Carrie Lance holds her son, Eric, 4, as he receives an MMR vaccine in Salt Lake City. Laura Seitz, Deseret News

      A number of groups, including the World Health Organization, the U.S. Institute of Medicine and Britain's Medical Research Council have reviewed a possible link between the vaccines and autism. But the latest project, published Tuesday in the Internet version of the journal Clinical Evidence, is the most comprehensive.
      This study and other recent reviews find no evidence of a connection between the inoculations and developmental and bowel problems in children. They say parents should be reassured the shots are safe.
      Still, parents who believe their children have been harmed by the vaccine, MMR, are not convinced.
      "We looked through over 2,000 studies on millions of children, covering 50 years of research," said lead investigator Dr. Anna Donald, whose company, Bazian Ltd., analyzes the quality of medical research and was contracted by the publishing arm of the British Medical Association to conduct the review.
      "The science is very rigorous, and this really does give a green light to MMR," she said. "The science on this issue is over; the scientific debate is dead."
      "This really confirms in a systematic and comprehensive way what we've felt and hoped. There's not a causal link between MMR and autism," said pediatrician Dr. George Delavan, division director of Community and Family Health Services in the Utah Department of Health.
      "I know a lot of parents have that concern and there is information that it is linked. This shows in a scientifically controlled study there is not such a link. It's a hopeful message for parents that they don't have to be concerned about this particular complication."
      While the link to autism or bowel disease is unproven, he said, there's no question that some children die from measles or get complications like brain inflammation that can lead to vision and hearing problems.
      Fellow pediatrician Dr. Louis Borgenicht characterized childhood vaccinations as an "important public health service."
      Utah law mandates that children have certain vaccinations, including the MMR combined vaccine, before they can enter kindergarten. Parents can, for certain reasons, have the requirement waived. But having a very high percentage of children vaccinated is the only way to control and hopefully eliminate certain illnesses, pediatricians and policymakers say.
      The result has been "night and day," Delavan said. Before immunizations, children died mostly from infectious diseases. That's no longer true.
      Still, many parents, some physicians and several national organizations believe that parents should be able to opt out of having their children vaccinated. A number of them believe the MMR vaccination is directly responsible for autism in their own families. The Deseret News gets frequent calls from several Utahns who say their children and grandchildren have autism as a direct result of the vaccine.
      The National Vaccine Information Center, which opposed mandated vaccinations, says that "vaccination is a medical procedure which carries a risk of injury or death. As a parent, it is your responsibility to become educated about the benefits and risks of vaccine in order to make the most informed, responsible vaccination decisions."
      Ann Coote from Jabs, a British-based support group for parents who believe their children were damaged by the vaccine, said the issue has not been settled.
      "It's not new evidence. It's only old evidence rehashed," she said. "That's what's annoying parents — if we've got all this money to throw away on keeping on reviewing things, haven't we got the money to start new research and look into it once and for all?"
      Donald said there is no doubt more research on autism is needed, but she would not endorse any more research into the link between autism and MMR.
      "This is a terrible distraction from limited funds that need to be looking at autism itself and not at something that has been answered more convincingly than most things we have ever tried to look at," she said.
      Dr. John Clemens, a medical officer in the immunization program at the World Health Organization, said WHO will continue to monitor future vaccine safety studies but the U.N. health agency sees no need to spend more money to further investigate a link to autism.
      Dr. Neal Halsey, director of the Institute for Vaccine Safety at Johns Hopkins University, said scientists should try to determine whether measles viruses linger in the intestines or other tissues, but the outcome of such studies would not alter his opinion that MMR is safe and effective.