Outbreak of pertussis in a residential facility for handicapped people

An outbreak of pertussis was recognized and investigated in a ward for neurologically impaired residents. Of 50 residents ranging in age from 8 to 25 years old, 41 (82%) had serological or bacteriological evidence of pertussis infection and 28 (56%) developed typical symptoms of pertussis. Of the 50 residents, nine were immunized and 41 were unimmunized. There were no significant differences in the rate of infection and rate of developing typical symptoms between the immunized and unimmunized (9/8/4 vs 41/33/24). Of 43 carers, 6 (14%) developed typical symptoms and four of the six showed serological evidence of pertussis infection. Epidemiological survey of this outbreak revealed that pertussis was introduced and spread by the carers. Erythromycin which was administered only to the residents did not prevent the spread of pertussis. We conclude that pertussis immunization including a booster dose should be considered for neurologically impaired people in a closed environment and erythromycin prophylaxis should include adult carers.