On Apr. 8, 2020, Novavax announced it had identified a coronavirus vaccine candidate, NVX-CoV2373, a stable, prefusion protein made using Novavax proprietary nanoparticle technology, and planned to initiate a first-in-human trial in mid-May.

Novavax proprietary Matrix-M adjuvant was incorporated with NVX-CoV2373 in order to enhance immune responses and stimulate high levels of neutralizing antibodies.