Pneumococcal infections and the possible need for a vaccine.

Antibiotics and chemotherapeutics have been available for about 40 years, but still bacterial infections constitute some of the greatest problems in medicine. Pneumococci causing pneumonia, bacteremia, meningitis and otitis are a leading cause of illness and death. The exact incidence and lethality of pneumococcal infections is not known, however, since they are not reportable diseases in most countries and since microbiological diagnosis is difficult. In the latest years some significant progresses have been made for the diagnosis of infections caused by pneumococci, especially pneumonia. This is for example the counterimmunoelectrophoresis (CIE) for antigen determination, the transtracheal aspiration (TTA) for direct bacterial cultivation from trachea, and serological assays like radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) for pneumococcal capsular antibody determination. These techniques have further emphasized the significance of pneumococcal infections. The recent finding of pneumococci resistant to penicillin and some other antibiotics also emphasizes the need for immunological prophylaxis. In recent years a vaccine consisting of the purified, most common pneumococcal polysaccharides has been introduced. It has been shown to protect against pneumonia, pneumococcal infections in splenectomized individuals and people with spherocytosis and probably partly against otitis media. Indications for the vaccine are suggested.