TUESDAY, Aug. 27 (HealthDay News) -- Vaccinating babies against rotavirus also protects older children and adults against infection with the stomach bug, a new study shows.
Since 2008, the vaccine has prevented up to 50,000 hospitalizations for rotavirus each year among children under the age of 5, according to researchers from the U.S. Centers for Disease Control and Prevention.
"Before the vaccine was introduced [in 2006], about 60,000 to 70,000 children were hospitalized every year, and between 20 and 60 died," said report co-author Ben Lopman, an epidemiologist in the division of viral diseases at the CDC. "This study also shows that hospitalizations for rotavirus have also gone down in older children and adults who have not been vaccinated. In other words, there is an indirect effect that we call 'herd immunity,'" Lopman explained.
"By vaccinating infants, you prevent them from getting infected, but you also prevent them from infecting others," he said. The CDC now recommends that all children be vaccinated against rotavirus, starting at 2 months of age.
The report was published in the Aug. 28 issue of the Journal of the American Medical Association.
"Rotavirus is very infectious, and is the most common cause of severe diarrhea," Lopman said. In addition, there can be fever, stomach cramps and vomiting that can continue for up to a week. "The real risk is that children can become dehydrated," he explained.
One expert said since rotavirus vaccinations began, cases of the stomach bug have become exceedingly rare.
"A resident trained now would say rotavirus was a disease that doesn't exist," said Dr. Marcelo Laufer, a pediatric infectious diseases specialist at Miami Children's Hospital. "That's the influence of the vaccine."
Laufer said it is important that infants be vaccinated against rotavirus. "The vaccine is safe and effective, and it does reduce the risk of rotavirus infections and hospitalizations," he noted.
Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia and a co-developer of the rotavirus vaccine, was surprised to hear that the vaccine has triggered a herd immunity to the disease.
"It surprises me, pleasantly, but it surprises me," Offit said. That's because even if one had the disease one could be re-infected with it, he explained.
At the time, Offit didn't think the vaccine would really change the amount of circulating virus in the community. "But that isn't true," he said.
"With vaccination, it looks like you are significantly decreasing the amount of circulating virus in the community, so you are getting a herd effect," Offit said.
For the study, the CDC researchers looked at hospitalizations for rotavirus before and after the vaccine was available.
The investigators found that, compared with the years before the vaccine was available, there were substantial reductions in hospitalizations of children under age 5 by 2008.
By 2010, these reductions were also seen among older children, teens and adults, the researchers found.
For more on rotavirus, visit the U.S. Centers for Disease Control and Prevention.
SOURCES: Ben Lopman, Ph.D., epidemiologist, division of viral diseases, U.S. Centers for Disease Control and Prevention; Marcelo Laufer, M.D., pediatric infectious diseases specialist, Miami Children's Hospital; Paul Offit, M.D., chief, division of infectious diseases, and director, Vaccine Education Center, Children's Hospital of Philadelphia; Aug. 28, 2013, Journal of the American Medical Association