‘The claim “vaccines do not cause autism” is not an evidence-based claim,’ the public health agency said on Nov. 19.
The Centers for Disease Control and Prevention now says that it’s possible vaccines cause autism, in a reversal of its previous stance.
“The claim ‘vaccines do not cause autism’ is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism,” the CDC said in a Nov. 19 update to its website. “Studies supporting a link have been ignored by health authorities.”
The CDC cited a 2006 paper that analyzed surveys of parents with children who have autism and found many parents believed vaccines caused the disorder, which has symptoms including difficulty communicating.
It also said that the rise in the prevalence of autism in the United States correlates with an increase in the number of vaccines given to young children.
“Though the cause of autism is likely to be multi-factorial, the scientific foundation to rule out one potential contributor entirely has not been established,” the CDC said. “For example, one study found that aluminum adjuvants in vaccines had the highest statistical correlation with the rise in autism prevalence among numerous suspected environmental causes. Correlation does not prove causation, but it does merit further study.”
A small number of studies have found an association between certain vaccines and autism. Others have identified no increased risk in autism following receipt of the measles, mumps, and rubella vaccine, including twopapers that cited the Department of Health and Human Services (HHS), the CDC’s parent agency, in a 2021 report, which said there is no evidence that the vaccine causes autism.
An earlier report from the agency said evidence was insufficient to rule on an association between vaccines against diphtheria, tetanus, pertussis, and hepatitis B and autism.
“In fact, there are still no studies that support the claim that any of the 20 doses of the seven infant vaccines recommended for American children before the first year of life do not cause autism,” the CDC said in the update to its site.
It said that there are issues with the studies on autism and the measles vaccine, including that they are retrospective rather than prospective.
HHS Secretary Robert F. Kennedy Jr. said at a Nov. 17 event, responding to a college student who said that vaccines do not cause autism, that “the people who told you that have been lying to you.” He said the studies on the matter should, but do not, compare health outcomes in a vaccinated group and an unvaccinated group, and that HHS is conducting those studies
HHS is currently engaged in an investigation into the causes of autism, which includes evaluating “plausible biologic mechanisms between early childhood vaccinations and autism,” the CDC said on Nov. 19. The evaluation will include aluminum salts, which are used as adjuvants in many childhood vaccines.
