Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Children's Vaccines Health Center

Font Size

Studies: No Link Between Autism, Vaccines

Preservative in Childhood Vaccines Not a Cause of Autism, Researchers Find
WebMD Health News

Sept. 7, 2004 -- Thimerosal, the preservative formerly used in vaccines, and autism are not linked, according to three new studies.

It's been controversial for years, this theory that vaccines containing thimerosal could cause neurological and psychological problems like autism. Many studies have discounted this link, but many parents have not been convinced.

In 2001, thimerosal was removed from all routinely recommended childhood vaccines as a precautionary measure.

In this month's issue of the journal Pediatrics, two large studies from the U.K. show no significant link between thimerosal-containing vaccines and abnormal neurological development. The third study is a careful review of all research published thus far.

The Newest Evidence

In the first study in Pediatrics, researchers analyzed data on more than 14,000 children, tracking their vaccinations at 3, 4, and 6 months of age as well as their calculated mercury exposure. They compared the data with information on the children's brain and motor development from age 6 months to age 7 or 8, when many children are diagnosed with autism.

The researchers looked at various outcomes including behavioral, speech, and other development milestones.

They also took into account other factors that might have skewed their data -- like the baby's birth weight, premature birth, whether the mother smoked, if the baby was breastfed, and ethnicity.

In the end, "we could find no convincing evidence" that early childhood exposure to thimerosal had any harmful effect on the children's brain, motor skill, or behavioral development, writes lead researcher Jon Heron, PhD, a pediatric epidemiologist with the University of Bristol in England.

"This is reassuring news," writes Heron.

However, there was a slight conflict with the second study in Pediatrics.

In the second study, children getting vaccines had more behavior tics -- possibly minor, short-lived tics, writes researcher Nick Andrews, MSc, an epidemiologist with the Communicable Disease Surveillance Centre in London.

Andrews analyzed data on nearly 110,000 British children, comparing the amount of thimerosal in the diphtheria-tetanus-pertussis (DTP) and the diphtheria-tetanus (DT) vaccines with incidence of developmental disorders.

The vaccines actually seemed to lower the risk of general developmental disorders, including attention deficit hyperactivity disorder (ADHD), writes Andrews.

Today on WebMD

Baby getting vaccinated
Is there a link? Get the facts.
syringes and graph illustration
Get a customized vaccine schedule.
baby getting a vaccine
Know the benefits and the risk
nurse holding syringe in front of girl
Should your child have it?

What To Know About The HPV Vaccine
24 Kid Illnesses Parents Should Know
Nausea and Vomiting Remedies Slideshow
Managing Immunization Schedules For Kids

Doctor administering vaccine to toddler
gloved hand holding syringe
infant receiving injection

WebMD Special Sections