Preventing Secondary Cases of Meningococcal Disease by Identifying and Eradicating Disease-Causing Strains in Close Contacts of Patients

Abstract

In Norway, the use of chemoprophylaxis after cases of meningococcal disease is not recommended. Instead, household members < 15 years are treated with penicillin for 7 days. Failures of this treatment have been reported. We therefore used DNA fingerprinting to identify the disease-causing strain in healthy contacts combined with selective rifampicin prophylaxis to these carriers to prevent secondary cases. During a 2-year period (1987–89) there were 13 cases of meningococcal disease in the County of Telemark (165000 inhabitants). 65 (14.7%) out of 441 contacts to these 13 patients harbored meningococci in their throat; 16 (3.6%) carried the disease-causing strain. Only 1 carrier fulfilled the criteria for being treated with penicillin; 8 were adults and the remaining 7 were not household members. No secondary cases of meningococcal disease occurred during the study period or the following 12 months. During the 4-year period (1984–87) preceding the study period there were 39 cases of meningococcal disease in Telemark; 7 of them were index cases for 12 bacteriologically verified and 4 clinically suspected secondary cases of meningococcal disease. We conclude that selective prophylaxis with rifampicin seems to be more efficient that penicillin treatment of household members < 15 to prevent secondary cases of meningococcal disease