title: 23-valent pneumococcal polyoside vaccination: efficacy not yet demonstrated.
mesh_terms: D006801:Humans; D015201:Meta-Analysis as Topic; D022242:Pneumococcal Vaccines / Q000276:immunology*; D016032:Randomized Controlled Trials as Topic; D014611:Vaccination
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D022242:Pneumococcal Vaccines