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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Immunoglobulin G antibody response to the Sputnik V vaccine: previous SARS-CoV-2 seropositive individuals may need just one vaccine dose.

INTRODUCTION: We evaluated the immunoglobulin (Ig) G antibody response against the nucleocapsid protein (NP) and the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 in a cohort of 86 individuals in Venezuela, before and after receiving the Sputnik V vaccine. METHODS: Antibody responses against NP and RBD were determined with an enzyme-linked immunosorbent assay just before, 3 weeks after the first, and 6 weeks after the second dose of the vaccine. RESULTS: Before vaccination, 59 individuals were seronegative, and 27 seropositive for NP and/or RBD. Of the seronegative cohort, 42% did not develop an IgG immune response against RBD after the first vaccine dose, but 100% had a strong IgG response after 2 doses. All seropositive individuals developed a strong IgG antibody response against RBD after the first vaccine dose, with antibody levels ∼40% higher than seronegative individuals who had received 2 doses. Previously seropositive subjects showed no significant increase in IgG antibody response against RBD after the second vaccine dose. CONCLUSIONS: We demonstrate that 2 doses of the Sputnik V vaccine triggered antibody response in all study individuals. The second Sputnik V dose had no impact on IgG response for those seropositive for SARS-CoV-2 antigens before vaccination.