Immunization strategies for the control of serogroup C meningococcal disease in developed countries.

In developed countries, the epidemiology of serogroup C meningococcal disease is characterized by unpredictable outbreaks and a bimodal distribution of cases, with the highest incidence rate among those below 1 year of age and a second peak in teenagers. Serogroup C meningococcal conjugate vaccines elicit a thymus-dependent immunological response that is already present in young infants and is characterized by the production of protective antibodies and the development of memory. Results from immunogenicity and effectiveness studies indicate that waning of immunity occurs over time, and the protection conferred by vaccination before 1 year of age seems to be shortlived. Very different control strategies have been implemented throughout the world and existing vaccination schedules may not be optimal. A schedule consisting of a first dose around 1 year of age and a second dose around 12 years of age seems to be a very cost-effective option in most epidemiological scenarios.