Vaccines protect against diarrhea virus - studies
BOSTON (Reuters) - Experimental vaccines by drug-makers Merck and GlaxoSmithKline can prevent severe childhood diarrhea caused by rotaviruses that kill thousands of children a year worldwide, two studies showed on Wednesday.
Rotaviruses cause diarrhea and vomiting that last for days, killing an estimated 600,000 children a year. Most of the deaths are in developing countries but the disease is found even in countries with good sanitation and clean water.
"After a long period of waiting, the time for a rotavirus vaccine may have finally arrived," said Roger Glass and Umesh Parashar of the Centers for Disease Control and Prevention in Atlanta.
An earlier vaccine, Wyeth's RotaShield, was withdrawn in 1999 after it seemed to increase the risk of intussusception, a sometimes-fatal bowel obstruction.
The new studies published in this week's New England Journal of Medicine showed that intussusception is not a problem with the new vaccines, Rotarix from GlaxoSmithKline Plc and RotaTeq from Merck & Co. Inc.
Rotarix, which tends to be more potent and requires only two oral doses one or two months apart, cut the hospitalization rate from diarrhea from any cause among 63,000 young children in 11 Latin American countries and in Finland by 42 percent.
RotaTeq does not grow as well in the human gut so it has to be given in three doses, each separated by at least a month. It cut the hospitalization rate for all types of diarrhea by 63 percent among 68,000 children before their first birthday.
In confirmed cases of rotavirus illness, 12 Rotarix recipients developed a severe infection compared to 77 in the placebo group. In the RotaTeq study, only 6 of 28,646 vaccinated children had to be hospitalized because they were infected by one of the rotavirus virus strains used in the vaccine, compared to 138 of 28,488 youngsters who got placebo.
Also, "RotaTeq reduced the number of lost work days (for parents) from rotavirus by nearly 87 percent, a welcome benefit with clear economic implications for families," Glass and Parashar said in a New England Journal of Medicine editorial.
Rotarix prevented 85 percent of severe rotavirus illness and RotaTeq succeeded 98 percent of the time, but the difference in the effectiveness may be due to differences in the way the severity of the illness was classified or the fact that Rotarix was studied in poorer families. Neither vaccine has been licensed in the United States, although Rotarix was approved last summer in Mexico.
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