Invasive meningococcal disease in adolescents and young adults

Context Incidence of invasive meningococcal disease has increased recently in persons aged 15 through 24 years. Objective To characterize meningococcal infection in adolescents and young adults in Maryland during the 1990s. Design and Setting Population-based surveillance study for meningococcal di sease from January 1, 1990, through December 31, 1999, in Maryland. Patients Maryland residents diagnosed as having invasive meningococcal dise ase. Main Outcome Measure Invasive meningococcal infection. Results Of 295 total cases, 71 (24.1%) occurred among persons aged 15 throu gh 24 years. Sixteen (22.5%) of these cases were fatal. The annual incidenc e rate increased from 0.9 to 2.1 cases per 100000 among 15 through 24 year olds (P=.01). The proportion of all disease increased from 16.0% to 28.9% ( P=.03). The incidence and proportion of cases subsequently decreased to 1.0 and 16.4% in 1998 through 1999, respectively. Infection in 15 through 24 y ear olds was more likely to be fatal than infection in those younger than a ge 15 years (22.5% vs 4.6%; P=.001). Infection in 15 through 24 year olds, compared with those aged 25 years or older, was more likely to be associate d with male sex (66.2% vs 34.8%; P<.001) and serogroup C infection (46.9% v s 20.2%; P<.001), respectively. Infections were potentially preventable wit h the licensed meningococcal vaccine in 82.8% of 15 through 24 year olds, 6 8.1% of those younger than 15 years, and 76.8% of adults aged 25 years or o lder. Conclusions Incidence of meningococcal infection in 15 through 24 year olds in Maryland increased and then declined during the 1990s. Infection in thi s age group was associated with an unusually high case-fatality ratio, and the vast majority of cases were potentially vaccine preventable.