Health researchers, physicians, and members of Congress are warning that Health and Human Services Secretary Robert F. Kennedy Jr. has spent the past year and a half dismantling core parts of the nation’s public health and biomedical research system, according to a wide-ranging review of his tenure. Since taking office in early 2025, Kennedy has overseen mass layoffs, grant cancellations, and leadership purges across the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA).
A pattern of cuts and departures
Scientists and former federal officials describe a steady erosion of institutional capacity rather than a single dramatic event. Thousands of NIH and CDC employees have been laid off or taken early retirement amid restructuring efforts, while entire research divisions focused on infectious disease, chronic illness, and vaccine safety have seen budgets slashed or programs shuttered outright.
Multiple studies examining long-term vaccine effectiveness and safety have reportedly been halted mid-stream, with grant funding pulled before results could be published. Researchers say the abrupt cancellations not only waste years of taxpayer-funded work but also make it harder to recruit and retain scientists who fear their projects could be defunded without warning.
"You cannot rebuild institutional knowledge overnight," one former NIH official said, describing colleagues who left government science entirely rather than continue working under the current leadership. Others pointed to the departure of senior CDC vaccine officials and the restructuring of the agency’s Advisory Committee on Immunization Practices (ACIP) — where Kennedy replaced the panel’s members with his own picks — as a turning point that undermined confidence in the agency’s independence.
Lawmakers demand answers
Congressional Democrats and some Republicans have pressed HHS for explanations, with several senators sending formal letters demanding documentation on canceled grants and personnel decisions. Members of the Senate Health, Education, Labor and Pensions Committee have held hearings scrutinizing Kennedy’s changes to vaccine policy and research funding priorities, and some lawmakers have called for independent audits of the cuts’ impact on ongoing clinical trials.
“When you defund the studies that tell us whether a treatment works, you’re not saving money — you’re flying blind,” one committee member said during recent testimony, echoing concerns raised by public health researchers nationwide.
Medical associations, including groups representing pediatricians and infectious disease specialists, have issued statements warning that the disruption to research pipelines could delay new treatments and weaken the country’s ability to respond to future disease outbreaks. Several university-based research centers that rely on federal grants have reported having to lay off staff or pause studies after funding was unexpectedly withdrawn.
HHS defends the overhaul
HHS officials have defended the changes as necessary corrections to what Kennedy has described as a captured and unaccountable research bureaucracy. The department has argued that eliminating conflicts of interest, particularly ties between federal scientists and pharmaceutical companies, will ultimately produce more trustworthy science. Kennedy has also pointed to a broader push to refocus federal health spending on chronic disease prevention rather than what he has called an overreliance on pharmaceutical interventions.
Critics counter that the restructuring has disproportionately targeted vaccine research and infectious disease programs specifically, rather than reflecting a neutral reallocation of resources. They note that several of the canceled projects had no clear ties to industry funding and were instead long-running academic studies tracking population-level health outcomes.
Long-term consequences
Public health experts caution that the effects of the cuts may not be fully visible for years. Clinical trials for new therapies typically take a decade or longer to complete, and interruptions can force researchers to restart data collection from scratch or abandon studies entirely. Some scientists say the loss of experienced staff — many of whom left for the private sector or academia — represents a harder problem to fix than any single funding shortfall, since institutional expertise built over decades cannot simply be reconstituted through new hires.
International collaborators have also expressed concern. Some global health partnerships that relied on US data-sharing agreements and joint funding have been paused or restructured, according to researchers who work with international health bodies. That has raised questions about the United States’ role in coordinating responses to emerging health threats going forward.
As the debate continues in Washington, both supporters and critics of Kennedy’s approach agree on one point: the scale of change to federal health research infrastructure over the past eighteen months has been unusually rapid, and its full impact on the country’s scientific capacity will likely take years to assess.
