Fauci, 81, served at NIAID for 38 years beginning in former President Ronald Reagan’s administration, a role in which he helped lead the U.S. response to the HIV/AIDS epidemic, as well as the West Nile virus, anthrax crises , the pandemic flu. various threats of bird flu, Ebola and Zika. He became one of the most public figures in the federal response to the Covid-19 pandemic in 2020. Biden praised Fauci’s work in a statement, noting his “unwavering” commitment to the work, as well as his “unparalleled spirit, energy and scientific integrity.” “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 steps down from the U.S. government, I know the American people and the entire world will continue to benefit from Dr. Fauci’s expertise in what he does next,” Biden said. Biden added: “Whether you have met him personally or not, he has touched the lives of all Americans through his work. I am deeply grateful for his public service. The United States of America is stronger, more resilient and healthier because of him.” Fauci said in a statement that he is “not retiring” and will “continue to advance science and public health and inspire and guide the next generation of scientific leaders as they help the world address future infectious disease threats.” Fauci and then-President Donald Trump publicly disagreed over how to approach the pandemic, what was the right message to the American people and how to balance opening and preventing further transmission. Through it all, Trump insisted he respected Fauci but disagreed with his approach. But at a low point in their relationship, Trump suggested he was considering firing the doctor. Attacks by Trump allies led to heightened security for Fauci. In 2020, Fauci told CNN’s Dr. Sanjay Gupta that he had to get security protection after his family received death threats and harassment. Fauci told CNN last month that political pressures did not influence his decision to ultimately leave the role. “It has nothing to do with pressures, nothing to do with all the other nonsense you hear about, all the bars and slings and arrows. That has no bearing on me,” he said. This story has been updated with additional reports.