CDC website no longer rejects possible link between autism and vaccines

A Centers for Disease Control and Prevention website that had previously claimed that vaccines do not cause autism contradicted that statement, contradicting the agency’s previous efforts to combat misinformation about a link between the two.

The agency’s vaccine and autism webpage, updated Wednesday, now reiterates the skepticism that Health and Human Services Secretary Robert F. Kennedy Jr. has expressed about the safety of vaccines, even though dozens of scientific studies have failed to find evidence of a link.

An earlier version of the website said studies had shown “no link between vaccination and the development of autism spectrum disorder.” It cited a 2012 review of scientific papers by the National Academy of Medicine and a 2013 CDC study.

On Thursday, the live version of the page said: “The claim ‘vaccines do not cause autism’ is not an evidence-based claim because studies have not ruled out the possibility that vaccines cause autism in infants.”

The updated text also claimed that health officials had “ignored” studies showing a link and that the Department of Health and Human Services was conducting a “comprehensive assessment” of the causes of autism.

Studies over the past three decades have consistently found no link between vaccines and autism, including a 2019 study in Denmark that looked at the country’s entire child population over a decade.

The new CDC page still contained the phrase “vaccines do not cause autism.” A footnote explained that the language had not been removed because of an agreement with Senator Bill Cassidy, Republican of Louisiana, that it should remain on the CDC website. Senator Cassidy is a physician and Chairman of the Senate Health, Education, Labor and Pensions Committee. At least one other CDC page continued to claim there was no link, as did a page on the website of the Food and Drug Administration, which Mr. Kennedy also oversees.

Senator Cassidy’s office did not immediately respond to a request for comment.

Andrew Nixon, communications director for the Health and Human Services Agency, defended the change and reiterated that it had begun “a comprehensive assessment of the causes of autism.”

The new website pleased vaccination opponents. “The CDC is finally beginning to acknowledge the truth about this disease that affects millions,” Children’s Health Defense, an anti-vaccine organization founded by Mr. Kennedy, said on social media on Wednesday.

Doctors, epidemiologists and health experts condemned it. “This revision represents political pressure that overrides the scientific consensus,” said Dr. Jake Scott, an infectious disease doctor at Stanford University, tweeted on social media Thursday, calling the change “a dangerous precedent for evidence-based medicine.”

In a statement, the Autism Science Foundation said it was “appalled” by the new website, saying the site was “now full of anti-vaccination rhetoric and outright lies about vaccinations and autism.” “The facts don’t change because the government does,” Alison Singer, the foundation’s president, said in a statement.

The CDC also deleted a page that informed pregnant women about the benefits of a Covid-19 vaccination. “The content of this page is currently being updated to align with recent recommendations from the Advisory Committee on Immunization Practices,” the page now reads. It is unclear when the revised content might appear.

Apoorva Mandavilli contributed reporting.