The U.S. is experiencing its most intense flu season in 15 years, with 24 million infections, 310,000 hospitalisations, and 13,000 deaths, according to the Centers for Disease Control and Prevention.

The United States is seeing a second peak in flu cases this season. After doctor’s office visits for flu dipped early this year, they jumped past the previous season peak at the end of last month, with a 30% test positivity rate — and there are still months to go.

So far this season, the CDC estimates, there have been 13,000 flu deaths — including at least 57 children. The flu has forced schools to shut down in some states.