If you\u2019ve been putting off your flu shot until the season really gets going, wait no longer. It\u2019s already here\u2014and it\u2019s looking like it\u2019s 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\u2019s come earlier than usual, just in time for a potential peak over the holidays.