The Dow Jones Industrial Average closed on Wednesday down sharply again, nearly erasing three years of gains under Donald Trump's watch that the president loudly boasted about just one month ago.

The Dow was down 1,333 points after a late rally capped another day of aggressive selling off amid the coronavirus outbreak as The Johns Hopkins University put the number of US cases at 7,323 and deaths at 55. It plummeted over 200 points around midday as the president and his public health team briefed reporters at the White House, another black eye for Mr Trump even as his public messaging and policy moves responding to the virus get more serious.

The Dow closed at 19,903 after falling all the way below the level at which it opened the morning Mr Trump was sworn into office in January 2017, 19,795; it closed that day at 19,827. The Senate passed a second emergency virus package shortly after markets closed that includes paid leave benefits; Mr Trump is expected to swiftly sign it into law.

White House officials and lawmakers are working on a stimulus package that could approach $1T, with financial experts warning they should do so sooner rather than later. And the Trump administration is crafting a plan under which some Americans could get up to two checks totally $2,000 to help with lost jobs. But all of those moves have yet to calm markets.

After spending three years boasting loudly about the state of the economy during his term and saying that's the biggest reason he deserves four more years in the Oval Office, Mr Trump this week has described US stock markets as an afterthought. His message has been he must lead a federal effort to nix the virus outbreak, arguing doing that will lead to a quick stock market and economic recovery.

"We have to get rid of this. We have to win this war, and, ideally, quickly. Quickly," he told reporters Tuesday. "Because the longer it takes, it's not a good situation. And I'm not even talking about the economy. I'm talking about the lives of a lot of people."

His shift away from an economic-based message comes as that issue is one of the few about which a majority of Americans believe he is doing a good job. One poll out this week found 51 per cent of registered voters approve of his economic stewardship. Aides hope the president is proven correct, and that a swift post-virus recovery just before the heat of campaign season will push him to a second term.

The stock market and economy were not a big collective focus of a Wednesday White House press briefing, even though one of Mr Trump's top political foes, Senate Minority Leader Chuck Schumer, minutes before it started said the American economy is almost certainly hurtling towards an election-year recession.

Mr Trump acknowledged as much earlier this week, with economic experts warning millions of jobs could be lost by summer as much of American life slows to a halt and industries like food service shed employees as restaurants and bars are closed.

The nonpartisan Economic Policy Institute called for an emerging bipartisan fiscal stimulus deal include "enough fiscal stimulus that is well-targeted and sustained so long as the economy remains weak, job loss will be substantially reduced relative to any scenario where policymakers drag their feet."

But the think tank delivered a sobering warning.

"Even with moderate fiscal stimulus, we're likely to see 3 million jobs lost by summertime. Keeping this number down and allowing any job loss to be quickly recouped after the crisis ends should spur policymakers to act," the institute said in a Tuesday white paper.

The president's tone this week on the economy and US stock markets amounts to a drastic change as the virus spreads across the country.

"We've set 144 records on the stock market in three years," he said during a 19 February campaign rally in Phoenix. "And you know what that means? That your 401(k)s are up 60, 70, 80, 90, 100 percent."

A few weeks later, on the eve of the Super Tuesday presidential primaries, the president again touted the markets' value.

"Our country is stronger than ever before and today we just had the largest one-day increase in the stock market in history. That's great," he said in Charlotte. "Do you think our opponents were thrilled when they saw the stock market today?"

Fast forward one month. The president's message is much different as he suspends campaigning for a second term to focus on the COVID-19 outbreak at what he has described as his White House "nerve centre."

"What I'm going, Jon, is very simple. We're getting rid of this virus. That's what we're doing. That's the best thing we can do," he told Fox News White House correspondent Jon Roberts. "By the way, for the markets, for everything - it's a very simple, very simple solution: We want to get rid of it. We want to have ... as few deaths as possible. This is a horrible thing.