Nevertheless, several authors have shown that IFN-γ by CD4+ T cells numerically dominated over IFN- γ by CD8+ T cells after COVID-19 immunization (Murugesan et al., 2021; Barreiro et al., 2022), similar to what was found in our study for individuals vaccinated with 2 doses of PZ and previous infection. The gene discussed is CD4; the disease is infection.