Immunogenicity and reactogenicity of new multivalent pneumococcal vaccines.

In a study conducted in two phases at one month's interval, 22 healthy adult volunteers received a tetravalent (1, 3, 4, 12F) polysaccharide pneumococcal vaccine; 21 other subjects received another tetravalent (14, 18C, 19F, 23F) vaccine and 25 received a pentadecavalent vaccine (1, 3, 4, 6A, 7F, 8, 9N, 11A, 12F, 14, 15F, 18C, 19F, 23F). Placebo was given under single blind conditions to eleven subjects in the first phase of the study and to 24 subjects in the second phase of the study. The vaccines were well tolerated giving rise to transient local reactions in a small proportion of subjects. Results obtained indicate that all 15 polysaccharides are satisfactorily immunogenic. Results so far obtained can be described as encouraging. Further studies to investigate the reactogenicity and immungenicity of multivalent pneumococcal polysaccharide vaccines with a greater number of serotypes are under way.