Seriously, Flu Could Be Bad This Year – The Atlantic

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 flus 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 Childrens Research Hospital, in Tennessee, told me at the time.

But those fears did not not come to pass. Flus winter 2021 season in the Southern Hemisphere was once again eerily silent; in the north, cases sneaked up in Decemberonly 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 planets lower half with more fervor than its 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.

Its 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 countrys worst in several years. In South Africa, its 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 countrys 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.

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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 hasnt seen its likes in years, and is already trying to marshal responses to several dangerous pathogens at once.

The worst-case scenario wont necessarily pan out. What goes on below the equator is never a perfect predictor for what will occur above it: Even during peacetime, were pretty bad in terms of predicting what a flu season is going to look like, Webby, of St. Jude, told me. COVID, and the worlds responses to it, have put experts few forecasting tools further on the fritz. But the souths 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 yearswhich is a good thing at face value, but also represents many months of missed opportunities to refresh peoples anti-flu defenses, leaving them more vulnerable at the seasons 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 fluespecially young children, many of whom have never tussled with the viruses. Its very, very likely that kids may end up disproportionately hit, Webby said, as they appear to have been in Australiathough 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, schoolsa fixture of flu transmissionhave loosened up enormously since last year. Theres 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.

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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. Australias 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 outbreaks beginning, before a mid-year BA.5 surge potentially hastened the sudden drop. Its 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 its 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 Hemispheres 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.

COVIDs 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 strainswhich harbor especially large pandemic potentialcould 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 years vaccines, the dominant strains that attack the north could yet shift, says Florian Krammer, a flu virologist at Mount Sinais 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 hitand 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 peoples defenses on high alert, making it that much harder for another pathogen to gain a foothold.

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No matter the odds we enter flu season with, human behavior can still alter winters 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 weve actually learned how to deal with infectious disease more seriously, McCauley told me.

But Webby isnt sure that hes optimistic. People have had enough hearing about viruses in general, he told me. Flu, unfortunately, does not feel similarly about us.

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Seriously, Flu Could Be Bad This Year - The Atlantic