CD8A and COVID-19: In this study, we used 5′ RACE combined with the third-generation high-throughput sequencing technology to confirm (a) the changes in TCR clones during the different convalescent phases of COVID-19 and the priority use of V and J gene fragments in COVID-19 patients compared with healthy controls; (b) there is persistent TCR dominant V(D)J recombination during the convalescent phase of COVID-19 from 2 weeks to 6 months; (c) the unique CDR3 motif specific for SARS-CoV-2 in CD8+ T cells at the convalescent phase in COVID-19 patients.