Evidence for transmission of pertussis in schools, Massachusetts, 1996: Epidemiologic data supported by pulsed-field gel electrophoresis studies

In 1996, 18 of 20 pertussis outbreaks reported in Massachusetts occurred in schools, Pertussis surveillance data were reviewed and a retrospective coh ort study was conducted in a high school that experienced an outbreak, Bord etella pertussis isolates from 9 school cases and from 58 cases statewide w ere examined by use of pulsed-field gel electrophoresis (PFGE), Statewide i ncidence rates were highest among children aged <1 year, 10-14 years, and 1 5-19 years (106, 117, and 104 cases per 100,000, respectively). Among 34 co nfirmed and 20 probable cases at the school, 61% had cough onset within 8 w eeks of school opening. Five different PFGE types were identified among the 58 B. pertussis isolates from throughout the state, All 9 isolates from th e affected high school were the same PFGE type. School-aged children may pl ay an important role in pertussis epidemics. Consideration should be given to use of acellular pertussis vaccines among school-aged children.