Bacteria that colonise the nasopharynx and can lead to serious diseases, e.g. meningitis. They are transmitted from person to person by droplet infection, for example when coughing, sneezing or kissing. There are 13 known meningococcal groups (A, B, C, D, 29E, H, I, K, L, W-135, X, Y and Z). In Germany, group B is the most frequently detected group of meningococcal infections. Infants/babies are most often affected. Early antibiotic therapy is crucial because the death rate is up to 10%. Vaccination is possible against meningococcus groups A, B, C, W-135 and Y.