Pneumococcal vaccine in the prevention of community-acquired pneumonia: a skeptical view of cost-effectiveness.

Streptococcus pneumoniae (pneumococcus) is an important pathogen that causes pneumonia, bacteremia, and meningitis in adults. In recent years, pneumococcal isolates resistant to penicillin have become increasingly prevalent in the U.S. For these reasons, wide use of the pneumococcal vaccine has been advocated. Pneumococcal vaccines have been proven to be effective in preventing the invasive complications of S pneumoniae infection. The efficacy of pneumococcal vaccines in preventing non-bacteremic pneumonia in high-risk subjects, however, has not been proven. The current pneumococcal vaccine is limited because it includes the antigens of the serotypes known to be associated with invasive infection, and it elicits a thymus-independent, B-cell response that evokes no memory and a poor immunologic response in many of the patients at greatest risk for pneumococcal infection. In the absence of data concerning efficacy of the pneumococcal vaccine against pneumonia, it is difficult to argue that it is cost-effective for this purpose. I concur with the recommendations for use of pneumococcal vaccine to prevent bacteremia, but I am skeptical about the vaccine's efficacy against pneumonia. More data and an improved vaccine are necessary.