PROS1 and COVID-19: B cell clones that are specific for the 887RSAIEDLLF895 epitope of the proteolytic cleavage sites and the fusion peptide region (E589-F972) might provide cross-reactive neutralizing antibodies against SARS-CoV-2 and variants of concern, given that bnAbs, discovered in COVID-19 convalescent patients and in vaccinated individuals previously infected with SARS-CoV-2, exhibited epitope specificities of 815RSFIEDLLF823 and K811PSKRSFIEDLLFNK825, the region encompassing S2’ cleavage site and the fusion peptide of the SARS-CoV-2 S protein (34, 35).