Link found between autism and vaccines

A new scientific study indicates that vaccines may be a risk factor for autism, according to a research presented at a conference in Australia.

"We see a high risk factor for autism among people who have had both MMR (measles, mumps and rubella) and measles as well as any one-dose immunization given in an adjuvant (potentially) at very high doses," said Geoffrey Currie, a researcher at Monash University in Melbourne and lead author of the study, which was presented at the annual Australian Pediatric Academic Meeting in April.

The study's findings do not explain why, but they could have a major impact on vaccination policy, according to Dr. Cate Branback, an associate professor at the University of Adelaide's School of Human Welfare.

Link between autism and autism spectrum disorder?

Currie and his team, whose findings will be published in the Journal of Infectious Diseases, analyzed data from a historical study that monitors the incidence of autism among children born between 1964 and 1968. They found that men and women who received either the MMR vaccine -- which protects against measles and mumps -- or the measles, mumps and rubella vaccine before age 8 had a 70% higher risk of autism by the age of 13 years.

"When we saw that children who had had the first of the vaccinations before their age 8 were much more likely to be autistic, we thought there might be something to the systemic vaccination," Currie told CNN on Wednesday. "But it seemed to be the low dose versions of the vaccines that were involved, which suggests that the vaccines that we vaccinate against are somehow more harmful and lead to higher incidence of autism."

Currie says that this was the first study that examined the intersection of the MMR vaccine and autism risk.

"There have been many studies about other vaccinations that have come out before, but not this particular one," he said. "This study is looking at vaccines as a whole. But the study does not really provide a definitive answer as to what causes autism, and that's where it gets complicated because there's so many different reasons -- genetics, infections, there's a whole set of factors involved."

Next steps

Currie says that the full report of his study will appear in the journal's July issue.

"I think it's important to present results like this in order to provoke more research, because we need to understand this," he said. "In the rest of the world, autism rates have been rising quite rapidly. ... So it's very important to understand these things so we can avoid it."

Experts disagree, however, and say that while more research needs to be done, there is not enough evidence to draw any long-term conclusions.

"I think this study is spurious and a major distraction from the more important work," said Dr. Robert Spitzer, an associate professor of pediatrics at Columbia University and chair of the Nuffield Council's Vaccine Safety Committee.

Spitzer said the link between vaccines and autism is "something like zero percent," adding that there has been "virtually no link" between the MMR vaccine and autism "in either children or adults."

Dr. Mark Henderson, an assistant professor of pediatrics at the University of Connecticut and a member of the Infectious Diseases Society of America's council on immunization, agrees that the study fails to support a causal relationship.

"No one has any evidence that vaccines caused autism. The authors in this case have tried to find a link but have failed," Henderson said. "What they reported, the findings don't support a link."

"There are lots of cases where it's been impossible to do it with MMR," he added. "You can look at both the immune system and at neurodevelopment."

While the relationship between vaccines and autism is currently a debate, Branback, the University of Adelaide professor, said the research has still had a "concrete benefit" because it may help guide vaccine policy.

"We should be aware of these types of associations," she said. "We should be aware of the possibility that a high rate of immunization causes side effects and autism."