[Heptavalent pneumococcal conjugate vaccine immunogenicity and safety in Japanese infants: primary and booster immunization results].

A phase II clinical trial designed as a multicenter open study with 30 participating institutions in Japan was conducted in 167 of 181 infants aged 2 to 6 months to evaluate heptavalent pneumococcal conjugate vaccine (7vPnCV) immunogenicity and safety. From September 22, 2004, to September 16, 2006, of 181 infants registered 167 meeting inclusion criteria were include in the immunogenicity analysis. Among the subjects include in the immunogenicity analysis after primary immunization (3 doses), the percentage with IgG antibody levels of at least 0.5 g/mL--a primary endpoint of this study--was 94.6% or higher. In the same cohort after the booster immunization (dose 4), the percentage was 96.0% or higher. Serious adverse event whose causal relationship to 7vPnCV vaccination could not be ruled out were fever of 38 degrees C and urticaria in 1 each subject, in whom the study was thus discontinued prematurely. Major adverse systemic postvaccination events were fever, irritability and somnolence. Major local adverse events were redness, swelling or induration, and pain. All adverse events were transient and recovered spontaneously. The vaccine's immunogenicity and safety profile are therefore favorable following primary and booster immunization and compatible with those reported in overseas studies. 7vPnCV is expected to show the safety and efficacy similar to that in other countries and to reduce pneumococcal disease in Japan.