Acellular Pertussis Vaccine Proves Effective in Adults, Adolescents
Vaccine Clinical Trial
A vaccine to protect adults and adolescents against illness due to Bordetella pertussis infection, or whooping cough, has proved more than 90 percent effective in a national, large-scale clinical study, according to research results published in this week's issue of The New England Journal of Medicine. The vaccine, researchers say, could be used to stem the increase in pertussis cases among adults and adolescents in the United States and thereby prevent the prolonged cough illness, which can result in hospitalization, pneumonia and cracked ribs in those populations. An important additional benefit of the vaccine may be to decrease transmission of the B. pertussis bacterium to infants, who are particularly vulnerable to severe illness, complications and death resulting from whooping cough. The illness annually affects 50 million people worldwide.
"During the 1990s, the number of reported pertussis cases among adolescents and adults more than doubled in the United States as the protective effects of earlier childhood immunizations have waned," says Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, which funded the study. "This new study shows that an effective adult acellular pertussis vaccine is feasible and if routinely used could provide the U.S. population greater protection against the disease."
Known as the Adult Pertussis Trial, the 2.5-year study involved 2,781 healthy individuals between 15 and 65 years of age. Volunteers were randomly assigned to one of two similarly sized groups that received either the acellular pertussis vaccine or the control hepatitis A vaccine (Havrix). For purposes of the trial, pertussis cases were defined as illnesses with a cough lasting at least five days that occurred more than 28 days after vaccination and were confirmed through blood and nasal mucus testing.
Joel I. Ward, M.D., of the Center for Vaccine Research at the University of California, Los Angeles, led the multicenter clinical study. GlaxoSmithKline, based in Philadelphia, supplied both the pertussis test vaccine and the hepatitis A vaccine.
Ten confirmed cases of pertussis occurred during the trial