WEDNESDAY, Jan. 4, 2006 (HealthDayNews) -- Two vaccines that guard against a leading cause of childhood deaths in developing countries have shown promise in large trials.
Both protect against rotavirus, which causes the severe diarrhea responsible for 50,000 hospital admissions and about 20 deaths among children each year in the United States. Worldwide, it causes an estimated 500,000 childhood deaths each year, mostly in countries where sanitation is poor.
A vaccine made by Merck was 98 percent effective in preventing severe gastroenteritis and reduced hospitalizations by 63 percent during the first year of life in an international trial including more than 68,000 children, according to a report in the Jan. 5 issue of the New England Journal of Medicine.
A GlaxoSmithKline vaccine was not quite as effective, reducing incidence of severe gastroenteritis by 85 percent and hospitalizations by 42 percent during the first year of life in an international trial including more than 63,000 children, said a second report in the same issue of the journal.
But "you can't say that one is better than the other, because they have not been evaluated head to head," said Dr. Penny Heaton, senior director of vaccine clinical research at Merck. "We do know that we have a good vaccine, even if three doses are required."
The GlaxoSmithKline vaccine is ahead in market availability. The company has reported that it got approval for its use in Mexico in July 2004, and said it is moving to market the vaccine in "over 20 countries." Just this month, the GlaxoSmithKline vaccine got a "positive opinion" from European regulators. The company said the vaccine should be available in Europe by late February.
Merck submitted an application to the U.S. Food and Drug Administration last April, said company spokeswoman Jennifer Allen, and is applying for approval "in more than 50 countries around the world."
"Those applications already are in place," she said. "Approval depends on the amount of time regulatory agencies need to review the applications."
Approval of a new rotavirus vaccine by the FDA would close a gap created in 1999 when the agency withdrew a previously available vaccine because it was linked to 15 cases of intussusception, a life-threatening bowel blockage.
The new vaccines work in different ways. The GlaxoSmithKline version, Rotarix, uses a weakened version of the human rotavirus. It is taken orally, in two doses given one to two months apart.
The Merck vaccine, Rotateq, is based on a strain of the virus that infects cows. Three oral doses are given, with at least one month between each dose.
An accompanying editorial in the journal said the difference in the trial results might be attributed to the different populations in each study -- primarily low-income Latin American children in the GlaxoSmithKline trial, and mostly middle-class U.S. and Finnish children in the Merck trial.
"Both vaccines demonstrate an impressive efficacy profile," the editorial said, calling the reduction in hospitalizations "a particularly exciting finding of great importance to public health."
More information
The facts about rotavirus are given by the U.S. Centers for Disease Control and Prevention.
