CD8A and tetanus: All together these results show that i) vaccines with tetanus-diphtheria toxoids can be a priming source of cross-reactive T cell immunity to SARS-CoV-2 and ii) SARS-CoV-2-specific CD8+ T cell epitopes in TDX pool are indeed cross-reactive with tetanus-diphtheria antigens, as predicted by Levenshtein edit distances.