An outbreak of serogroup C meningococcal disease in the province of Antwerp (Belgium) in 2001-2002.

In 2001 an outbreak of Neisseria menigitidis serogroup C occurred in the province of Antwerp (Belgium). Over a year the incidence rate of meningococcal disease (MD) increased from 3.9 per 100,000 to 9.1 per 100,000 with a shift from serogroup B (87%) in 2000 to serogroup C (66%) in 2001. The most prominent phenotype was C:2a:P1.2,5. The incidence rate for serogroup C MD increased from 0.4 per 100,000 to 4.5 per 100,000 in 2001. The case fatality rate was 6.7% in 2001. After the introduction of a mass vaccination campaign with a conjugated vaccine against serogroup C MD the incidence of serogroup C MD fell from 4.5 to 1.8 per 100,000. As a result of the analysis of this outbreak, it was proposed to offer a vaccine against serogroup C to all people under 19 years of age. Part of this plan has been implemented to date in Belgium.