Pneumonia occurs more commonly in older adults than in younger adults, and it also tends to be more serious. In many older adults, the infection spreads beyond the lungs.

Older adults have weakened defenses against infection. The mechanisms that clear microorganisms from the airways are not as effective in older adults as they are in younger adults. Weakness may make coughing less vigorous. Aging also weakens the immune system. Older adults at greater risk of developing pneumonia include those

• Whose lungs have been damaged by smoking (smoking irritates the lining of the lungs and paralyzes the cells that normally sweep and cleanse the airways) or chronic obstructive pulmonary disease

• Whose lungs have recently been irritated by a mild infection, such as a cold or, especially, influenza

• Who have a poor cough reflex, for example, resulting from a previous stroke, or who are too weak (or who are in pain from recent surgery or an accident) to cough vigorously

• Who are less able to fight off infections, including people who are undernourished

• Who are taking certain medications that weaken the immune system, such as corticosteroids

• Who have certain diseases, such as heart failure or diabetes

• Who have cancer in or near the airways of the lungs (the cancer may block the airways and trap any microorganisms that have reached the air sacs)

• Who are paralyzed (for example, because of a spinal injury or stroke)

• Who are not fully conscious (they may be unable to cough)

Infection with some of the microorganisms that cause pneumonia can be prevented with vaccinations. So doctors recommend that people who are 65 years old or older receive the pneumococcal vaccine. People younger than 65 who have medical conditions that make them at higher risk of developing pneumonia should also receive the vaccine. Doctors also recommend that older adults in particular receive full COVID-19 vaccination and an annual influenza vaccine because the influenza virus can also cause or contribute to pneumonia. The vaccine for respiratory syncytial virus is indicated for adults age 60 years or older, based on shared clinical decision-making.

Most older adults who get pneumonia are treated in the hospital with intravenous antibiotics. Pneumonia can cause older adults to get very sick very quickly, and older adults tend to respond less well to oral antibiotics.