Annual flu shots are recommended for all ages, starting at 6 months old. Formerly promoted for adults over 65, there has been a shift in recent years encouraging all age groups to receive the shot.

The flu (influenza) attacks the respiratory system (the nose, throat, and lungs) producing symptoms which include sore throat, runny nose, and fever. For young and healthy individuals, the seasonal flu is not typically serious. Most people will get better within a couple of days. People more at risk—the very young and the very old, pregnant women, people with compromised immune systems or chronic illness—are in danger of developing complications like pneumonia, bronchitis, or sinus infections.

If you’ve already had the flu or vaccination against it, your immune system recognizes the virus next time around and is prepared to fight it. What your immune system can’t do is fight new forms of the virus.

While the CDC encourages people to get a vaccination, the flu vaccine is not 100 percent effective. Preventive measures to help stop the spread of infection include frequently washing your hands, covering sneezes and coughs (into a tissue or your elbow), and staying away from crowds.