Invasive meningococcal disease (IMD) is an important cause of morbidity and mortality in children and adults. This study was conducted to determine a possible increase in IMD in recent years with special interest focused on serogroup C disease. From January 1st 1993 to December 31st 2002, IMD was studied in one million residents of Austria. We used active, population-based surveillance data from the Office of Public Health. A total of 126 patients with positive blood and/or cerebrospinal fluid culture or positive swabs for Neisseria meningitidis were studied. The median age of all patients was 9.5 years (range 1 month to 63 years). The average incidence of all IMD subgroups was 1.05 cases per 100,000 person years and was highest in children 0-4 years old (7.08 cases per 100,000 person years) followed by young adults aged 15 to 19 years (4.35 cases per 100,000 person years). Serogroup C IMD occurred in 1.30 cases/100,000 person years in patients aged 0 to 4 years and in 1.92 cases/100,000 person years in patients aged 15 to 19 years. Overall mortality was 11.1%. There was a significant increase (P =0.001) in IMD due to serogroup B disease within the last 10 years. In contrast, serogroup C disease did not increase during the last decade.
Conclusion: Currently, we do not recommend mass vaccination against serogroup C disease in Austria, but young adults aged 15 to 19 years display a high incidence of meningococcal C disease. In this age group, vaccination against serogroup C disease should be considered.