The study comes after some parents chose not to get their children immunized.
When Mary Catherine Walther was born, her mother Suzanne decided not to have her vaccinated.
"I had been told vaccines were dangerous," said Suzanne Walther.
But when Mary Catherine was a year old, she got meningitis, a serious infection of the central nervous system.
"When I found out, oh, this is a germ. This is a germ that is a vaccine-preventable disease, I was just stunned. I was really angry," Walther said.
Like many other parents, Walther had heard of a link between vaccines and autism. Now after a four-year investigation, the Institute of Medicine of the National Academy of Sciences has released its final report on vaccines and autism and found no connection.
The report states "the body of evidence favors rejection of a causal relationship between both the measles-mumps-rubella vaccine and autism, and between vaccines that contained a mercury compound called thimerosal and autism."
Scientists evaluated tens of thousands of people and tried to answer it this way:
Is the incidence of autism greater in those who receive vaccines than in those who don't receive vaccines?
And the answer has been clear and the same, no.
Paul Offit, chief of infectious diseases at Children's Hospital of Philadelphia, PA has seen children die of preventable diseases.
"If someone chooses not to get vaccines, it won't decrease the risk of getting autism. All you do is increase the risk of getting diseases that can be prevented by vaccines," said Offit.
That's what happened to Mary Catherine. Her mom knows it could have been worse.
"We were given her at birth and then we were re-given her when she could recover from this disease that she so easily have died from," said Walther.
Today Mary Catherine is all caught up on her vaccinations.
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