Serogroup C meningococcal disease outbreak associated with discotheque attendance during carnival

In the week following a carnival during 19-24 February 1998, an outbreak of meningococcal disease occurred in a rural German county. The available isolates belonged to phenotype C:2a:P1.2,5 and were clonally related by pulsed-field gel electrophoresis. A case-control study was done to identify risk factors for the outbreak and to define possible vaccination target groups. Five persons aged 13-16 years who fell ill during 24-27 February were included in the study. Four of 5 cases and 10 of 32 controls visited local discotheques (OR = 8.8; P = 0.06). Cases also visited discotheques more frequently than controls (chi(2) for trend, P = 0.0002). Multiple discotheques during the carnival may have been predominant locations of transmission in this outbreak. Because this risk factor was limited in time, a mass community vaccination campaign was not initiated.