AUTHOR=Kajanova Ivana , Jelenska Lenka , Lukacikova Lubomira , Grossmannova Katarina , Belisova Martina , Istvanova Nikola , Gasparovicová Natalia , Zelnik Vladimir , Pastorekova Silvia , Radikova Zofia , Kopacek Juraj TITLE=Influence of the SARS-CoV-2 Omicron (B.1.1.529) variant and booster vaccine doses on the seroprevalence of specific IgG antibodies in the staff of the Slovak Academy of Sciences JOURNAL=Acta Virologica VOLUME=67 YEAR=2023 URL=https://www.frontierspartnerships.org/journals/acta-virologica/articles/10.3389/av.2023.11637 DOI=10.3389/av.2023.11637 ISSN=1336-2305 ABSTRACT=

The presented seroprevalence study focused on specific antibodies to the SARS-CoV-2 virus is the second survey conducted among SAS employees. Its realization enabled monitoring of the impact of booster vaccination doses and the spread of the Omicron variant in a defined group of people. The total seropositivity of the involved SAS employees in autumn 2022 was 96.04%. In the group of vaccinated participants (1,189) the seropositivity rate was 99.5%, while among unvaccinated participants (176) it was 72.73%. By October 2022, when the study was conducted, 65.05% (888) of the participants have had a positive PCR/Ag test for SARS-CoV-2 at least once. Based on the presence of antibodies against the nucleoprotein (NCP) of SARS-CoV-2 it was proven, that 27.39% of participants (25.12% of vaccinated; 51.22% of non-vaccinated) who have never had a positive PCR/Ag test for SARS-CoV-2, overcame the COVID-19. According to self-assessment of the disease course, it was shown that a severe course occurred in 6.31% of the participants who overcame the disease without prior vaccination and in 1.44% of the participants who overcame COVID-19 after completing the baseline vaccination scheme. The most significant finding of the study is the evidence of significantly lower levels of specific antibodies after overcoming the Omicron variant of SARS-CoV-2, and thus its reduced immunogenicity compared to ancestral virus and earlier variants of concern.