The role of adults in household outbreaks of pertussis

SummaryObjectivesThis study describes the role of adults in 57 household outbreaks of pertussis.MethodsParents/guardians of children with suspected pertussis seen at a university hospital were interviewed. Once a case of pertussis was confirmed, all household members were enrolled in the study. The US Centers for Disease Control and Prevention (CDC) definitions for pertussis were used .ResultsAmong 349 household members, 150 were adults and one in five had pertussis during the household outbreaks. Of the adult cases, 70.6% were aged 19–39 years. The secondary attack rate in adults was 12.6%. Adults were the primary case in a 21.1% of households, resulting in 43% of all secondary cases. Most adult cases had typical symptoms of pertussis, but none had been diagnosed before the investigation.ConclusionsAdults, particularly those aged between 19 and 39 years, play an important role in pertussis transmission in households. Pertussis vaccination in adolescents/young adults may decrease the dissemination of pertussis in households.