WASHINGTON, April 21 (UPI) -- If it seems redundant, it's because it is. Every major peer-reviewed study examining the relationship between vaccines and autism has come to the same conclusion -- there is no link between the two.
Now there is another study -- a big one -- and the findings are the same. There is still no link between the MMR vaccine and autism. The MMR vaccine is the immunization vaccine against measles, mumps and rubella; its underutilization is blamed for recent outbreaks of measles in the United States.
The authors of the latest study -- published this week in JAMA -- weren't oblivious to the obviousness of their findings. They argued their work was necessary because it looked specifically at populations that are at an increased risk of developing autism.
"Could it be that if all the requisite genetic and other risks are present, MMR can lead to the development of autism?" Bryan H. King, a psychiatrist at the Seattle Childrens Hospital, asked in an editorial accompanying the new study. "If so, the population in which there might be such a signal would be families already affected by autism."
While environmental conditions may promote autism, the disorder is largely correlated with genetic factors. In other words, it is a mostly inherited disorder. For this reason, brothers and sisters of children on the autism spectrum are more likely to be diagnosed with the autism than those with no family history.
The new study -- conducted by researchers with the Lewin Group, a healthcare consulting firm -- found no correlation between MMR and autism. The confirmation was derived from information about the family health and vaccination history of some 95,000 children.
"Our study confirmed that in kids with older siblings who we know are at increased risk of developing autism themselves, those kids are being vaccinated less," Dr. Anjali Jain, lead researcher, told TIME. "But in the kids who did develop autism who were vaccinated, there was no increased risk from the vaccine compared to kids who did not get the vaccine."