The latest analysis of childhood vaccines confirms they're generally safe.
The report should be reassuring to parents, the researchers say. For example, there still is no evidence the measles-mumps-rubella vaccine causes autism. Nor is there any proof vaccines cause childhood leukemia.
The assessment mirrors and updates a 2011 report on vaccine safety by the U.S. Institute of Medicine. That report found vaccines can cause certain side effects but serious ones are very rare.
Experts say such risks need to be balanced against the benefits of vaccines - the prevention of millions of illnesses and thousands of deaths annually.
But that message seems lost on some parents. A small but growing numbers of parents have tried to get their children exempted from school attendance vaccination requirements. And one recent study found vaccine safety messages actually reduced some parents' willingness to get their kids vaccinated.
"I don't think this report, alone, will convince parents that vaccines are safe," said Dr. Courtney Gidengil, one of the RAND Corp. researchers who did the report for federal health officials.
But maybe it will at least influence their family doctors, she and others said.
"Many parents look to their physicians as the ultimate sources of information," said Dr. Walter Orenstein, associate director of Emory University's Vaccine Center, adding "now it's up to them."
The new analysis looked at dozens of medical studies completed since the 2011 report. It echoes some of those findings and included vaccines that report hadn't addressed.
The journal Pediatrics published the report online Tuesday. Among its conclusions:
-Newer evidence confirms a link between the measles-mumps-rubella vaccine and fever-triggered seizures. The seizures rarely cause long-term health problems, but can be frightening for parents.
-Apparently, flu shots can also spur fevers that can trigger seizures. The seizures seem to happen more often in children who get a vaccine against pneumococcal bacteria the same day.
-Newer vaccines against rotavirus, a severe diarrheal disease in children, slightly raise the risk of a rare bowel blockage.
The risks of serious side effects were deemed very low. For example, the rotavirus vaccines were linked to no more than five extra cases of the blockage for every 100,000 kids vaccinated.