“Although the U.S. continues to struggle with COVID-19, it has apparently beaten the flu into submission. Since the end of September, the combined total of positive flu cases identified by both public health and clinical labs is fewer than 1,500. There are high schools with more people in them. The phenomenon is not only in the United States — worldwide, rates of influenza are nearly off-the-charts low. When you line multiple years up on the same graph, it can even look like there are no cases of flu this year. That’s how out of step we are with the norm.”
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“This massive shift, experts told me, is likely tied to the precautions we’ve taken to avoid catching COVID-19: mask-wearing, social distancing, obsessive cleaning of surfaces (which doesn’t do much to prevent COVID-19 but probably is preventing flu) and even keeping kids out of the classroom. “The major vector for influenza is children,” said David Topham, co-director of the New York Influenza Center of Excellence in Rochester. If they don’t get to breathe on each other like normal, they also can’t transmit as much flu. And that trick still works, even if flu isn’t the reason we’re keeping them distanced.
Influenza hasn’t been our target with all these interventions, but we’ve certainly given it a good pummelling. And that’s because flu just isn’t as transmissible as COVID-19.”
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“Our strategies are working on COVID-19, as well. Just not as dramatically, because it was more likely to spread to more people to begin with.”
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“Significantly reduced international travel has probably played a role in that, Brammer said. Usually, our flu season follows that of the Southern Hemisphere. But if there wasn’t much of one there, and there wasn’t much travel to transport the virus — the flu has no way to travel.”
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“scientists don’t know for certain what’s happening because the trouble with a really, really minuscule flu season is that it doesn’t leave you enough cases to make solid statistical inferences. We don’t know, for example, much about what happens when you get both the flu and COVID-19, because there haven’t been enough cases of it to do good research. We don’t really know how this bottleneck is affecting which strains of flu are circulating for the same reason. We don’t even know, for certain, that it is the masks and distancing that are squashing the flu because there are so few flu cases left to look at.”
https://fivethirtyeight.com/features/how-covid-19-ended-flu-season-before-it-started/