FDA approves Rotarix vaccine to prevent rotavirus gastroenteritis in infants

The FDA has approved Rotarix, the second oral US licensed vaccine for the prevention of rotavirus, which causes gastroenteritis in infants and children. Without vaccination, nearly every child in the United States would likely be infected at least once with rotavirus by 5 years of age, according to the FDA.

Rotarix is a liquid and is given in a two doses series to infants from 6 to 24 weeks of age. The vaccine protects against rotavirus gastroenteritis caused by the G1, G2, G4 and G9 strains.

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

In 1999, a different rotavirus vaccine from another manufacturer was voluntarily withdrawn from the US market because of an association with an increased risk of intussusception, an interstinal folding which can occur in children spontaneously in the absence of vaccination.To help ensure that Rotarix did not increase this risk, the manufacturer, conducted a study of more than 63,000 infants; there was no increase in the risk of intussusception study, these events were not observed in other studies conducted by the manufacturer.

The FDA has concluded that the available data do not establish that these events are related to the vaccine. However, the agency has requested that the manufacturer conduct post-marketing safety studies of more than 40,000 infants to provide additional safety information.