(Bloomberg) -- Francis Collins, the doctor and geneticist who has led the U.S. National Institutes of Health through three presidential administrations, said he plans to retire by the end of the year, leaving a key position to fill in the government’s pandemic response team. 

Collins, 71, was appointed as the 16th director of the NIH by President Barack Obama in 2009. Lawrence Tabak, who’s been the agency’s second in command since 2010, would be in line to serve as acting director until the Biden administration nominates a new one.

Collins is leaving at a time when leadership of the nation’s health agencies is in flux. The Biden administration has yet to nominate a permanent head of the Food and Drug Administration. And Bloomberg has reported that the government’s Covid-19 response has sometimes blurred the lines of decision-making, with the White House making pronouncements on booster shots before they were authorized by the FDA and the Centers for Disease Control and Prevention. 

Anthony S. Fauci, the White House chief medical adviser for Covid-19, has already turned down the nomination several times under previous administrations because he wanted to focus on his work as director of the National Institute of Allergy and Infectious Diseases.

With more than a dozen years at NIH, Collins is the second-longest-serving director in the agency’s history, and he’s the only one to be appointed by three different presidents.

“Few people could come anywhere close to achieving in a lifetime what Dr. Collins has at the helm of NIH,” Health and Human Services Secretary Xavier Becerra said in a statement.

At the onset of the pandemic, Collins and Fauci were among the career public-health professionals trying to provide Americans with clear guidance in a chaotic period for the Trump administration. Collins kept a lower profile than Fauci, but the two kept in close communication, and Collins was quick to defend Fauci from President Donald Trump’s criticism.

Collins first joined the agency in 1993 to lead the National Human Genome Research Institute, where he led the mapping of the human genome. His nomination in 2009 moved swiftly through the Senate, and he’s remained popular on Capitol Hill, with his agency’s budget climbing to $42 billion in 2021 from $29.5 billion in his first year.

As director, he led an overhaul of the agency’s hospital after an external review found widespread problems with the NIH Clinical Center. He also pushed forward a major reorganization of the NIH’s 27 institutes and centers a decade ago when the agency established a new center for translational sciences, eliminating another center for research resources. 

Collins led the agency through big ticket research initiatives on brain research, opioids, precision medicine and cancer. He’s now one of the leaders to build a major new entity at the center that would serve as an incubator for biomedical discoveries, drawing on lessons learned from the Covid-19 response to develop vaccines and diagnostics in record time.

The NIH director said in an interview two years ago that he wasn’t interested in a lifelong directorship and that he’d like to see a woman lead the agency. There’s only been one female director in the agency’s history when Bernadine Healy led it in the early 1990s.

Collins was awarded the Presidential Medal of Freedom in November of 2007, and two years later received the National Medal of Science. He’s an elected member of the National Academy of Medicine and the National Academy of Sciences, and is a devout Christian and prolific musician.

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