As leading public health experts from across the government have tried to provide clear and consistent information about the deadly coronavirus, they have found their messages undercut, drowned out and muddled by President Trump’s push to downplay the outbreak with a mix of optimism, bombast and pseudoscience.

Speaking almost daily to the public about an outbreak that has spread across states and rocked the markets, Trump has promoted his opinions and at times contradicted the public health experts tasked with keeping Americans safe.

The president has repeatedly misstated the number of Americans who have tested positive for the virus and claimed it would “miraculously” disappear in the spring. He has given a false timeline for the development of a vaccine, publicly questioned whether vaccinations for the flu could be used to treat the novel coronavirus and dismissed the World Health Organization’s coronavirus death rate estimate, substituting a much lower figure and citing a “hunch.”

On Wednesday night, Trump made an uncritical reference to people who continue to go to work while infected with the coronavirus — placing himself at odds with doctors who have strongly urged those with even minor symptoms to stay home.

“If, you know, we have thousands or hundreds of thousands of people that get better just by sitting around, and even going to work — some of them go to work, but they get better,” Trump said in an interview with Fox News host Sean Hannity in which he disputed the WHO fatality rate.

On Thursday morning, Trump said his comments were misconstrued and blamed the Democrats and the media. “I NEVER said people that are feeling sick should go to work,” he tweeted.

The president’s running commentary about the coronavirus, untethered to script or convention, indicates that the Trump administration’s greatest obstacle to sending a clear message about the outbreak may be Trump himself.

“As we go forward . . . we have to dispel some of the misinformation that has been put out there,” House Speaker Nancy Pelosi (D-Calif.) told reporters Thursday, before listing several statements made by Trump.

The White House defended the president’s handling of the outbreak, saying he put Vice President Pence in charge of coordinating the government’s response, is updated regularly and is prepared to take further action if needed.

“Unfortunately what we are seeing from the Left and some in the media is a disgusting effort to distract and disturb the American people with fearful rhetoric and palace intrigue,” White House spokesman Judd Deere said in an email.

Trump argued in his interview with Hannity that the WHO’s estimated mortality rate for the coronavirus is overstated, a conclusion he’s come to based partially on a hunch.

“I think the 3.4 percent is really a false number,” Trump told Hannity. “Now, and this is just my hunch, and — but based on a lot of conversations with a lot of people that do this.”

Trump insisted the WHO figure was inflated because, he reasoned, some people who have the virus never get tested because the symptoms are so mild. He claimed that the true rate was “way under 1 percent.”

Public health experts, including officials from Trump’s administration, have repeatedly cited data from the WHO as they’ve sought to inform the public about a virus that began in China and spread across continents.

An administration official, who spoke on the condition of anonymity to describe the basis for Trump’s comment, said his hunch was based on data provided to the United States from South Korea that estimates the morality rate at 0.5 percent to date.

Epidemiologists are studying the death rate to try to determine a more precise number after WHO Director General Tedros Adhanom Ghebreyesus said that 3.4 percent of “reported” cases have resulted in death. The eventual rate will partly depend on the country involved and the strength of its public health system, as well as the sweep of its testing program.

Trump has made several misleading claims that have forced government scientists and officials to navigate publicly contradicting a president who has placed a premium on loyalty.

On Wednesday, Trump said the Obama administration was responsible for the inability of the federal government to ensure widespread testing for potential coronavirus patients, an unsubstantiated claim that even his own administration officials could not back up.

“The Obama administration made a decision on testing that turned out to be very detrimental to what we’re doing,” Trump said during a briefing at the White House in which he boasted that he “undid” that decision.

The unsupported claim, made for the first time publicly by the president, put Trump administration officials in the uncomfortable position of responding to questions about its accuracy.

House Democrats had a tense exchange with the nation’s top health officials in a closed-door briefing Thursday about Trump’s attempt to shift blame to his predecessor, lawmakers said.

“The briefing did get rather heated,” said Rep. Katie Porter (D-Calif.).

Porter said lawmakers were told by Health and Human Services Secretary Alex Azar that “nothing about the prior policy had worsened our response, and nothing about any change in policy is going to dramatically improve our response.”

An HHS spokeswoman disputed Porter’s account.

Addressing reporters after the briefing, Azar and other officials did not confirm the president’s assertion when asked if it was true.

Anthony S. Fauci, the veteran director of the National Institute of Allergy and Infectious Diseases, demurred when pushed to explain Trump’s comment blaming Obama: “I can’t comment on that because I don’t even know about what that is.”

Azar then interjected, telling reporters, “He doesn’t run the FDA. It’s an FDA question.”

While Trump has repeatedly heaped praise on the government scientists helping to shepherd the response — calling them the “best people in the world” — he has also credited his own expertise as more valuable.

Trump has repeatedly credited his decision to restrict travel from China, saying it saved lives. While that move may prove to be a key moment in the government’s response to the virus, Trump has also claimed without evidence that there was widespread opposition to the idea and that it was done “against the advice of a lot of great professionals” in his administration.

“Everybody said, ‘It’s too early, it’s too soon,’ and good people, brilliant people, in many ways, doctors and lawyers and, frankly, a lot of people that work on this stuff almost exclusively,” Trump told Hannity. “And they said, ‘Don’t do it.’ And my theory was that we take a lot of people in. . . . And I thought it was a wise thing to do.”

In an interview last week with Politico, Fauci acknowledged the tension between maintaining his credibility with the public and not getting crosswise with Trump.

“You should never destroy your own credibility. And you don’t want to go to war with a president,” he told Politico. “But you got to walk the fine balance of making sure you continue to tell the truth.”

Democrats have seized on the discrepancies between the president’s statements and the facts, including Trump’s initial claims that there were only 15 cases of coronavirus in the country to his assertion that a vaccine could be ready in three to four months. Fauci and others have said the timeline is at least a year to a year and a half for the vaccine.

Pelosi said Thursday that lawmakers have had to repeatedly press administration officials to “correct the record” after the president speaks about the virus.

For his part, Trump has accused Democrats of politicizing the response, referring to the criticism as a “hoax.”

His decision to use the word “hoax” while speaking about a virus that has killed more than 3,000 people globally and is threatening to spread throughout communities in the United States was roundly criticized by Democrats.

Some of the president’s supporters, however, have opted to take his word — even if it contradicts his administration’s experts.

At a rally in North Carolina on Monday, several of Trump’s backers said they did not consider the coronavirus dangerous — with one telling an NBC News reporter she did not believe the virus existed.

“It’s not that dangerous,” Deborah Cardwell, 63, of Iron Station, N.C., who attended Trump’s rally on Monday told The Washington Post. “I mean, the flu is a whole lot worse.”

Cardwell said Trump’s leadership on the coronavirus was reminiscent of “George Washington or some of the early presidents.”

Others at the rally said they didn’t see the new virus as much different than the flu, a comparison that Trump has made, and that they have confidence in what the president has said and done.

“He has handled it just fantastic,” said Tish Schultheiss, 68, of Greensboro, N.C. “Because he stopped it early, the flights coming in from countries that did have it. He has got a task force now that’s working on this. A vaccine will be made before long. I feel safe about that, too.”

Among the broader public, Trump’s handling of the virus is viewed less favorably, according to polling.

An Economist-YouGov poll conducted Sunday through Tuesday found that a 41 percent plurality of Americans thought Trump’s policies were not taking the risks seriously enough; another 34 percent said his policy was appropriate, and 4 percent said he was overreacting to the actual risks associated with the virus. The poll found that 68 percent of Americans were either “somewhat” or “very” concerned about a coronavirus epidemic in the United States, up slightly from 62 percent in February.

Amy Goldstein, Seung Min Kim, Colby Itkowitz and Emily Guskin contributed to this report.

Find a video about Trump’s comments at wapo.st/TrumpVirus