of the practical problems posed for so long by placing books in purgatory, but she had a wider concern: that all this research promoted an undue obsession, or even a fear, of the items that librarians are supposed to share with the public joyfully. It was difficult to understand what those numbers, the number of days, the number of viral particles that remained, actually meant to spread Covid-19 across books, but among her colleagues, their very presence had caused anxiety. And she suspected that it was taking attention away from all the other tasks she and her colleagues had to do to safely reopen, to reimagine a shared space in which citizens could no longer remain secure, in which Plexiglass will now mediate social connection. "I was starting to get really irritated. I hear, "We are librarians." We need to be doing research,' says Berman. "We should not be operating in fear of all industries."
For Emanuel Goldman, a Rutgers University virologist, the worries started with his elderly mother-in-gentle law's nagging. "She said to me, 'Wipe this down, wipe that down,'" he says. At the height of the pandemic, he was compulsive. The demands, a series of small acts to keep his household secure, seemed fair. He recognized that it was possible to spread other viruses, the technical term for spreading a virus across objects, and at that time the Centers for Disease Control and Prevention had no guidance on SARS-CoV-2. But he became concerned as he delved into the study himself. There was not much evidence at all that it was applicable to how Covid-19 actually spread, despite all the fixation on how long and how much virus last on surfaces. In July, in a tersely worded commentary in The Lancet entitled "Exaggerated risk of Covid-19 transmission by fomites," he addressed these concerns.
The risk of transmission through inanimate surfaces, in my view, is very small, and only in cases where an infected person coughs or sneezes on the surface, and someone else touches the surface shortly after the cough or sneeze (within 1-2 h),' he wrote. "I do not disagree with erring on the cautionary side, but this can go to extremes that the data does not justify."
That was months ago, and the empirical evidence has tipped in favor of Goldman since then. And yet, here, among countless other disinfection practices influenced by those early experiences, we are all the same, wiping down pews and hiding away books. "It is not possible to undo what was done," Goldman tells me now. "And in order to turn things around, it will take a lot of time and effort."
I wrote in March about what we learned about our knowledge of surface spread at the time, which was very little. It's time to ask, almost a year into the Covid-19 pandemic: What do we know now?
A analysis of how long the novel coronavirus lasted on various types of surfaces was the first widely covered study on fomites and Covid-19, published as a preprint in March by researchers at the University of California, Los Angeles, the National Institutes of Health, and Princeton. Nothing was understood at the time about how the virus was transmitted, so the issue was important. The researchers could still detect the virus after a few hours on cardboard, and after several days on plastic and steel, depending on the material. They were careful to note that their results went just as far as that. They stated how easily in a laboratory setting the virus decayed, not whether it could still infect a human or was even a probable mode of transmission.
But several people had already taken up fastidious practices in the hazy hysteria of the time: quarantining packages at the entrance, bleaching packets of cereal brought back from the supermarket, wearing outdoor hospital booties. A single collection of study findings did not initiate these habits, but it seemed to provide validation along with other early studies finding the virus on surfaces in hospital rooms and on cruise ships.
Dylan Morris, a Princeton mathematical biologist who coauthored the article, remembers with annoyance seeing what he terms "the great freakout fomite." The number of days the virus remained detectable on a laboratory surface was not useful for personal risk assessment, he says, since that amount would depend on how much there was to begin with and on environmental factors that they did not measure in the real world. Plus, the amount of virus that remains does not tell us anything about whether it can reasonably get into the airways of someone and cause an infection. People were really picking up on those utter detectability moments," he says." Everyone wants to know the magical period when everything becomes stable." He says he has avoided giving hard temporal cutoffs in subsequent research."
Since March, additional studies have painted a picture that is much more subtle and less scary. But like that first study, each can be easily misinterpreted in isolation. One clear takeaway is that, given an adequate initial dose, some amount of the virus can linger for days or even weeks on some surfaces, like glass and plastic, in controlled lab conditions. Emphasis on controlled. For example, earlier this month, an Australian study published in Virology Journal found traces of the virus on plastic banknotes and glass 28 days after exposure. The reaction to that number felt to some like a replay of March: a single study with a bombshell statistic sparked new fears about touchscreens and cash. “To be honest, I thought that we had moved on from this,” says Anne Wyllie, a microbiologist at Yale University.
Of course, this was another laboratory study done with specific intentions. The study was done in the dark, because sunlight is known to quickly deactivate the virus, and it involved maintaining cool, favorable temperatures. Debbie Eagles, a researcher at Australia’s national science agency who coauthored the research, tells me that taking away those environmental variables allows researchers to better isolate the effect of individual factors, like temperature, on stability. “In most ‘real-world’ situations, we would expect survival time to be less than in controlled laboratory settings,” Eagles writes in an email. She advises handwashing and cleaning “high-touch” surfaces.
The second consistent finding is that there’s plenty of evidence of the virus on surfaces in places where infected people have recently been. Wherever there has recently been an outbreak, and in places where people are asked to quarantine or are treated for Covid-19, “there’s viral RNA everywhere,” says Chris Mason, a professor at Weill Cornell Medicine. That makes going out and swabbing a useful tool for keeping track of where the virus is spreading.
It’s tempting to piece those two elements together: If the virus is on the surfaces around us, and it also lasts for a long time in lab settings, naturally we should vigorously disinfect. But that doesn’t necessarily reflect what’s happening. In a study published in September in Clinical Microbiology and Infection, researchers in Israel tried to piece it all together. They conducted lab studies, leaving samples out for days on various surfaces, and found they could culture the remaining virus in tissue. In other words, it remained infectious. Then they gathered samples from highly contaminated environments: Covid-19 isolation wards at a hospital, and at a hotel used for people in quarantine. The virus was abundant. But when they tried to culture those real-world samples, none were infectious. Later that month, researchers at an Italian hospital reported similar conclusions in The Lancet.
In addition to environmental conditions, a confounding factor might be saliva, or the stuff that we often mean when we talk about droplets sticking onto surfaces. In her own research, Wyllie has studied how long certain viral proteins remain intact in saliva to help determine the reliability of Covid-19 spit tests. For her purposes, stability is a good thing. But some proteins have appeared to denature more quickly than others, she notes, suggesting the virus as a whole does not remain intact and infectious. That could be because saliva tends to be less hospitable to pathogens than the synthetic substances or blood serums often used in lab-based stability studies.
Consider, Wyllie says, the extraordinary chain of events that would need to happen to successfully spread SARS-CoV-2 on a surface. A sufficiently large amount of the virus would need to be sprayed by an infected person onto a surface. The surface would need to be the right kind of material, exposed to the right levels of light, temperature, and humidity so that the virus does not quickly degrade. Then the virus would need to be picked up—which you would most likely do with your hands. But the virus is vulnerable there. (“Enveloped” viruses like SARS-CoV-2 do not fare well on porous surfaces like skin and clothing.) And then it needs to find a way inside you—usually through your nose or your eye—in a concentration big enough to get past your mucosal defenses and establish itself in your cells. The risk, Wyllie concludes, is low. “I’ve not once washed my groceries or disinfected my bags or even thought twice about my mail,” she says.
Low risk is not, of course, no risk, she adds. There are high-touch objects that merit disinfection, and places like hospitals need clean rooms and furniture. People at high risk from Covid-19 may want to take extra precautions. But the best advice for breaking that object-to-nose chain, according to all the health experts I spoke with: Wash your hands.
Goldman, too, had come to similar conclusions months before all this additional research came out, and US public health guidance followed right along with him. Since his Lancet paper in July, the focus on fomites has waned, and has been replaced by a focus on person-to-person transmission through respiration. The shift was based on epidemiological evidence. Experts knew all along that droplets passed by sneezing, coughing, or speaking were likely an important mode of transmission—that’s just how respiratory viruses tend to move. Over time, it became clear that aerosols, which remain suspended in the air, can better explain why so many infections seemed to be passing between people who did not directly interact, but could have shared the same indoor air. That’s why public health officials now emphasize mask wearing and ventilation. The CDC’s most recently updated guidance, from early October, holds that “spread from touching surfaces is not thought to be a common way that Covid-19 spread.” For those reasons, or perhaps out of fatigue, the scrubbing became less scrupulous over the summer.
But not for everyone. “I think that one thing that has been tough about this pandemic is there has been such a strong initial message that gave people the wrong intuition,” says Morris, the Princeton researcher. For some people, and especially for institutions that were trying to reopen, liable to employees and visitors, priorities had been set based on what we knew back in the spring. It was also a way to show that they were doing something, Morris adds, even if it didn't do much. In July, The Atlantic’s Derek Thompson coined the term “hygiene theater” to describe the rash of corporate disinfection. It’s still around. It’s part of the reason why New York City has committed tens of millions of dollars to cleaning each subway car each night, why Airbnb requires “enhanced” cleaning from its landlords, why countless schools, stores, churches, and offices continue to emphasize disinfection. It’s why some libraries are quarantining books this fall for a week or more. It’s also a factor in what we are now less likely to do, a rationale for why many businesses no longer take cash and why playgrounds have often been among the last outdoor venues to reopen.
“There are bizarre policies that haven’t changed or adapted,” says Julia Marcus, an epidemiologist at Harvard Medical School. “It’s one thing for an individual to decide to stop bleaching their groceries. It’s much more difficult to steer the ship of an institution as the science evolves, with different levels of decisionmaking and different levels of health literacy and risk tolerance.”
What is it about fomites? There’s surely something psychological in the belief that we can “see” an invisible virus, manifesting as an object that we can quarantine, avoid, wipe down. That’s evident in how we think about the research, even. Recall the salt shaker in Germany? Or the elevator buttons in a Chinese high-rise? In New Zealand, there was that hypothesis that containers of frozen fish were responsible for an outbreak there. Some of those conclusions can be attributed to aerosol starting off as a dirty, alarmist word. Public health officials were searching for something, anything, to explain why groups of people who didn’t gather closely were becoming infected.
It’s impossible to rule out that some transmission could occur that way—and examples still come up, like a case in New Zealand possibly linked to a communal trash can—but most incidents now look like a case of shared air. Wyllie points to a friend who remains convinced they got the virus from a contaminated door handle. She thinks that’s unlikely, but for her friend, it’s an answer to a question of how they got sick that ambient virus floating in the air simply doesn’t offer. It’s a good story.
Sharon Streams, director of the Realm project, says she sympathizes with that demand for answers. The group’s research on library materials was conceived after the surface research in March. At the time, the talk was all fomites, at the time. Library employees wanted specifics to better understand how the virus interacts with the billions of materials they handle each year, many of which are currently marooned in people’s homes, exposed to who knows what. “They’re pulling their hair out about what is the appropriate level of quarantine,” she says.
Streams acknowledges that the conditions modeled in their experiments are based on a vague foundation. It’s hard to know whether the researchers started with a realistic dose of the virus, or whether the amount of it that remains on surfaces after a few days or hours would actually cause an infection. (The group’s latest research release, last week, included more language about aerosols and droplets being the likeliest modes of transmission.) But to her, that’s the point of gathering more data. And Streams points out that even if a weeklong quarantine looks like overkill to some virologists or health experts, quarantines and disinfection satisfy an emotional need that’s often overlooked. Much like the wiping down store shelves, church pews, or subway cars, cleaning policies are also about signaling which spaces are safe to come back to—that libraries are ready for visitors and employees. “‘Hygiene theater’ has been thrown around as a bad word, but they’re embracing it to show that we care about the people coming here,” she says. “They feel comforted.”
But communicating that point is difficult. Marcus points back to the original paper on surface spread in March: “They couched it appropriately. But even with those caveats, it spun into a lot of obsessive behaviors,” she says. Even seemingly benign procedures, like quarantining items, can wear people out over time. “There’s such a high level of tension in our lives and decisionmaking right now. We all need to feel some ease,” Marcus says. “For me, the question is, where are the low-risk areas where we can ease off the gas now that we know more about how transmission happens—which is overwhelmingly from being together in indoor environments? It’s not from a book that somebody sneezed on and brought to the library a week ago.”
Worrying about the small stuff exhausts people from focusing on things that do matter. There are all sorts of ways to imagine what might go wrong. Maybe a person feels so confident in the disinfection methods around them that they eat indoors without a mask, despite the much more substantial known risks. Or perhaps someone feels they don’t need to quarantine themselves after traveling because they wore disposable gloves and booties over their shoes on the plane. “When you ask more of people than what is needed, they grow tired of doing what actually matters,” Marcus says. Her advice: Keep it simple.
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That sort of clear, simple guidance is hard to come by. Since The Lancet publication, Goldman has become a consultant and therapist of sorts for people who are questioning the utility of overly rigorous disinfection, but who are unsure of what to make of the scientific evidence. He’s been in touch with administrators at a local school that planned to close once a week for “a deep clean,” but who weren’t paying attention to their ventilation systems. He has fielded inquiries from people who still leave their groceries out for days, and who barely leave the house, encouraging them to find a healthier balance. He may be able to change minds one at a time, he reasons, or at least help people put the risks in perspective. It worked, he says, on his mother-in-law. But behaviors are hard to shift, especially when the decision is made by committee. The tendency, in the absence of firm guidance to do otherwise, is to cater to the most cautious.
In Minnesota, Kalb, who is one of his acolytes, says her concerns about the pews, and the lack of evidence driving the deep cleaning, were carefully considered by the church reopening committee. But her fellow parishioners advised caution. The daily disinfection was part of a list of changes for safe reopening, including cordoning off rows for social distancing and a sign-up process to enable contact tracing. It was safest, the committee decided, to continue doing it all, much like every other nearby church and school and store was doing. After all, Kalb couldn’t point to a specific study that said fomite transmission was never happening. And there was news going around of an outbreak at a church in Texas. “It was like, OK, we don’t want to be that church,” she says. The church now uses a misting machine to spray disinfectant, which requires less active wiping.
It’s tempting, in other words, to play it conservatively, says Berman, the librarian. “Some of it is just making sure the employees or the public feel safe,” she says, and she sees the benefits of disinfecting library surfaces that get a lot of use. But she points out that institutions have the power to alter our perception of safety, cutting through the ambiguity of risk by offering clear guidance. Holding out these scientific conclusions—the number of days the virus lasts on every imaginable type of library material surface—had done just the opposite, she believed, producing more fear than empowerment.
Like so many decisions about risk and public safety in this pandemic, the burden had been displaced onto people like her, a librarian, not a virologist. She marveled at how much effort she was personally expending trying to educate herself and the people around her about the risk of books as fomites, when there was so much else to worry about. And, well, now she had done the research, and she knew the biggest risk in a library is the risk of sharing the same air, not touching the same book. Wouldn’t it be nice if someone with more authority would just come out and say so? “There’s so much fear out there,” she says. “I don’t want to put anyone at undue risk, but I want us to reopen.”
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