The effectiveness of pneumococcal polysaccharide vaccination in HIV-infected adults: a systematic review

Objective The effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPV-23) in preventing pneumococcal disease in HIV-infected people is a subject of debate. We reviewed the clinical evidence for recommending PPV-23 for use in HIV-infected patients. Methods A systematic search of peer-reviewed publications (EMBASE, the Cochrane Library, and PubMed/BioMed Central), the Internet and grey literature was conducted. Three hundred and eighteen documents were reviewed. Studies reporting risk estimates for all-cause pneumonia, all-pneumococcal disease, and/or invasive pneumococcal disease after PPV-23 immunization in HIV-infected adults were included. Results We identified one randomized trial and 15 observational studies. While the randomized trial found a 60% increased risk of all-cause pneumonia among vaccinees, 11 of the 15 observational studies found various degrees of disease protection associated with PPV-23 immunization. However, most studies suffered from limited confounder control in their multivariate analyses, despite study data suggesting substantial differences between the characteristics of exposed and unexposed individuals. Conclusions The current clinical evidence provides only moderate support for PPV-23 immunization of HIV-infected adults. More data are needed on the efficacy of newer conjugated pneumococcal vaccines, which may be more immunogenic and could potentially replace PPV-23 in the future.