Rotavirus vaccine for infants protects others too, CDC study says

LOS ANGELES — The infants who get the rotavirus vaccine aren’t the only ones who benefit. New research shows that older children and even adults were less likely to be hospitalized with the gastrointestinal virus after the vaccine was introduced in the U.S. in 2006.

Rotavirus causes “severe watery diarrhea, often with vomiting, fever, and abdominal pain,” according to the Centers for Disease Control and Prevention. Before the RotaTeq and Rotarix vaccines came on the market, nearly all U.S. children became infected with rotavirus before their 5th birthday. Worldwide, more than half a million children under age 5 die as a result of rotavirus each year, the CDC says.

Among the youngest group of hospital patients-those under the age of 4 — the incidence of rotavirus dropped by 80 percent between the pre-vaccine years of 2000-06 and the post-vaccine years of 2008-10. In addition, there was a 70 percent drop for children ages 5 to 14 and a 53 percent drop for patients between the ages of 15 and 24.

The researchers also saw fewer hospitalizations for cases of gastroenteritis of unspecified cause after infants started getting the rotavirus vaccine. However, these reductions were smaller.

The research team, from the CDC’s Division of Viral Diseases, analyzed data from the Nationwide Inpatient Sample, which tracks a nationally representative group of hospital patients. The researchers did not include figures from 2007 in their analysis because it was a “transition year” with limited vaccine coverage, they wrote.

The CDC experts gave the infant vaccine credit for reducing rotavirus hospitalizations in children and adults, and they cited several reasons. For starters, the biggest reduction in hospitalized patients came in March and April, which are usually peak months for rotavirus. Also, the more the vaccine was used in infants, the less likely older children and adults were to be hospitalized with rotavirus. By 2010, the last year in the analysis, “significant reductions” were seen in people of all ages, they wrote.

“These results point to the primacy of children in the transmission of rotavirus and illustrate how indirect benefits may amplify the effect of the U.S. rotavirus vaccination program,” they concluded.

The results appear in Wednesday’s edition of the Journal of the American Medical Association.