Summary and conclusions Pneumococcal diseases are a major public-health problem all over the world. Differences in the composition of this capsule permit the serological differentiation between about 90 capsular types, some of which are frequently associated with pneumococcal disease, others rarely. At least one million children die of pneumococcal disease every year, most of these being young children in developing countries. In the developed world, elderly persons carry the major disease burden. Conditions associated with increased risk of serious pneumococcal disease include HIV infection, sickle-cell anaemia, and a variety of chronic organ failures.
Vaccination is the only available tool to prevent pneumococcal disease.
The recent development of widespread microbial resistance to essential antibiotics underlines the urgent need for more efficient pneumococcal vaccines. Immunity following pneumococcal disease is directed primarily against the capsular serotype involved. However, in the healthy elderly population, the polysaccharide vaccine provides relatively efficient protection against invasive pneumococcal disease. Extensive clinical trials are now under way with a new generation of pneumococcal vaccines. Such groups include splenectomized patients and persons with chronic organ failure or sickle-cell disease, and the elderly population.