Immunization back on agenda as whooping cough increases

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.

The Center for Child Health Care Studies is a research center dedicated to improving the health of children. It is located within the Department of Ambulatory Care and Prevention (DACP), a research and teaching collaboration between Harvard Pilgrim Health Care and Harvard Medical School. The principal goals of the DACP are to influence health policy, enhance collaborations between health care delivery systems and traditional public health agencies, train clinicians to manage care effectively, develop improved methods for delivery of health care and develop new information about disease and therapeutics. The DACP conducts research on a wide variety of topics, including cancer, diabetes, asthma, and drug policy. The Center has close ties with Children's Hospital Boston For more information, visit the DACP Web site: http://www.hms.harvard.edu/ambulatory/.

Children’s Hospital Boston is home to the world’s largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults for over 100 years. More than 500 scientists, including seven members of the National Academy of Sciences, nine members of the Institute of Medicine and nine members of the Howard Hughes Medical Institute comprise Children’s research community. Founded in 1869 as a 20-bed hospital for children, Children’s Hospital Boston today is a 300-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. It is also the primary pediatric teaching affiliate of Harvard Medical School. For more information about the hospital visit: http://www.childrenshospital.org.