Omicron variant escapes therapeutic mAbs contrary to eight prior main VOC

Monocolonal antibodies (mAbs) are currently used for active immunization of COVID-19 in immunocompromised patients. We herein show that in spite there are variations in susceptibility to available mAbs that are authorized for clinical use in France tested on the original B.1.1 virus and 9 variants of concern or of interest, the cocktail casirivimab/imdevimab (REGN-CoV-2) showed a major synergistic effect. However, none of the four mAbs either alone or in combination neutralized the new Omicron variant. Our data strongly warrant a reinforcement of protective measures against infection for immunocompromised patients.