Conversations spike after CDC announces study of debunked autism-vaccine link

This week, the measles outbreak in the South Central and Southwestern U.S. continued to fuel false claims while online posts discussed new bills and lawsuits targeting childhood and mRNA vaccines.

This week, CDC sources confirmed reports that the agency plans to launch a large-scale study into the myth that vaccines cause autism despite decades of research disproving any link. The reports caused concern online that federal health agencies may sow public doubt about the importance and safety of vaccines as state-level legislation and lawsuits target mRNA vaccines and school vaccine requirements. Meanwhile, as the measles outbreak affecting Southwestern states spread to Oklahoma, vaccine opponents promoted false claims about the safety and importance of measles vaccination.

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What’s trending in vaccine conversation:

On March 8, an HHS spokesperson confirmed reports that the CDC will investigate whether vaccines cause autism, a link that has been thoroughly researched and disproven over the last three decades. The spokespeople stated that the “CDC will leave no stone unturned.” Online, many experts and critics highlighted the many large-scale studies showing there is no link between autism and childhood vaccines, calling the new study a “waste of time and money.” Some speculated that the study would be conducted by anti-vaccine and non-CDC researchers, while others claimed without evidence that research proving the link has been “suppressed.” Vaccine skeptics showed their support for the new study by repeating debunked myths about vaccine safety, including falsely claiming that vaccine adjuvants cause autism and other developmental disorders.

False claims and conspiracy theories about measles continued to circulate online this week as the measles outbreak in the Southwest spread to a third state. Many conversations focused on vitamin A as a vaccine alternative, a response to HHS Secretary Robert F. Kennedy’s promotion of the vitamin to treat measles. Vaccine opponents suggested vaccination is unnecessary because improved sanitation and hygiene are responsible for declining measles rates and advocated for natural immunity instead of vaccination. Posts repeated the myth that MMR vaccines cause autism, claimed without evidence that the vaccine has caused far more deaths than measles, and speculated that the measles outbreak is a ploy to introduce a combination measles-COVID-19 vaccine. Florida’s surgeon general appeared to downplay the importance of vaccination, describing it as an “option” for parents who want it and repeating Kennedy’s recommendation to use vitamin A as a measles treatment.  

Social media users in several U.S. states are discussing controversial legislation and court decisions related to vaccines. Iowa voted to advance a bill banning a vaccine from being distributed, sold, or administered unless the manufacturer waives legal immunity. Critics argue that the bill would undermine the National Childhood Vaccine Injury Act, discourage health care providers from practicing in the state, and cause residents to lose access to routine vaccines. Supporters claimed that vaccines are dangerous and advocated for a similar national law. Vaccine opponents expressed disappointment over two lawsuits in Maine and New York. The Maine case ruled that parents cannot sue medical providers for vaccinating a child without parental consent unless there is evidence of willful misconduct, while the New York case ruled that Amish children must comply with the state’s vaccination requirements to enroll in school. The decisions are being criticized as “blows to religious freedom and parental rights.” Finally, several states are attempting to ban mRNA vaccines, a move lauded by vaccine opponents.

Read the fact checks: 

• Public Good News: Debunking the myth that vaccines cause autism
• Science Feedback: Side effects from vaccination aren’t more dangerous than measles outbreaks 
• NHS: Why vaccination is important and the safest way to protect yourself

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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. These helpful tips can be used when creating content, updating web pages and FAQs, and to inform strategy for messaging about vaccines.

A June 2024 study found that nearly a quarter of Americans believe that vaccines may cause autism, underscoring the pervasiveness of the myth. The proposed CDC study into the debunked link between autism and vaccines may further undermine public confidence in vaccines. Debunking may explain that ample evidence gathered through decades of research proves that vaccines don’t cause autism. Messaging may also emphasize that the myth originated in a study that has since been retracted and whose author was discredited and stripped of his medical license. Highlighting that no reputable study has ever found evidence of any link between autism and vaccines is recommended.

Some vaccine opponents and political figures are attempting to downplay the ongoing measles outbreaks in the U.S. Debunking messaging may explain that vaccination is the only way to prevent measles and that MMR is 97 percent effective against infection. Messaging may also emphasize that vitamins and supplements do not prevent measles and are not a substitute for vaccination. Talking points may highlight that the MMR vaccine has been safely given to millions of children.

Legislation and lawsuits targeting specific types of vaccinations and vaccine requirements may weaken trust in vaccines. Messaging may explain that all vaccines undergo many rounds of safety testing before approval and are monitored for safety as long as they are in use. These systems work together to detect even extremely rare vaccine safety concerns and make them known to the public.

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