If you’ve been putting off your flu shot until the season really gets going, wait no longer. It’s already here—and it’s looking like it’s going to be a doozy. Influenza viruses quietly circulate year-round in the US, but every winter they go big, triggering a seasonal epidemic of sniffles, sweats, and sore throats. And this year it’s come earlier than usual, just in time for a potential peak over the holidays.