Every American traveling abroad needs to take an antigen test to return to the United States. But the start of the trip is often even more cumbersome, as many other countries (nearly every one I have ...

New high-tech Covid-19 tests promise better and earlier detection of the virus—similar to a PCR test. WSJ’s Joanna Stern (and her mannequin clone) tried out the Detect Covid-19 Test and Cue Health ...