Pneumonia - Risk Factors - Risk Factors

Your risk of pneumonia may be higher because of your age, environment, lifestyle habits, and other medical conditions.


Pneumonia can affect people of all ages. However, two age groups are at higher risk of developing pneumonia and having more serious pneumonia.

  • Babies and children, 2 years old or younger, because their immune systems are still developing. The risk is higher for premature babies.
  • Older adults, age 65 or older, because their immune systems generally weaken as they age. Older adults are also more likely to have other chronic (long-term) health conditions that raise the risk of pneumonia. 

Babies, children, and older adults who do not get the recommended vaccines to prevent pneumonia have an even higher risk.

Environment or occupation

Most people get pneumonia when they catch an infection from someone else in their community. Your chance of getting pneumonia is higher if you live or spend a lot of time in a crowded place such as a military barrack, prison, homeless shelter, or nursing home. 

Your risk is also higher if you regularly breathe in air pollution or toxic fumes. 

Some germs that cause pneumonia can infect birds and other animals. You are most likely to encounter these germs if you work in a chicken or turkey processing center, pet shop, or veterinary clinic.

Lifestyle habits

  • Smoking cigarettes can make you less able to clear mucus from your airways.
  • Using drugs or alcohol can weaken your immune system. You are also more likely to accidentally inhale saliva or vomit into your windpipe if you are sedatedor unconscious from an overdose.

Other medical conditions

You may have an increased risk of pneumonia if you have any of the following medical conditions.

  • Brain disorders, such as a stroke, a head injury, dementia, or Parkinson’s disease. These conditions can affect your ability to cough or swallow. This can lead to food, drink, vomit, or saliva going down your windpipe instead of your esophagus and getting into your lungs.
  • Conditions that weaken your immune system, such as pregnancy, HIV/AIDS, or an organ or bone marrow transplant. Chemotherapy, which is used to treat cancer, and long-term use of steroid medicines can also weaken your immune system.
  • Critical diseases that require hospitalization. Receiving treatment in a hospital intensive care unit raises your risk of hospital-acquired pneumonia. Your risk is higher if you cannot move around much or are sedated or unconscious. Using a ventilator raises the risk of a type called ventilator-associated pneumonia.
  • Lung diseases, such as asthma, bronchiectasis, cystic fibrosis, or COPD.
  • Other serious conditions, such as malnutrition, diabetes, heart failure, sickle cell disease, or liver or kidney disease.