In our analysis, IGHV3-23, IGKV3D-20, and IGKV2-29 expression levels were higher in the BCR of PBMC from the HD-COVID-19 group, while IGHV3-69 and IGKV1D-39 were detected in HDs with vaccine, and IGKV4-1 in HDs without vaccine (Figures 2B, C). This evidence concerns the gene BCR and COVID-19.