WASHINGTON — Congress delivered a nearly $500 billion infusion of coronavirus spending Thursday, rushing new relief to employers and hospitals buckling under the strain of a pandemic that has claimed almost 50,000 American lives and one in six U.S. jobs.

The measure passed almost unanimously, but the lopsided tally belies a potentially bumpier path ahead as battle lines are being formed for much more ambitious future legislation that may prove far more difficult to maneuver through Congress.

The bipartisan measure neared passage as lawmakers gathered in Washington as a group for the first time since March 27, adopting stricter social distancing rules while seeking to prove they can do their work despite the COVID-19 crisis.

Lawmakers’ face masks and bandannas added an somber tone to their effort to aid a nation staggered by the health crisis and devastating economic costs of the pandemic.

“Millions of people out of work,” said House Speaker Nancy Pelosi, D-Calif. “This is really a very, very, very sad day. We come to the floor with nearly 50,000 deaths, a huge number of people impacted, and the uncertainty of it all. We hope to soon get to a recovery phase. But right now we’re still in mitigation.”

Anchoring the bill is the Trump administration’s $250 billion funding request to replenish a fund to help small- and medium-size businesses with payroll, rent and other expenses. The payroll program provides forgivable loans so businesses can continue paying workers while forced to stay closed for social distancing and stay-at-home orders.

It also contains $100 billion demanded by Democrats for hospitals and a nationwide testing program, along with a $60 billion set-aside for small banks and an alternative network of community development banks that focus on development in urban neighborhoods and rural areas ignored by many lenders. There’s also $60 billion for small-business loans and grants delivered through the Small Business Administration’s existing disaster aid program.

President Donald Trump celebrated the bill’s passage at his daily White House briefing Thursday. “At a time when many Americans are enduring significant economic challenges, this bill will help small businesses to keep millions of workers on the payroll,” he said.

The 388-5 vote — with Rep. Justin Amash, I-Mich., voting “present” — came at the end of a nettlesome path to passage. Republicans sought immediate action on Trump’s “clean” request for the small business money — backed by powerful, GOP-leaning business groups — but Democrats demanded equal funding for their priorities, frustrating Republicans who accused them of seeking leverage during the crisis. Republicans said delays in replenishing the paycheck subsidy program probably pushed some struggling businesses over the edge into closure.

Signs of the pandemic were everywhere in the House chamber Thursday. As Pelosi spoke from the floor, she lowered a white scarf that had covered much of her face. House Chaplain Patrick Conroy delivered the opening prayer wearing a yellow protective mask, and most lawmakers and aides on the chamber’s sparsely populated floor wore masks as well.

With the entire Capitol closed to the public, visitors’ galleries were set aside for lawmakers in an effort to separate them.

Passage of more coronavirus relief is likely in the weeks ahead.