Lasting SARS-CoV-2 specific IgG Antibody response in health care workers from Venezuela, 6 months after vaccination with Sputnik V

•We measured RBD-IgG levels in Sputnik V vaccinated 6 months after vaccination.•The GMT of RBD-IgG antibodies in a COVID-19 naïve cohort was 327 BAU/ml.•The GMT of RBD-IgG antibodies in previously infected people was 910 BAU/ml.•94% of both cohorts had a good to excellent neutralizing activity in an in vitro test.•The Sputnik V vaccine induced a long-lasting immune response of at least 6 months Scarce information is available regarding the long-term immunogenicity of the Sputnik V vaccine. Here Sputnik V vaccinated subjects were evaluated 6 months after receiving the 2-dose prime-boost schedule. Eighty-six hospital workers from Venezuela, 32 with a previous COVID-19 infection and 54 SARS-CoV-2 naïve subjects, were enrolled. IgG antibodies levels against the wild-type Receptor Binding Domain (RBD) were measured in an ELISA and with an in vitro ACE2-surrogate RBD binding inhibition assay at day 42 and day 180 after receiving the second dose. IgG levels were expressed in BAU/ml. Binding inhibition antibodies were expressed in IU/ml. On average, RBD-IgG levels decreased by approximately 50% between the two time-points in the COVID-19 naïve cohort (geometric mean concentration (GMC) 675 BAU/mL vs. 327 BAU/ml) and decreased by approximately 25% in the previously infected cohort (GMC 1209 BAU/mL vs 910 BAU/ml). Within our cohort, 94% showed a “good to excellent” neutralizing activity measured with the in vitro test 6 months after vaccination. The Sputnik V vaccine provided long-term and durable humoral immunity in our cohort specially if a person has been both vaccinated and had a previous infection with SARS-CoV-2.