Risk factors

Not everyone exposed to legionella bacteria becomes sick. You're more likely to develop the infection if you:

• Smoke. Smoking damages the lungs, making you more susceptible to all types of lung infections.
• Have a weakened immune system. This can be a result of HIV/AIDS or certain medications, especially corticosteroids and drugs taken to prevent organ rejection after a transplant.
• Have a chronic lung disease or other serious condition. This includes emphysema, diabetes, kidney disease or cancer.
• Are 50 years of age or older.

Legionnaires' disease can be a problem in hospitals and nursing homes, where germs can spread easily and people are vulnerable to infection.