SCB-2019 is a protein subunit COVID-19 vaccine developed by Clover Biopharmaceuticals using an adjuvant from Dynavax technologies. Positive results of Phase I trials for the vaccine were published in The Lancet and the vaccine completed enrollment of 29,000 participants in Phase II/III trials in July 2021. In September 2021, SCB-2019 announced Phase III results showing 67% efficacy against all cases of COVID-19 and 79% efficacy against all cases of the Delta variant. Additionally, the vaccine was 84% effective against moderate cases and 100% effective against hospitalization.