Evolving meningococcal immunization strategies.

Meningococcal disease is a major public health problem and immunization is considered the best strategy for prevention. The introduction of meningococcal C conjugate immunization schedules that targeted adolescents, with catch-up programs in several European countries, Australia and Canada proved to be highly effective, with dramatic reduction in the incidence of serogroup C disease, not only in vaccinated, but also in unvaccinated individuals. Meningococcal quadrivalent (A, C, W, Y) conjugate vaccines are now licensed and are being used in adolescent programs in North America and to control serogroup W disease in South America. In the African meningitis belt, a mass immunization campaign against serogroup A disease using a meningococcal A conjugate vaccine is now controlling the devastating epidemics of meningococcal disease. After introducing new immunization programs, it is of importance to maintain enhanced surveillance for a better understanding of the changing nature of disease epidemiology. This information is crucial for identifying optimal immunization policies.