Immunogenicity and Reactogenicity of Pneumococcal Polysaccharide and Conjugate Vaccines in Native Elders

To test the hypothesis that immune responses to 23-valent pneumococcal polysaccharide vaccine (PPV-23) could be improved in Alaska Native elders by immune priming with 7-valent pneumococcal conjugate vaccine (PCV-7), we assessed post-vaccination immune responses among Natives aged 55 years and older who were randomized into three arms: (1) one dose of PPV-23 according to current state and ACIP recommendations; (2) one dose of PCV-7 followed two months later with a dose of PPV-23; and (3) one dose of PCV-7 followed six months later with a dose of PPV-23.