Regarding morphological changes upon infection with SARS-CoV-2, Delta infection resulted in large multinuclear syncytia and Omicron subvariants displayed small syncytia, but XBB.1.5 formed an intermediate number of syncytia (Fig. 4F), supporting data showing a stronger affinity of XBB.1.5 S protein. The gene discussed is PROS1; the disease is infection.