Kennedy Issues Demands for Vaccine Approvals That Could Affect Fall Covid Boosters

Health Secretary Robert F. Kennedy Jr. on Thursday announced plans to require all new vaccines to be tested against placebos and to develop new vaccines without using mRNA technology, moves that extend his reach deep into vaccine development and raise questions about whether Covid boosters will be available in the fall.

A spokesman for the Department of Health and Human Services called the requirement for placebo testing “a radical departure” from existing standards. But that will depend on how the department defines “new,” because most new vaccines are already tested either against placebos — inert substances — or, in some cases, against vaccines for other diseases.

Mr. Kennedy is one of the nation’s leading vaccine skeptics, and he has been vocal about his disdain for mRNA technology, which was used to develop coronavirus vaccines during the first Trump administration. He once wrote on social media that “mRNA jabs don’t stop infection, don’t block transmission, don’t block mutants, don’t last, don’t work at all.”

Mr. Kennedy’s activism in recent years included petitioning the Food and Drug Administration to pull the Covid vaccine off the market in 2021, during a deadly phase of the pandemic. He also urged the F.D.A. not to authorize Covid shots for children. Mr. Kennedy has also maintained that there could be a link between vaccines and autism, and hired a discredited researcher into his agency whose work aligns with that view.

Since becoming health secretary in February, Mr. Kennedy has made few high-profile pronouncements on vaccine policy, with the exception of his tepid endorsement of the measles shots in response to the outbreak in Texas that has killed two children and one adult. But he and the Trump administration have waded into the issue in other ways, by ordering a study on vaccines and autism and delaying approval of another Covid vaccine.

Mr. Kennedy’s announcements on Thursday represent an extraordinary use of his power as secretary to make decisions ordinarily left to career scientists at the F.D.A. The moves follow his recent instructions that parents of newborns considering vaccination should “do your own research.”