Analytical study of the correlation between the level of igg antibodies and previous exposure to SARS-CoV-2 antigen in a Private Health Institution in the Month of July 2021

The COVID-19 is a disease caused by the infection of coronavirus, SARS-CoV-2. Serological tests, performed using conventional Enzyme Linked Immunosorbent Assay (ELISA) by detection on chemiluminescence (CLIA) or electrochemiluminescence (EIA) platforms, are intended to identify antibodies to SARS-CoV-2 and contribute to the identification of people who have been exposed to the virus, through active immunization or by previous coronavirus infection. To correlate the amount of IgG antibodies in the serological samples analyzed by chemiluminescence, and previous exposure to the SARS-CoV-2 antigen, in a private health institution, specialized in clinical pathology/laboratory medicine, in the period of July 2021. An analytical, observational cross-sectional study was carried out. The level of IgG antibodies obtained in the serological samples and the type of vaccine against SARS-CoV-2 received by each employee with a result detected were evaluated in July 2021. There was a significant association between IgG level and previous Covid-19 (p=0.008): of 220 individuals with a very high IgG level, 54.1% had previous Covid-19; at the low IgG level, 91 (63.6%) did not have Covid-19. It is concluded that among employees who were vaccinated, those who had already acquired COVID-19 prior (about 54%) produced high and very high levels of IgG.