Epidemiology and prevention of pneumococcal infections.

There are comparatively few data on the incidence and morbidity from pneumococcal disease, which is greatly underestimated by case ascertainment from sterile site isolates alone. New diagnostic methods, such as serology and polymerase chain reaction, to detect components of the pneumococcal cell wall promise to significantly enhance detection of pneumococci causing childhood pneumonia. There is increasing evidence that excessive antibiotic use in children is a major factor promoting antibiotic resistance in pneumococci. Resistance is a problem worldwide and has focused attention on vaccine prevention. Fortunately, antibiotic-resistant pneumococci appear to belong to a limited range of serotypes, those commonly colonizing children, in all areas so far studied. If conjugate pneumococcal vaccines prove to eradicate carriage, immunization may be the major weapon against the spread of antibiotic-resistant pneumococcal infection. Conjugate pneumococcal vaccines are now being studied in large-scale efficacy trials with outcomes of bacteremia and otitis media, the results of which are eagerly awaited.