On Dec. 22, 2021, Novavax announced initial data evaluating the immune response of its COVID-19 vaccine, NVX-CoV2373, against the Omicron variant as well as additional data from its ongoing Phase 2 boost study.

The results demonstrated broad cross-reactivity against Omicron and other circulating variants from a primary 2-dose regimen, with responses that increased following a third dose at six months.