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

  • Infants and children younger than age 2 years, because their immune systems are still developing
  • People older than age 65

Other risk factors include:

  • Certain chronic diseases, such as asthma, chronic obstructive pulmonary disease and heart disease
  • Weakened or suppressed immune system, due to factors such as HIV/AIDS, organ transplant, chemotherapy for cancer or long-term steroid use
  • Smoking, which damages your body's natural defenses against the bacteria and viruses that cause pneumonia
  • Being placed on a ventilator while hospitalized
May. 21, 2013