Vague federal directives have led to frantic action, and perhaps overreaction, before a Friday deadline.

Robert F. Kennedy Jr. also disclosed that he had reached at least one settlement agreement with a company or individual that has accused him of “misconduct or inappropriate behavior.”

Robert F. Kennedy, President Trump’s nominee for health secretary, vigorously defended his views on vaccines, and a key senator still has clear doubts.

Robert F. Kennedy Jr., the nominee to lead the Department of Health and Human Services, made disputed claims before the Senate Committee on Health, Education, Labor and Pensions.

Robert F. Kennedy Jr., Kash Patel and Tulsi Gabbard, three of President Trump’s high-profile picks, on Thursday will make their cases for confirmation.

In a Senate hearing, Robert F. Kennedy, Jr. said that efforts to address the high rates of chronic disease need to start with fixing the food supply.

In a scathing letter to lawmakers weighing Robert F. Kennedy Jr.’s nomination for health secretary, Ms. Kennedy called her cousin unfit for the job and a “predator” who led family members to addiction.

Mr. Kennedy appears to have most Republicans behind him as he seeks the job of health secretary, though he couldn’t escape his past stances on vaccines and abortion.

As he seeks to lead the health department, Mr. Kennedy wore a thin tie dotted with feathered creatures to cap a classic suit.

Robert F. Kennedy Jr., who has taken different positions on the issue, has pledged to promote President Trump’s anti-abortion agenda in a bid to get confirmed as health secretary.

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

In a wide-ranging interview, Xavier Becerra, President Biden’s health secretary, defended his tenure and hinted that he might run for governor of California.

There are an estimated 300,000 polio survivors in the United States. For some, the nomination of Robert F. Kennedy Jr. as health secretary is reviving their painful memories.

The positions of Robert F. Kennedy Jr. on vaccines and drug companies are well known. His approach to addiction has been far less scrutinized.

Agencies and unions have put in place new guardrails designed to limit political interference in government research.

The government is expected to pay lower prices for Ozempic and Wegovy starting in 2027. The Trump administration will decide whether to expand coverage for millions of Americans.

A private business has helped supercharge a controversial federal drug program. Patients and insurers have been left with big bills.

A coalition opposing the nominee for health secretary includes faculty members from leading U.S. academic institutions, including public health schools at Yale and Harvard.

The administration is committing an additional $306 million toward battling the virus, and will distribute the money before President-elect Donald J. Trump takes office.