Inmunogenicidad humoral inducida por esquemas de vacunación homólogos y heterólogos contra SARS-CoV-2

Objective: To evaluate the humoral immunogenicity induced by homologous and heterologous vaccination schedules through a comparison of two methods for detecting IgG antibodies against SARS-CoV-2. Materials and methods: Serum concentrations of specific IgG antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein were measured. Samples were collected from 60 individuals who received different COVID-19 vaccination schedules established by the Peruvian health system. Additionally, 20 pre-pandemic serum samples were retrieved from a serum bank. An enzyme-linked immunosorbent assay (ELISA), considered the reference standard test for such measurements, was used. Additionally, OJABIO rapid diagnostic test kit (PRO) was also employed to qualitatively assess the IgG response. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Cohen’s kappa and Wilson-Brown interval for the PRO tests were calculated and compared with those obtained for ELISA. Results: Both the qualitative (PRO) and quantitative (ELISA) tests detected specific IgG antibodies against the spike protein in all vaccinated individuals. ELISA results indicated that IgG concentrations were not affected by the type of vaccination schedule or the time since the last dose. Prior SARS-CoV-2 infection also had no significant effect on antibody levels. The PRO test demonstrated high sensitivity and specificity, with adequate PPV and NPV. Conclusions: The homologous and heterologous SARS-CoV-2 vaccination schedules induced similar IgG antibody concentrations and half-life, with potential neutralizing capacity, as confirmed by both a quantitative assay and a high-performance qualitative assay. The potential impact of homologous and heterologous vaccination schedules on IgG antibody subclasses remains an area of interest for further research.