Only the group with Allele-1 showed that serum IgG levels for SARS-CoV-2 antigens (IgG-COVID-19) had a negative correlation with BMI values, especially at the time before vaccination, whereas serum IgG levels for CMV antigens (IgG-CMV) were positively associated not only with systemic pro-inflammatory status but also with the presence of senescent T cells (both CD4+ T and CD8+ T cells) at the post-vaccination time point, regardless of the time point studied. Here, CD4 is linked to COVID-19.