The Changing Epidemiology of Pertussis in Young Infants

Abstract

We reviewed 400 bacteriologically confirmed cases of pertussis in infants and children during the past 18 years. Several changes in the epidemiology have occurred in the most recent six-year period. The incidence of whooping cough in children has decreased by at least 50%, but the proportion of cases occurring in infants younger than 12 weeks of age has doubled to 30% of all cases. Formerly most young infants acquired their illness from siblings or other children, but in the recent period adults in the household were the most common source of infection to neonates and young infants. This observation plus the increasingly high level of immunization in preschool and school-aged children suggest that young adults with waning immunity and mild illness are a major reservoir for transmission of pertussis to infants too young to be immunized.

The Increasing Incidence of Pertussis in Massachusetts Adolescents and Adults, 1989–1998

“…Nationwide, in the period 1990-1996, cases in 5-19-year-olds (school-age children, analyzed as a single combined group) also peaked in October-December [25]. The lack of a clear seasonal pattern in Massachusetts infant cases accords with findings from other regions of the United States [30,31], although we did note a consistent and marked increase in infant cases between the second and third quarters.…”

Molecular Pathogenesis, Epidemiology, and Clinical Manifestations of Respiratory Infections Due toBordetella pertussisand OtherBordetellaSubspecies

“…This pattern is different from that of other diseases which have been controlled by immunization (135, 149, 550 (244). It was also noted in the 1970s that the source of infection in hospitalized infants was most often an adult (583). The above observations led one of us (J.D.C.)…”

Pertussis in infants: Preventing deaths and hospitalisations in the very young

“…Adults, especially parents, were first noted in the USA in the 1970s to have replaced older siblings as the major source of pertussis infection in young infants 19 . This was confirmed in Australia by the APSU study.…”