Two papers in this week's neuroscience journal Acta Neurobiologiae Experimentalis point to vaccines and heavy metals including mercury as causes of the alarming rise in autism. The Centers for Disease Control now estimate autism to affect one in 110 children, up 40% from just a few years ago.

"The rapid increase in autism cannot be explained solely by changes in diagnostic practices and awareness," said Sallie Bernard, president of SafeMinds. "We must look at what babies and pregnant women are being exposed to that has created this epidemic and take immediate steps to protect our children from these hazardous substances."

In the first study, researchers compared two sets of infant macaque monkeys. One set was unvaccinated while the second set received vaccines identical to the 1990s pediatric schedule, most of which contained mercury. Infant macaques were used due to their similarity to human infants.

The vaccinated monkeys showed increased brain growth. Larger head size is a hallmark of human infants who later develop autism. The vaccinated primates also showed altered maturation of the brain's amygdala. The amygdala is responsible for emotions, memory and learning. Individuals with autism often struggle in these areas.The second paper was a critical appraisal of research on autism and heavy metals such as mercury. A re-examination of several studies demonstrated higher metal levels in autistic children than controls. The authors calculated that 43 out of 58 scientific reports suggest a heavy metals-autism link, while 15 suggest no link. They concluded that "the weight of evidence favor[s] a connection."

SafeMinds is calling for Federal legislation to ban mercury in vaccines as has been done already by many states. Most influenza vaccines still contain mercury. SafeMinds also asks Congress to pass the Safe Chemicals Act of 2010 to discontinue use of harmful substances when proof of safety is absent."While we wait for government action, the public can limit their exposures to toxicants which alter infant development leading to conditions like autism," said Ms. Bernard. "The public can refuse vaccines with mercury, can make choices for their child's vaccine schedule, and can create homes that are largely mercury-free."