Drugmaker Moderna Inc. has shipped the first batch of its rapidly developed coronavirus vaccine to U.S. government researchers, who will launch the first human tests of whether the experimental shot could help suppress the epidemic originating in China.

Moderna on Monday sent vaccine vials from its Norwood, Mass., manufacturing plant to the National Institute of Allergy and Infectious Diseases in Bethesda, Md., the company said. The institute expects by the end of April to start a clinical trial of about 20 to 25 healthy...