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Tag: flu-transmission expert

  • Should Everyone Be Masking Again?

    Should Everyone Be Masking Again?

    Winter is here, and so, once more, are mask mandates. After last winter’s crushing Omicron spike, much of America did away with masking requirements. But with cases once again on the rise and other respiratory illnesses such as RSV and influenza wreaking havoc, some scattered institutions have begun reinstating them. On Monday, one of Iowa’s largest health systems reissued its mandate for staff. That same day, the Oakland, California, city council voted unanimously to again require people to mask up in government buildings. A New Jersey school district revived its own mandate, and the Philadelphia school district announced that it would temporarily do the same after winter break.

    The reinstated mandates are by no means widespread, and that seems unlikely to change any time soon. But as we trudge into yet another pandemic winter, they do raise some questions. What role should masking play in winters to come? Is every winter going to be like this? Should we now consider the holiday season … masking season?

    These questions don’t have simple answers. Regardless of what public-health research tells us we should do, we’ve clearly seen throughout the pandemic that limits exist to what Americans will do. Predictably, the few recent mandates have elicited a good deal of aggrievement and derision from the anti-masking set. But even many Americans who diligently masked earlier in the pandemic seem to have lost their appetite for this sort of intervention as the pandemic has eased. In its most recent national survey of health behavior, the COVID States Project found that only about a quarter of Americans still mask when they go out, down from more than 80 percent at its peak. Some steadfast maskers have started feeling awkward: “I have personally felt like I get weird looks now wearing a mask,” Saskia Popescu, an epidemiologist at George Mason University, told me.

    Even so, masking remains one of the best and least obtrusive infection-prevention measures we have at our disposal. We haven’t yet been slammed this winter by another Omicronlike variant, but the pandemic is still here. COVID cases, hospitalizations, and deaths are all rising nationally, possibly the signs of another wave. Kids have been hit especially hard by the unwelcome return of influenza, RSV, and other respiratory viruses. All of this is playing out against the backdrop of low COVID-19-booster uptake, leaving people more vulnerable to death and severe disease if they get infected.

    All of which is to say: If you’re only going to mask for a couple of months of the year, now is a good time. “Should people be masking? Absolutely yes, right now,” Seema Lakdawala, a flu-transmission expert at Emory University, told me. That doesn’t mean masking everywhere all the time. Lakdawala masks at the grocery store, at the office, and while using public transportation, but not when she goes out to dinner or attends parties. Those activities pose a risk of infection, but Lakdawala’s goal is to reduce her risk, not to minimize it at all costs. A strategy that prevents you from enjoying the things you love most is not sustainable.

    Both Lakdawala and Popescu were willing to go so far as to suggest that masking should indeed become a seasonal fixture—just like skiing and snowmen, only potentially lifesaving and politically radioactive. Even before the pandemic, influenza alone killed tens of thousands of Americans every year, and more masking, even if only in certain targeted settings, could go a long way toward reducing the toll. “If we could just say, Hey, from November to February, we should all just mask indoors,” Lakdawala said, that would do a lot of good. “The idea of the unknown and the perpetualness of two years of things coming on and off, and then the confusing CDC county-by-county guideline—it just sort of makes it harder for everybody than if we had a simple message.” Universal mandates or recommendations that people mask at small social gatherings are probably too much to ask, Lakdawala told me. Instead, she favors some limited, seasonal mandates, such as on public transportation or in schools dealing with viral surges.

    David Dowdy, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, is all for masking season, he told me, but he’d be more hesitant to resort to mandates. “It’s hard to impose mandates without a very strong public-health rationale,” he said, especially in our current, hyperpolarized climate. And although that rationale clearly existed for much of the past two crisis-ridden years, it’s less clear now. “COVID is no longer this public-health emergency, but it’s still killing thousands of people every week, hundreds a day … so it becomes a more challenging balancing act,” Dowdy said.

    Rather than requirements, he favors broad recommendations. The CDC, for instance, could suggest that during flu season, people should consider wearing masks in crowded indoor spaces, the same way it recommends that everyone old enough get a flu shot each year. (Although the agency has hardly updated its “Interim Guidance” on masks and the flu since 2004, Director Rochelle Walensky has encouraged people to mask up this winter.) Another strategy, Dowdy said, could be making masks more accessible to people, so that every time they enter a public indoor space, they have the option of grabbing an N95.

    The course of the pandemic has both demonstrated the efficacy of widespread masking and rendered that strategy so controversial in America as to be virtually impossible. The question now is how to negotiate those two realities. Whatever answer we come up with this year, the question will remain next year, and for years after that. The pandemic will fade, but the coronavirus, like the other surging viruses this winter, will continue to haunt us in one form or another. “These viruses are here,” Lakdawala said. “They’re not going anywhere.”

    Jacob Stern

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  • What Happened to Hand-Washing?

    What Happened to Hand-Washing?

    Way back in the early, whirlwind days of the pandemic, surfaces were the thing to worry about. The prevailing scientific wisdom was that the coronavirus spread mainly via large droplets, which fell onto surfaces, which we then touched with our hands, with which we then touched our faces. (Masks, back then, were said by public health authorities to be unnecessary for the general public.) So we washed our hands until they were raw. We contorted ourselves to avoid touching doorknobs. We went through industrial quantities of hand sanitizer, and pressed elevator buttons with keys and pens, and disinfected our groceries and takeout orders and mail.

    And then we learned we’d had it all backwards. The virus didn’t spread much via surfaces; it spread through the air. We came to understand the danger of indoor spaces, the importance of ventilation, and the difference between a cloth mask and an N95. Meanwhile, we mostly stopped talking about hand-washing. The days when you could hear people humming “Happy Birthday” in public restrooms quickly disappeared. And wiping down packages and ostentatious workplace-disinfection protocols became a matter of lingering hygiene theater.

    This whole episode was among the stranger and more disorienting shifts of the pandemic. Sanitization, that great bastion of public health, saved lives; actually, no, it didn’t matter that much for COVID. On one level, this about-face should be seen as a marker of good scientific progress, but it also raises a question about the sorts of acts we briefly thought were our best available defense against the virus. If hand-washing isn’t as important as we thought it was in March 2020, how important is it?

    Read: Don’t worry, it’s not COVID

    Any public-health expert will be quick to tell you that, please, yes, you should still wash your hands. Emanuel Goldman, a microbiologist at Rutgers New Jersey Medical School, considers it “commonsense hygiene” for protecting us against a range of viruses 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 COVID.

    Even so, the pandemic has piled on evidence that the transmission of the coronavirus via fomites—that is, inanimate contaminated objects or surfaces—plays a much smaller role, and airborne transmission a much larger one, than we once thought. And the same likely goes for other respiratory pathogens, such as influenza and the coronaviruses that cause the common cold, Linsey Marr, an environmental engineer and aerosols expert at Virginia Tech, told me.

    This realization is not an entirely new one: A 1987 study by researchers at the University of Wisconsin found that a group of men playing poker with “soggy,” rhinovirus-contaminated cards were not infected, while a group playing with other sick players were. Now Goldman intends to push this point even further. At a conference in December, he is going to present a paper arguing that, with rare exceptions, such as RSV, all respiratory pathogens are transmitted predominantly through the air. The reason we’ve long thought otherwise, he told me, is that our understanding has been founded on faulty assumptions. Generally speaking, the studies pointing toward fomite-centric theories of transmission were virus-survival studies, which measure how long a virus can survive on a surface. Many of them either used unrealistically large amounts of virus or measured only the presence of the virus’s genetic material, not whether it remained infectious. “The design” of these experiments, he said, “was not appropriate for being able to extrapolate to real-life conditions.”

    The upshot, for Goldman, is that surface transmission of respiratory pathogens is “negligible,” probably accounting for less than .01 percent of all infections. If correct, this would mean that your chance of catching the flu or a cold by touching something in the course of daily life is virtually nonexistent. Goldman acknowledged that there’s a “spectrum of opinion” on the matter. Marr, for one, would not go quite so far: She’s confident that more than half of respiratory-pathogen transmission is airborne, though she said she wouldn’t be surprised if the proportion is much, much higher—the only number she would rule out is 100 percent.

    Read: The very real lessons America has learned from COVID

    For now, it’s important to avoid binary thinking on the matter, Saskia Popescu, an epidemiologist at George Mason University, told me. Fomites, airborne droplets, smaller aerosol particles—all modes of transmission are possible. And the proportional breakdown will not be the same in every setting, Seema Lakdawa, a flu-transmission expert at Emory University, told me. Fomite transmission might be negligible at a grocery store, but that doesn’t mean it’s negligible at a day care, where kids are constantly touching things and sneezing on things and sticking things in their mouths. The corollary to this idea is that certain infection-prevention strategies prove highly effective in one context but not in another: Frequently disinfecting a table in a preschool classroom might make a lot of sense; frequently disinfecting the desk in your own private cubicle, less so.

    Much of the conspicuous cleaning we did early in the pandemic was excessive, Popescu said, but she worries that we may have slightly overcorrected, lumping some useful behaviors—targeted disinfection, even hand-washing in some cases—into the category of hygiene theater. Whatever the setting, the experts I spoke with all agreed that these behaviors remain important for contending with non-respiratory pathogens. Recently, when several members of Marr’s family came down with norovirus, an extremely unpleasant stomach bug that causes vomiting, diarrhea, and stomach cramping, she disinfected a number of high-touch surfaces around the house. Picture that: one of the country’s foremost experts on airborne transmission wiping down doorknobs and light switches.

    Marr isn’t convinced we’ve overcorrected. Hand sanitizer still abounds, businesses still tout their surface-cleaning protocols, and air quality still gets comparatively little attention. Recently, she watched a person use their shirt to open the door of a visitor center without touching the handle … then proceed inside unmasked. There’s nothing wrong with taking certain precautions to prevent fomite transmission, she said—these should not all be dismissed en masse as hygiene theater—as long as they don’t come at the expense of efforts to block airborne transmission. “If you’re doing extra hand washing … then you should also be wearing a good mask in crowded indoor environments,” Marr said. “If you’re bothering to clean the surfaces, then you should be bothering to clean the air.”

    On Friday, with respiratory-virus season looming, CDC Director Rochelle Walensky tweeted out three pieces of advice for staying healthy: “Get an updated COVID-19 vaccine & get your annual flu vaccine,” “Stay home if you are sick,” and—not to be forgotten—“Practice good hand hygiene.” She made no mention of masks or ventilation.

    Jacob Stern

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  • The Strongest Signal That Americans Should Worry About Flu This Winter

    The Strongest Signal That Americans Should Worry About Flu This Winter

    Sometime in the spring of 2020, after centuries, perhaps millennia, of tumultuous coexistence with humans, influenza abruptly went dark. Around the globe, documented cases of the viral infection completely cratered as the world tried to counteract SARS-CoV-2. This time last year, American experts began to fret that the flu’s unprecedented sabbatical was too bizarre to last: Perhaps the group of viruses that cause the disease would be poised for an epic comeback, slamming us with “a little more punch” than usual, Richard Webby, an influenza expert at St. Jude Children’s Research Hospital, in Tennessee, told me at the time.

    But those fears did not not come to pass. Flu’s winter 2021 season in the Southern Hemisphere was once again eerily silent; in the north, cases sneaked up in December—only to peter out before a lackluster reprise in the spring.

    Now, as the weather once again chills in this hemisphere and the winter holidays loom, experts are nervously looking ahead. After skipping two seasons in the Southern Hemisphere, flu spent 2022 hopping across the planet’s lower half with more fervor than it’s had since the COVID crisis began. And of the three years of the pandemic that have played out so far, this one is previewing the strongest signs yet of a rough flu season ahead.

    It’s still very possible that the flu will fizzle into mildness for the third year in a row, making experts’ gloomier suspicions welcomingly wrong. Then again, this year is, virologically, nothing like the last. Australia recently wrapped an unusually early and “very significant” season with flu viruses, says Kanta Subbarao, the director of the WHO Collaborating Centre for Reference and Research on Influenza at the Doherty Institute. By sheer confirmed case counts, this season was one of the country’s worst in several years. In South Africa, “it’s been a very typical flu season” by pre-pandemic standards, which is still enough to be of note, according to Cheryl Cohen, a co-head of the country’s Centre for Respiratory Disease and Meningitis at the National Institute for Communicable Diseases. After a long, long hiatus, Subbarao told me, flu in the Southern Hemisphere “is certainly back.”

    Read: The pandemic broke the flu

    That does not bode terribly well for those of us up north. The same viruses that seed outbreaks in the south tend to be the ones that sprout epidemics here as the seasons do their annual flip. “I take the south as an indicator,” says Seema Lakdawala, a flu-transmission expert at Emory University. And should flu return here, too, with a vengeance, it will collide with a population that hasn’t seen its likes in years, and is already trying to marshal responses to several dangerous pathogens at once.

    The worst-case scenario won’t necessarily pan out. What goes on below the equator is never a perfect predictor for what will occur above it: Even during peacetime, “we’re pretty bad in terms of predicting what a flu season is going to look like,” Webby, of St. Jude, told me. COVID, and the world’s responses to it, have put experts’ few forecasting tools further on the fritz. But the south’s experiences can still be telling. In South Africa and Australia, for instance, many COVID-mitigation measures, such as universal masking recommendations and post-travel quarantines, lifted as winter arrived, allowing a glut of respiratory viruses to percolate through the population. The flu flood also began after two essentially flu-less years—which is a good thing at face value, but also represents many months of missed opportunities to refresh people’s anti-flu defenses, leaving them more vulnerable at the season’s start.

    Some of the same factors are working against those of us north of the equator, perhaps to an even greater degree. Here, too, the population is starting at a lower defensive baseline against flu—especially young children, many of whom have never tussled with the viruses. It’s “very, very likely” that kids may end up disproportionately hit, Webby said, as they appear to have been in Australia—though Subbarao notes that this trend may have been driven by more cautious behaviors among older populations, skewing illness younger.

    Interest in inoculations has also dropped during the pandemic: After more than a year of calls for booster after booster, “people have a lot of fatigue,” says Helen Chu, a physician and flu expert at the University of Washington, and that exhaustion may be driving already low interest in flu shots even further down. (During good years, flu-shot uptake in the U.S. peaks around 50 percent.) And the few protections against viruses that were still in place last winter have now almost entirely vanished. In particular, schools—a fixture of flu transmission—have loosened up enormously since last year. There’s also just “much more flu around,” all over the global map, Webby said. With international travel back in full swing, the viruses will get that many more chances to hopscotch across borders and ignite an outbreak. And should such an epidemic emerge, with its health infrastructure already under strain from simultaneous outbreaks of COVID, monkeypox, and polio, America may not handle another addition well. “Overall,” Chu told me, “we are not well prepared.”

    Read: The most important vaccine I’ll get this fall

    At the same time, though, countries around the world have taken such different approaches to COVID mitigation that the pandemic may have further uncoupled their flu-season fate. Australia’s experience with the flu, for instance, started, peaked, and ended early this year; the new arrival of more relaxed travel policies likely played a role in the outbreak’s beginning, before a mid-year BA.5 surge potentially hastened the sudden drop. It’s also very unclear whether the U.S. may be better or worse off because its last flu season was wimpy, weirdly shaped, and unusually late. South Africa saw an atypical summer bump in flu activity as well; those infections may have left behind a fresh dusting of immunity and blunted the severity of the following season, Cohen told me. But it’s always hard to tell. “I was quite strong in saying that I really believed that South Africa was going to have a severe season,” she said. “And it seems that I was wrong.” The long summer tail of the Northern Hemisphere’s most recent flu season could also exacerbate the intensity of the coming winter season, says John McCauley, the director of the Worldwide Influenza Centre at the Francis Crick Institute, in London. Kept going in their off-season, the viruses may have an easier vantage point from which to reemerge this winter.

    COVID’s crush has shifted flu dynamics on the whole as well. The pandemic “squeezed out” a lot of diversity from the influenza-virus population, Webby told me; some lineages may have even entirely blipped out. But others could also still be stewing and mutating, potentially in animals or unmonitored pockets of the world. That these strains—which harbor especially large pandemic potential—could emerge into the general population is “my bigger concern,” Lakdawala, of Emory, told me. And although the particular strains of flu that are circulating most avidly seem reasonably well matched to this year’s vaccines, the dominant strains that attack the north could yet shift, says Florian Krammer, a flu virologist at Mount Sinai’s Icahn School of Medicine. Viruses also tend to wobble and hop when they return from long vacations; it may take a season or two before the flu finds its usual rhythm.

    Another epic SARS-CoV-2 variant could also quash a would-be influenza peak. Flu cases rose at the end of 2021, and the dreaded “twindemic” loomed. But then, Omicron hit—and flu “basically disappeared for one and a half months,” Krammer told me, only tiptoeing back onto the scene after COVID cases dropped. Some experts suspect that the immune system may have played a role in this tag-team act: Although co-infections or sequential infections of SARS-CoV-2 and flu viruses are possible, the aggressive spread of a new coronavirus variant may have set people’s defenses on high alert, making it that much harder for another pathogen to gain a foothold.

    Read: Don’t worry, it’s not the flu

    No matter the odds we enter flu season with, human behavior can still alter winter’s course. One of the main reasons that flu viruses have been so absent the past few years is because mitigation measures have kept them at bay. “People understand transmission more than they ever did before,” Lakdawala told me. Subbarao thinks COVID wisdom is what helped keep Australian flu deaths down, despite the gargantuan swell in cases: Older people took note of the actions that thwarted the coronavirus and applied those same lessons to flu. Perhaps populations across the Northern Hemisphere will act in similar ways. “I would hope that we’ve actually learned how to deal with infectious disease more seriously,” McCauley told me.

    But Webby isn’t sure that he’s optimistic. “People have had enough hearing about viruses in general,” he told me. Flu, unfortunately, does not feel similarly about us.

    Katherine J. Wu

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