Flu activity remains high across the U.S. as a “second wave of severe infections” hits some states, CNN reports. According to the CDC, there have reportedly been 26.3 million flu illnesses in the U.S. between October 1 and March 2—with 347,000 flu hospitalizations. Nine children died of flu-related causes last week, bringing the total number of recorded fatalities to 64. While hospitalization rates are reportedly a lot lower than last season, the CDC recorded approximately 37 hospitalizations for every 100,000 people last week. CNN reports that the H1N1 virus has been the predominant strain this flu season, but the more severe H3N2 virus has been passed along in the Southeast—causing potentially fatal complications. “All of these viruses, but particularly H3N2, have a tendency to try to put you in the hospital and set you up for a secondary case of pneumonia,” Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases, told the network.