We’re in the middle of a severe and record-breaking flu season throughout the United States.

Flu-related doctor’s visits are at an all-time high as millions of people come down with the virus. Flu deaths have also been reported in states across the country, including New Jersey, New Hampshire, Oregon and Louisiana.

“This flu season seems to be worse than previous flu seasons in that we are seeing more cases and we are seeing more hospitalizations associated with influenza than we have in previous years,” said Suruchi Sood, an assistant professor at Johns Hopkins University in Baltimore.

According to Dr. Jeb Teichman, a former pediatrician and medical adviser for Families Fighting Flu, the U.S. has experienced 15 million flu cases so far this season compared to 9.1 million cases at this point last year.

Flu season is expected to worsen before it improves. Here’s what to know.