Flu season is gearing up in the northern hemisphere, and this year’s strains appear more virulent than usual. In the United States, the Centers for Disease Control declared an epidemic on January 11; the CDC estimates that between 3,000 and 49,000 people die from influenza or its complications every year. By comparison, the infamous flu of 1918 may have killed 500,000 Americans. Although the very young, elderly, and diseased bear the highest risk of death, healthy adults still bear the responsibility of minimizing overall transmission of the virus. In other words, everyone should get vaccinated. On ERV, Abbie Smith writes that the influenza virus is highly mutable, and we must devise a fresh vaccine every year in anticipation of its new forms. This year’s vaccine has an efficacy of 62%, better than average. Meanwhile, on We Beasties, Kevin Bonham explains what happens when you are infected by more than one pathogen at a time.