While we often refer to it as "the flu," the influenza virus has several strains, with flu A and flu B considered the most common and the most severe.

Illinois is seeing a “notable increase” in hospital admissions for flu cases, according to state health officials, as levels of respiratory viruses continue to tick up. But which type of flu is circulating most and what should you know?

The flu is spreading far and wide across the U.S. – and influenza A is largely to blame. Of all the flu tests reported to the Centers for Disease Control and Prevention since the start of flu season last fall,