Lets start with Thiomersal. The concern here is that it is a mercury based preservative. Mercury is toxic, yadda yadda. The use of Thiomersal was stopped in 1999, as a preventative measure in all vaccines except for the Flu.
Thiomersal's main use is as an antiseptic and antifungal agent. In multidose injectable drug delivery systems, it prevents serious adverse effects such as the Staphylococcus infection that, in one 1928 incident, killed 12 of 21 children inoculated with a diphtheria vaccine that lacked a preservative.(source) Unlike other vaccine preservatives used at the time, Thiomersal does not reduce the potency of the vaccines that it protects. Bacteriostatics like thiomersal are not needed in more-expensive single-dose injectables.
There is no convincing evidence that Thiomersal is a factor in the onset of autism. Despite this, many parents, and some scientists and doctors, believe there is a connection. Parents may first become aware of autistic symptoms in their child around the time of a routine vaccination, and parental concern about vaccines has led to a decreasing uptake of childhood immunizations and an increasing likelihood of measles outbreaks. More than 5,000 U.S. families have filed claims in a federal vaccine court alleging autism was caused by vaccines, most implicating Thiomersal; the majority of these claims are still being adjudicated. The U.S. federal government agreed to award damages in one case, to a girl with a mitochondrial enzyme deficiency who developed autistic-like symptoms after receiving a series of vaccines, some of which contained Thiomersal. Many parents view this ruling as confirming that vaccines cause regressive autism; however, most children with autism do not seem to have mitochondrial disorders, and the case was conceded without proof of causation.
It's easy to dismiss Thiomersal as a danger because of this fact:
In the United States, countries in the European Union and a few other affluent countries, Thiomersal is no longer used as a preservative in routine childhood vaccination schedules.(Source) In the U.S., the only exceptions among vaccines routinely recommended for children are some formulations of the inactivated influenza vaccine for children older than two years.
Most conclusively, eight major studies (as of 2008) examined the effect of reductions or removal of Thiomersal from vaccines. All eight demonstrated that autism rates failed to decline despite removal of Thiomersal, arguing strongly against a causative role.
Thank you Wikipedia. With only the basic details we have easily removed the threat of Thiomersal from the anti-vaccination crowds list. If only Jenny McCarthy would use the Google once in a while. What is also quite fantastic is it makes that idiots other claim that Chelation Therapy (a process of removing heavy metals, like mercury, from your system) is effective in treating autism all that much more ridiculous. Furthermore, there is no scientific study to support this idea. (source)
Jenny McCarthy has also said she gives her son B-12 shots and keeps him on a strict diet which she says has helped him "recover." How does she know this? Well, she says: “My science is Evan, and he’s at home. That’s my science.” Simply incredible.
Why hasn't "big pharma" latched onto this miracle cure and raked in the money? I guess those MMR shots are where the real money is...
The next concern is overdosing, like the MMR (Measles, Mumps and Rubella )vaccine. The concern here is that it's too much at one time. It overloads the childs system and suddenly he falls into some wide ranging spectrum of autism that can result in simple social awkwardness to card counting in Vegas with your jerk brother.
This has been effectively dismissed as well thanks to the fraud Andrew Wakefield. Whose 1998 Lancet paper on the subject of MMR and Autism has been shown to be complete garbage (that's scientific jargon)
Two down. How many to go? Honestly, I have no idea. The alternative medicine, pharma conspiracy crowed is ever evolving. It's difficult to say what other stupid nonsense these people will come up with, but I'll be sure to make fun of them childishly every chance I get.
Parents: Please, for the love of your children, get them immunized.
While you're at it, be sure to visit the Science-Based Medicine blog: www.sciencebasedmedicine.org
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