When Donald Trump nominated David Weldon, a 71-year-old doctor from Florida who has long questioned the safety of vaccines, to lead the US Centers for Disease Control and Prevention (CDC), anti-vaccine activists celebrated.
The move comes as the US faces increased threats from bird flu and mpox as well as resurgences of whooping cough, measles and other vaccine-preventable diseases.
“He is one of us!!” the co-director of the anti-vax group Mississippi Parents for Vaccine Rights wrote on Facebook. “Since before our movement had momentum. Dream Come True.”
“Every day more good news!” wrote another prominent anti-vaxxer in West Virginia.
“SUCH GREAT NEWS TODAY!!!!!!!!!!!!!!!” announced AutismOne, a group that has platformed the anti-vaxxer who recommended chlorine dioxide, essentially industrial bleach, to “cure” autism. The organization also gave Weldon an award in 2013.
“He’s definitely someone who’s very sympathetic to the anti-vaccine cause,” said Dorit Reiss, a professor of law at UC Law San Francisco.
As a representative to the US House from 1995 to 2009, Weldon was a founding member of the Congressional Autism caucus, and he introduced two bills related to vaccines.
One bill would have limited who can receive vaccines containing thimerosal, even though nearly all vaccines were already made without the preservative by then, despite the evidence that low doses of thimerosal are safe.
Another bill sought to move the CDC’s vaccine safety work to a separate, independent agency, a major change.
When he left the US House of Representatives in 2008, Weldon signaled he was done with politics. Politics, at least, seemed done with him: after failed primaries for the US Senate in 2012 and the US House again in 2024, Weldon returned to practicing medicine privately.
Now, Weldon has been nominated for one of the most politicized agencies in the country.
But Weldon never disappeared from the public spotlight entirely. Robert F Kennedy Jr, Trump’s pick to lead health and human services, has frequently invoked Weldon to claim agencies like the CDC are captured by pharmaceutical interests.
Weldon appeared in the anti-vaccine films Shoot ‘Em Up and Vaxxed, which was directed by the gastroenterologist Andrew Wakefield, to cast doubt on vaccines.
Weldon said he attempted to slow the CDC’s process of investigating the link between autism and the measles, mumps, and rubella (MMR) vaccine – a thoroughly discredited theory advanced by Wakefield based on unethical research.
“It just didn’t seem to me like we were, we were running a system that was credible,” Weldon said in 2016’s Vaxxed. He claimed that the agency tried to “short-circuit important research and draw premature conclusions” in order to “shut the door permanently and completely” on any link between the MMR vaccine and autism, which research has repeatedly debunked.
Children’s Health Defense, the anti-vaccine organization that was led by RFK Jr until he left to pursue the US presidency last year, said that officials like Weldon would remove the federal law that compensates people for rare complications after vaccines rather than holding vaccine makers liable for each case – which could effectively end the production of key childhood vaccines.
“That would be a real risk,” Reiss said. “If you remove liability protection from routine childhood vaccines, manufacturers may just leave that market, leaving kids without access to these vaccines.”
Such a move would also make it more difficult for people to receive compensation for their very rare side effects, because their claims would need to be adjudicated individually in court.
Kennedy, as HHS secretary, could also replace members of CDC’s independent vaccine advisory committee. As CDC director, Weldon could reject recommendations from the advisers.
The CDC makes evidence-based recommendations for immunizations, including the ones given routinely in childhood. While states aren’t required to follow the recommendations, most do.
Insurance companies are only required to cover vaccines that are recommended through this process, while public health departments could lose funding to administer shots to the uninsured – creating significant access issues.
Weldon could also influence public messaging from the CDC about the safety and effectiveness of vaccines.
All of the nominees will need to be confirmed by Congress, a process that can take months. But even if they don’t make it through the confirmation process, even being named to positions like these can elevate dangerous and anti-scientific ideas, Reiss said.
“I think it increases their legitimacy. It gives them a microphone … to express their views and promote this information,” Reiss said.
“It sends a message that the Trump administration is willing to work with the anti-vaccine movement. And I think it also sends a message that science-based decisions are not the priority.”