The health secretary spoke at a conference featuring misinformation about vaccines, including a claim that the success of the polio vaccines was a “fraud.”

Decades of research have turned up no miracle treatment for measles, but studies show the M.M.R. shot is 97 percent effective in preventing the disease.

The New England Journal of Medicine received a letter suggesting that it was biased and compromised by external pressure. Other journals have also received the letter.

The New England Journal of Medicine received a letter suggesting that it was biased and compromised by external pressure. Other journals have also received the letter.

An interim U.S. attorney is demanding information about the selection of research articles and the role of N.I.H. Experts worry this will have a chilling effect on publications.

In the first clinical trial of its kind, an A.I. chatbot eased mental health symptoms among participants. The technology may someday help solve the provider shortage.

States have been told that they can no longer use grants that were funding infectious disease management and addiction services.

After the health secretary promoted vitamin A as a cure, parents in West Texas began giving their children high doses, sometimes to prevent infection.

Public health leaders are horrified by Robert F. Kennedy Jr.’s approach to measles, but government and industry are responding to him.

Children’s Health Defense, founded by the health secretary, had published online a vaccine-safety page that looked like the agency’s but that suggested links to autism.

Children’s Health Defense, founded by the health secretary, had published online a vaccine-safety page that looked like the agency’s but that suggested links to autism.

The health secretary has suggested allowing the virus to spread, so as to identify birds that may be immune. Such an experiment would be disastrous, scientists say.

In West Texas, some with severe illness have not been taken to a doctor until their conditions worsened, officials said.

The new exemption would take effect for K-12 public schools in the 2026-2027 school year and for colleges and universities in the same academic year.

In a recent interview, the health secretary also suggested that the measles vaccine had harmed children in West Texas, center of an outbreak.

Robert F. Kennedy Jr., the H.H.S. secretary, claimed that doctors had successfully treated children with unconventional remedies, including cod liver oil.

After weeks of disruption to scientific federal grants, the National Institutes of Health has fallen behind in funding research into treatments for deadly diseases.

As of Tuesday, 22 children and two adults had been infected, all of whom were unvaccinated, local officials said.

The federal order temporarily halts the Trump administration’s plans to slash $4 billion in overhead costs for research at universities and medical centers into diseases like cancer.

Robert F. Kennedy Jr., President Trump’s nominee for health secretary, doesn’t just hold fringe views on vaccines. We fact-checked five recent statements.

PEPFAR’s computer systems also are being taken offline, a sign that the program may not return, as Republican critics had hoped.

R.F.K. Jr. and others have blamed the ingredient for allergies and other illnesses. Scientists say it actually bolsters the immune response.

Scientific meetings were canceled, and research data on the bird flu outbreak was delayed, amid confusion over the directive.

Scientific meetings were canceled, and research data on the bird flu outbreak was delayed, amid confusion over the directive.

Aaron Siri, who specializes in vaccine lawsuits, has been at Robert F. Kennedy Jr.’s side reviewing candidates for top jobs at the Department of Health and Human Services.

Elevating Mr. Kennedy to secretary of H.H.S. “would put the public’s health in jeopardy,” more than 75 laureates wrote.

Elevating Mr. Kennedy to secretary of H.H.S. “would put the public’s health in jeopardy,” more than 75 laureates wrote.

It’s not just the elderly. More than three-quarters of heat-related deaths in Mexico occurred among people younger than 35, researchers reported.

The agency long benefited from broad bipartisan support. But Republican criticism has intensified, and new choices for top health posts hope to upend the organization.