Dr. Dave Weldon, a former Republican representative and President Trump’s pick to lead the Centers for Disease Control and Prevention, will appear before the Senate health committee on Thursday, the first time an agency director has been subject to the confirmation process.
Dr. Weldon, 71, is perhaps the least known of the men nominated to lead major agencies at the Department of Health and Human Services. But he is the one aligned most closely with Robert F. Kennedy Jr., the nation’s new health secretary.
Dr. Weldon, like Mr. Kennedy, has long questioned the safety of certain vaccines, and the two have maintained a 25-year relationship. The health secretary has cited Dr. Weldon’s criticisms of the C.D.C. along with his own.
Dr. Weldon served in Congress for 14 years, from 1995 to 2009. His signature legislative accomplishment was the Weldon Amendment, which bars health agencies from discriminating against hospitals or health insurance plans that choose not to provide or pay for abortions.
He also argued that abstinence is the most effective way to curb sexually transmitted infections. Cases have soared in recent years and only began to level out in 2023.
Dr. Weldon’s hearing takes place amid significant measles outbreaks in Texas and New Mexico, which have infected more than 250 people and claimed two lives; a flu season that led to record numbers of hospitalizations; and the potential for a bird flu epidemic.
He is likely to face tough questions about his views on the measles vaccine, whose safety he has repeatedly questioned, and on the C.D.C. itself, which he has sharply criticized for not doing enough to prove that vaccines are safe.
While in Congress, Dr. Weldon pushed to move the vaccine safety office away from C.D.C. control, saying the agency had a conflict of interest because it also purchases and promotes vaccines.
In an interview with The New York Times in late November, Dr. Weldon said that he had worked “to get the mercury out of the childhood vaccines,” but described himself as a supporter of vaccination.
Both his adult children are fully immunized, he said. As a doctor in coastal Florida, he prescribes thousands of doses of flu and other vaccines to his patients.
“I’ve been described as anti-vaccine,” Dr. Weldon said, but added: “I give shots. I believe in vaccination.”
Members of the Senate Committee on Health, Education, Labor and Pensions have also questioned Mr. Kennedy — whom they later endorsed — as well as Dr. Jayanta Bhattacharya and Dr. Marty Makary, the respective nominees to lead the National Institutes of Health and the Food and Drug Administration.
(The hearing for Dr. Mehmet Oz, the nominee to run the Centers for Medicare and Medicaid Services, is scheduled for Friday.)
Apart from a handful of tough questions from the committee’s chair, Senator Bill Cassidy, Republican of Louisiana, comments from members have largely fallen along partisan lines. Dr. Weldon’s hearing is not expected to be different.
Senator Cassidy, who is a physician, may press Dr. Weldon on use of the hepatitis B vaccine, which is administered to children at birth.
Dr. Weldon, like Mr. Kennedy, has questioned the need to immunize children against hepatitis B, describing it as primarily a sexually transmitted disease afflicting adults.