Autism and Vaccines

Do vaccines cause autism? A large group of people believe that the vaccines that have been developed and being given to children in the past decades may have a great deal to do with the sudden rise in the prevalence of autism in the general population. They cite the following evidence to support their belief:

The symptoms of autism often occur about the time that a child receives an MMR (measles, mumps and rubella) vaccine.
A California study reported that the numbers of children diagnosed with autism have been rising since the introduction of the MMR vaccine. Many experts in statistics state that the interpretation of that data is faulty, but the belief has persisted.
Many vaccines contain thimerosal, a preservative that contains mercury, and mercury poisoning is one of the suspected causes of autism

There are some very vocal advocacy groups that continue to call for investigation into the connection between vaccines and autism. There have been many studies and reviews of research done into that connection, and none have found a positive link between any vaccine and the onset of autism. Those who feel that the vaccines do cause autism point out that there are some overwhelming financial reasons why the medical establishment, pharmaceutical companies and the government would want any link between vaccines and autism to remain undiscovered and unproven.

However, the research conducted both here and in foreign countries seems clear and conclusive in stating that vaccines do not cause autism. Among those studies are:

A 1999 study that reviewed all known cases of Autism spectrum disorders in certain London districts and compared them with vaccination records. That study found that:
ASD cases rose steadily between 1978 and 1999, but they did not rise faster after doctors started using the MMR in 1987
Children who were vaccinated earlier than 18 months showed symptoms of autism at the same time as those vaccinated after 18 months. If the vaccine caused the autism, then those vaccinated earlier should have showed symptoms earlier.
There was no difference in percentage between children who had ASD and were vaccinated and children who did not have ASD who were vaccinated. If the vaccine was the cause, there should have been a higher percentage of children vaccinated in the group of children who have ASD
The first signs of autism weren't any more likely to appear after an MMR vaccination than at other times.

A Swedish study that compared the rates of autism in two Swedish towns before and after 1982, when the MMR vaccine was introduced
The study found no difference in the rates of autism before and after the vaccine was introduced in either town.
An Institutes of Medicine review published in 2001 that studied all completed and ongoing research regarding vaccines and autism concluded that there was no link.

Based on this research and other ongoing and completed research, the Center for Disease Control, the American Academy of Pediatrics and other medical bodies believe that there is no connection between vaccines and autism, and that all children should be vaccinated against common childhood diseases.