MARBLEHEAD — Dr. Amanda Ritvo addressed growing public concern after a change appeared on the Centers for Disease Control and Prevention website regarding the long-standing scientific consensus that vaccines do not cause autism.
The updated wording — described by Dr. Ritvo as “a double negative” that requires careful parsing — states that the assertion “vaccines do not cause autism” is not evidence-based because studies have not definitively ruled out the possibility that infant vaccines cause autism.
According to Dr. Ritvo, this shift in language does not reflect any new scientific findings. Rather, she emphasized, “the sole change was the viewpoint of one individual, the Health Secretary, RFK Jr., not emerging scientific evidence.”
This alteration has raised alarm among physicians, scientists, and public health leaders who argue that such messaging contradicts decades of rigorous research.
Dr. Ritvo provided a clear explanation of why the medical community maintains confidence in vaccine safety, despite the CDC’s wording update.
The gold standard for establishing causation in medicine is a randomized clinical trial, in which participants are assigned to treatment and placebo groups. But in the context of childhood vaccination, such a trial would require withholding proven, life-saving immunizations from children — a method she described as “incredibly unethical.”
Instead, scientists rely on large observational studies. These studies compare outcomes in vaccinated and unvaccinated children across many years and populations.
“Millions of children have been studied across the world,” Dr. Ritvo noted, “and the conclusion has been consistent every time: there is no increased risk of autism in vaccinated children.”
The MMR (measles, mumps, and rubella) vaccine, in particular, has been extensively researched. Despite this overwhelming evidence, she said, RFK Jr.’s motivations remain unclear. What is clear, she warned, is that promoting doubt about vaccines “is very dangerous, and we know from history that it can lead to tragic, preventable illness and death.”
Dr. Ritvo referenced a strong rebuttal issued by Massachusetts Public Health Commissioner Robbie Goldstein, which stated, “Vaccines do not cause autism, and there is no link between childhood vaccines and autism. This has been proven repeatedly through decades of rigorous, high-quality research involving millions of children worldwide. The evidence is clear, consistent, and overwhelming.”
The statement continued, “The Massachusetts Department of Public Health (DPH) rejects the assertion posted Nov. 19, 2025, on the Centers for Disease Control and Prevention (CDC) website, which suggests that the statement “vaccines do not cause autism” is not evidence-based or that studies have failed to rule out a connection between childhood vaccines and autism. Such claims are factually incorrect and deliberately misleading. They contradict the global scientific consensus and undermine public confidence in vaccines. Vaccines are one of the most effective and life-saving interventions in the history of medicine and public health. For an official federal website to include such misinformation is deeply troubling and even dangerous. It fuels misinformation and leads to misplaced doubt that puts children, families, and communities at risk for serious illness. These claims reflect ideology, not evidence.”
When asked whether the recent language change undermines trust in the CDC as a reliable source of health information. Dr. Ritvo responded candidly. “It’s such a sad thing because [the CDC] has been a trusted source for so many things, and now, because it can be changed on a whim of one man — who’s not in the healthcare industry… it definitely sows mistrust in the agency as a whole.”
She emphasized that the Health Secretary is a lawyer, not a physician or scientist, which further complicates public confidence.
With trust in the CDC shaken, Dr. Ritvo advised that families and clinicians turn to respected medical institutions whose guidance remains grounded in research.
- The American Academy of Pediatrics (AAP) has issued its own vaccine schedule.
- The American Academy of Family Physicians (AAFP) has done the same.
- Given recent concerns about the Advisory Committee on Immunization Practices (ACIP), many medical professionals are reviewing evidence independently.
She also highlighted the work of Dr. Paul Offit, a prominent infectious disease expert from the Children’s Hospital of Philadelphia, as an example of respected, evidence-driven analysis.
“I think we have to look at statements of trusted doctors who review the data, and also the studies themselves,” she said.
Yet despite these alternate sources, Dr. Ritvo lamented what she described as the “slow death of such a respected organization.” She expressed hope for the CDC’s restoration in the future.
Dr. Ritvo closed by reaffirming the importance of scientific rigor and transparent communication, especially during a time when misinformation can rapidly influence public perception. She reiterated that the research remains unequivocal: vaccines do not increase the risk of autism.
