2nd virus vaccine shows striking success in US tests

FILE - In this May 18, 2020, file photo, a bicyclists pedals past an entrance to a Moderna, Inc., building in Cambridge, Mass. Moderna said Monday, Nov. 16, 2020, its COVID-19 vaccine is proving to be highly effective in a major trial. (AP Photo/Bill Sikes, File)

FILE - In this March 16, 2020, file photo, Neal Browning receives a shot in the first-stage safety study of a potential vaccine for COVID-19 at the Kaiser Permanente Washington Health Research Institute in Seattle. Moderna Inc., said Monday, Nov. 16, its COVID-19 vaccine is proving to be highly effective in a major trial. (AP Photo/Ted S. Warren, File)

A second experimental COVID-19 vaccine — this one from Moderna Inc. — yielded extraordinarily strong early results Monday, another badly needed dose of hope as the pandemic enters a terrible new phase.