A link between autism and vaccinations remains unproven.
A newly released U.S. government study finds children who receive multiple vaccines are not at an increased risk for developing autism, confirming an abundance of earlier research that found childhood vaccines are not related to autism.
According to a report published in the current edition of the Journal of Pediatrics, researchers at the Centers for Disease Control and Prevention (CDC) investigated close to 1,000 children with and without autism. The study found no connection between autism and either the number of vaccines a child receives or the number of vaccines a child receives in a single day.
“This study looked into the concern that receiving too many vaccines at one doctor’s visit or too many vaccines during the first two years of life may be linked to the development of autism,” the report’s lead author, Dr. Frank DeStefano, said in an interview with NBC’s chief medical editor, Dr. Nancy Snyderman. “We found they’re not related.”
Researchers examined the vaccination schedules of 256 children with autism spectrum disorders (ASD) and 752 children without ASD. By calculating the maximum amount of antigens each child received from immunizations during a single doctor’s visit, they were able to determine the degree the child’s immune system was stimulated to produce antibodies against the diseases they were being vaccinated against. They also calculated a child’s overall exposure to antigens in three different age groups: birth to three months, birth to seven months, and birth to two years. Across the age groups, they found no correlation between increasing exposure to antigens and the number of autism diagnoses.
Health care professionals have voiced concern over recent reports showing a significant number of parents delaying or even foregoing vaccinations for their children, due to fears about a connection between vaccines and autism. The fears were first raised in 1998, when an article appeared in the Lancet claiming a link between the measles-mumps-rubella vaccine and autism. Although the study’s author, Dr. Andrew Wakefield, was discredited and the Lancet eventually retracted the article, parents have remained anxious, leading to an alarming reduction in vaccination compliance and an increase in childhood diseases, such as measles and whooping cough.
Dr. Stefano, head of the CDC’s Immunization Safety Office, hopes that this new study will reassure parents about the safety of vaccines. Each day, the immune systems of babies are exposed to many more antigens than are present in vaccines, Stefano told HealthDay News. “Most infants can handle exposure to many antigens,” he said.
The study adds to the existing literature, involving large epidemiological studies, showing no link between vaccines and autism, according to Geraldine Dawson, professor of psychiatry at University of North Carolina, Chapel Hill, and chief science officer for the advocacy group, Autism Speaks, who did not participate in the research.
“The concern around vaccines has been a very significant issue. Many parents are now deciding to wait or space out vaccines. There has been a concern that when parents are worried about whether vaccines are associated with autism that they are going to choose not to vaccinate their child,” Dawson told Time magazine online. “That’s one of the reasons we see this as very good news, because we hope this will reassure parents that the number of vaccines your child received during the first couple years of life is not associated with a risk in developing autism,” Dawson added.