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

• Published in: International journal of infectious diseases Vol. 111; pp. 261 - 266
• Main Authors: Claro, Franklin, Silva, Douglas, Rodriguez, Melissa, Rangel, Hector Rafael, de Waard, Jacobus H.
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01-10-2021; The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases; Elsevier
• Subjects: Antibodies, Viral; Antibody Formation; COVID-19; Humans; IgG antibodies; Immunoglobulin G; nucleocapsid protein (NP); receptor-binding domain (RBD); S/P ratio; SARS-CoV-2; Sputnik V vaccine; vaccine booster dose; Vaccines; IgG antibodies; vaccine booster dose; nucleocapsid protein (NP); Sputnik V vaccine; S/P ratio; receptor-binding domain (RBD)
• ISSN: 1201-9712; 1878-3511; 1878-3511
• DOI: 10.1016/j.ijid.2021.07.070

•A longitudinal study to determine the immoglobulin G response after Sputnik V vaccine•SARS-CoV-2 seronegative vaccinees showed a primary response upon vaccination•Seropositive individuals displayed a booster or secondary immune response•This immoglobulin G response was stronger than 2 vaccine doses in the seronegatives•A single vaccine dose did not always protect; we registered breakthrough infections
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.