WATCH: President Donald Trump to address coronavirus concerns

WASHINGTON (AP) - President Donald Trump faces a critical challenge in grappling with the new coronavirus outbreak: Asking Americans to believe him after he and top advisers have contradicted federal scientists in playing down the threat.

The stakes could be enormous from a public health and economic perspective, and also for Trump’s personal credibility.

As Americans prepare for what experts say is an inevitable outbreak in the U.S., the X-factor may be an unpredictable president who has clashed repeatedly with scientists in his own administration and tends to see any crisis through the lens of his own reelection chances.

After two days of the stock market tumbling , Trump took to Twitter on Wednesday morning to blame the media and Democrats for causing undue alarm and harming American financial markets.

He singled out MSNBC and CNN for “doing everything possible to make the Caronavirus look as bad as possible, including panicking markets, if possible,” and added that ”incompetent Do Nothing Democrat comrades are all talk, no action. USA in great shape.”

The president scheduled an evening press conference to address how the administration is handling the virus threat.

In advance, Trump played down the mortality rate for a pathogen that has been confirmed to have killed 2,700 people globally. His top economic adviser, Larry Kudlow, echoed Trump’s outlook, saying Tuesday that the U.S. had “contained” the threat of a domestic outbreak.

Trump’s and Kudlow’s comments were at odds with warnings from Centers for Disease Control and Prevention officials who said that American communities need to prepare now for when the disease starts spreading domestically. So far, there have been just 60 confirmed cases in the U.S.

“The messaging by the White House is unhelpful,” said Lawrence Gostin, a professor of global health law at Georgetown University. “What the White House is doing is conveying a sense of overconfidence. ... Of course, we do want to maintain calm with the public, but it flies in the face of facts. There is strong likelihood that we will see an outbreak in the United States and that we could see community transmission.”

Trump’s public efforts to project calm masked a behind-the-scenes focus.

During his 36-hour visit to India, Trump received briefings from staff and periodically checked the impact on Wall Street, tweeting at all hours to try to reassure Americans and the markets about the spread of the virus.

Trump expressed deep concern to aides about the impact on the markets, according to White House officials and Republicans close to the West Wing. Trump has tied his fortunes to Wall Street more closely than any of his recent predecessors and has made a strong economy his No. 1 one argument for reelection.

As the media coverage of the virus has increased, Trump has grown concerned that even fears of an outbreak would stagger Wall Street, leading him to wonder aloud if Health and Human Services Secretary Alex Azar was the right person to lead the administration’s response, the officials said.

The White House has considered naming a virus czar to be the point person on the disease, but is not sure that is the right route.

Since the start of the crisis, Trump has been reluctant to blame China, where the virus originated, for fear of upsetting President Xi Jinping or damaging ongoing trade talks.

But he is also fearful that he could be accused of being unresponsive to the crisis. At the urging of a number of his internal and outside advisers, he directed the White House to adopt a more public presence, leading to a briefing by officials and emails to the press stressing the administration’s response.

“Americans want to see their president taking charge and showing leadership, and that is exactly what President Trump is doing,” said Trump campaign spokeswoman Kayleigh McEnany. “ In restricting travel and implementing quarantines, President Trump has taken unprecedented action to protect American citizens from the coronavirus.”

Privately, aides say concerns have spiked in recent days inside the Trump reelection campaign over the impact the virus could have on the November election.

The most pressing concern, aides said, is not the possibility of widespread outbreak in the U.S. - Trump’s aides do believe existing monitoring and restrictions are working - but the downstream effects of the virus on the global economy and public sentiment.

The virus has already shut Chinese factories that are part of the U.S. supply chain, such that Mark Zandi, an economist at Moody’s Analytics, estimated Wednesday that U.S. growth could slow to 1.7% this year - roughly the same level as in 2016. Zandi said the situation could become worse if a pandemic emerges.

“The U.S. economy is more insulated from the impact of the virus, but it is not immune, and it too would likely suffer a downturn in this scenario,” Zandi said.

Trump moved swiftly to severely curtail most travel to China a month ago, a move that administration officials believe slowed the spread of the virus to the U.S., even if it drew criticism for being too extreme in the moment.

Until now, federal health authorities have been preparing for the coronavirus’ arrival in the U.S. with little if any White House interference. They’re following the playbook: pandemic preparedness plans that were put into place in anticipation of another flu pandemic, but that will work for any respiratory-borne disease.

Part of those plans call for educating the public on what to expect if the virus begins spreading in U.S. communities, such as school closures or calls for people to telework.

One of the lessons learned in prior crises is not to offer false assurances when scientists have questions about the illness.

As Trump plays down the threat of an outbreak, his past attacks on government scientists on everything from hurricane forecasts to climate change and his reputation for straining the truth all factor into the credibility of his message.

The flap over Trump’s off-base comments about Hurricane Dorian last fall -- when he went so far as to display a weather map that had been altered with a black marker to extend the hurricane’s possible path -- demonstrated the pitfalls when a president veers from the message provided by government scientists and career professionals.

Trump, who pilloried President Barack Obama over his response to the Ebola epidemic, now finds himself having to fend off a wave of criticism from Democratic presidential rivals who claim he’s discounted science and has inadequate response plans.

At Tuesday’s presidential debate, Mike Bloomberg claimed “there’s nobody here to figure out what the hell we should be doing.” Sen. Amy Klobuchar criticized Trump for trying to cut back funding of the CDC and the National Institutes of Health.

Trump’s budgets have proposed cuts to public health, only to be overruled by Congress, where there’s strong bipartisan support for agencies like the CDC and NIH. Instead, financing has increased.