The ability of the S protein to fuse infected with uninfected cells is believed to contribute to COVID-19 pathogenesis [26,27,28], which is why we assessed the capacity of BA.2.87.1 S to drive cell–cell fusion using a split beta-galactosidase reporter assay (Figure 1c and Supplementary Figure S1d). The gene discussed is GLB1; the disease is COVID-19.