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If the flu were a folklore character, it would a trickster—and an annoying and sometimes very deadly one at that. The legendary 1917–18 flu pandemic killed 50 million people worldwide. Not content to be devastatingly lethal, the disease in those years also behaved in weird ways that are not typically flu-like. While influenza deaths usually are concentrated in the very young and very old, during the pandemic, almost half the deaths were in young adults 20–40 years old, something never seen before or since. The 1917–18 pandemic also came in waves, hitting several locations repeatedly.
We’re not having an influenza pandemic this year—the term pandemic is only used to refer to the emergence of a strain of flu that is so different from what human immune systems have previously encountered that we are particularly vulnerable. What we appear to be having this year is a flu-the-trickster season. And while that new coronavirus is getting a lot of attention, here in the United States at least, the plain old flu viruses currently circulating in schools, subways, and public spaces are probably a much bigger threat—and perhaps a better reason to consider joining the dystopian fashion wave with a Luis Vuitton surgical mask.
The influenza that produces miserable winters for many of us typically has two flavors, influenza A and influenza B. The A strains are usually the first to get here. The B strains come much later, like an obnoxious party guest who arrives just as others are leaving and you’re ready to go to bed. A few months ago, there were concerns that the 2019–20 flu season would be a bad one because it would be dominated by an A strain called H3N2, which can make people especially sick. That hasn’t happened—at least not yet. (The most common A strain thus far is called H1N1, which is not as big of a threat.)
But the reason it’s shaping up to be a bad flu season is that, for some reason, influenza B flipped the script: It arrived way early—surprise!—and is now making a mess of the place. It’s a dangerous head-scratcher. Usually flu season is still just simmering in December. Instead, led by the surge of influenza B infections, which can be particularly rough for kids, it was raging full boil as the holidays arrived. Flu already has killed 54 children, more than twice the number of flu-related pediatric deaths reported at this point last year. Fifteen of those deaths were reported in just the last week, at a time when all eyes were on the coronavirus.
In some ways, the early, rapid spread mirrors what recently happened in the Southern Hemisphere, where their winter flu season—which occurs in our summer—is often seen as a preview of what could happen in the Northern Hemisphere. But their early surge was caused by an H3N2 strain, which is why there were concerns it would be a problem here as well. Instead, our surge is due to this unusual predominance of a B strain. Still, it’s relatively early—a dangerous H3N2 strain could still cause problems, as one did in the latter part of last year’s flu season.
That would be particularly bad because the seasonal flu vaccine used in the Northern Hemisphere is a poor match for both the influenza B now in vogue and the H3N2 strain that caused a lot of illness in the Southern Hemisphere. This is a perennial problem with seasonal flu vaccines. First, there is the long lead-time required to manufacture vaccines, which means, for the U.S., experts have to predict by February what they believe will be the dominant strains eight months or nine months later. They don’t always get it right. Moreover, almost all influenza vaccine strains are grown in eggs. Those nasty H3N2 strains tend to undergo changes in eggs that can significantly reduce the efficacy of vaccine strains, even when experts predict the right strain.
Meanwhile, as the influenza virus executes its confounding seasonal shape shifting, it’s also playing an ominous long game. There are various versions of influenza constantly circulating the globe in wild and domestic bird populations. Over the last few years, a form of avian influenza called H7N9 has infected more than 1,500 people who have come into contact with sick birds and 615—more than one-third of those infected—have died.
The H7N9 virus is not well suited for human to human transmission. That could change if it’s able to acquire key genes from a human strain. There are significant biological constraints to what scientists call genetic “reassortment,” but there is the potential it could happen, which would put us back in the realm of pandemic. And once pandemic strains emerge, they move very fast. Back in 2009, the H1N1 pandemic strain had circled the globe within six months of when it was first discovered.
The threat of a pandemic and the periodic arrival of a bad seasonal outbreak regularly generate calls for a better way to produce annual vaccines, or for a move to a universal vaccine—one that would provide long-term protection against multiple strains. Efforts are underway on both fronts.
But influenza urgency rises and falls. It never seems to carry the durable passion attached to other disease fights. There is nothing analogous to the pink cleats occasionally worn by NFL players supporting breast cancer awareness. Joe Biden is not calling for a “moonshot” to fight influenza. There are no celebrities testifying on Capitol Hill about the flu. And the depressing number of militant anti-vaxxers, along with the “vaccine-hesitant,” adds another obstacle. But the last time the U.S. had a bad flu season, in 2017–18, about 61,000 people died, including 643 children (that’s some 20,000 more than die each year from breast cancer). Yet even a bad season like that generates nowhere near the all-hands-on-deck action like we are seeing with the coronavirus.
Unless there is a big breakthrough on the science side of things or a massively deadly pandemic shocks the public out of its relative complacency and unlocks new funding, the flu will continue doing what the flu does, which is to keep coming up with fresh ways to fool our current defenses. The writer and oncologist Siddhartha Mukherjee called cancer “the emperor of all maladies.” Influenza is the court jester of all viruses—but perhaps unlike a jester, we’re not paying it enough attention.
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