Dr. Anthony Fauci, the president’s chief medical adviser and director of the National Institute of Allergy and Infectious Diseases, said he is leaving his post in December. In a statement, Fauci said he is not retiring and is going to pursue the next chapter in his career.

“Over the coming months, I will continue to put my full effort, passion and commitment into my current responsibilities, as well as help prepare the Institute for a leadership transition. NIH is served by some of the most talented scientists in the world, and I have no doubt that I am leaving this work in very capable hands,” Fauci said in his announcement.

Fauci has served as the institute’s director for 38 years under seven presidents. He has helped lead the national response to the COVID-19 pandemic in addition to HIV/AIDS, Zika, West Nile, and Ebola outbreaks, among others.

President Joe Biden praised Fauci in a statement, “Because of Dr. Fauci’s many contributions to public health, lives here in the United States and around the world have been saved. As he leaves his position in the U.S. Government, I know the American people and the entire world will continue to benefit from Dr. Fauci’s expertise in whatever he does next.”

But for all the accolades Fauci has received, he has just as many critics. Sen. Rand Paul, R-Ky. moved to fire Fauci and have his position eliminated and broken up into three separate Senate-confirmed posts.

“To ensure that ineffective, unscientific lockdowns and mandates are never foisted on the American people ever again, I’ve introduced this amendment to eliminate Dr. Anthony Fauci’s position as Director of the National Institute of Allergy and Infectious Diseases, and divide his power into three separate new institutes,” Paul said in a statement.