In addition to genetics and metabolism, mercury exposure and vaccines have been implicated as a possible cause of autism. My previous article covered studies about genetic and metabolism causes and this article continues with research regarding vaccines.
Old style DPT vaccines used to contain thimerosal, a 49 percent mercury compound. Some DTaP vaccines still contain small amounts of mercury, according to the CDC Pink Book. Other vaccines, such as Hepatitis B and flu shots contain the full amount of thimerosal.
Some researchers believe that the increasing number of vaccines given at one time to a developing infant are a cause of autism, particularly as the blood/brain barrier is not yet complete.
A study in the Annals of Epidemiology found that newborn boys who had received Hepatitis B vaccine were three times more likely to be diagnosed with an ASD compared with boys who hadn’t had the jab.
"Findings suggest that U.S. male neonates vaccinated with hepatitis B vaccine had a 3-fold greater risk of ASD; risk was greatest for non-white boys." (2)
Autism symptoms and mercury poisoning symptoms are virtually identical. The Journal of Immunotoxicology wrote:
"Autistic brains show neurotransmitter irregularities that are virtually identical to those arising from mercury exposure. Due to the extensive parallels between autism and mercury poisoning, the likelihood of a causal relationship is great."
These neurotransmitter irregularities may be the reason why some autistic children have sensory processing disorders. (1)
MMR vaccine is considered a possible cause of autism. In 1998 a gastroenterologist called Andrew Wakefield and his team of clinicians identified 12 children, eight of whom suffered regressive autism and gastrointestinal disease. After publishing this case paper, concluding that it did NOT prove an association with MMR, Dr. Wakefield studied a further 161 children, 91 of whom had bowel disease and a further 70 who did not.
He found measles virus in the guts of 75 of the children with bowel disease and only in five of the healthy children. He called this condition "measles enterocolitis".