Our results showed that during the first week of the early immune response, SARS-CoV-2 natural infection (Nat-early) induced, on average, almost a 3-fold higher percentage of activated CD8+ T cells (27.26 ± 21.94%, average ± stdv) compared to vaccinees that have received the first vaccine dose (Vac-1X) (9.54 ± 8.23%); however, when we applied a GLS model followed by Tukey’s multiple comparison test, we observed that this difference was not statistically significant, probably due to variations inside the groups and the low number of samples analyzed. This evidence concerns the gene CD8A and infection.