Health experts criticize the promotion of unproven links between Tylenol, autism, and vaccines

Plus, the internet reacts to a “chaotic” CDC vaccine meeting and new research finds increased rejection of childhood vaccines.

This week, reactions to the Trump administration’s claim that Tylenol and vaccines are linked to autism and the CDC’s vaccine advisory meeting dominated online conversations about vaccines. Health care providers online responded to President Trump’s claim that Tylenol use during pregnancy causes autism with a mix of confusion and alarm. Meanwhile, after two days of confusion and conflict, the committee voted to shift away from universal COVID-19 vaccine recommendations, instead making COVID-19 vaccination a “shared decision” between patient and provider. The vote did little to ease public concern about COVID-19 vaccine availability and cost in the coming months. Finally, new research suggests that parents are increasingly rejecting or delaying childhood vaccines, sparking fears that many communities lack herd immunity.

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What’s trending in vaccine conversation:

In a September 22 press conference, President Donald Trump and several Health and Human Services Secretary officials claimed that the use of acetaminophen (name brand: Tylenol) during pregnancy is linked to autism and repeated the myth that vaccines cause autism. This claim has been roundly criticized by experts, who say the evidence to support the link is inconclusive and does not prove that the drug causes autism. The president told reporters that the Food and Drug Administration will begin notifying physicians immediately of its recommendation that use during pregnancy should be avoided unless necessary. He added that the FDA will update acetaminophen labeling to include information about the purported risk and will begin the approval process for the drug leucovorin to treat autism. Health care providers, including the American College of Obstetricians and Gynecologists, condemned the announcement, with many expressing skepticism about the validity of the link and concern for pregnant patients who have limited safe pain relief options.

On September 18 and 19, the CDC’s Advisory Committee on Immunization Practices met to review recommendations for several vaccines. Days before the meeting, Health Secretary Robert F Kennedy Jr. added five new members to the committee, which he had fully replaced in June. The meeting was marked by confusion and disagreements before members voted to end universal COVID-19 vaccine recommendations. Updated vaccines remain available and covered by insurance for everyone 6 months and older, but only as part of a “shared clinical decision” between health care providers and patients. The committee also delayed a vote on hepatitis B vaccination at birth and voted to stop recommending the combination measles, mumps, rubella, and chicken pox (varicella) vaccine for children under age 4. While some vaccine opponents celebrated the change in COVID-19 guidance, others argued that it did not go far enough. Spanish-language accounts spread the false claim that the CDC had issued a warning against COVID-19 vaccines. Public health experts and vaccine advocates criticized the meeting as “chaotic” and “confused,” urging caution in relying on the new committee’s recommendations. Other users questioned the need for hepatitis B vaccination and cited the MMRV vaccine decision as supposed evidence that combination vaccines are unsafe.

New research into immunizations drew concern about the increased rejection of routine vaccines in the U.S. An NBC News and Stanford University investigation on immunization rates found that 67 percent of U.S. counties have immunization rates below herd immunity levels, and 77 percent of counties have had notable declines in immunization since 2019. Responses to the report largely blamed declining immunization on the anti-vaccine movement and right-wing politicians. Many responses also expressed strong opposition to certain “new” vaccines and questioned the safety and necessity of other routine vaccines. A recent KFF/Washington Post poll, which found that one in six parents report skipping or delaying at least one childhood vaccine, received a similarly mixed response. Some celebrated that “people are waking up” to the alleged dangers of vaccines, while others harshly criticized parents who don’t vaccinate.

Read the fact checks: 

• PBS News: Research doesn’t show using Tylenol during pregnancy causes autism. Here are 5 things to know 
• Your Local Epidemiologists: Covid-19 vaccine changes: What it means for you 
• Nemours KidsHealth: What Is Herd Immunity?

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Recommendations for public health professionals

Each week, the Infodemiology.com team will provide messaging recommendations in response to some of the trending narratives outlined above. Use these helpful tips when creating content, updating web pages and FAQs, and to inform strategy for messaging about vaccines.

The Trump administration’s announcement will likely cause alarm and confusion about acetaminophen use, especially among parents and pregnant people. Health communicators may explain that autism is complex and does not have a single cause, that there is no evidence that acetaminophen use or vaccines cause autism, and that the data used to support these links are flawed, incomplete, and prone to bias. Messaging may highlight that the most rigorous and large-scale studies on the topic—including a 2024 study of nearly 2.5 million children—found no link between acetaminophen use during pregnancy and autism or other neurodevelopmental disorders. Additionally, communicators may emphasize that ACOG continues to recommend acetaminophen to treat pain and fever during pregnancy and that the organization stated that the HHS announcement “is not backed by the full body of scientific evidence and dangerously simplifies the many and complex causes of neurologic challenges in children….In more than two decades of research on the use of acetaminophen in pregnancy, not a single reputable study has successfully concluded that the use of acetaminophen in any trimester of pregnancy causes neurodevelopmental disorders in children.” Finally, continuing to explain that the myth that vaccines cause autism has been disproven repeatedly is recommended. 

Conversations about COVID-19 vaccine access and cost provide health communicators with an opportunity to clarify the current state of vaccine availability. Messaging may explain that the recent ACIP vote ensures that COVID-19 vaccines remain available for everyone 6 months and older through a shared decision between patients and health care providers. Communicators may emphasize that patients should talk to a health care provider, such as a doctor or pharmacist, about getting the 2025-2026 COVID-19 vaccine. Additionally, talking points may highlight that major physician organizations recommend COVID-19 vaccines for all individuals 6 months and older, and that many large insurers will continue to cover COVID-19 vaccines. Continuing to emphasize that COVID-19 vaccines are safe and the best way to prevent severe illness, long COVID, and death is recommended.

Some parents are concerned about the safety and necessity of childhood vaccines, causing them to reject or delay routine immunizations. Health communicators can help allay these fears by explaining how vaccines protect children, families, and communities. Messaging may emphasize that high vaccination rates are necessary to achieve community protection, ensuring that even those too young to be vaccinated or with weakened immune systems can still be protected from vaccine-preventable diseases.

Interested in recommendations tailored to health care providers? Click here.