Summary (tl;dr)

The Centers for Disease Control and Prevention (CDC) has dramatically altered its official website, retracting its long-held stance that vaccines do not cause autism, a move that has ignited widespread controversy and alarm among public health experts.

Essential Background

For decades, the scientific and medical consensus, supported by numerous large-scale studies globally, has firmly concluded that there is no link between vaccines and autism spectrum disorder. The CDC, as a leading U.S. public health agency, has historically affirmed this position on its website to inform the public and prevent vaccine hesitancy. However, Health Secretary Robert F. Kennedy Jr. and former President Donald Trump have publicly questioned vaccine safety and promoted theories suggesting a connection between vaccines and autism, despite a lack of scientific evidence. This has led to concerns about political influence impacting scientific integrity within federal health agencies.

The Full Story

On November 19-20, 2025, the CDC updated its "Autism and Vaccines" webpage to state that "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 revised page further suggests that health authorities have "ignored" studies that support a link between vaccines and autism. This significant reversal was reportedly made by political appointees within the Department of Health and Human Services (HHS) without the input of relevant CDC scientific staff, blindsiding many career officials. The agency has also announced a "comprehensive assessment of the causes of autism." While the header "Vaccines do not cause autism" remains on the page, this is due to an agreement with the chair of the U.S. Senate Health, Education, Labor, and Pensions Committee.

Why It Matters

This unprecedented change by the CDC is seen by many in the public health community as a dangerous legitimization of scientifically unfounded claims, potentially eroding public trust in established medical science and increasing vaccine hesitancy. Organizations like the American Academy of Pediatrics and the Autism Science Foundation have strongly condemned the update, calling it "false information" and "anti-vaccine rhetoric" that contradicts decades of robust scientific evidence. Critics warn that such actions could lead to a decline in childhood vaccination rates, putting children at increased risk of preventable infectious diseases, especially following recent increases in measles cases and a severe flu season.

Geographic Location

• Washington, D.C., District of Columbia, United States (location of the U.S. Department of Health and Human Services, where the changes to the CDC website were reportedly directed by political appointees)
• Atlanta, Fulton County, Georgia, United States (headquarters of the Centers for Disease Control and Prevention, whose official website was updated)