Figure 7.

Analysis of anti-RBD IgA and IgG and anti-spike IgG serum production in relation to the history of SARS-CoV-2 infection. Serum from individuals immunized with ChAdOx1 nCoV-19, BNT162b2, and CoronaVac was collected at T3 (4–6 months after the application of the second dose or pre-third dose—(A–C)) to evaluate the influence of the history of infection by SARS-CoV-2 in antibody production. A total of 22 subjects reported SARS-CoV-2 infection at some point before or during the study. The detection of anti-RBD IgA (A) and IgG (B) and anti-spike IgG (C) antibodies was performed via the enzyme immunoassay (ELISA) described in the methods section. The results are expressed through the index calculated between the ratio: mean optical density (OD) of the sample/cutoff (S/CO-Signal/Cutoff). Each point represents a single individual. Numbers below the graphs indicate the number of individuals evaluated according to the history of COVID-19 and the evaluated vaccine. The end of the bar indicates the median value and the horizontal bars above and below the median indicate the 95% confidence interval. The Mann–Whitney U test was used to compare the indices of induced antibodies between vaccines. Statistical significance was adopted for p < 0.05.