Q&A: How contagious is the flu?

As a healthy, middle-aged adult, I usually don't get a flu shot. But since I work with many people, how likely am I to develop flu symptoms if I catch it, and for how long will I be contagious? —C.H., Anchorage, Alaska

About two out of three people who become infected with the flu virus develop symptoms, research shows.
Whether or not you have symptoms, you're contagious from the day you catch the flu until about five days afterward, though it appears to peak around the second day. Get an annual flu shot if you have close contact with anyone at the highest risk for catching or developing complications from the illness, including young children, seniors, pregnant women, and people with chronic illnesses or weakened immunity. Wash your hands often, since they can carry and spread the virus even if you don't catch it.

For more on flu prevention and treatment, see our new flu shot survey and our Treatment Ratings (subscribers only).