Updated at 9:32 p.m. ET

President Trump announced a total ban on travel from European countries to the United States for the next 30 days, beginning on Friday at midnight, in a bid “to keep new cases” of coronavirus “from entering our shores.” The restrictions, he said late Wednesday, do not apply to travelers from the United Kingdom.

Trump also announced economic measures that he said would help the country overcome “temporary economic disruptions” caused by the disease.

His remarks followed an announcement by the World Health Organization Wednesday morning, declaring the outbreak a pandemic. In Washington, lawmakers scramble to propose ways to contain the economic fallout of the fast-spreading virus.

“This is the most aggressive and comprehensive effort to confront a foreign virus in modern history,” Trump said.

“I am confident that by counting and continuing to take these tough measures, we will significantly reduce the threat to our citizens and we will ultimately and expeditiously defeat this virus.”

Trump explained the travel restrictions will be adjusted “subject to conditions on the ground.” However, he added, the government will make travel exemptions for Americans who have undergone appropriate screening.

Globally, the number of cases has exceeded 125,000, with more than 1,000 of those reported in the United States.

Investors yet again have taken notice.

Stocks took a nosedive on Wednesday, with the Dow Jones Industrial Average slumping 5.9%. The slide moved the market decline from a correction to a bear market, which traders usually define as a drop of 20% or more from a recent high point. It marks the first time since the 2008 financial crisis that the Dow dipped into bear market territory.

Outside Wall Street, as the coronavirus increasingly disrupts daily American life — from school cancellations to companies pushing employees to work from home to cities banning large public gatherings — the Trump administration and Congress are rushing to unveil countermeasures.

Trump said this week that the stimulus plan could include payroll tax relief for hourly wage workers to shore up the economy. That proposal is facing stiff resistance from congressional Democrats, who argue that a payroll tax break would help the wealthiest Americans the most.

Instead, Democrats are pushing paid sick leave, expanded unemployment assistance and food assistance.

At a meeting on Wednesday with bankers about how the outbreak is impacting the financial sector, Trump, who has repeatedly downplayed the severity of the coronavirus, suggested that the U.S. was blinded by how rapidly the virus is spreading.

“We’re having to fix a problem that four weeks ago nobody thought would be a problem,” Trump said.

Whatever shape the economic response takes, the nation’s top infectious disease experts are cautioning that the number of cases and fatalities linked to the coronavirus in the U.S. are expected to keep rising.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said federal officials are working to stay ahead of the virus, but efforts have been complicated by the number of infected people entering the country after visiting other parts of the world.

“I can say we will see more cases, and things will get worse than they are right now,” Fauci told the House Oversight and Reform Committee on Wednesday.

While more than 80% of confirmed coronavirus cases are mild and the risk remains low for those who are young and healthy, Fauci emphasized just how dangerous the coronavirus can be for the elderly and those with underlying medical conditions.

The seasonal flu, Fauci said, has a mortality rate of about 0.1%, compared with the coronavirus fatality rate, which is around 1% when all available data are analyzed.

In other words, Fauci said: “It is 10 times more lethal than the seasonal flu.”

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