Even as covid-19 continues to dominate the public health spotlight, our old friend the flu is showing up with some new surprises. This year’s flu season is not following the usual bell curve pattern, as an NBC graphic illustrates, where cases peak around January and February and then fall toward the end of April. Instead, the flu has kept up its pace into May.
Things were on a relatively normal trajectory until about 10 weeks in, when cases declined and leveled off. By March, cases started to rise and peaked at about 10% of all tests coming up positive for the flu by April. The flu has now lingered into May, though overall cases are still low compared to the average flu season before covid-19.
The U.S. Centers for Disease Control and Prevention estimates that, between last October and April 30, the number of people who caught the flu is between 5.7 million and 9.6 million. There have been an estimated 59,000 to 120,000 hospitalizations and between 3,600 to 10,000 flu deaths. While these numbers are higher than last year’s season—which was practically non-existent, as people wore masks and avoided gathering—they still paint a picture of a relatively mild flu season. In 2018-19, for example, around 35.5 million people were sick with the flu, and 34,200 people died from it.
Experts told NBC that the country is not nearing epidemic flu levels by any means, but the lingering nature is notable compared to practically any other year since 1982, when the U.S. experienced a few intense outbreaks in late May.
It’s fortunate that we avoided a large or even moderate flu season this year, as the most recent vaccines were ill-matched to the circulating virus strains, resulting in a vaccine efficacy of only 16%. While the CDC has said this year’s vaccine might not have reduced the chance of getting sick from the flu, it continued recommending the shot, since data shows it makes symptoms less severe and reduces the chance of hospitalization or death.
Efforts to fight covid-19, including mask wearing, helped stop the flu in its tracks, even as the more contagious coronavirus continued to spread. As more people resume in-person gatherings and mask requirements are lifted, however, it’s no shock that the flu is creeping back into our lives. Hopefully, masking while sick and during outbreaks is now normalized enough in the U.S. that we may be able to avoid the devastating flu seasons we once accepted as routine.