The U.S. Food and Drug Administration announced the approval of Rotarix, the second oral U.S. licensed vaccine for the prevention of rotavirus, an infection that causes gastroenteritis (vomiting and diarrhea) in infants and children. Rotarix is a liquid and given in a two-dose series to infants from 6 to 24 weeks of age.

Although the disease is usually self-limiting, rotavirus causes about 2.7 million cases of gastroenteritis in U.S. children each year-about 55,000 to 70,000 of those require hospitalization; and between 20 and 60 deaths are attributed to it. Without vaccination, nearly every child in the United States would likely be infected at least once with rotavirus by age 5.

There are many different strains of rotavirus. The vaccine protects against rotavirus gastroenteritis caused by the G1, G3, G4, and G9 strains.

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

During studies involving more than 24,000 infants, Rotarix was effective in preventing both severe and mild cases of rotavirus-caused gastroenteritis during the first two years of life. The most common adverse reactions reported during clinical trials were fussiness, irritability, cough, runny nose, fever, loss of appetite and vomiting.

In 1999, a different rotavirus vaccine from another manufacturer was voluntarily withdrawn from the U.S. market because of an association with an increased risk of intussusception, or intestinal folding, which can lead to potentially life-threatening intestinal blockage. Intussusception can occur in children spontaneously in the absence of vaccination, but to help ensure that Rotarix does not increase the risk of intussusception, its manufacturer conducted a study of more than 63,000 infants.

In that study, there was no increase in the risk of intussusception in those who received Rotarix (31,673 infants) compared to those who received placebo (31,552 infants). Increased rates of convulsion and pneumonia-related deaths were observed in the Rotarix recipients in the intussusception study, however these events were not observed in other studies conducted by the manufacturer. Although the FDA has concluded that the available data do not establish that these events are related to the vaccine, the agency has requested the manufacturer to conduct post-marketing safety studies involving more than 40,000 infants to provide additional safety information.

Rotarix is manufactured by GlaxoSmithKline Biologicals, Rixensart, Belgium.