Confirmed U.S. cases of the new coronavirus rose above half a million and the pandemic’s global death toll topped 100,000, even as officials voiced cautious optimism that social-distancing measures were slowing the contagion’s spread.

The number of reported infections of the new coronavirus across America stood at 501,301, according to data compiled by Johns Hopkins University. The actual number is likely higher, experts say, due to lack of widespread testing, false negatives and differences in reporting standards.

...