|Acellular Pertussis Vaccine Proves Effective in Adults, Adolescents
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
Ten confirmed cases of pertussis occurred during the trial — nine of which
occurred among individuals who received the hepatitis A vaccine. The researchers
concluded that a single dose of the test vaccine was safe and 92 percent effective
in protecting adolescents and adults against pertussis.
Although infants are routinely inoculated against pertussis through a series
of three diphtheria-tetanus-acellular pertussis (DTaP) vaccines given in the
first year of life, immunity has been shown to weaken after six to 10 years.
“The purpose of an adult pertussis vaccine is to prevent the disease in adults
with the added benefit that it may help to put up a roadblock in the transmission
of the disease, so that parents, grandparents and other adults are not unknowingly
passing the disease along,” says David Klein, Ph.D., of NIAID’s Respiratory Diseases
In 2004, the highest number of U.S. pertussis cases was among individuals 10
to 18 years of age with roughly 6,500 cases reported, according to data from
the Centers for Disease Control and Prevention. Infants less than six months
old experienced the second highest number of pertussis cases last year, with
an estimated 2,200 cases reported.
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on the NIAID Web site at http://www.niaid.nih.gov.
NIAID is a component of the National Institutes of Health, an agency of
the U.S. Department of Health and Human Services. NIAID supports basic and
applied research to prevent, diagnose and treat infectious diseases such as
HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis,
malaria and illness from potential agents of bioterrorism. NIAID also supports
research on transplantation and immune-related illnesses, including autoimmune
disorders, asthma and allergies.
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Agency — includes 27 Institutes and Centers and is a component of
the U. S. Department of Health and Human Services. It is the primary Federal
agency for conducting and supporting basic, clinical, and translational medical
research, and it investigates the causes, treatments, and cures for both common
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