ABSTRACT
Background: In December 2020, Sputnik V was the first vaccine incorporated to the National Strategic COVID-19 Immunization Plan in Argentina. An interim phase three analysis carried out in the Russian Federation had shown 98% of Sputnik V vaccinees developed specific antibodies to SARS-CoV-2. To date, data on immunogenicity in Argentina are scarce. The objective of this study was to assess the immune response following vaccination with two doses of Sputnik V in health-care workers (HCW) at a Children’s Hospital.Methods: A prospective, cohort study in HCWs immunized with two doses of Sputnik V between February and May 2021. The following variables were assessed: age, gender, profession, risk factors for severe COVID-19 or mortality, immunosuppressive therapy and history of COVID-19 infection. Blood samples were drawn on the day of the first dose and 21-40 days after the second. Anti-Spike IgG was measured using an ELISA assay and antibody levels classified into five semi-quantitative categories: non-reactive, < 1/100, ≥1/100-< 1/1000, ≥1/1000-<1/5000 and ≥1/5000. Antibody response was compared using Chi squared test for categorical variables and T-test or Mann-Whitney for continuous variables. Interaction effects were tested in ANOVA.Findings: Five hundred and twenty eight individuals were included, mean age 41·5 years, 82·9% were female, 14·58% (77/528) had had previous SARS-CoV-2 infection, and seroprevalence was 13·26% (70/528).All subjects developed antibody titres post-vaccination. Levels were significantly higher in women (p 0·001) and in those who had experienced prior infection (p < 0·001, Chi square), no interactions between variables were observed.Interpretation: After completing a two-dose Sputnik V schedule, all vaccinees developed antibodies. Prior infection and female gender were associated with higher antibody titres.Funding Information: This stage of the study received no funding support.Declaration of Interests: The authors have no conflicts of interest to declare. Ethics Approval Statement: The study was approved by the Research and Ethics Review Committee at the RGCH (register number 4033). Subjects voluntarily agreed to participate in the research and signed an inform consent form.