The extensive layoffs of federal health workers that began on Tuesday will greatly curtail the scope and influence of the Centers for Disease Control and Prevention, the world’s premier public health agency, an outcome long sought by conservatives critical of its handling of the Covid-19 pandemic.

The reorganization of the Department of Health and Human Services shrinks the C.D.C. by 2,400 employees, or roughly 18 percent of its work force, and strips away some of its core functions.

Some Democrats in Congress described the reorganization throughout H.H.S. as flatly illegal.

“You cannot decimate and restructure H.H.S. without Congress,” said Senator Patty Murray, Democrat of Washington, and a member of the Senate health committee.

“This is not only unlawful but seriously harmful — they are putting Americans’ health and well-being on the line,” she added.

Ms. Murray noted that the Trump administration had not detailed which units are being cut at the C.D.C. and other health agencies. Robert F. Kennedy Jr., the health secretary, said last week the layoffs would affect primarily administrative functions.

But according to information gathered by The New York Times from dozens of workers, the reductions were more broadly targeted. Scientists focused on environmental health and asthma, injuries, lead poisoning, smoking and climate change were dismissed.

Researchers studying blood disorders, violence prevention and access to vaccines were let go. The agency’s center on H.I.V. and sexually transmitted diseases was among the hardest hit, losing about 27 percent of its staff.

The National Institute for Occupational Safety and Health, which makes recommendations on how to keep workers safe, was all but dissolved.

What remains is a hobbled C.D.C., with a smaller global footprint, devoting fewer resources to environmental health, occupational health and disease prevention, public health experts said.

Instead, the agency will be trained more narrowly on domestic disease outbreaks. Communications will be centralized at H.H.S. in Washington.

The department intends “to ensure a more coordinated and effective response to public health challenges, ultimately benefiting the American taxpayer,” said Emily Hilliard, deputy press secretary at the department.

“C.D.C. scientists have conducted numerous interviews on a variety of topics and will continue to do so,” she added.

Critics predicted the move would prevent scientists from speaking frankly about public health.

“American taxpayers provide the resources for C.D.C.’s specialists and have the right to hear directly from them without interference by politicians,” said Dr. Thomas R. Frieden, who led the agency from 2009 to 2017.

The sweeping reductions arrive as the nation confronts an outbreak of measles in Texas and elsewhere, a spreading bird flu epidemic on poultry and dairy farms, and a raft of new questions about public health measures like water fluoridation and school vaccine requirements.

“What we seem to be seeing is a dismantling rather than a restructuring” of the public health system, said Dr. Richard Besser, chief executive of the Robert Wood Johnson Foundation and a former acting director of the C.D.C.

On Capitol Hill, the Senate health committee, which recommended confirmation of Mr. Kennedy as secretary, scheduled a hearing on the reorganization of H.H.S., citing the possible impacts on public health.

Mr. Kennedy has described the reorganization as an effort to clean up waste and bureaucracy while promising that federal health agencies would do more to improve the health of Americans.

“We’re going to eliminate an entire alphabet soup of departments and agencies while preserving their core functions by merging them into a new organization called the Administration for a Healthy America,” the secretary said in a videotaped message announcing the layoffs.

The department did not respond to requests for more detailed information.

Society’s most vulnerable — the poor, Black, Latino and Native American people, rural Americans with less access to health care, the disabled and those at highest risk for illness — are likely to be hit hardest, experts said.

“These communities rely on public health to a larger extent than wealthy communities do,” Dr. Besser said.

For decades, public health and medical research drew support across the political spectrum.

But the C.D.C. has been in the political cross hairs since the first Trump administration, when the White House muzzled the agency’s communications, meddled with its publications and blamed its scientists for bungling the pandemic response.

In recent years, lawmakers have harshly criticized the agency’s advice on masks, lockdowns, social distancing, school closures and various other attempts to contain the pandemic, calling them economically and socially disastrous.

Project 2025, the conservative blueprint for reshaping the federal government, described the C.D.C. as “perhaps the most incompetent and arrogant” federal agency, and called on Congress to curb its powers.

Through staffing cuts, the administration reduced critical divisions of the National Center for Injury Prevention and Control, and employees studying how to prevent gun violence, child abuse and elder abuse were fired.

Injuries are the leading cause of death among Americans under 45. About 47,000 Americans are killed by firearms each year, more than half of them suicides.

But gun violence is a politically fraught topic. Pressure from the National Rifle Association and conservative politicians led to a ban on using federal funds to study gun violence for almost 25 years. Funding was restored in 2019.

The injury center studied ways to improve gun safety and promoted the use of gun locks, particularly in homes where children live.

“People think of gun violence as a question for law enforcement, but the public health approach has made a big difference,” said Dr. Mark Rosenberg, a former center director.

Most of the C.D.C.’s Division of Reproductive Health, which studies maternal health, was also shuttered. Whether some or all of its portfolio will be assumed by the new organization created by Mr. Kennedy was not clear.

Pregnant women and newborns die in the United States at a far higher rate than in other industrialized nations.

In recent years, the C.D.C. focused on stark racial health disparities that put Black American women at nearly three times the risk of dying of pregnancy complications than white women.

But the Trump administration has been defunding studies of health disparities in racial, ethnic and gender minorities, saying they do not align with the president’s executive orders ending diversity, equity and inclusion initiatives.

Mr. Kennedy said last week that the National Institute for Occupational Safety and Health, which makes recommendations for preventing work-related injuries and illnesses, would be absorbed into the health department.

But on Tuesday, most of its divisions were eliminated, among them offices dedicated to protecting workers in various industries, including mine inspectors.

Even one of the agency’s most essential functions, infectious disease research, was affected.

The Trump administration had been weighing moving the H.I.V. prevention division to a different agency within the health department.

But on Tuesday, teams leading H.I.V. surveillance and research within that division were laid off. It was unclear whether some of those functions would be recreated elsewhere. (A team in the global health center working on preventing mother-to-child transmission of H.I.V. was also cut.)

Until now, the C.D.C. provided funds to states and territories for responding to and preventing H.I.V. outbreaks. Roughly one in four new diagnoses of H.I.V. is made with agency funds.

Some H.I.V. experts warned that the move could lead to a rise in H.I.V. infections among Americans.

“H.I.V. prevention is a lot more than just giving out condoms,” said Dr. John Brooks, who served as chief medical officer for the division of H.I.V. prevention until last year. “It saves lives, averts illness and produces enormous cost savings.”

Broadly, the reorganization aligns with Mr. Kennedy’s preferred emphasis on research into chronic diseases; federal research has been far too focused on infectious diseases, he has said.

But the line between them is not always clear, said Dr. Anne Schuchat, former principal deputy director of the C.D.C. Research that seems disconnected from outbreak response may also be a key for fighting pathogens.

“For Zika, we needed experts in birth defects, entomology and vector control, virologists and environmental health experts,” she said. “Emerging threats don’t respect borders of C.D.C. organizational units.”

The reorganization risks choking the talent pipeline for public health, said Ursula Bauer, former director of the agency’s National Center for Chronic Disease Prevention and Health Promotion.

“Once you decimate an agency like C.D.C., which is full of high-caliber highly trained individuals, building back is going to be incredibly difficult,” she said.

“It will take two to three times as long to undo the damage as it took to inflict it.”

The cuts also will take a toll on the agency’s ability to gather and analyze data, which are keys to identifying trends and developing interventions, Dr. Phil Huang, director of Dallas County Health and Human Services, said at a news briefing.

“You take away those systems, and it takes away the ability to see the impact of all these cuts,” he added.

Getting vaccinated against shingles can reduce the risk of developing dementia, a large new study finds.

The results provide some of the strongest evidence yet that some viral infections can have effects on brain function years later and that preventing them can help stave off cognitive decline.

The study, published on Wednesday in the journal Nature, found that people who received the shingles vaccine were 20 percent less likely to develop dementia in the seven years afterward than those who were not vaccinated.

“If you’re reducing the risk of dementia by 20 percent, that’s quite important in a public health context, given that we don’t really have much else at the moment that slows down the onset of dementia,” said Dr. Paul Harrison, a professor of psychiatry at Oxford. Dr. Harrison was not involved in the new study, but has done other research indicating that shingles vaccines lower dementia risk.

Whether the protection can last beyond seven years can only be determined with further research. But with few currently effective treatments or preventions, Dr. Harrison said, shingles vaccines appear to have “some of the strongest potential protective effects against dementia that we know of that are potentially usable in practice.”

Shingles cases stem from the virus that causes childhood chickenpox, varicella-zoster, which typically remains dormant in nerve cells for decades. As people age and their immune systems weaken, the virus can reactivate and cause shingles, with symptoms like burning, tingling, painful blisters and numbness. The nerve pain can become chronic and disabling.

In the United States, about one in three people develop at least one case of shingles, also called herpes zoster, in their lifetime, the Centers for Disease Control and Prevention estimates. About a third of eligible adults have received the vaccine in recent years, according to the C.D.C.

Several previous studies have suggested that shingles vaccinations might reduce dementia risk, but most could not exclude the possibility that people who get vaccinated might have other dementia-protective characteristics, like healthier lifestyles, better diets or more years of education.

The new study ruled out many of those factors.

“It’s pretty strong evidence,” said Dr. Anupam Jena, a health economist and physician at Harvard Medical School, who was not involved in the study but reviewed it for Nature.

The study emerged from an unusual aspect of a shingles vaccine rollout in Wales on Sept. 1, 2013. Welsh officials established a strict age requirement: people who were 79 on that date were eligible for the vaccine for one year, but those 80 and older, were ineligible. As younger people turned 79, they became eligible for the vaccine for one year.

The age cutoff — imposed because of a limited supply and because the vaccine was then considered less effective for people over 80 — set up a “natural experiment,” said Dr. Pascal Geldsetzer, an assistant professor of medicine at Stanford and the study’s senior author.

It allowed scientists to compare relatively equal groups: people eligible for the vaccine with people just slightly older who couldn’t get it. “If I take 1,000 people born one week and 1,000 people born one week later, there shouldn’t be any difference between them, except for the large difference in the vaccination uptake,” Dr. Geldsetzer said.

Researchers tracked health records of about 280,000 people who were age 71 to 88 and without dementia when the rollout began. Over seven years, nearly half of those eligible for the vaccine received it, while only a tiny number from the ineligible group were vaccinated, providing a clear before-and-after distinction.

To limit the likelihood of differences between the groups, researchers used statistical analysis to more heavily weigh data from people just one week on either side of the cutoff: those who turned 80 in the week before rollout and those who turned 80 in the week after.

They also examined medical records for possible differences between the vaccinated and unvaccinated. They evaluated whether unvaccinated people received more diagnoses of dementia simply because they visited doctors more frequently, and whether they took more medications that could increase dementia risk.

“They do a pretty good job at that,” said Dr. Jena, who wrote a commentary about the study for Nature. “They look at almost 200 medications that have been shown to be at least associated with elevated Alzheimer’s risk.”

He said, “They go through a lot of effort to figure out whether or not there might be other things that are timed with that age cutoff, any other medical policy changes, and that doesn’t seem to be it.”

The study involved an older form of shingles vaccine, Zostavax, which contains a modified version of the live virus. It has since been discontinued in the United States and some other countries because its protection against shingles wanes over time. The new vaccine, Shingrix, which contains an inactivated portion of the virus, is more effective and lasting, research shows.

A study last year by Dr. Harrison and colleagues suggested that Shingrix may be more protective against dementia than the older vaccine. Based on another “natural experiment,” the 2017 shift in the United States from Zostavax to Shingrix, it found that over six years, people who had received the new vaccine had fewer dementia diagnoses than those who got the old one. Of the people diagnosed with dementia, those who received the new vaccine had nearly six months more time before developing the condition than people who received the old vaccine.

There are different theories about why shingles vaccines might protect against dementia. One possibility is that by preventing shingles, vaccines reduce the neuroinflammation caused by reactivation of the virus, Dr. Geldsetzer said. “Inflammation is a bad thing for many chronic diseases, including dementia,” he said, so “reducing these reactivations and the accompanying inflammation may have benefits for dementia.”

Both the new study and the Shingrix study provide support for that theory.

Another possibility is that the vaccines rev up the immune system more broadly. The new study offers some evidence for that theory too. It found that women, who have more reactive immune systems and larger antibody responses to vaccination than men, experienced greater protection against dementia than men, Dr. Geldsetzer said. The vaccine also had a bigger protective effect against dementia among people with autoimmune conditions and allergies.

Dr. Maria Nagel, a professor of neurology at University of Colorado School of Medicine, who was not involved in the study, said both theories could be true. “There’s evidence for a direct effect as well as an indirect effect,”, said Dr. Nagel, who has consulted for the manufacturer of Shingrix, GSK.

She said some studies have found that other vaccines, including those against flu, create a generalized neuroprotective effect, but that because the shingles virus hides in nerves, it makes sense that a shingles vaccine would be particularly protective against cognitive impairment.

The study did not distinguish between types of dementia, but other research suggests that “the effect of the shingles vaccine for Alzheimer’s disease is much more pronounced than for another dementia,” said Svetlana Ukraintseva, a biologist at Duke who coauthored a recent study on Alzheimer’s and other dementias and vaccines. She said that might be because some Alzheimer’s cases are associated with compromised immunity.

The Welsh population in the study was mostly white, Dr. Geldsetzer said, but the report also suggested similar protective effects by analyzing death certificates in England for deaths caused by dementia. His team has also replicated the results in Australia, New Zealand and Canada.

Dr. Jena said the connection should be studied further and noted that reducing dementia risk is not the same as preventing all cases. Still, he said, the evidence suggests that “something about the exposure or access to the vaccine has this effect on dementia risk years later.”

The American Psychological Association, which sets standards for professional training in mental health, has voted to suspend its requirement that postgraduate programs show a commitment to diversity in recruitment and hiring.

The decision, by the organization’s commission on accreditation, comes as accrediting bodies throughout higher education scramble to respond to the executive order signed by President Trump attacking diversity, equity and inclusion policies. It pauses a drive to broaden the profession of psychology, which is disproportionately white and female, at a time of rising distress among young Americans.

The A.P.A. is the chief accrediting body for professional training in psychology, and the only one recognized by the U.S. Department of Education. It provides accreditation to around 1,300 training programs, including doctoral internships and postdoctoral residencies.

Mr. Trump has made accrediting bodies a particular target in his crusade against D.E.I. programs, threatening in one campaign video to “fire the radical Left accreditors that have allowed our colleges to become dominated by Marxist maniacs and lunatics” and “accept applications for new accreditors.”

Department of Justice officials have pressured accrediting bodies in recent weeks, warning the American Bar Association in a letter that it might lose its status unless it repealed diversity mandates. The A.B.A. voted in late February to suspend its diversity and inclusion standard for law schools.

The concession by the A.P.A., a bastion of support for diversity programming, is a particular landmark. The association has made combating racism a central focus of its work in recent years, and in 2021 adopted a resolution apologizing for its role in perpetuating racism by, among other things, promulgating eugenic theories.

Aaron Joyce, the A.P.A.’s senior director of accreditation, said the decision to suspend the diversity requirement was driven by “a large influx of concerns and inquiries” from programs concerned about running afoul of the president’s order.

In many cases, he said, institutions had been instructed by their legal counsels to cease diversity-related activities, and were worried it might imperil their accreditation.

“The Commission does not want to put programs in jeopardy of not existing because of a conflict between institutional guidelines” and accreditation standards, Dr. Joyce said.

He would not describe the tally of the March 13 vote, which followed about three weeks of deliberation. “Nothing about this was an easy decision, and not taken lightly,” he said. “The understanding of individual and cultural diversity is a core facet of the practice of psychology.”

The commission opted to retain another diversity-related standard: Programs must teach trainees to respect cultural and individual differences in order to treat their patients effectively. In reviewing each standard, the commission weighed “what may put programs in a compromised position” against “what is essential to the practice of psychology that simply cannot be changed,” he said.

A spokesman for the Department of Justice said the A.P.A. had taken a good step, but would have to take further steps to eliminate diversity mandates, which he said “encourage or require illegal discrimination.”

“Suspension is a welcome development, but it is not nearly enough,” said the spokesman. “These kinds of rules are unlawful and have no place in a society that values individuals for their character.”

Kevin Cokley, a professor of psychology at the University of Michigan, said he was “absolutely devastated” to learn of the A.P.A.’s decision on a psychology listserv this week.

“Frankly, I think the decision is really unconscionable, given what we know of the importance of having diverse mental health providers,” Dr. Cokley said. “I don’t know how the A.P.A. can make this sort of decision and think that we are still maintaining the highest standards of training.”

He said he thought the A.P.A. had acted prematurely, and could have waited until it faced a direct challenge from the administration.

“I think that there is always a choice,” he said. “I think this is a classic example of the A.P.A. engaging in anticipatory compliance. They made the move out of fear of what might happen to them.”

According the data from the A.P.A., the psychology work force is disproportionately white. In 2023, more than 78 percent of active psychologists were white, 5.5 percent were Black, 4.4 percent were Asian and 7.8 percent were Latino. (The general population is around 58 percent white, 13.7 percent Black, 6.4 percent Asian and 19.5 percent Latino.)

The demographic breakdown of graduate students in Ph.D. programs, in contrast, is more in line with the country. According to 2022 data from the A.P.A., 54 percent of doctoral students were white, 10 percent were Black, 10 percent were Asian and 11 percent Latino.

John Dovidio, a professor emeritus of psychology at Yale and the author of “Unequal Health: Anti-Black Racism and the Threat to America’s Health,” said the A.P.A.’s focus on diversity in recruiting had played a major part in that change.

“It really is something that departments take very, very seriously,” he said. “I have seen the impact personally.”

A memorandum announcing the decision describes it as an “interim action while awaiting further court guidance” on Mr. Trump’s executive order, which was upheld by a federal court of appeals on March 13. The order, it says, “is currently law while litigation is pending.”

Cynthia Jackson Hammond, the president of the Council for Higher Education Accreditation, which coordinates more than 70 accreditation groups, said it is “unprecedented” for such bodies to receive direct orders from the government.

“The government and higher education have always worked independently, and in good faith with each other,” she said. “Throughout the decades, what we have had is a healthy separation, until now.”

The federal government began taking a role in accreditation after World War II, as veterans flooded into universities under the G.I. Bill. Accrediting bodies are regularly reviewed by the National Advisory Committee on Institutional Quality and Integrity, which advises the Secretary of Education on whether to continue to recognize them.

But government officials have never used this leverage to impose ideological direction on higher education, Ms. Jackson Hammond said. She said diversity in recruitment remains a serious challenge for higher education, which is why the standard is still so commonly used.

“If we think about what our institutions looked like before,” she said, “that might be a barometer of what it’s going to look like if there’s not attention paid.”

It’s not just the high price of eggs or the rising cost of housing that is contributing to Americans’ unhappiness over the cost of living. Health care remains stubbornly unaffordable for millions of people, according to a new survey released Wednesday that underscores the struggle many people have in paying for a doctor’s visit or a prescription drug — even before any talk of cutting government coverage.

In the survey, 11 percent of people said they could not afford medication and care within the past three months, the highest level in the four years the survey has been conducted. More than a third of those surveyed, representing some 91 million adults, said if they were to need medical care, they would not be able to pay for it.

The survey, conducted from mid-November to late December 2024 by West Health and Gallup, also showed widening disparities for Black and Hispanic adults and for those making the least amount of money. A quarter of those with an annual household income of less than $24,000 said they could not afford or access care within the past three months.

“The extent to which that has broadened and expanded really exposes how vulnerable these classes of individuals are,” Dan Witters, a senior researcher at Gallup, said.

White adults and high earners said they experienced no real change in their ability to pay. Eight percent of white adults reported being unable to afford care, the same share as in 2021, according to the survey.

Higher premiums, the added cost of going to the doctor and the recent rollback in Medicaid coverage have all contributed to making it harder for people to afford care. Health care costs continue to rise, and dramatic cuts to Medicaid and the elimination of tax subsidies that lower the cost of Obamacare plans, as discussed by the Trump administration and Republican lawmakers, will likely exacerbate the problem, according to experts.

“It puts further pressure on a system that already has a financial toxicity that is pervasive, “ said Tim Lash, president of the West Health Policy Center. Many families are already struggling with medical debt, he said. Unlike doing without a new blender, people who forgo care can suffer or die, he said.

While there have been significant improvements in the past 15 years under the Affordable Care Act, which significantly expanded Medicaid, “we’re not a country where health care is affordable,” said Sara R. Collins, a health economist who is vice president for health care coverage and access for the nonprofit Commonwealth Fund. Even when people have insurance, many do not have sufficient coverage to pay their medical bills.

If the hundreds of billions of dollars in cuts go through that Republican lawmakers and the Trump administration are considering, the number of people who will not able to afford care is likely to climb, she said, as millions of people lose their coverage or replace it with less generous plans.

“We’re getting back to levels that existed before the Affordable Care Act,” she said.

Senator Josh Hawley, the Missouri Republican, said on Monday that he had decided to support the nomination of Dr. Mehmet Oz to lead Medicare and Medicaid because Dr. Oz told him that he would no longer support transgender care for minors and was “unequivocally pro-life.”

The Senate is expected to vote on Dr. Oz’s nomination to become administrator of the Centers for Medicare and Medicaid Services sometime this month.

Mr. Hawley was vocal about withholding his support for Dr. Oz, a cardiothoracic surgeon who became a daytime TV celebrity, over concerns about his previous positions on transgender care and certain state abortion laws. Dr. Oz featured segments on the television show about transgender care and had also previously raised possible objections to proposed state legislation that would prohibit abortion based on fetal heartbeats.

In his responses to Mr. Hawley’s written questions, Dr. Oz assured the senator that he “disavows his previous support for trans surgeries & drugs for minor children,” Mr. Hawley posted on X, the social media site. He added that he “also walks back past criticism of state pro-life laws.” Dr. Oz said he would also “work to end funding for abortion providers,” Mr. Hawley said.

Mr. Hawley’s opposition could have jeopardized Dr. Oz’s confirmation, given that Democrats seemed likely to vote against him along party lines. C.M.S. is a $1.5 trillion agency responsible for providing health care coverage to nearly half of Americans.

Last month, Mr. Hawley successfully forced the ouster of a new chief counsel, Hilary Perkins, at the Food and Drug Administration over her work as a Biden administration lawyer who argued in defense of the availability of the abortion pill. She is an anti-abortion conservative.

A spokesman for Dr. Oz did not return a request for comment.

A few days ago, Robert F. Kennedy Jr., the health secretary, embarked on a media tour to defend his decision to lay off thousands of his department’s workers.

He announced a plan last week to cut 10,000 jobs, in addition to the estimated 10,000 jobs cut through retirements and buyouts in the early weeks of the Trump administration.

Mr. Kennedy had called the Health and Human Services Department “the biggest agency in government, twice the size of the Pentagon, $1.9 trillion dollars,” during an interview with NewsNation. He went on to suggest that the department was doing little to improve the health of Americans, “with all the money that was being thrown at it, with all the personnel that were being brought in.”

H.H.S. does spend more than the Department of Defense, which has a discretionary budget of about $850 billion. But according to several budget experts, the overwhelming majority of the H.H.S. department’s $1.8 trillion budget is not spent on its staff.

Spending on personnel at the federal health agencies accounts for a small fraction of its budget — less than 1 percent, according to three budget experts. That includes the staff of the Food and Drug Administration, the Centers for Disease Control and Prevention, the National Institutes of Health and others.

The overwhelming majority of the money is spent through Medicare, for the health care of people older than 65, or through Medicaid, for people with low incomes. Those funds filter out to hospitals, clinics, nursing homes, dialysis centers, pharmaceutical companies, medical device makers and Medicare Advantage private insurance plans.

Melinda Buntin, professor of health policy and economics at Johns Hopkins University, said the $17.6 billion in costs for H.H.S. employees made up less than 1 percent of the department’s budget, and has risen in line with overall spending.

“I think that most people would be surprised by what a small share of Health and Human Services spending is for personnel, both their wages and compensation and benefits,” she said, noting that it made sense in the context of the agency’s spending on care.

Bobby Kogan, senior director of federal budget policy at the Center for American Progress, a left-leaning think tank, said Mr. Kennedy’s framing was “incredibly misleading.”

“It would leave someone with a super wrong understanding of what is going on really,” Mr. Kogan said. “The only story of what’s going on in H.H.S. is that we have a huge increase in the elderly population.”

An H.H.S. spokesman said the work force reductions are meant to cut $1.8 billion a year in federal spending, and that the amount is significant.

The Administration for Children and Families, another agency within H.H.S., also spends billions of dollars on services to the public. It operates Head Start programs, foster care, Temporary Assistance for Needy Families, formerly known as welfare, and care homes for unaccompanied minors from other countries.

Chris Towner, policy director for the Committee for a Responsible Federal Budget, made his own calculation, also concluding that H.H.S. staff costs appeared to be shy of 1 percent of the department’s spending. The figure could be slightly higher, he said, given the number of health agency workers with advanced degrees.

So far, the Trump administration has talked about fraud in the federal government repeatedly — though not the type that’s long been a target in Congress. Lawmakers have repeatedly raised the idea of reeling in Medicare Advantage insurance plans, which were estimated to overcharge Medicare by tens of billions of dollars a year.

The United States is ending its financial support for family planning programs in developing countries, cutting nearly 50 million women off from access to contraception.

This policy change has attracted little attention amid the wholesale dismantling of American foreign aid, but it stands to have enormous implications, including more maternal deaths and an overall increase in poverty. It derails an effort that had brought long-acting contraceptives to women in some of the poorest and most isolated parts of the world in recent years.

The United States provided about 40 percent of the funding governments contributed to family planning programs in 31 developing countries, some $600 million, in 2023, the last year for which data is available, according to KFF, a health research organization.

That American funding provided contraceptive devices and the medical services to deliver them to more than 47 million women and couples, which is estimated to have averted 17.1 million unintended pregnancies and 5.2 million unsafe abortions, according to an analysis by the Guttmacher Institute, a sexual health research organization. Without this annual contribution, 34,000 women could die from preventable maternal deaths each year, the Guttmacher calculation concluded.

“The magnitude of the impact is mind-boggling,” said Marie Ba, who leads the coordination team for the Ouagadougou Partnership, an initiative to accelerate investments and access to family planning in nine West African countries.

The funding has been terminated as part of the Trump administration’s disassembling of the United States Agency for International Development. The State Department, into which the skeletal remains of U.S.A.I.D. was absorbed on Friday, did not reply to a request for comment on the decision to stop funding family planning. Secretary of State Marco Rubio has described the terminated aid projects as wasteful and not aligned with American strategic interest.

Support for family planning in the world’s poorest and most populous countries has been a consistent policy priority for both Democratic and Republican administrations for decades, seen as a bulwark against political instability. It also lowered the number of women seeking abortions.

Among the countries that will be significantly affected by the decision are Afghanistan, Ethiopia, Bangladesh, Yemen and the Democratic Republic of Congo.

The money to support international family planning programs is appropriated by Congress and was extended in the most recent spending bill that keeps the government operating through September. The move by the State Department to cut these and other aid programs is the subject of multiple lawsuits currently before federal courts.

The Trump administration has also terminated American funding for the United Nations’ sexual and reproductive health agency, U.N.F.P.A., which is the world’s largest procurer of contraceptives. The United States was the organization’s largest donor.

Although the United States was not the sole supplier of contraception in any country, the abrupt termination of American funding has created chaos in the system and has already caused clinics to run out of products.

An estimated $27 million worth of family planning products already procured by U.S.A.I.D. are stuck at different points in the delivery system — on boats, in ports, in warehouses — with no programs or employees left to unload them or hand them over to governments, according to a former U.S.A.I.D. employee who was not authorized to speak to a reporter. One plan proposed by the new U.S.A.I.D. leadership in Washington is for remaining employees to destroy them.

Supply chain management was a major focus for U.S.A.I.D., across all areas of health, and the United States paid to move contraceptive supplies such as hormonal implants, for example, from manufacturers in Thailand to the port in Mombasa, Kenya, from where they were taken by trucks to warehouses across East Africa and then to local clinics.

“To put the pieces back together is going to be very difficult,” said Dr. Natalia Kanem, executive director of U.N.F.P.A. “Already this has had a catastrophic impact — it’s literally affecting millions of women and families. The poorest countries don’t have the resilient buffer.”

The United States also paid for data and information systems that helped governments track what was in stock and what they needed to order. None of those systems have operated since the Trump administration sent a stop-work order to all programs that received U.S.A.I.D. grants.

Bellington Vwalika, a professor of obstetrics and gynecology at the University of Zambia, said that contraceptives had already begun to run short in some parts of the country, where the United States supplied a quarter of the national family planning budget.

“The affluent can buy the commodity they want — it is the poor people who have to think, ‘Between food and contraception, what should I get?’” he said.

Even before the United States pulled out of family planning programs, surveys found that globally, a billion women of reproductive age wished to avoid pregnancy but did not have access to a modern contraceptive method.

At the same time, there had been great progress. Demand for contraception has been rising steadily — with long-acting methods that offer women greater privacy and secure protection — in Africa, the region of the world with the lowest coverage. Supply has improved with better infrastructure that helped get products to rural areas. And “demand creation” projects, of which the United States was a major funder, used advertisements and social media to inform people about the range of contraceptive choices available and the advantages of spacing or delaying pregnancies. Women’s rising levels of education boosted demand, too.

Thelma Sibanda, a 27-year-old engineering graduate who lives in a low-income community on the edge of the Zimbabwean capital, Harare, two weeks ago received a hormonal implant that will prevent pregnancy for five years, at a free pop-up clinic run by Population Services Zimbabwe, which had a multiyear U.S.A.I.D. grant to deliver free family planning services.

Ms. Sibanda has a 2-year-old son and says she cannot afford more children: She can’t find a job in Zimbabwe’s fractured economy, and neither can her husband. They subsist on the $150 he earns each month from a vegetable stand. She had been relying on “hope and faith and natural methods” to prevent another pregnancy since her son was born, Ms. Sibanda said, and had wished for something more reliable, but it simply wasn’t possible in her family’s budget — until the free clinic came to her neighborhood.

With its U.S.A.I.D. funding, the Zimbabwean organization that provided her implant last year was able to buy six sturdy Toyota vehicles and camping equipment so that an outreach team could travel to the most remote regions of the country, delivering vasectomies and IUDs in pop-up clinics. Since the Trump executive order, they have had to stop using all of that equipment.

The international nonprofit MSI Reproductive Choices has stepped in with temporary funds so the teams can continue to provide free care for the women they can reach, such as Ms. Sibanda.

Ms. Sibanda said her priority was providing the best possible education for her son, and because school fees are costly, that means no more children. But many African women have no way to make this kind of choice. In Uganda, while the national fertility rate is 4.5 children per woman, it’s not unusual to meet women in rural areas with limited education who have eight or 10 children, said Dr. Justine Bukenya, a lecturer in community health and behavioral science at Makerere University in Kampala. These women become pregnant for the first time as teenagers and have little space between pregnancies.

“By the time they are 30 they could have their 10th pregnancy — and these are the women who will be affected,” she said. “We are losing the opportunity to make progress with them. The United States was doing a very strong job here of creating demand for contraception with these women, and mobilizing young men and women to go for family planning.”

Some women who have relied on free or low-cost service through public health systems may now try to buy contraceptives in the private market. But prices of pills, IUDs and other devices will most likely rise significantly without the guaranteed, large-volume purchases from the United States.

“As a result, women who previously relied on free or affordable options through public health systems may now be forced to turn to private sector sources — at prices they cannot afford,” said Karen Hong, chief of U.N.F.P.A.’s supply chain unit.

The next largest donors to family planning after the United States are the Netherlands, which provided about 17 percent of donor government funding in 2023, and Britain, with 13 percent. Both countries recently announced plans to cut their aid budgets by a third or more.

Ms. Ba said the focus in the West African countries where she works was mobilizing domestic resources and figuring out how governments can try to reallocate money to cover what the United States was supplying. Philanthropies such as the Gates Foundation and financial institutions including the World Bank, which are already significant contributors to family planning, may offer additional funding to try to keep products moving into countries.

“We were getting so optimistic — even with all the political instability in our region, we were adding millions more women using modern methods in the last few years,” Ms. Ba said. “And now all of it, the U.S. support, the policies, it’s all completely gone. The gaps are just too huge to fill.”

Many people use a smartwatch to monitor their cardiovascular health, often by counting the number of steps they take over the course of their day, or recording their average daily heart rate. Now, researchers are proposing an enhanced metric, which combines the two using basic math: Divide your average daily heart rate by your daily average number of steps.

The resulting ratio — the daily heart rate per step, or DHRPS — provides insight into how efficiently the heart is working, according to a study conducted by researchers at the Feinberg School of Medicine at Northwestern University and published today in the Journal of the American Heart Association.

The study found that people whose hearts work less efficiently, by this metric, were more prone to various diseases, including Type II diabetes, hypertension, heart failure, stroke, coronary atherosclerosis and myocardial infarction.

“It’s a measure of inefficiency,” said Zhanlin Chen, a third-year medical student at the Feinberg School of Medicine at Northwestern University and lead author of the new study; his coauthors included several Feinberg faculty physicians. “It looks at how badly your heart is doing,” he added. “You’re just going to have to do a tiny bit of math.”

Some experts said they saw wisdom in DHRPS as a metric. Dr. Peter Aziz, a pediatric cardiologist at the Cleveland Clinic, said it appeared to be an advance on the information provided by daily steps or average heart rate alone.

“What is probably more important for cardio fitness is what your heart does for the amount of work it has to do,” he said. “This is a reasonable way to measure that.”

The metric does not look at heart rate during exercise. But, Dr. Aziz said, it still provided an overall sense of efficiency that, importantly, was shown by researchers to have an association with disease.

The size of the study added validity to the findings, Dr. Aziz said. The scientists mapped Fitbit data from nearly 7,000 Smartwatch users against electronic medical records.

Mr. Chen said that a simple way to grasp the value of the new metric was to compare two hypothetical individuals. Both take 10,000 steps a day, but one has an average daily resting heart rate of 80 — in the middle of the healthy range — while the other’s daily resting heart rate is 120.

The first person would have a DHRPS of 0.008, the second 0.012. The higher the ratio, the stronger the signaling of cardiac risk.

In the study, the 6,947 participants were divided into three groups based on their ratios; those with the highest showed a stronger association with disease than other participants did. The D.H.R.P.S. metric was also better at revealing disease risk than were step counts or heart rates alone, the study found.

“We designed this metric to be low-cost and to use data we’re already collecting,” Mr. Chen said. “People who want to be in charge of their own health can do a little bit of math to figure this out.”