Exposure to mercury does not cause autism–another myth debunked

Mercury PoisoningOne of the tropes of the antivaccination crusade is that mercury in vaccines cause autism. Of course, this myth of the vaccine deniers is based on several assumptions, all of which are more or less facetious, if not outright fabrications. For example, few vaccines actually contain mercury in the form of thiomersal, and the few that have it (typically, the flu vaccine), have single dose injections that don’t contain it. Furthermore, there is no evidence that thiomersal causes autism. And there is no evidence that children with autism spectrum disorder (ASD) have higher blood or urine levels of mercury. Of course, mercury can cause numerous neurological deficits, but that’s almost always from the methylmercury form, not the ethyl-mercury form (including thiomersal), and certainly not in the tiny quantities delivered in a vaccine.

In a new, and very extensive, study examining the link between environmental mercury, which is usually found in the methylmercury form, and ASD, the results appear to rule out any connection between the two. Basically, the research showed no correlation between high levels consumption of fish, which bioaccumulate methyl mercury, during pregnancy and ASD diagnoses in children. Presumably, if methyl-mercury had a neurological effect on the developing fetus, mothers who consumed a lot of it would have put their children at risk of ASD, if we go with the hypothesis that mercury causes autism. Continue reading “Exposure to mercury does not cause autism–another myth debunked”

Risk of autism is NOT increased with “too many vaccines”

wakefieldThe myth of vaccines causing autism is based upon the fraudulent claims of Mr. Andy Wakefield, which caused the original article making said claims to be retracted by The Lancet. Despite this fraud, Wakefield’s acolytes, minions, and disciples in the vaccine denialist world continue to make the claim that vaccines cause autism. But there are over 250 studies that show that vaccines do not cause autism. And there is a boatload of evidence that the MMR vaccine, specifically mentioned in Wakefield’s original study, does not cause autism.

But one of the enduring myths of the vaccine denialist crowd is that it’s not just MMR vaccine that causes autism, but it’s the number of vaccines of all types that are given to children in a short period of time (pdf). Even though the best scientific evidence supports the hypothesis that vaccines do not cause autism, approximately one-third of parents continue to express concern that vaccines may cause autism, and nearly 1 in 10 parents refuse or delay vaccinations because they believe it is safer than following CDC vaccine schedule. Continue reading “Risk of autism is NOT increased with “too many vaccines””

Flu during pregnancy linked with increased risk of autism

Autism Spectrum Disorders (ASD) appear to be an increasing medical issue in the United States. According to the Centers for Disease Control and Prevention, ASD is diagnosed in approximately 1 in 88 children, and are reported to occur in all racial, ethnic, and socioeconomic groups. ASD refers to a broad range of symptoms, from mild social awkwardness to mental retardation, repetitive behaviors and an inability to communicate. The CDC states that diagnosing ASD can be difficult, because there are no medical tests, such as a genetic or blood test, that can provide a definitive diagnosis. Physicians make a diagnosis through observation of a child’s behavior and development.

Medical science agrees that the increase in diagnosis is not only a result of better diagnostic standards, but also because there appears to be more children who are actually developing autism. Unfortunately, science has not uncovered the cause. Genetics are a critical factor, for example, since it has been shown that if one twin has autism there is a high likelihood that the other twin will also develop ASD. But are there other factors?

Continue reading “Flu during pregnancy linked with increased risk of autism”