OLIVE BRANCH, Miss. — Workers on Sunday began packaging shipments of the second COVID-19 vaccine authorized in the U.S., a desperately needed boost to efforts to bring the coronavirus pandemic under control.

Employees at a factory in the Memphis area were boxing up the vaccine developed by Moderna Inc. and the National Institutes of Health. The much-needed shots are expected to be given starting Monday, just three days after the Food and Drug Administration authorized their emergency rollout.