At a moment when the United States is experiencing its worst year for measles in decades, the nation's top health official delivered a very different message to one of the country's most prominent vaccine-skeptic organizations.
Health and Human Services Secretary Robert F. Kennedy Jr. appeared at a Children's Health Defense conference in Washington, D.C., telling attendees that their movement now has powerful allies inside the Trump administration.
"Let me be clear: You have a strong and steadfast friend in the White House," Kennedy told the audience.
The statement was particularly significant because Kennedy previously chaired Children's Health Defense and served as its chief legal counsel before entering government.
Now he oversees the federal department responsible for many of the agencies charged with protecting the nation's public health.
A Homecoming for Kennedy
Kennedy's appearance represented something of a political homecoming.
Long before joining President Donald Trump's administration, Kennedy became one of America's most prominent critics of established vaccine policy.
Children's Health Defense became an important platform for those efforts.
Kennedy stepped away from the organization when he launched his presidential campaign in 2023, and after becoming Trump's health secretary he sometimes sought to distinguish his position from the label "anti-vaccine."
His appearance before the organization, however, demonstrated that his relationship with the vaccine-skeptic movement remains significant.
Kennedy told attendees that the administration has already accomplished things that would have seemed impossible only two years earlier.
He also acknowledged frustration among activists who expected changes to happen more quickly.
Kennedy explained that government procedures and legal requirements prevented him from immediately implementing everything he wanted.
But his message to the audience was unmistakable: be patient.
The administration, he said, is continuing to pursue changes.
The Timing Could Hardly Be More Striking
Kennedy delivered those remarks while the United States is experiencing its worst year for measles since 1991.
More than 3,000 measles cases have been reported this year, and several measles-associated deaths have been reported during the past two years.
Measles is also one of the most contagious infectious diseases known.
The Centers for Disease Control and Prevention has long maintained that vaccination is the most effective method of preventing measles, and extensive scientific evidence supports the safety and effectiveness of the measles, mumps and rubella vaccine.
Kennedy has said that the MMR vaccine is the most effective way to prevent measles infection.
But his broader statements about vaccines have repeatedly generated controversy among physicians and public-health experts.
Kennedy Again Questions Vaccine Safety
During his speech, Kennedy returned to several themes that have defined his vaccine activism.
He questioned whether vaccines have been adequately studied, discussed alleged vaccine injuries and said the administration is investigating whether childhood vaccinations could contribute to chronic disease.
Kennedy also argued that parents who question established vaccine recommendations should not be dismissed or stigmatized.
"We have not taken vaccines away from anybody," Kennedy told the audience. "We have preserved access."
That distinction is central to Kennedy's defense of his policies.
He argues that the government should conduct additional research, provide parents with more information and preserve individual choice rather than simply expecting Americans to accept existing recommendations.
Medical experts who have criticized Kennedy argue that this framing creates doubt about vaccines whose safety profiles have already been extensively studied.
Some of Kennedy's Claims Have Been Challenged by Medical Experts
Independent fact-checkers reviewing Kennedy's speech identified multiple claims they described as false or misleading.
Kennedy has repeatedly questioned whether childhood vaccines have been properly safety-tested and has continued discussing a possible connection between vaccines and autism.
Decades of scientific research have failed to establish that vaccines cause autism.
The original 1998 paper that fueled widespread fears about a connection between the MMR vaccine and autism was subsequently retracted, and its author, Andrew Wakefield, lost his license to practice medicine in the United Kingdom.
Wakefield was also among the speakers appearing at the Children's Health Defense conference.
That made the event particularly unusual: the sitting United States Secretary of Health and Human Services was addressing a conference featuring some of the best-known figures in the modern movement challenging mainstream vaccine science.
Kennedy Has Already Begun Reshaping Federal Vaccine Policy
Kennedy's rhetoric isn't occurring in isolation.
Since becoming health secretary, he has attempted significant changes to the federal government's approach to vaccination.
The administration has sought to reduce the recommended childhood vaccination schedule and restructure an influential federal vaccine advisory committee.
Some of those efforts have been halted by the courts.
President Trump has also ordered federal officials to pursue changes involving the MMR vaccine, including separating the combined measles, mumps and rubella vaccination into individual shots administered at different times.
Major medical organizations have opposed that approach.
Kennedy nevertheless portrayed the administration's actions as evidence that vaccine skeptics now have an opportunity to influence federal health policy that they did not previously possess.
Supporters See Long-Overdue Scrutiny
Kennedy's supporters see the situation very differently from his critics.
They argue that pharmaceutical companies and federal health agencies have historically received too much deference and that questioning existing vaccine policies should not automatically make someone "anti-vaccine."
Children's Health Defense describes its mission more broadly as protecting children from environmental and health risks.
Kennedy has similarly framed his agenda around chronic disease, nutrition, food additives and environmental exposures in addition to vaccines.
His supporters argue that additional research and greater transparency can strengthen public confidence rather than undermine it.
Public-Health Experts See a Dangerous Moment
Many physicians and public-health officials, however, believe Kennedy's position carries unusual consequences because he is no longer simply an activist questioning government policy.
He now runs the government agency responsible for much of that policy.
Critics argue that repeatedly questioning established vaccine science from such a powerful position can contribute to public confusion and declining vaccination rates.
Those concerns become considerably more urgent when outbreaks are actually occurring.
Measles was declared eliminated from the United States in 2000, meaning the disease was no longer continuously spreading domestically.
Yet outbreaks have continued to occur when infected travelers introduce the virus into communities where vaccination rates are insufficient to stop transmission.
The current surge demonstrates how quickly the disease can return.
The Movement Now Has Someone Inside the Government
Perhaps the most consequential part of Kennedy's speech wasn't any individual claim about vaccines.
It was his description of the relationship between the movement gathered before him and the federal government he now helps lead.
For years, Children's Health Defense challenged federal health agencies from the outside.
Robert F. Kennedy Jr. helped lead that challenge.
Today, Kennedy is Secretary of Health and Human Services.
When he told the organization's members that they have a "strong and steadfast friend in the White House," he was acknowledging a remarkable reversal.
The activists who once fought federal vaccine policy from outside the government now have one of their most prominent former leaders running the department responsible for much of that policy.
And while measles spreads again across the United States, the consequences of that transformation are no longer merely theoretical.