The changing epidemiology of meningococcal disease in the United States 1992-1996

New meningococcal vaccines are undergoing clinical trials, and changes in t he epidemiologic features of meningococcal disease will affect their use. A ctive laboratory-based, population-based US surveillance for meningococcal disease during 1992-1996 was used to project that 2400 cases of meningococc al disease occurred annually. Incidence was highest in infants; however, 32 % of cases occurred in persons greater than or equal to 30 years of age. Se rogroup C caused 35% of cases; serogroup B, 32%; and serogroup Y, 26%. Incr easing age (relative risk [RR], 1.01 per year), having an isolate obtained from blood (RR, 4.5), and serogroup C (RR, 1.6) were associated with increa sed case fatality. Among serogroup B isolates, the most commonly expressed serosubtype was P1.15; 68% of isolates expressed 1 of the 6 most common ser osubtypes. Compared with cases occurring in previous years, recent cases ar e more likely to be caused by serogroup Y and to occur among older age grou ps. Ongoing surveillance is necessary to determine the stability of serogro up and serosubtype distribution.