The number of coronavirus infections was set to top a half-million worldwide on Thursday as both Italy and the United States appeared poised to surpass China, where the pandemic began, and Spain’s death toll climbed to more than 4,000. Health care systems in Europe and New York buckled under the strain.

Faced with the spread of the pandemic, the U.S. Senate passed a $2.2 trillion economic rescue package steering aid to businesses, workers and health care facilities. Millions of Americans hoped the measure, which is expected to be voted on in the House on Friday, would give them a lifeline as they lost jobs, income and child care due to lockdowns, travel restrictions and business closures.