Immunogenicity of two efficacious outer membrane protein-based serogroup B meningococcal vaccines among young adults in Iceland

Serum bactericidal activity (SEA) and ELISA antibody levels elicited by two efficacious serogroup B meningococcal vaccines were measured in a controlled trial involving 408 15- to 20-year-olds. Subjects were given two doses at a 6-week interval of a serogroup B or control vaccine. Response was defined as greater than or equal to 4-fold rise in antibody level, After two doses of the Finlay Institute (Havana) vaccine at 12 months, the proportions of SEA and ELISA responders were not different from those of the control group (15% and 17% [vaccine] vs. 13% and 98 [control], P > .05). After two doses of the National Institute of Public Health (Oslo) vaccine, there were more SEA and ELISA responders than in the control group (47% and 34% [vaccine] vs. 10% and 1% [control]) or the Finlay Institute vaccine group (P < .05 for both), SEA and ELISA may be insensitive correlates for protective efficacy for some outer membrane protein-based serogroup B meningococcal vaccines.