SARS-CoV-2 variants resistant to monoclonal antibodies in immunocompromised patients constitute a public health concern.

COVID-19 in immunocompromised hosts has emerged as a difficult therapeutic management problem. Immunocompromised hosts mount weak responses to SARS-CoV-2 and manifest infection outcomes ranging from severe disease to persistent infection. Weakened immune systems mean greater viral loads and increased opportunities for viral evolution. Gupta, Konnova, et al. report the emergence of resistant SARS-CoV-2 variants in immunocompromised patients after monoclonal antibody (mAb) therapy. mAbs target only a single determinant in the viral Spike protein, which is a weakness of such therapy when treating a mutagenic and variable virus. Hence, the emergence of mAb resistance could have been anticipated, but its documentation is important because it has major public health implications, since such resistant variants have the potential to spread and escape vaccine immunity. For immunocompromised patients, these findings suggest the need for combination therapy with antiviral drugs and the use of polyclonal antibody preparations such as convalescent plasma.