Inefficacy of pneumococcal vaccine in a high-risk population.

Use of pneumococcal vaccine remains controversial. To further study this question, 89 patients hospitalized at the Denver Veterans Administration Medical Center with pneumococcal bacteremia were chosen as the case group for a case-control study. The control group was made up of patients matched on the basis of age, date of admission, and comorbid conditions. Vaccination status in the bacteremic patients and control patients was determined, as were pneumococcal serotypes among the bacteremic patients. If the vaccine were protective, vaccination rates should be higher among the control patients, and serotype distribution should be different in vaccinated and nonvaccinated bacteremic patients. There were no differences between vaccination rates among bacteremic patients (29 percent) and control patients (24 percent). Furthermore, 65 percent of the blood isolates from nonvaccinated bacteremic patients were serotypes included in the vaccine, as compared with 69 percent of the isolates in vaccinated bacteremic patients. Pneumococcal vaccine did not appear to be protective in this high-risk population.