The U.S. Capitol building on March 25, 2020, in Washington, D.C. The U.S. Senate was poised to pass a massive relief package on Wednesday for Americans and businesses ravaged by the coronavirus pandemic as New York hospitals braced for a wave of virus patients.

Senate Majority Leader Mitch McConnell said the chamber would adjourn for nearly a month after it passed a historically huge $2 trillion coronavirus relief package late Wednesday night.

But as the outbreak takes a toll on American health and financial well-being, the unprecedented crisis may force Congress to act again sooner than the Senate's planned return date of April 20. McConnell acknowledged that reality Wednesday night, promising the chamber would stay "nimble" as the pandemic spreads.

"If circumstances require the Senate to return for a vote sooner than April the 20th, we will provide at least 24 hours of notice," he said.

The legislation provides one-time payments for individuals, enhanced unemployment insurance, and loans and grants for businesses small and large. It also allocates more funding for hospitals, states and municipalities, and requires insurers to cover coronavirus preventive services with no cost-sharing.

Despite the amount of money piled into combating the crisis, unseen before in U.S. history, congressional leaders predict Congress will need to take more steps to fight the outbreak as it shows few signs of abating soon.

"I think the odds are we will need new legislation, more legislation after this," Senate Minority Leader Chuck Schumer said after the vote. "First, we don't know the extent of the crisis in terms of the magnitude, so that could rise, but there are going to be problems that we don't realize now that we are going to have to grapple with."

House Speaker Nancy Pelosi echoed the sentiment Thursday morning as she outlined other priorities she would like to see addressed, including expanded paid family and medical leave, more money for states, more food assistance funding and another possible round of direct payments. Responding to the Senate's plans to leave until April 20, she told reporters, "I think everybody has to be on call for what we need when we need it, and we don't know what that might be."

Data released Thursday shed light on the early economic wreckage left by COVID-19 as businesses across the country shutter to slow its spread. Initial jobless claims skyrocketed last week to a record 3.3 million, more than four times the highest mark previously seen in 1982.

Speaking to CNBC by phone Thursday morning, Senate Finance Committee Chairman Chuck Grassley, R-Iowa, said the $2 trillion package will "hopefully" buoy the economy for 90 days.

"And when I say hopefully and it turns out in 90 days not to be as hopeful as we thought, we'll be back here trying to tackle the same thing again," he said.

The outbreak has forced Congress into thorny decisions. The coronavirus has created a desperate need for government intervention unseen in decades. At the same time, the very lawmakers crafting the relief have started to test positive for COVID-19, forcing some of their colleagues into isolation to slow its spread.

Most House members are currently away from the Capitol after two representatives tested positive for COVID-19 and several other representatives who had contact with them went into quarantine. The chamber plans to pass the $2 trillion bill by voice vote on Friday morning.

Still, House Majority Leader Steny Hoyer wrote to colleagues Wednesday night that representatives "who want to come to the House Floor to debate this bill will be able to do so."

On the Senate side, Schumer acknowledged the uncertainty in setting a schedule for being in Washington. He said determining when to return to the Capitol is "not even up to Leader McConnell or Leader Schumer, it is up to the medical experts and how long this disease goes on."

"It is how deep the coronavirus spreads that will determine when we will come back. And if we can't come back for a long time, I think we should explore as Sen. Klobuchar, and Durbin and Wyden and Warren are doing a way to vote remotely only in an emergency situation," he said.

Lawmakers in both parties and both chambers have increasingly pushed for remote voting as the crisis spreads. Rep. Katie Porter, a California Democrat and one of the most vocal supporters of conducting business from outside the Capitol during the outbreak, said Wednesday that she was in quarantine while awaiting a coronavirus test result.

The House Rules Committee released a report this week outlining "serious" challenges with remote voting. The panel's staff said it could take a long time to set up the process, adding that a remote system could be vulnerable to cyberattacks or face court challenges.

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