The new vaccines slightly raise the risk of a twisted bowel problem that doomed the first vaccine, but to a much smaller degree. Doctors say the benefits of the new vaccines, which came out in 2006 and 2008, greatly outweigh the small risk of the bowel problem.
Rotavirus kills more than 400,000 young children a year, mostly in poor countries. In the United States, good medical care usually keeps it from being fatal, but it causes many hospitalizations.
The vaccine safety studies were published online Tuesday by the New England Journal of Medicine.