If you have heart disease—or any other health conditions that affect your body’s ability to fight off infection—it’s best to get a flu shot early on, ideally by the end of October. This way, you’ll be protected at the start of the flu season.
The flu season usually begins in October and peaks sometime between December and mid-February.
But flu activity can occur into April and even May. So even when winter rolls around, or the flu season has kicked into high gear, it’s not too late to get a flu shot and protect yourself and those around you.