Pneumonia risk factors: who is most at risk

Babies can show breathing problems such as a bluish tone to the skin and lips, grunting, the muscles between the ribs pulling inward with each breath, rapid breathing, or the nostrils widening with each breath (NHLBI symptoms). General safety advice (not NHLBI wording): for these signs, or for anyone who is struggling to breathe, get emergency care or call 911.

What pneumonia is

Pneumonia is an infection in one or both lungs. It makes the air sacs fill up with fluid or pus, and it can range from mild to severe depending on the cause, your age and your overall health (MedlinePlus).

Bacteria are a common cause in adults, and Streptococcus pneumoniae (pneumococcus) is the most common cause in the United States. Flu and common cold viruses are the most common causes of viral pneumonia in adults, and RSV is the most common cause of viral pneumonia in young children. Fungi can also cause pneumonia, especially in people with weakened immune systems (NHLBI causes and risk factors). Breathing food or fluid into the lungs (aspiration) can cause it too (MedlinePlus).

Age

Two age groups are at higher risk of getting pneumonia and of having more serious pneumonia (NHLBI causes and risk factors):

• Babies and children 2 years old or younger, because their immune systems are still developing. The risk is higher for premature babies.
• Adults 65 or older, because immune systems generally weaken with age, and older adults are more likely to have other long-term conditions that raise the risk.

Babies, children and older adults who do not get the recommended vaccines to prevent pneumonia have an even higher risk (NHLBI causes and risk factors). For who is advised to get flu and RSV protection, see flu high-risk groups and RSV risk factors.

Where you live and work

• Living or spending a lot of time in a crowded place such as military barracks, prison, a homeless shelter or a nursing home (NHLBI causes and risk factors).
• Regularly breathing in air pollution or toxic fumes (NHLBI causes and risk factors).
• Working in a chicken or turkey processing center, pet shop or veterinary clinic, where some germs that infect birds and other animals are found (NHLBI causes and risk factors).

Lifestyle habits

• Smoking makes you less able to clear mucus from your airways (NHLBI causes and risk factors). The quit smoking help check covers the help available.
• Drugs or alcohol can weaken the immune system, and being sedated or unconscious makes it more likely that saliva or vomit is breathed into the windpipe (NHLBI causes and risk factors). MedlinePlus lists heavy alcohol use and malnourishment (MedlinePlus).

Health conditions

• Lung diseases such as asthma, bronchiectasis, cystic fibrosis or COPD (NHLBI causes and risk factors). See COPD risk factors.
• Brain disorders such as stroke, head injury, dementia or Parkinson's disease, which can affect coughing or swallowing so that food, drink, vomit or saliva goes into the lungs (NHLBI causes and risk factors).
• A weakened immune system, including during pregnancy, with HIV/AIDS, after an organ or bone marrow transplant, during chemotherapy, or with long-term steroid use (NHLBI causes and risk factors).
• Other serious conditions: malnutrition, diabetes, heart failure, sickle cell disease, and liver or kidney disease (NHLBI causes and risk factors).
• A recent cold or flu (MedlinePlus).

Hospital stays

Critical illness that needs a hospital stay, especially in an intensive care unit, raises the risk of hospital-acquired pneumonia. The risk is higher if you cannot move around much or are sedated or unconscious, and using a ventilator raises the risk of ventilator-associated pneumonia (NHLBI causes and risk factors).

Symptoms

Young children, older adults and people with serious health conditions are at risk of more serious pneumonia or life-threatening complications (NHLBI symptoms). Symptoms may include (NHLBI symptoms):

• chest pain when you breathe or cough
• chills and fever
• cough, with or without mucus
• shortness of breath
• low oxygen levels, measured with a pulse oximeter

Headache, muscle pain, extreme tiredness, nausea, vomiting and diarrhea can also occur. Older adults and people with serious illnesses or weak immune systems may not have typical symptoms: they may have a lower-than-normal temperature instead of a fever, and older adults may feel weak or suddenly confused (NHLBI symptoms).

For clinicians: the Pneumonia Severity Index and the CURB-65 calculator are severity scores for diagnosed pneumonia, not tools for checking your own risk.

Common questions

Who is most at risk for pneumonia?

Children 2 and under and adults 65 and older are at higher risk of getting pneumonia and of more serious illness, as are people with lung disease, a weakened immune system or other serious health conditions (NHLBI causes and risk factors) (NHLBI symptoms).

Can a cold or the flu turn into pneumonia?

Yes. Bacterial pneumonia can develop after a viral infection such as a cold or the flu, and a recent cold or flu is on MedlinePlus's list of risk factors (MedlinePlus).

Why are older adults at higher risk?

Immune systems generally weaken with age, and older adults are more likely to have other long-term conditions that raise the risk (NHLBI causes and risk factors). They may also have less typical symptoms, such as confusion or a low temperature (NHLBI symptoms).