In vitro activity of therapeutic antibodies against SARS-CoV-2 Omicron BA.1 and BA.2

Abstract The replacement of the Omicron BA.1 variant of SARS-CoV-2 by the BA.2 sub lineage, which has a different set of mutations in the spike glycoprotein, alters the spectrum of activity of therapeutic antibodies. In this study, we compared the neutralising power of monoclonal antibodies against the Omicron BA.1 and BA.2 variants, with an ancestral strain (D614G) and a Delta variant as reference. Sotrovimab is less active against BA.2 than against BA.1 (fold change reduction ~1,5). Within the Evusheld/ AZD744 cocktail, Cilgavimab is more active against BA.2 than against BA.1 (fold change increase ~32), whilst activity of Tixagevimab remains very low. In total, the activity of Evusheld is significantly improved (fold change increase ~10 compared to BA.1).