Seroprevalence in Argentinian health care workers after vaccination with Sputnik V

Introduction: Health care workers (HCW) are at increased risk of Coronavirus Disease 2019 (COVID-19). It is essential to guarantee protection in this population. In Argentina, the vaccination campaign began on December 29, 2020 and HCW were among first beneficiaries. The first available vaccine was Sputnik V. Previous studies showed efficacy over 91%. We aimed to corroborate this. Objectives: To determine presence and quantity of Anti-RBD IgG antibodies in HCW at Hospital Universitario Austral. Methods: Seroprevalence study in HCW 3 or more weeks after the second dose of Sputnik V. We excluded those with history of COVID- 19 (positive RT-PCR, positive IgG before vaccination, symptoms not evaluated). Participants had a blood sample taken and processed using Abbott® SARS-CoV-2 IgG II Quant. A chemiluminescent microparticle immunoassay (CMIA) used for qualitative and quantitative determination of IgG antibodies to SARS-CoV-2 on the Alinity and ARCHITECT i Systems. Quantitative results were used in analyses. As per manufacturer's instructions, a value ≥ 50 AU/ml was considered positive. Descriptive analysis;Stata 10.0 Software. Results: Characteristics of the cohort (Table 1). All of the participants developed Anti-RBD IgG. Antibody concentrations (Picture 1). No difference was found in antibody concentrations between 20 to 40 days versus 40 to 100 days from second vaccine dose. Conclusion:: The entire cohort developed antibodies after immunization with Sputnik V with no difference in concentration between extraction 20-40 days from second dose and more than 40 days. Further studies are needed to determine duration of immunity, influence of variants of concern, and to establish concentrations of IgG correlated with neutralizing antibodies. (Figure Presented).