Pneumococcal Disease: Causes, How It Spreads and Who Is at Risk

Pneumococcal disease is the name for any infection caused by the bacterium Streptococcus pneumoniae, also called pneumococcus. A person's risk depends on many factors; talk to a doctor if you are concerned.

How it spreads

The bacteria pass from person to person through direct contact with respiratory secretions, such as saliva or mucus.

Many people — children especially — have the bacteria in their nose or throat at some point without being ill. This is called carriage, and it only rarely leads to sickness.

Who is at higher risk

Age, health conditions and other factors can raise the risk of pneumococcal disease, including severe infection.

• Age: children under 5 and adults 50 or older.
• Race and ethnicity: for reasons experts do not know, rates are higher among Alaska Native people, African American people and certain American Indian people.
• Childcare: young children in childcare are at higher risk of severe pneumococcal disease and of ear infections.

Health conditions and other factors

• alcoholism;
• a leak of cerebrospinal fluid, the fluid around the brain and spinal cord;
• chronic heart, kidney, liver or lung disease — lung disease including chronic obstructive pulmonary disease (COPD), emphysema and asthma;
• cigarette smoking;
• a cochlear implant, a hearing device implanted by surgery for severe hearing loss;
• diabetes;
• a weakened immune system.

Conditions that weaken the immune system

• a damaged spleen, or no spleen;
• diseases or conditions that weaken the immune system;
• diseases or conditions treated with medicines that weaken it, including cancer and solid organ transplants;
• HIV infection;
• kidney failure needing regular dialysis, or nephrotic syndrome, a kidney disorder;
• sickle cell disease and other inherited blood disorders.

Sources

• Centers for Disease Control and Prevention, "Causes of Pneumococcal Disease." https://www.cdc.gov/pneumococcal/causes/index.html
• Rewritten in hubnx's own words.