THE ESTIMATION OF NATURAL AND VACCINE-INDUCED IMMUNITY FOR PROTECTION OF NEW CORONAVIRUS INFECTION IN PERSONS WHO HAVE CONTACT WITH COVID-19. CLINICAL OBSERVATIONS

Abstract

Objectives. The aim of the study was to estimate the protection level by anti-IgG to RBD S-protein of the SARS-CoV-2 delivered from natural and vaccine-induced immunity in persons who have contact with COVID-19. Methods. Fourteen (14) persons presented a lab medical stuff and their relatives aged 19-72 years with several COVID-status (CoV-ST) who had contact with COVID-19 the last 10 days before blood collection was underwent to clinical trials. The CoV-ST presented by 1) non-vaccinated, recovered, nV-Recover; 2) unvaccinated, non-contact, V-nC; 3) recovered and then vaccinated (hybrid), R-V (hybrid); 4) vaccinated and then infected and recovered, V-R; 5) vaccinated, now ill, |V-Ill; 6) non-vaccinated, now ill, nV-Ill. Quantitative ELISA was conducted by anti-IgG RBD S-protein SARS-CoV-2 kit in blood serum with resulting in BAU “binding antibody units” (First WHO International Standart for anti-SARS-CoV immunoglobulin (human), NIBSC code: 20/136). The estimation was performed according manual for kit and immunoassay analyser in optical density of solutions at one main wavelength of 405 nm. The Spearman’s rank correlation coefficient of nonparametric measure was used due to small numerous of cohort. Statistical analyses was calculated with GraphPad Prism 8.0.1 and Microsoft® Excel® for Microsoft 365 MSO (verse 2201 16.0.14827.20158) programs. Results. All fourteen (14) persons who had contact with COVID-19 was immunized. Three (3) female persons aged less than 30 years had anti-IgG RBD S-protein SARS-CoV-2 in diapason from 19.2 till 230.1 BAU/mL which was infected and got ill with might-to-moderate symptoms of COVID-19 (f,34 nV-Recover; f,33 nV-Ill; f,22 V-Ill). Eleven (11) persons which was not infected and got ill 1) six (6) with R-V (hybrid) and vector technology vaccine had anti-IgG < 500 BAU/ml; 2) eight (8) persons, seven (7) of them with R-V (hybrid), vector and mRNA-technology vaccines had anti-IgG >500 BAU/ml; 3) four (4) persons with R-V (hybrid), one (1) of them had a vector technology vaccine, three (3) of them had an mRNA technology vaccine had anti-IgG > 5000 BAU/ml; 4) the highest concentration of specific anti-IgG 50,000 BAU/ml was detected in 19-year-old men with R-V (hybrid) and mRNA technology vaccine. Conclusion. Direct moderate and moderate inverse correlation was noted between many factors which can determine an adaptive human immunity. The observe study showed a rapid immune response to neutralization of viruses in medical stuff and their relatives who had closest contact with COVID-19, aged 19 to 50 years and who previously was ill and subsequently was vaccinated triply by vector vaccine or previously was ill and then was vaccinated twice by mRNA vaccine.