In the first year of President Donald Trump’s second term, Robert F. Kennedy Jr. has overseen a broad reworking of the U.S. Department of Health and Human Services that includes major staffing reductions and revisions to how agencies address health guidance, particularly vaccines. The department’s shift also aligns with the administration’s MAHA push, which seeks to steer Americans toward changes in diet and related public-health priorities.
HHS’s transformation has been both praised and criticized. Supporters of MAHA have said they long viewed HHS as corrupt and untrustworthy and welcomed disruption, while some Democrats and Republicans have praised individual steps the administration says aim to encourage healthier eating and exercise or lower drug prices.
But many doctors and public health experts have raised concerns about the impact of the changes, including whether the cuts and leadership upheaval will weaken scientific capacity inside the agencies that advise the country on health. Lawrence Gostin, a Georgetown University public health law professor, said the changes would hobbled the nation’s ability to lead scientifically.
“At least in the immediate or intermediate future, the United States is going to be hobbled and hollowed out in its scientific leadership,” Gostin said, adding that he believed it would be “extraordinarily difficult to reverse all the damage.” In response, an HHS spokesperson, Andrew Nixon, denied any threat to scientific expertise and said in a statement that the department would carry its 2025 work into 2026 to “strengthen accountability, put patients first, and protect public health.”
One of the most prominent changes has centered on Kennedy’s approach to vaccines and how HHS agencies communicate vaccine guidance. During his confirmation process, Kennedy had sought to reassure senators that he would not take a “wrecking ball” to vaccine science, but the administration’s actions later drew immediate questions from public health experts who said there was no new data justifying changes.
In May, Kennedy announced the CDC would stop recommending COVID-19 vaccines for healthy children and pregnant women. The following months included actions affecting the CDC vaccine advisory structure: in June, Kennedy fired a 17-member CDC vaccine advisory committee and installed replacements that included vaccine skeptics, according to the account. The group’s subsequent decisions, described as shocking by medical professionals, included declining to recommend COVID-19 shots for anyone, adding new restrictions on the combination shot against chickenpox, measles, mumps and rubella, and reversing a longstanding recommendation that all babies receive a hepatitis B shot at birth.
Kennedy also directed the CDC in November to abandon the agency’s position that vaccines do not cause autism. While the old language remained on the CDC website, the administration added a disclaimer tied to a promise Kennedy made to Republican Sen. Bill Cassidy, while researchers and advocates said scientists have studied the question for decades and that the evidence points to vaccines not causing autism.
Alongside the CDC guidance changes, the administration has also promoted what critics describe as unproven links between vaccines, Tylenol and autism, including in an Oval Office event with Trump in September. Critics also said they reject the administration’s account of environmental factors as a substitute for evidence-based vaccine policy.
Beyond vaccine guidance, Kennedy moved quickly to restructure HHS and reduce its workforce and research spending. Within two months of taking office, he announced an effort that would shut down entire agencies, consolidate others into a new one focused on chronic disease, and lay off thousands of employees, after prior buyouts. The department’s overhaul also included forced out or fired leaders at agencies such as the National Institutes of Health and the Food and Drug Administration, and a director of the CDC whom Kennedy had hired less than a month earlier.
The administration’s changes also included cuts to scientific research, including NIH slashing billions of dollars in research projects and terminating $500 million in contracts to develop vaccines using mRNA technology. HHS also proposed or funded new research tied to MAHA priorities, including topics related to autism, Lyme disease and food additives.
MAHA itself has grown in the administration’s communications, while critics have challenged parts of the effort as unsupported. Kennedy made “MAHA” a centerpiece of his work after using the phrase on the campaign trail, and the account describes HHS efforts including a focus on ultra-processed foods, pressure for companies to phase out artificial food dyes, criticism of fluoride in drinking water, and a push to ban junk food from a program that subsidizes grocery store runs for low-income Americans.
The MAHA framing has also appeared beyond HHS, with Defense Secretary Pete Hegseth joining Kennedy in promoting fitness, Transportation Secretary Sean Duffy partnering with Kennedy on early December funding for airports to install amenities such as playgrounds and nursing pods, and EPA administrator Lee Zeldin describing plans to unveil a MAHA agenda for his department, according to the account. Still, the year also included setbacks: in May, HHS faced scrutiny for releasing a MAHA report that contained citations to studies that the outlet described as not existing. Critics said that, where MAHA calls for actions not based on science—such as distrust in vaccines or promoting raw milk—could be dangerous.
At the same time, the department’s upheaval has unfolded amid broader uncertainty in the health system, including Medicaid cuts passed by Congress and expiring Affordable Care Act subsidies that are described as putting millions of Americans’ insurance coverage in jeopardy.