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Date: Wednesday, July 31, 1996 FOR IMMEDIATE RELEASE Contact: Lenore Gelb (301)443-3285
The Food and Drug Administration today announced it has licensed the first acellular pertussis vaccine for use in infants and children two months of age and older for the primary series of immunizations. The vaccine protects infants against whooping cough while causing fewer side-effects than whole-cell pertussis vaccines now on the market.
Currently, U.S. children receive a whole-cell pertussis vaccine in combination with diphtheria-tetanus toxoid, commonly called DTP, at 2, 4 and 6 months of age, with additional doses of either a DTP or DT vaccine with an acellular pertussis component (DTaP) at 12-18 months and before going to school.
The vaccine approved today for infants is one of two DTaP vaccines already approved for children to be given as fourth and fifth doses following three DTP doses. This approval should give parents more confidence in the safety of the pertussis vaccine their infants will receive.
Acellular pertussis vaccines contain only the parts of the pertussis bacterium thought to be important for immunity, while whole-cell vaccines, such as the DTP vaccines currently used in the United States for infants, contain the whole, killed bacterium.
"Safety data from several studies show that acellular pertussis vaccines cause fewer adverse reactions in the primary series of immunizations than whole-cell vaccines," said Commissioner of Food and Drugs David A. Kessler, M.D. "For a long time there has been concern about side effects with whole-cell vaccine. This new acellular pertussis vaccine, the first of several in the pipeline, represents an important advance."
Whooping cough is a highly communicable disease of the respiratory tract that can be especially serious for infants less than one year old. It can cause spells of coughing and choking that make it hard to breathe; the coughing can last several weeks. Occasionally, infants can die from the disease. According to the Centers for Disease Control and Prevention (CDC), in 1994 and 1995, a total of approximately 9500 cases of pertussis were reported in the United States. The World Health Organization (WHO) reports that the disease is responsible each year for approximately 350,000 deaths worldwide in unvaccinated persons.
Several studies, including one randomized, controlled study of 673 infants sponsored by Connaught Laboratories, Inc., indicate that the DTaP vaccines cause fewer adverse reactions than DTP vaccines. These can include local reactions, such as redness or swelling, as well as systemic reactions, such as fever, drowsiness, irritability, or prolonged, high-pitched crying. Studies are in progress to help determine the extent of these reactions when children receive the acellular pertussis vaccine for the entire series of immunizations. Infrequent, serious events such as seizures have been reported after immunizations with both DTP and DTaP vaccines.
Two clinical studies were conducted to assess the efficacy of the pertussis component of this DTaP vaccine for infants. The first placebo-controlled, randomized trial, of the pertussis component conducted in the mid-1980's, included children 5-11 months old in Sweden, and was supported in part by the National Institute of Allergy and Infectious Diseases (NIAID). They were immunized according to a different schedule from the one recommended in the United States.
The second study, in Germany, used an immunizing schedule similar to the one used in the United States for the DTaP, and involved over 16,000 infants. Parents were allowed to choose the type of pertussis vaccine their infants would receive, or whether the vaccine even contained a pertussis component. Approximately 75% of the parents chose the DTaP vaccine.
In these studies, the acellular pertussis vaccine was estimated to be between 69 and 80% effective in preventing pertussis, depending on the way the study was designed and completed.
On July 13, 1995, NIAID announced results of two large European clinical trials showing that three acellular pertussis vaccines were highly effective in protecting infants while causing fewer of the common side-effects. The acellular pertussis vaccine licensed today for infants was not studied in those trials.
The application for this first DTaP vaccine for infants wasreceived July 21, 1995. Additional clinical data were presented after the Vaccines and Related Biological Products Advisory Committee met in January to discuss this application.
Children who have begun their immunizations with DTP should continue to receive their fourth and fifth doses as DTaP. For those children who will now receive DTaP at 2, 4, and 6 months of age, a fourth dose of DTaP is recommended in the second year of life. Studies are now being planned to help determine recommendations for the fifth dose.
The acellular pertussis component of the vaccine is being produced by the Research Foundation for Microbial Diseases of Osaka University in Japan. It is combined with diphtheria and tetanus toxoids by Connaught Laboratories, Inc., Swiftwater, Pa., and is sold under the trade name, Tripedia.