Epidemiology and prevention of pneumococcal disease.

There are comparatively little data on the incidence and morbidity from pneumococcal disease in Australia and elsewhere. Available data suggest that the overall incidence of invasive pneumococcal disease in Australia is comparable with similar populations. Very high rates are reported in Central Australian Aborigines, similar to invasive Haemophilus influenzae type b (Hib) disease. Disease incidence is probably greatly underestimated by case ascertainment from sterile site isolates alone. New diagnostic methods, such as serology to detect components of the pneumococcal cell wall, promise to significantly enhance detection of pneumococci as a cause of pneumonia, especially in childhood, but are epidemiologic rather than clinical tools. Resistance to penicillin and other antibiotics is an increasing problem worldwide, promoted by excessive antibiotic use, especially in children. This has focused attention on vaccine prevention. Fortunately, antibiotic-resistant pneumococci appear to belong to a limited range of serotypes, those commonly colonising children, in all areas so far studied. If conjugate pneumococcal vaccines prove to eradicate carriage, in a similar fashion to conjugate Hib vaccines, vaccination may be the major weapon against the spread of antibiotic-resistant pneumococcal infection. Conjugate pneumococcal vaccines are now in large scale efficacy trials, with outcomes of bacteraemia (California) and otitis media (Finland). Results of these trials are eagerly awaited.