Controversy over autism and childhood vaccines settled once and for all

Jan 7 2008

The results of a new study into the link between childhood vaccines and autism may settle once and for all the controversy over the issue.

According to researchers at the California Department of Public Health, though the suspected culprit the mercury-containing preservative thimerosal has been removed from childhood vaccines, cases of the disorder continue to crop up at an alarming rate in California.

Researchers Dr. Robert Schechter and Judith Grether, encouraged by the Institute of Medicine, examined cases in children between 3 and 12 years of age, which were reported from 1995 to 2007 who were receiving some form of assistance from the state to cope with their condition.

Thimerosal was removed from most vaccines by 2001 and as exposure dropped the researchers continued to examine cases of autism that were appearing as the expectation was that autism cases too would fall.

The researchers found instead that the autism rate in January 1995 was 0.6 per 1,000 live births and rose to 4.1 per 1,000 live births as of March 2007 among children ages 3 to 5.

The researchers say the findings show "no evidence of mercury poisoning in autism" since there was no decline in autism rates even after the elimination of thimerosal.

Many experts suggest that a possible reason for the increased diagnosis of the condition, may be due to improved methods of detection and the fact that children are being diagnosed at a much earlier age than in previous years.

Some studies in the past had suggested a link between mercury and autism, but a report in 2004 from the U.S. Institute of Medicine declared a review of existing studies did not support the mercury-autism theory.

So the cause of autism remains a mystery.

People with autism spectrum disorders suffer in varying degrees from limited social interactions, lack of verbal and nonverbal communication and other abilities; the disorder affects all aspects of their lives and can be very disabling.

As many as 1.5 million people in the United States have some form of autism, which is generally diagnosed around the age of 2, after most vaccinations have occurred - hence the link in many parents minds.

Dr. Eric Fombonne of Montreal Children's Hospital however suggests that regardless of this study and earlier ones, some people will persist in the belief that autism is related to mercury-preserved vaccines or specifically to the triple measles-mumps-rubella vaccine.

Dr. Fombonne says parents of autistic children should be reassured that autism in their child did not occur through immunizations and autistic children, and their siblings, should be normally vaccinated as there is no evidence of mercury poisoning in autism.

He also says 'ineffective and dangerous' treatments such as chelation therapy should be avoided.

The report is published in this month's Archives of General Psychiatry.