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.