Transmission of Bordetella pertussis to young infants

Abstract : BACKGROUND: Pertussis vaccination has reduced the number of notified cases in industrialized countries from peak years by more than 95%. The effect of recently recommended adult and adolescent vaccination strategies on infant pertussis depends, in part, on the proportion of infants infected by adults and adolescents. This proportion, however, remains unclear, because studies have not been able to determine the source case for 47%-60% of infant cases. METHODS: A prospective international multicenter study was conducted of laboratory confirmed infant pertussis cases (aged