New pertussis vaccines safer, more effective.
In studies of 15,000 infants in Italy and 10,000 infants in Sweden, the new pertussis vaccines provided better protection and caused fewer and milder side effects. "This is truly an effective vaccine," announced Anthony S. Fauci at a press conference in Bethesda, Md., last week. Fauci is director of the National Institute of Allergy and Infectious Diseases, which cosponsored the vaccine trials. The U.S. Public Health Service hopes to expedite approval of the new vaccines, perhaps in 6 months.
Pertussis is an extremely contagious respiratory infection caused by the bacterium Bordetella pertussis. It causes violent spells of coughing, vomiting, and inability to breathe. Gasping for breath between coughing spells creates the "whooping" sound characteristic of the disease. Pertussis may lead to pneumonia and neurological damage.
Worldwide, more than 50 million people contract pertussis every year, and more than 350,000 die--primarily infants. In the United States, mandatory vaccination at 2, 4, 6, and 18 months, with a booster at age 4 to 6, has lowered the number of infections from 160,000 in 1947 to fewer than 5,000 in 1994.
But pertussis vaccination carries some risk. Current vaccines used in the United States contain whole, but inactive, bacteria that cause fever, swelling, fussiness, and--very rarely--neurological damage (SN: 7/30/88, p.72). For this reason, some countries, including Italy and Sweden, don't require a pertussis vaccination.
The new vaccines remove these risks. Referred to as acellular vaccines, they include only the bacterial proteins needed to stimulate protection against pertussis. Two acellular vaccines are available in the United States, but only for children who are at least a year old.
The international team of researchers tested acellular vaccines in infants during pertussis epidemics in Italy and Sweden. Children in both studies got vaccines at 2, 4, and 6 months.
In the Swedish study, infants received a five-component or a two-component acellular vaccine, the standard whole-cell vaccine, or no vaccine. The five-component acellular vaccine gave 85 percent protection, while the two-component vaccine gave 58 percent protection. The Italian study tested two kinds of three-component acellular vaccines against the standard vaccine or no vaccine. Both acellular vaccines offered 84 percent protection.
Surprisingly, the whole-cell vaccine offered no better than 48 percent protection. Fauci speculates that it performed poorly because the trials omitted boosters.
Until the acellular vaccines make it to the U.S. market, Fauci advises parents to continue with the standard immunization schedule.
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|Title Annotation:||two European studies of 25,000 infants found acellular vaccines superior to current vaccines in the treatment of whooping cough|
|Article Type:||Brief Article|
|Date:||Jul 22, 1995|
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