A randomized clinical trial comparing revaccination with pneumococcal conjugate vaccine to polysaccharide vaccine among HIV-infected adults

Background. The risk of pneumococcal disease persists, and antibody responses to revaccination with the 23-valent polysaccharide vaccine (PPV) are low among human immunodeficiency virus (HIV) - infected adults. We determined whether revaccination with the 7-valent pneumococcal conjugate vaccine (PCV) would enhance these responses. Methods. In a randomized clinical trial, we compared the immunogenicity of revaccination with PCV (n=131) or PPV (n=73) among HIV-infected adults (median CD4 cell count, 533 cells/mm³) who had been vaccinated with PPV 3-8 years earlier. HIV-uninfected adults (n=25) without prior pneumococcal vaccination received 1 dose of PCV. A positive response was defined as a ≥2-fold increase (from baseline to day 60) in capsule-specific immunoglobulin G, with a postvaccination level ≥1000 ng/mL for at least 2 of the 4 serotypes. Results. HIV-infected persons demonstrated a higher frequency of positive antibody responses to PCV than to PPV (57% vs 36%) (P=.004) and greater mean changes in the immunoglobulin G concentration from baseline to day 60 for serotypes 4, 9V, and 19F (P<.05, for all), but not for serotype 14. However, by day 180, both outcomes were similar. Responses to PCV were greater in frequency and magnitude for all serotypes in HIV-uninfected adults, compared with those in HIV-infected adults. Conclusions. Among persons with HIV infection, revaccination with PCV was only transiently more immunogenic than PPV, and responses were inferior to those in HIV-uninfected subjects with primary vaccination. Pneumococcal vaccines with more robust and sustained immunogenicity are needed for HIV-infected adults. Clinical trial registration. ClinicalTrials.gov identifier NCT00622843.