Why vaccines cause autism

This meant the study was both unethical and not scientifically valid. In , the journal retracted the paper because the results reported in it could not be trusted. Over the past two decades, many scientists have done large, rigorous studies to find out if any aspect of vaccines could cause autism. For example, scientists compared vaccinated children who do and do not have autism, and compared children who have and have not gotten vaccines. Some studies focus on specific vaccine ingredients, such as preservatives like thimerosal or aluminum-containing adjuvants.

Others focus on the possible effects of getting multiple vaccines in a short period of time. Over the past few years, scientists have made many discoveries about what causes autism in a child's brain. Autism-related patterns of brain structure and growth can be seen well before a child receives any vaccines. In fact, some studies suggest that early signs of autism begin even while a baby is still in the womb.

Scientists have found several genetic factors that seem to affect a child's chance of getting autism. It is also possible that exposure to toxic chemicals or infections during early pregnancy could lead to autism. So far, no studies have shown that vaccines given either during pregnancy or after birth cause autism.

Even with the overwhelming evidence that vaccines are safe and effective, some parents still decide not to have their children vaccinated or to delay vaccinations. But this is extremely risky because vaccine-preventable diseases like measles are still around.

An unvaccinated child who gets one of these preventable diseases could get very sick or even die , as could other people around the child. Sometimes, kids can have a reaction to a vaccine like a mild fever or rash. But it's clear that the risk of serious reactions to the MMR and other recommended vaccines is small compared with the health risks associated with the often-serious diseases they prevent. Because the exact cause of this sometimes devastating condition is not known, some parents will continue to have concerns despite the evidence.

In these cases, parents should be aware of the risks of serious disease in children who are not vaccinated. In some areas, outbreaks of these dangerous diseases have occurred in people who have not been immunized. Some parents have questioned whether mercury-containing thimerosal used as a preservative in vaccines might cause autism. Today, with the exception of some influenza vaccines, childhood vaccines used in the United States contain no thimerosal or only trace amounts.

Influenza vaccine is available both with thimerosal as a preservative and preservative-free. More importantly, studies have not found a link between thimerosal-containing vaccines and autism.

The U. Food and Drug Administration FDA keeps a list of all vaccines that are given to children and how much, if any, thimerosal the vaccines contain. To view the list, go to www. Some parents also questioned whether the MMR vaccine—which combines 3 vaccines into 1 injection—causes autism since symptoms of the disorder often become apparent about the time children start getting immunized. In response to this concern, researchers in Europe, Canada, and the United States looked closely at this issue.

Studies have looked at the timing of the vaccine and the vaccine itself and have found no link between the vaccines and autism. It's risky if you don't vaccinate your child. Immunizations are important for many reasons. Lots of research has already been done, and research continues to show that vaccines are safe. Author: Healthwise Staff. This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information.