Experts say this is the worst flu season in the U.S. in more than a decade and cases are still trending up. Flu infections have reached the highest level since the winter of 2010 and 2011 when the swine flu swept across the nation, data from the Centers for Disease Control and Prevention shows.

Says a pediatric infectious disease physician, “Our expectation is that we’re going to have several more weeks yet of a lot of people being sick.”