WASHINGTON — Most of the times Dr. Anthony S. Fauci made an appearance in the White House briefing room in 2020 — before eventually being banished from public view for his grim assessments of the coronavirus pandemic — he had President Donald J. Trump glowering over his shoulder.
On Thursday, Dr. Fauci, the nation’s foremost infectious disease specialist, was back, this time with no one telling him what to say. And he made no effort to hide how he felt about it.
“The idea that you can get up here and talk about what you know — what the evidence, what the science is — and know that’s it, let the science speak,” Dr. Fauci said, pausing for a second. “It is somewhat of a liberating feeling.”
Dr. Fauci’s presence in the room where Mr. Trump and other administration officials repeatedly spread misleading and false information about the virus was part of a daylong effort by the Biden administration to show a willingness to level with the public about how severe the pandemic is and what can be done to slow its spread.
Using the kind of blunt language that had so often infuriated Mr. Trump, Dr. Fauci said that the health threat from the virus was still “a very serious situation” and called the pandemic “historic, in the very bad sense.”
He told reporters that the government was keeping a close eye on variations of the virus that had mutated in South Africa, Brazil and Britain, in some cases showing signs of being more contagious than the predominant strain circulating in the United States.
The good news, Dr. Fauci said, is that the current vaccines appear to be effective, though maybe slightly less so, against the new variants. The bad news, he conceded, is that a virus that is more easily transmitted can ultimately lead to more sickness and death without concerted efforts like mask-wearing and social distancing.
“We are paying very close attention to it,” he assured those watching the briefing.
But what he said about the virus on Thursday may have been less important than the mere fact that he was able to say it without the possibility that Mr. Trump or his aides would undercut him, challenge him or try to silence him.
As director of the government’s National Institute of Allergy and Infectious Diseases, Dr. Fauci has spent decades fighting the worst of the world’s diseases. He became something of a national celebrity as he sought to navigate the need to level with the public about the raging pandemic while dealing with Mr. Trump’s insistence that the threat was overblown and would “disappear” overnight.
Dr. Fauci recalled on Thursday how frustrating those days became.
“I don’t want to be going back over history, but it’s very clear that there were things that were said, be it regarding things like hydroxychloroquine and other things like that, that really was uncomfortable because they were not based on scientific fact,” he said, referring to Mr. Trump’s embrace of an unproven and untested drug for use as a treatment for the coronavirus.
Despite the president’s enthusiasm, hydroxychloroquinewas eventually shown not to be an effective treatment, as Dr. Fauci often tried to suggest.
After Dr. Fauci noted on Thursday that his efforts to challenge Mr. Trump’s assertions often meant that he “got into trouble sometimes,” he was asked to elaborate.
“You said I was joking about it. I was very serious,” he said. “I can tell you I take no pleasure at all in being in a situation contradicting the president, so it was really something that you didn’t feel that you could actually say something, and there wouldn’t be any repercussions.”
Despite the change of administrations, Dr. Fauci remains at the center of the worst health crisis to hit the United States in more than a century. And the country remains deeply divided about the right way to respond. Some health care workers have refused to take the vaccine, worried about its safety. A large number of Mr. Trump’s voters continue to be angry about shutdowns that have closed businesses and put people out of work, and are still not convinced of the coronavirus’s lethality.
That means Dr. Fauci will still be addressing the tension between medicine and politics as President Biden struggles to balance competing interests.
But the initial evidence suggests that Dr. Fauci and his colleagues in the nation’s leading health agencies will be given far more leeway to operate without specific orders from the White House.
On Thursday morning, just hours after Mr. Biden’s inauguration, Dr. Fauci spoke to the executive board of the World Health Organization, telling the body that the United States would not be following through with Mr. Trump’s demand to leave the group in the middle of a pandemic.
“The United States stands ready to work in partnership and solidarity to support the international Covid-19 response, mitigate its impact on the world, strengthen our institutions, advance epidemic preparedness for the future and improve the health and well-being of all people throughout the world,” Dr. Fauci said in a video appearance.
During the Trump administration, Dr. Fauci’s appearances in the White House briefing room were often preceded by rambling, contentious meetings in the Oval Office with Mr. Trump and his aides, many of whom pushed rosy scenarios or misleading data.
On Thursday, Dr. Fauci described a different scene.
“One of the things that was very clear as recently as about 15 minutes ago when I was with the president is that one of the things that we’re going to do is to be completely transparent open and honest,” he said. “If things go wrong, not point fingers but to correct them and to make everything we do be based on science and evidence.”
Dr. Fauci paused, as if to marvel at what he had just said.
“I mean, that was literally a conversation I had 15 minutes ago,” he said. “And he has said that multiple times.”
A reporter noted that Dr. Fauci — who had last appeared in the briefing room in November — had largely disappeared from public view at the end of last year after angering Mr. Trump one too many times.
Are you back now, he was asked.
He smiled and glanced at Jen Psaki, the White House press secretary.
“I think so,” he said.