pneumococcal vaccine

The pneumococcal vaccine teaches the immune system to recognize and fight the pneumococcus, a common bacterium that causes pneumonia and other serious infections. Like a fire drill for the immune system, it lets the body practice on a harmless preview so it can respond fast if the real germ arrives.

There are two main types. Conjugate vaccines link pieces of the bacterium's sugar coat to a carrier protein, producing a strong, lasting response that even works well in young children; polysaccharide vaccines present the sugar coats alone and cover more strains but give a weaker, shorter response in the very young. Both prime the body against the capsule that the pneumococcus uses to evade defenses, lowering the risk of invasive disease such as bloodstream infection and meningitis.

Vaccination is recommended for infants, older adults, and people with chronic lung, heart, liver, or kidney disease, weakened immunity, or no spleen. It reduces but does not eliminate the chance of pneumococcal pneumonia, and it does not cover every strain or other causes of pneumonia, so it complements rather than replaces other protective measures such as the influenza vaccine and not smoking.