On Jul. 27, 2020, the National Institutes of Health (NIH) announced that a phase 3 clinical trial designed to evaluate if an investigational vaccine can prevent symptomatic coronavirus disease 2019 (COVID-19) in adults has begun.

The vaccine, known as mRNA-1273, was co-developed by the Cambridge, Massachusetts-based biotechnology company Moderna, and the National Institute of Allergy and Infectious Diseases. The trial, which was conducted at U.S. clinical research sites, was expected to enroll approximately 30,000 adult volunteers who do not have COVID-19.