Mythbuster Series: Thimerosal

Posted on April 2nd, 2014

Myth: Thimerosal in vaccines causes autism.

FACT: Thimerosal is no longer used in children’s vaccines and has never been proven to cause autism.

Some myths are more powerful and damaging than others. The myth that thimerosal, a preservative that has mercury in it, causes autism in children is a very powerful myth. It has frightened many Maine parents for too long and has kept them from protecting their children from dangerous diseases with safe, effective vaccines.

A powerful myth is still just a myth. We still don’t know what causes autism. What we do know for a fact is that it isn’t thimerosal in vaccines.


Thimerosal was added to vaccines 70 years ago as a preservative. Just like the preservatives used in food, thimerosal was added to vaccines to keep them from  going bad while they were shipped and stored. Just like eating spoiled food can make us sick, using “spoiled” vaccines can cause serious health problems. The thimerosal in vaccines was a way to keep vaccines safe and at full strength, saving lives.


Thimerosal was added to vaccines to protect people and that is all it has ever done. But, in 1999, the Centers for Disease Control (CDC) and the American Academy of Pediatrics (AAP) asked vaccine manufacturers to remove thimerosal from children’s vaccines. This was not because they believed it caused autism, but as a general push to remove all types of mercury from children’s products.

Maine parents still unconvinced by all of these studies and court rulings should know that they can vaccinate their children on the CDC-recommended schedule until age six without ever exposing them to thimerosal.

Since thimerosal is proven to be safe and because it works so well as a preservative, it can still be found in some adult doses of the flu vaccine. Parents who are still concerned about thimerosal can ask their healthcare provider for a thimerosal-free dose of the flu vaccine.

The truth is that thimerosal has never caused autism and is no longer found in children’s vaccines. Don’t let a myth keep you from making an informed decision to follow the recommend vaccination schedule for your children.

Vax Maine Kids highly recommends that Maine parents keep their kids on the CDC-recommended vaccination schedule. Is your family up-to-date? Visit our Vaccine Schedules page to find out.

Leave a Reply

Your email address will not be published. Required fields are marked *