In lab-dish experiments, the mutant virus escaped antibodies from the plasma of COVID-19 survivors as well as pharmaceutical-grade antibodies. Mutations arose in an immunocompromised patient with chronic SARS-CoV-2 infection. Patient-derived virus harbored structural changes now seen cropping up independently in samples across the globe. Findings underscore the need for better genomic surveillance to keep track of emerging variants. Results highlight importance of therapies aimed at multiple targets on SARS-CoV-2 to minimize risk of resistance.