The U.S. Food and Drug Administration approved Thursday GlaxoSmithKline PLC’s vaccine Rotarix, for the prevention of rotavirus, an infection that causes gastroenteritis (vomiting and diarrhea) in infants and children.

The approval follows a phase III trial on more than 15,000 healthy infants from ten Latin American countries conducted by researchers from the Institute of Biomedical Sciences, Faculty of Medicine, University of Chile. The children were randomly assigned to receive two oral doses of Rotarix or placebo. The results of the trial showed that only 31 infants developed gastroenteritis out of 7,025, compared with 161 in 7,081 infants who were given the placebo. The vaccine was also tested on a number of 60,000 infants before receiving the FDA approval.

"This vaccine provides another option to combat and reduce a potentially severe illness that affects so many children," Jesse L. Goodman, M.D., M.P.H., director of FDA's Center for Biologics Evaluation and Research said on the FDA’s Web Site.

Rotavirus infection usually hits children before age five, causing about 2.7 million cases in the U.S. each year – about 55,000 to 70,000 of those require hospitalization. The infection also causes between 20 and 60 deaths per year. Frequent hand washing is the best way to limit the spread of rotavirus infection.  

Rotarix will be given in a two-dose series to infants from 6 to 24 weeks of age and will protect them against rotavirus gastroenteritis caused by G1, G3, G4 and G9 strains of rotavirus.

Rotarix will compete with Merck’s already marketed Rotateq, a similar product, which is usually given in three doses over the course of six months. Rotateq was Merck’s second-best selling vaccine last year with revenue of $525 million.

“With only two doses, Rotarix allows infants to complete the vaccination series against rotavirus earlier than ever before, which may prevent many of the emergency department visits and hospitalizations that are a burden on families and the healthcare system,” said Barbara Howe, a company vice president.