Dr. Dave Weldon, a former Republican congressman who is President-elect Donald J. Trump’s pick to lead the Centers for Disease Control and Prevention, has been off the political stage for more than 15 years.
Now running a private medical practice in Malabar, Fla., Mr. Weldon was hardly regarded as a leading candidate to run the federal agency, a $9 billion behemoth with a staff of more than 13,000 that has become a locus of conservative rage.
Yet over the years his views have aligned in many ways with those of Robert F. Kennedy Jr., Mr. Trump’s choice for health and human services secretary, and Dr. Weldon’s potential boss. The two have maintained a 25-year relationship.
Like Mr. Kennedy, Dr. Weldon, 71, has claimed that some children may develop autism when vaccinated against measles because of genetics or other factors, despite dozens of robust studies that thoroughly disproved the claim.
Reached by phone on Tuesday, he declined to say whether he still held those beliefs and added that he could not yet comment on “anything of substance.”
Dr. Weldon said that in his time in the House of Representatives, he worked with Mr. Kennedy “to get the mercury out of the childhood vaccines.” Still, he described himself as a supporter of vaccination.