The role of immunodeficiency virus infection in pneumococcal bacteremia in San Francisco residents

Persons infected with human immunodeficiency virus (HIV, which causes AIDS) appear to be at high risk for pneumococcal disease. Failure of the humoral immune system, important in immunity to pneumococcal disease, and the progressive loss of cell-mediated immunity occur in HIV-infected patients. The extent of involvement, the clinical course of infection, and the serotypes of pneumococcal bacteria most frequently encountered have not been widely studied in this vulnerable population. (Serotypes are combinations of foreign antigens.) To evaluate the risk of pneumococcal disease in these patients and develop methods of prevention, the authors conducted a retrospective review of male and female patients with pneumococcal bacteremia, based on medical records of 10 San Francisco hospitals from 1983 to 1987. (Bacteremia involves bacteria in the blood and may be life-threatening.) HIV seropositivity, an indication of HIV infection, was reviewed for patients between 20 and 55 years of age. A total of 294 cases (62 women and 232 men) conformed to the study parameters. Pneumococcal bacteremia resulted from pneumonia, meningitis, peritonitis, otitis media, pericarditis, septic arthritis, and sinusitis. At the time of diagnosis, 32 patients had AIDS; 43 were HIV-positive, but did not have AIDS; and 12 HIV-positive patients developed AIDS following pneumococcal bacteremia. The most common pneumococcal serotypes identified are among those included in the currently available pneumococcal vaccine. Further, these serotypes were identified in 82 percent of HIV-infected patients, and 90 percent of non-HIV patients. These findings indicate that, if the current pneumococcal vaccine is effective in HIV-positive patients, it may provide them with significant protection against pneumococcal disease. (Consumer Summary produced by Reliance Medical Information, Inc.)