Nirmatrelvir, Molnupiravir, and Remdesivir maintain potent in vitro activity against the SARS-CoV-2 Omicron variant

Abstract Variants of SARS-CoV-2 have become a major public health concern due to increased transmissibility, and escape from natural immunity, vaccine protection, and monoclonal antibody therapeutics. The highly transmissible Omicron variant has up to 32 mutations within the spike protein, many more than previous variants, heightening these concerns of immune escape. There are now multiple antiviral therapeutics that have received approval for emergency use by the FDA and target both the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and the main protease (Mpro), which have accumulated fewer mutations in known SARS-CoV-2 variants. Here we test nirmatrelvir (PF-07321332), and other clinically relevant SARS-CoV-2 antivirals, against a panel of SARS-CoV-2 variants, including the novel Omicron variant, in live-virus antiviral assays. We confirm that nirmatrelvir and other clinically relevant antivirals all maintain activity against all variants tested, including Omicron.