SARS-CoV-2(18) inhibitor(14) COVID-19 pandemic(13) M pro(11) inhibitors(11) protease(11) Analysis(9) COVID-19(9) variants(8) drug target(8) Antiviral agents(7) effort(7) antiviral agent(7) variant(6) SARS-CoV-2.(6) death(6) in vitro(6) Compound(6) molecular(6) Infection(6) Antiviral(5) main protease(5) structures(5) Multiple(4) dose response curves(4) catalytic(4) susceptible(4) binding energy(4) Efficacy(4) anticipated(4)