Risk factors

Pneumonia can affect anyone. But the two age groups at highest risk are:

• Children who are 2 years old or younger
• People who are age 65 or older

Other risk factors include:

• Being hospitalized. You're at greater risk of pneumonia if you're in a hospital intensive care unit, especially if you're on a machine that helps you breathe (a ventilator).
• Chronic disease. You're more likely to get pneumonia if you have asthma, chronic obstructive pulmonary disease (COPD) or heart disease.
• Smoking. Smoking damages your body's natural defenses against the bacteria and viruses that cause pneumonia.
• Weakened or suppressed immune system. People who have HIV/AIDS, who've had an organ transplant, or who receive chemotherapy or long-term steroids are at risk.