Volunteer Jennifer Haller receives a first dose of Moderna's Covid-19 vaccine on March 16, 2020 at the Kaiser Permanente Washington Health Research Institute in Seattle. AP Photo
Volunteer Jennifer Haller receives a first dose of Moderna's Covid-19 vaccine on March 16, 2020 at the Kaiser Permanente Washington Health Research Institute in Seattle. AP Photo

Coronavirus: early trial of Moderna vaccine shows promise