U.S. Health and Human Services Secretary Robert F. Kennedy Jr. has intensified his challenge to the nation’s immunisation system by cancelling roughly $500 million in federal grants for mRNA-based vaccine research and replacing the entire 17-member Advisory Committee on Immunization Practices with eight appointees, several of whom have questioned vaccine safety. The newly constituted panel is preparing a sweeping re-evaluation of COVID-19 shots and other long-standing vaccines, with MIT operations-research professor Retsef Levi—a vocal critic of mRNA technology—named to lead the review. Vaccine manufacturers and public-health experts warn that Kennedy’s multipronged strategy could destabilise the market. Industry executives told KFF Health News that his push to expand the list of conditions eligible for payouts under the Vaccine Injury Compensation Program could expose companies to new liability risks and prompt them to stop producing widely used shots. The concern has sharpened after reports that the administration is reassessing aluminium adjuvants and other common vaccine components. Doctors’ groups and academics cite early signs of the fallout. CDC data show the country’s lowest paediatric vaccination coverage in decades, and the agency’s hamstrung response to this year’s West Texas measles outbreak—now the worst in 30 years—has drawn criticism from state officials who say federal scientific staff were sidelined. Abroad, the termination of U.S. support for mRNA research and other health programmes has coincided with clinic closures in South Africa, where more than 220,000 people have struggled to obtain HIV medication. Speculation that the administration will remove COVID-19 vaccines from the U.S. market "within months" was dismissed by a White House spokesman as "baseless." Still, the controversy underscores the political dimension of Kennedy’s agenda: a Harvard-Harris survey released this week put his national favourability at a net plus-7, even as leading paediatric and infectious-disease societies petition for his removal. Lawmakers from both parties say they expect renewed hearings on HHS vaccine policy when Congress returns from recess.