The U.S. broke a 15-year record for pediatric flu deaths this season, according to new federal data released Friday. 

There were 216 children who died, according to a preliminary count from the Centers for Disease Control and Prevention (CDC), the most since 2009 when there was a global swine flu pandemic. This year also broke a record for deaths in a non-pandemic season set during 2023-2024. 

Flu activity is declining nationally, though twelve pediatric deaths were reported during the week ending April 26. 

Experts said the numbers will likely increase once the data is official and flu season ends.  

It was a particularly virulent season, and experts said it was made worse because flu vaccination rates for children are declining.  

CDC recommends that everyone ages 6 months and older get an annual flu vaccine. As of April 19, just 49 percent of children had received one, lower than last season at the same time point, when 53 percent were vaccinated.  

The flu vaccine won’t stop a person from experiencing symptoms but it is effective at preventing hospitalization and death. 

The deaths are “a reminder that influenza is still a really serious disease. And I think … people don’t differentiate mild respiratory viruses from the flu,” said Jesse Goodman, a professor of medicine and infectious diseases at Georgetown University. 

“Flu immunization is still a good idea. It’s not perfect, we need much better vaccine,” Goodman said, “but this is something people need to take seriously.” 

The CDC classified this season as “high severity” for all age groups. So far this season there have been at least 47 million illnesses, 610,000 hospitalizations, and 26,000 deaths.