This Past Flu Season Was the Longest in 10 Years, the CDC Says

The 2018-2019 flu season may not have been as severe as the one that came before it, but it set a record of its own, the Centers for Disease Control and Prevention (CDC) say. It was the longest in a decade, lasting 21 weeks.

Fewer illnesses, hospitalizations and deaths were reported this year than during last year’s notoriously brutal flu season, earning the 2018-2019 season an overall severity rating of “moderate,” according to a new CDC recap. But the length and trajectory of the most recent flu season—which began in November, peaked in mid-February and trailed off in April—was unique, the CDC says.

Most flu seasons start off with lots of infections from influenza A viruses, which can be more severe and less responsive to vaccination than other subtypes, while generally less-severe influenza B viruses often strike later. But this year, the CDC says, two different phases of influenza A activity dominated the season, contributing to its unusual length. H1N1 circulated widely from October to mid-February, then H3N2 picked up from mid-February into the spring, according to the new report.

Even still, high early-season vaccination rates and a relatively effective annual vaccine appeared to help suppress illnesses. In total, the CDC estimates that up to 42.9 million people got sick during the 2018-2019 flu season, 647,000 people were hospitalized and 61,200 died. That’s fairly on par with a typical season, and well below the CDC’s 2017-2018 estimates of 48.8 million illnesses, 959,000 hospitalizations and 79,400 deaths.

Pediatric hospitalizations were similar to last year’s levels, the CDC says, but there were fewer pediatric deaths: 116 children died from the flu this year, compared to 183 last year.

Although the 2018-2019 flu season is over, the CDC is already reminding people to get vaccinated ahead of the 2019-2020 season, since it’s the best way to reduce the risk of getting and transmitting influenza. October, ahead of the bulk of flu season, is the best time to get vaccinated, according to the CDC.