Dr. Anthony Fauci
© Stefani Reynolds for The New York TimesDr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, will be a chief medical adviser to President Joseph R. Biden Jr.
Call it the Return of Fauci.

It's not that Dr. Anthony S. Fauci, America's top infectious disease expert, ever actually went anywhere. It just often seemed that way as he fell out of favor with his boss, President Trump, and was sidelined even as the country grappled with a pandemic.

Now it is Mr. Trump who is leaving, and on Thursday, his successor had a message for Americans: Dr. Fauci will soon be back in the mix.
"I asked him to stay on in the exact same role he's had for the past several presidents," President-elect Joseph R. Biden Jr. said, "and I asked him to be a chief medical adviser for me as well, and be part of the Covid team."

On Friday morning, Dr. Fauci told NBC's "Today" show he had accepted the offer "right on the spot."

Mr. Trump had at times been openly scornful of Dr. Fauci, the director of the National Institute of Allergy and Infectious Diseases, and appeared put off by his popularity. The president, who often dismissed the threat of the coronavirus, was also frustrated by Dr. Fauci's endorsements of masks and restrictions on movement, preferring the counsel of advisers who backed his call to reopen the economy as soon as possible.

Even before Mr. Biden's announcement Thursday, Dr. Fauci found himself in the news as American and British health officials skirmished over the U.K.'s announcement that it had beaten the U.S. in the race to approve a vaccine.

Gavin Williamson, Britain's education secretary, appeared to be crowing.
"We've obviously got the best medical regulators," he said. "Much better than the French have. Much better than the Belgians have. Much better than the Americans have."
Dr. Fauci seemed more than a little skeptical.

The British authorities, he said, moved more quickly only because they had not scrutinized the vaccine test data as carefully as their American counterparts. "We have the gold standard of a regulatory approach," he said.

Later, a chagrined-looking Dr. Fauci, who is ordinarily averse to public conflict, appeared on British television saying that he wanted to apologize.

"We do things a bit more differently, that's all — not better, not worse, just differently," he told the BBC.