Pneumococcal Vaccine

Pneumococcal vaccines are subunit vaccines against the bacterium Streptococcus pneumoniae, used to prevent some cases of pneumonia, meningitis and sepsis, and given by injection into a muscle or just under the skin. There are two types, conjugate vaccines and polysaccharide vaccines, with the World Health Organization recommending the conjugate vaccine for routine childhood immunization, where three or four doses are between 71 and 93 percent effective against severe pneumococcal disease. Whole-cell vaccinations were developed alongside the characterization of pneumococcus subtypes from the early 1900s; the first tetravalent polysaccharide vaccine was developed in 1945, the current 23-valent polysaccharide vaccine in the 1980s, and the first heptavalent conjugate vaccine reached market in 2000. It is on the World Health Organization's List of Essential Medicines.