Serogroup B meningococcal disease in the Norwegian aimed forces - What can we learn from an inconclusive vaccine protection trial?

Military recruits serving in the armed forces were severely affected during the latest serogroup B meningococcal epidemic in Norway. The risk of developing systemic meningococcal disease (SMD) proved highest during the first 12 weeks of service. A double-blind, placebo-controlled protection trial with a meningococcal outer membrane vesicle vaccine took place between 1988 and 1991, but the number of proven SMD cases was too low to allow for any conclusions. However, the results of a parallel efficacy study of the same vaccine among students in secondary school, cross-society examinations for asymptomatic throat carriage of meningococci and recent immunogenicity studies after two-and three-dose vaccination schedules, suggest that a basic immunization of young teenagers followed by a booster injection at enrolment would contribute significantly to preventing SMD in the armed forces.