Late-stage study of first single-shot vaccine begins in US

Johnson & Johnson is beginning a huge final-stage study to try to prove if a single-dose COVID-19 vaccine can protect against the virus. It will be one of the world’s largest coronavirus vaccine studies so far, testing in 60,000 volunteers in the U.S., South Africa, Argentina, Brazil, Chile, Colombia, Mexico and Peru. A handful of other vaccines in the U.S. and elsewhere are already in final testing. Hopes are high that answers about at least one could come by year’s end, maybe sooner. U.S. health officials insist the race for a vaccine isn’t cutting corners, despite enormous political pressure.