But some experts advise against ringing the warning bell too soon.
"We focus on rare side effects," said Randall Bovbjerg, a health policy researcher at the Urban Institute.
"We don't focus on the millions of lives saved by vaccines," he told United Press International.
Rotavirus, an infection that causes diarrhea, vomiting, fever and severe dehydration, is extremely common in all countries. In the United States and other developed countries, most children have had several rotavirus infections by the time they reach adolescence, and cases are rarely serious -- though it leads to as many as 70,000 hospitalizations per year.
In developing countries, where health infrastructure is weak, children often die of rotavirus-related dehydration because there are no medical facilities available to rehydrate them. Each year, an estimated 600,000 children worldwide die after contracting rotavirus, more than 80 percent in developing countries.
In 1999, a vaccine against the disease, manufactured by Wyeth-Lederle Vaccines, was withdrawn from the U.S. market after just nine months because it was linked with a rare but potentially deadly intestinal condition called intussusception.
Last year, global health advocates celebrated government approval of a new Merck vaccine called RotaTeq. But last week the Food and Drug Administration issued a notification to doctors that some intussusception cases have occurred among vaccinated infants, urging them to report any cases.
"Intussusception, a form of bowel obstruction, occurs spontaneously in the absence of vaccination," the FDA notification says, adding "we are not surprised by the number of reported intussusception cases following RotaTeq vaccination."
The Centers for Disease Control and Prevention, which recommends routine infant vaccination against rotavirus, chose not to withdraw their recommendation based on the FDA warning.
But global health advocates and consumer health watchdogs are divided over the significance of the announcement.
A vaccine against the virus is "very important globally," said John Wecker, director of the rotavirus vaccine program at PATH, an international global health organization that is currently conducting large-scale trials of RotaTeq and other vaccines in Asia and Africa.
"Because of limited access to medical care, a vaccine is the best protection we can provide," he told UPI.
The FDA notification was an update, he said, and showed a lower than expected incidence of intussusception in the vaccinated age group.
"Kids get intussusception," he said. "The data does not suggest there's an association (with RotaTeq)."
Given the need for the vaccine to save children's lives, it is important for decisionmakers in the U.S. and other countries to have accurate information, and the vaccine's effects are being monitored carefully, he added.
"Poor information leads to poor decisions."
With any vaccination question, potential complications need to be weighed against the good the vaccine does, said Bovbjerg of the Urban Institute.
"One of the few things that is absolutely cost-effective, in general, is vaccines," he said. "Things have built-in defects. To work, knives have to be sharp, but that doesn't mean they're not useful."
Though a serious vaccine-related illness is a tragedy for the child and its family, we now have the luxury of not worrying about serious diseases like polio, Bovbjerg said. "It's quite rational for me to not be vaccinated if all my neighbors get vaccinated. But if everyone thinks like that, then everybody could get sick."
Some watchdog groups, however, question that logic.
"All children are important," said Barbara Loe Fisher, president of the National Vaccine Information Center, a consumer safety advocacy group.
"That includes those who suffer from disease, as well as babies who suffer intestinal blockage and die," Fisher told UPI.
"Rotavirus is not a widespread killer in this country. Anytime you get a signal that a vaccine causes a symptom you have to take it seriously -- especially given the similar issue with another vaccine."