Immunization for pertussis, also known as whooping cough, began in the mid-1940s and resulted in a sharp decline of this serious illness over the next 25 years. Over the last two decades, however, as immunity has waned, pertussis has re-emerged in the United States, with the greatest increase seen in adolescents, adults and young infants.
In an study titled “Pertussis in adolescents and adults: Should we vaccinate?” presented as an abstract at the Pediatric Academic Societies’ Annual Meeting in San Francisco on May 1, researchers from Children’s Hospital Boston and the Center for Child Health Care Studies in the Department of Ambulatory Care and Prevention at Harvard Medical School and Harvard Pilgrim Health Care in Boston determined that adolescent vaccination may potentially be cost-effective.
The goal of the study was to help federal health policymakers evaluate the potential health benefits, risks, and costs of a national booster vaccination program. A combined acellular pertussis vaccine (TdaP) with considerably lower side effects is now available for adolescents and adults in Canada and may be considered in the United States.
“In the past, vaccination programs were cost-saving and life-saving,” says Lee. “However, newer vaccines are now focused on reducing morbidity, rather than mortality, and we need to carefully weigh the risks and benefits of vaccination. By examining medical and non-medical costs as well as quality of life issues, we can determine the optimal strategy.”
Researchers from Boston, led by Grace Lee, MD, MPH, infectious disease specialist at Children’s Hospital Boston and the Center for Child Health Care Studies at Harvard Medical School and Harvard Pilgrim Health Care, modeled health states and immunity levels associated with pertussis disease and vaccination, and evaluated a number of vaccination strategies against them, including not vaccinating; vaccinating adolescents once; vaccinating adults once; vaccinating adults plus 10-year boosters; vaccinating adolescents plus 10-year boosters; and vaccinating new mothers immediately postpartum, along with their partners. Data on disease incidence, disease outcomes, vaccine efficacy and side effects were from published studies, recent clinical trials, and expert panel input. The researchers looked at medical and non-medical costs and health-related quality of life data from a recent study of adolescents and adults with confirmed pertussis in Massachusetts.
After working with a range of permutations on vaccine price, vaccine delivery, and pertussis incidence rates, they determined that all vaccination strategies were more costly and less effective compared to no vaccination. An adolescent booster strategy may be considered cost-effective under selected circumstances defined by disease incidence, vaccine efficacy, and cost. The results were also highly sensitive to assumptions about vaccine efficacy, vaccine adverse events, and the potential ability of vaccination to interrupt transmission to infants.
Other study authors included Tracy Lieu, MD, MPH, Center for Child Health Care Studies; Charles LeBaron and Trudy Murphy, National Immunization Program, Centers for Disease Control & Prevention; and Susan Lett and Stephanie Schauer, Massachusetts Department of Public Health.