Although the flu is not something most healthy Americans go around worrying about, the Centers for Disease Control and Prevention (CDC) is warning that this year’s flu season could be a brutal one. According to a press release issued just days before Christmas of last year, the flu season was officially declared on December 15, 2018, after CDC analysts confirmed the virus had met all of the criteria to make the pronouncement. As with previous flu seasons, these current outbreaks are especially detrimental to children.

“It’s too soon to make any assessment about this season’s severity; however, since this H1N1 virus emerged in 2009, it has been associated with significant illness and severe illness among young children,” the CDC wrote on its website. “At this point, most flu activity has been driven by illness in school-aged children, and hospitalization rates among children younger than 5 years old (7.7 per 100,000) are now the highest among all age groups.”

By January 1, 2019, at least 11 children had died from flu or flu-related complications, according to one report from Mass Live. Several different strains of the flu were responsible for the deaths, including influenza A, influenza B, H1N1, H3N2, or a mix, according to the CDC. During the previous flu season, 185 pediatric flu patients died, which is the highest the agency has ever recorded.

“While how long a flu season lasts varies, CDC expects that elevated flu activity will continue for weeks. The average duration of a flu season for the last five seasons has been 16 weeks, with a range of 11 weeks to 20 weeks. With significant flu still to come this season, CDC continues to recommend that anyone who has not yet gotten a flu vaccine this season should get vaccinated now. It takes approximately two weeks for the protection provided by vaccination to begin.”