Two oral vaccines for a dangerous diarrhea-causing virus among young children are safe and effective, according to two large clinical trials published in the
The New England Journal of Medicine.
The vaccines are Rotateq from
, which is now under review by the Food and Drug Administration, and Rotarix from
Rotarix was first sold in Mexico last March. The vaccine has been licensed in 24 countries and could be approved by the European Union next month.
GlaxoSmithKline executives said recently that they're discussing Rotarix with the FDA. Merck said last month that it plans conduct Rotateq clinical trials in Africa and Asia starting later this year. Merck has filed licensing applications in more than 50 countries.
Both vaccines are designed to fight the debilitating rotavirus, which Merck says is a major cause of diarrhea-related hospitalizations worldwide. Merck says the rotavirus-caused disease called gastroenteritis kills nearly 500,000 children under age 5 every year. Most of the damage is inflicted in developing nations. In the U.S., rotavirus causes 50,000 hospitalizations and 20 to 40 deaths a year, the company says.
Publication of test results in a prominent scientific journal adds a stamp of scientific credibility to company-sponsored tests. The Rotateq study of more than 68,000 infants, for example, was part of Merck's application to the FDA. Last month, a panel of medical experts unanimously recommended that the FDA approve Rotateq. Although the FDA isn't bound by advisory committees' recommendations, it usually follows their suggestions.
The Rotateq and Rotarix studies were made public by the
Wednesday after markets had closed. "Both vaccines demonstrate an impressive efficacy profile," says an editorial accompanying the articles. "After a long period of waiting, the time for a rotavirus vaccine may have finally arrived."
The editorial declares as "particularly exciting" results that showed Rotarix decreased by 42% hospitalizations for diarrhea among Latin American children under 12 months old and that Rotateq reduced such hospitalizations in the U.S. and Finland by 63%.
"This vaccine was efficacious in preventing rotavirus gastroenteritis, decreasing severe disease and health-care contacts," say the authors of the Rotateq clinical trial. "The risk of intussusception was similar in vaccine and placebo recipients."
Intussusception is the folding of the intestine, which is the most common cause of intestinal blockage in young children. This complication led to the withdrawal of a
rotavirus vaccine in 1999 after only a year on the market.
The Merck test compared infants who received Rotateq with those who received a placebo. Treatment requires three doses of the oral vaccine, the first at six to 12 weeks and the other doses at intervals of four to 10 weeks.
The authors add that because their clinical trial enrolled mostly healthy infants who were from developed countries, additional tests are needed to confirm that the vaccine works in children who are malnourished or ill.
The GlaxoSmithKline vaccine study looked at more than 63,000 healthy infants in 11 Latin American countries and Finland. Half received Rotarix, and the other half received a placebo. The first dose was given between the ages of six and 13 weeks and the next dose was given one to two months later.
The vaccine was "highly efficacious in protecting infants against severe rotavirus gastroenteritis, significantly reduced the rate of severe gastroenteritis from any cause, and were not associated with an increased risk of intussusception," the study says.
GlaxoSmithKline financed and coordinated the study, which lists 36 authors. A number of the authors have received lecture fees, consulting fees or grants from the company.