Wash your hands often, especially after blowing your nose, going to the bathroom, diapering a baby, and before eating or preparing foods. Don’t smoke. Tobacco damages your lungs’ ability to ward off infection. Vaccines may help prevent pneumonia in children, the elderly, and people with diabetes, asthma, emphysema, HIV, cancer, or other chronic conditions.

• A drug called palivizumab (Synagis) is given to some children under 24 months old to prevent pneumonia caused by respiratory syncytial virus.
• Flu vaccine prevents pneumonia and other problems caused by the influenza virus. It must be given each year to protect against new virus strains.

If your immune system is weak, stay away from crowds. Ask visitors who have a cold to wear a mask.