The authors were interested in the development of SARS-CoV-2 resistance against four antibodies to its spike protein that potently neutralise the virus. They found that the antibodies remain effective against all of the currently recorded spike variants that have arisen during the pandemic. However, some novel spike mutants did rapidly appear following in vitro passaging in the presence of the antibodies individually, leading to a loss of neutralisation. This escape was also seen with combinations of the antibodies, even when they were binding to diverse but overlapping regions of the spike protein. Importantly, escape mutants were not generated following treatment with a non-competing antibody cocktail.
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