Long-term antibody response following SPUTNIK V primary vaccination in healthcare workers with and without history of SARS-CoV-2 infection: Prospective cohort study from a hospital in Argentina

Abstract

Background: In December 2020, Sputnik V was incorporated to the National COVID-19 Immunization Plan in Argentina. Studies had shown 98% of antibody response rate. To date, data on immunogenicity and antibody persistence in Argentina are scarce.The objective was to assess humoral immune response after two doses of Sputnik V in Health Care Workers (HCWs) at the Ricardo Gutierrez Children's Hospital (RGCH).

Methods: A prospective, cohort study in HCWs immunized with two doses of Sputnik V between February and March 2021. The following variables were assessed: age, gender, risk factors for severe COVID-19 or mortality, immunosuppressive therapy and history of SARS-CoV-2. Blood samples were drawn on the day of the first dose, 28 days and 180 days after the second. Anti-Spike IgG was measured using an ELISA assay. Differences in immune response were evaluated according to study variables. Comparison analyses between groups with or without history of infection were performed, with T-test and ANOVA or Mann-Whitney tests. For each subject, we compared baseline values with 28 days and 180 days after the second vaccine.STATA version 14 and R Sofware were used for data analyses.

Results: We included 528 individuals, mean age 41.5 years, 82.9% female, 14.4% (76/528) reported previous SARS-CoV-2 infection.All subjects developed antibodies post-vaccination. At day 28, concentrations were significantly higher in previously infected than naïve subjects (p < 0.001) with no differences according to age, gender and comorbidities.At day 180, 17% (95% CI 13.17-21.53) of naïve subjects were negative. Antibody concentrations decreased significantly in all subjects except in those who reported SARS-CoV-2 infection after vaccination (n = 31). This last group had significantly higher antibody concentrations.

Conclusion: This study assessed immune response to a new COVID-19 vaccine in real life in a cohort of subjects. Antibody concentrations varied according to history of SARS-COV-2 infection and decreased over time.

Keywords: Antibodies; COVID-19; Health-care workers; Sputnik V vaccine.

Fig. 1

Study flow chart. HCW who received two vaccine doses were included. Blood samples were drawn at day of first dose to determine previous seroprevalence. Two groups were defined at the beginning of the study according to the history of SARS-CoV-2 before vaccination: Group 1: those subjects with evidence of SARS-CoV-2 infection prior to vaccination, Group 2: naïve subjects. Epidemiological follow up during 180 days was performed to asses SARS-CoV-2 infection and two blood samples were drawn at days 28 and 180 after second dose. Those subjects who presented SARS-CoV-2 infection between the first dose and up to day 28 of the second dose and those who presented a second SARS-CoV-2 infection during follow-up were excluded. Losses during follow up were documented. At day 180 participants in group 2 were subclassified: subgroup 2A: those subjects without infection prior to vaccination who presented SARS-CoV-2 infection between days 28 and 180 post second dose, and subgroup 2B: those seronegative subjects in the baseline sample, who did not report infection during follow-up.

Fig. 2

Antibody response after vaccination with Sputnik V. Red colour describes antibody response in group 1 at days 0, 28 and 180. Green colour shows antibody response at day 28 in subjects without previous SARS-COV-2 infection (group 2), and at day 180 in subgroups 2A and 2B.