Systemic vaccination of the BNT162b2 mRNA stimulates humoral response. The aim of our study was to compare the intensity of humoral immune response, measured by SARS CoV-2 IgG, SARS CoV-2 IgM, and neutralization S-RBD IgG antibodies level, post COVID-19 vaccination versus post SARS COV-2 infection. We analysed 1060 people in the following groups: convalescents, healthy vaccinated, vaccinated with COMIRNATY, AstraZeneca, Moderna, Johnson&Johnson and vaccinated SARS CoV-2 convalescents. A concentration of SARS CoV-2 IgG, SARS CoV-2 IgM, and neutralizing S-RBD IgG was estimated in Bialystok Oncology Center laboratory by chemiluminescent immunoassay- CLIA, MAGLUMI. Results: 1. We observed a raise of antibodies response in both, convalescent SARS CoV-2 and COVID-19 vaccinated groups 2. The level of all antibodies’ concentrations in vaccinated COVID-19 convalescents was significantly higher. 3. We differentiated an asymptomatic SARS CoV-2 convalescents from control group. Based on our analysis we suggest that it is important to monitor SARS CoV-2 antibodies concentrations as an indicator of asymptomatic COVID-19 infection, and as an equivalent of effectiveness of humoral response in convalescents and vaccinated people. Taking into consideration the time-limited nature of the effects of post infection SARS CoV-2 recovery or vaccination, among others physiological half-life, we suggested monitoring IgG antibodies level as a criterium for next vaccination.
