ASSAULT ON SCIENCEHow RFK Jr.’s Misguided Science on mRNA Vaccines Is Shaping Policy − a Vaccine Expert Examines the False Claims
On Kennedy’s instructions, NIH is funneling money away from new mRNA technologies toward a single project developing universal vaccines based on traditional whole-virus vaccine technology. Kennedy justified the decision with a series of false assertions about vaccines and their underlying technology. Abandoning mRNA vaccine research may lead to lives needlessly lost, whether due to potential medicines untapped or to pandemic unpreparedness.
At a Sept. 4, 2025, hearing before the Senate Finance Committee, Health and Human Services Secretary Robert F. Kennedy Jr. faced heated questions from numerous senators about his vaccine policies, including his stance on COVID-19 vaccines and mRNA vaccine technology generally.
Although Kennedy agreed that Operation Warp Speed, President Donald Trump’s signature initiative to produce COVID-19 vaccines in nine months, was a tremendous achievement, he also maintained that COVID-19 vaccines cause widespread and serious harm, including death, particularly in young people – a claim for which there is no evidence.
Some especially pointed questions came from Republican Sen. Bill Cassidy of Louisiana, a physician who provided the final vote needed for Kennedy’s confirmation in February 2025 after Kennedy promised him that he would not change the Centers for Disease Control and Prevention’s process for recommending vaccines. Cassidy pointed out that with the limitations and confusion caused by the CDC’s new rules around COVID-19 vaccines, “I would say effectively we are denying people vaccines.” To which Kennedy replied, “Well, you’re wrong.”
At the hearing, Kennedy stood by his decision to cut US$500 million in HHS funding for 22 research contracts on mRNA vaccine technology. HHS has said it will instead pour these funds into research on a traditional approach to designing vaccines that was first used more than 200 years ago. With such vaccines, called whole-virus vaccines, a person’s immune system is presented with the whole virus, often in weakened or inactivated form. This switcheroo has puzzled many scientists.
A few days before the hearing, on Sept. 1, Trump demanded that pharmaceutical companies prove that COVID-19 mRNA vaccines work, saying that the CDC was “being ripped apart over this question.” It was his first public acknowledgment of the chaos roiling the CDC amid the firing of its director, Susan Monarez, and subsequent resignations of four high-level agency officials.
Meanwhile, public health experts and HHS staffers are calling for Kennedy to be fired, and several senators at the hearing echoed that call.
As a vaccinologist who has studied and developed vaccines for over 35 years, I see that the science behind mRNA vaccine technology is being widely misstated. This incorrect information is shaping long-term health policy in the U.S.– which makes it urgent to correct the record.
