Getting a yearly flu shot keeps you healthy in more ways than one. An analysis of several studies found that recent heart attack sufferers who got a flu shot were 55% less likely to have further heart problems. Researchers believe the heart-health benefits of a flu shot could extend to people who have not had past cardiac problems. Medical experts say the research proves the flu is a body-wide infection that affects the heart and can make underlying conditions worse. The CDC recommends that all people older than six months get an annual flu vaccine; people who are middle-aged or older or at risk of heart attack are especially advised to get the shot.