Weldon, 71, is a medical doctor and former lawmaker who served in the House, representing Florida. The former congressman has been a strong critic of the CDC, especially its vaccine program. Weldon has championed the long-debunked notion that thimerosal, a vaccine preservative, is linked to autism.

Weldon has questioned the safety of some vaccines and advocated for limits on abortion. He'll be the first CDC director to face Senate confirmation.

In selecting a doctor who is skeptical of vaccine safety, the president-elect is emphasizing his commitment to reforming the role of federal health agencies in radical ways.