Evidence for school transmission of Neisseria meningitidis during a Vermont outbreak

A meningitis outbreak due to Neisseria meningitidis, serogroup C, serotype 2b, occurred in central Vermont in February, 1984. The highest incidence was in Northfield, where 7 cases occurred (129 per 100,000 population). Of these 7 cases 2 were students at Northfield High School and 5 were younger children; all had had close contact with Northfield High School students or staff in the week before illness. A case-control study demonstrated that these cases had significantly more exposure to Northfield High School students or staff in the 2 weeks before illness (112 hours) than did controls (8 hours) (P = 0.006). This finding was confirmed by a second case-control study designed to determine risk factors for the entire outbreak. School children in Northfield and their household contacts were given meningococcal A-C vaccine and sulfisoxazole prophylaxis. No further cases of meningococcal disease occurred in Northfield after the week that these control methods were initiated. Transmission of the outbreak strain of N. meningitidis appears to have occurred in a school setting with subsequent illness in household and close contacts of carriers of the outbreak strain.