Almost all vaccinees (either previously infected or not) displayed cross-recognition of the BA.1 RBD (subjects receiving 2 doses of mRNA vaccine: 95.91%; N positive plus 2x mRNA vaccine: 91.30%; 3x mRNA vaccine: 100%; 2x adenoviral plus 1xmRNA: 97.14%), whereas only 40.54% of unvaccinated COVID-19 patients showed binding activity towards the variant RBD. Here, CFB is linked to COVID-19.