Health and Human Services Secretary Robert F. Kennedy Jr. is advancing a sweeping overhaul of the nation’s vaccine testing protocol, declaring that all new vaccines must undergo placebo-controlled trials before receiving approval. While Kennedy says the move is intended to boost transparency and public trust, health experts warn it could undermine confidence in immunization programs, delay access to critical vaccines, and increase risks to public health.
Placebo-controlled trials—where participants receive either the vaccine or an inert substance like saline—are typically reserved for new pathogens where no existing treatments exist. However, Kennedy’s proposal could extend such trials to vaccines for long-controlled diseases like measles or polio. Experts say such a shift is not only unnecessary but potentially unethical, as it would leave some trial participants without protection from known dangerous diseases.
The Department of Health and Human Services has yet to clarify which vaccines would be affected or how broadly the policy would apply. While flu shots, updated annually, are reportedly exempt, the department has not ruled out revisiting already approved vaccines, especially COVID-19 shots. That uncertainty has raised alarm across the medical community.
Kennedy, who has long questioned vaccine safety, insists he is not anti-vaccine but instead supports stronger oversight and accountability. “Secretary Kennedy is not anti-vaccine — he is pro-safety, pro-transparency, and pro-accountability,” an HHS spokesperson said. Yet many scientists say his approach spreads misleading information and misrepresents scientific evidence. They argue that U.S. vaccine safety systems already rigorously monitor adverse events and that Kennedy’s rhetoric risks dismantling public confidence in proven medical safeguards.
The proposal comes as measles outbreaks surge and public vaccine confidence declines. Experts like Paul Offit, a leading pediatrician and vaccine educator, warned that Kennedy’s policy could lead to fewer vaccines being produced and higher costs, thereby limiting access and increasing vulnerability to preventable diseases. “You are watching the gradual dissolution of the vaccine infrastructure in this country,” Offit said.
Kennedy has also appointed known vaccine skeptics to key positions, while longtime vaccine regulators have resigned under pressure. This shifting leadership, coupled with Kennedy’s public comments and media appearances, has fueled concerns that his administration is politicizing vaccine oversight in ways that could harm public health.
Critics further point out that many vaccines have already been tested against placebos or proven through scientific methods called “correlates of protection.” In cases where diseases are severe and preventable, withholding vaccines from placebo groups can be deemed unethical. “Ethics must be taken into account when you set up a study,” said Stanley Plotkin, a pioneer in vaccine development. “Can I ethically agree to having people acquire the disease because they receive a placebo?”
The policy shift also touches on COVID-19 vaccines, with regulators signaling that future approvals may require new data and possibly new trials. This could delay the annual COVID shot and complicate efforts to maintain population immunity. Notably, the FDA has paused the full approval of a more traditional protein-based Novavax vaccine pending further review—despite its previous emergency use authorization.
Some lawmakers, such as Sen. Bill Cassidy of Louisiana, are calling for adherence to existing vaccine review protocols. Cassidy emphasized that requiring placebo trials for already established vaccines is unnecessary and deprives individuals of known protections.
Public health experts say the most troubling aspect of Kennedy’s approach is the potential erosion of trust in vaccines that have already saved millions of lives. “Claiming vaccines have risks the data doesn’t show or trying to overstate vaccine risks is not transparency,” said Dorit Reiss, a law professor who studies vaccine policy. “It’s misinformation, and it undermines real transparency and informed consent.”
As HHS signals broader scrutiny of vaccines under Kennedy’s leadership, many in the scientific community are urging a return to evidence-based policy grounded in decades of data—not political or ideological agendas. Without it, they warn, the country could see a resurgence of diseases once thought to be under control.
