As the flu season gets underway, health officials have a weighty job convincing the public that the H1N1 vaccine is safe – if they can get it. Meanwhile, some parents juggle safety concerns while confronting the popular belief that mercury-laden vaccines can cause autism in children, though this myth has been widely debunked in the scientific community.
A recent environmental study pokes another hole in this theory, finding that mercury blood levels in autistic and non-autistic children are similar and in line with standard for normal levels.
The amount of fish a participant ate on a regular basis was the largest predictor of mercury levels, according to the study, published in Environmental Health Perspectives. Mercury gets particular attention because of its known neurotoxicity. Some flu vaccines contain thimerosal, a mercury-containing preservative that prevent bacterial contaminations and has been in use since the 1930s.
Initially, mercury levels were lower for children with autism, possibly because they tend to be finicky eaters and eat less fish. However, when adjusted for lower fish consumption, blood-mercury concentrations were roughly similar between both groups.
“It’s time to abandon the idea that a single ‘smoking gun’ will emerge to explain why so many children are developing autism,” says the lead author of the study, Irva Hertz-Picciotto, a researcher at the University of California-Davis MIND Institute. “The evidence to date suggests that, without taking account of both genetic susceptibility and environmental factors, the story will remain incomplete.”
So, then what causes autism? It is still unclear. In the U.K., scientists have highlighted a possible chromosomal defect that impairs the growth of brain cells that are essential for neuron development -– increasing the likelihood of autism. Another British professor, Simon Baron-Cohen (whose brother is the actor, Sasha Baron-Cohen of “Borat” fame), cites 133 genes that have now been linked to the condition.
The Center for Disease Control now shows autism spectrum disorder prevalence rates along the lines of 100-per-10,000, or a whopping one percent of U.S. children. And a Cambridge (U.K.) University study shows that for every three known cases of autism spectrum, there may be a further two cases that are undiagnosed.
The autism community still holds out for good news, some of which is shared by academics at the Johns Hopkins University, Harvard College, and other institutions, who believe that if this common genetic variant were corrected, autism rates could be decreased by 15 percent.
With so much research in the autism space, it’s hard not to make personal conclusions. But for the sake of our society, we must continue to ask tough questions about what the future holds, and how we can care for and provide services to this group.