Sputnik V update: safety and neutralizing antibodies in healthy adults and adolescents

Background During the COVID-19 pandemic, adenoviral vector-based Sputnik V vaccine was used to vaccinate the civilian population of 74 countries worldwide. As part of laboratory monitoring of the effectiveness of the Sputnik V vaccine, a decrease in effectiveness was detected against Omicron BA.5 and XBB variants. XBB variant quickly displaced all previously circulating variants, so the antigen composition of the Sputnik V vaccine was changed to the XBB variant. Methods The Gam-COVID-Vac XBB (Sputnik V XBB) vaccine was developed, manufactured, and stored by Gamaleya NRCEM (Moscow, Russia). Two open prospective clinical study of the safety, reactogenicity and immunogenicity of the Sputnik V XBB vaccine was conducted in 50 adult participants over 18 years old and 50 adolescent participants 12–17 years old (ClinicalTrials.gov Identifier: NCT06068569 and NCT06068556). Immunogenicity study included ELISA assay for detection glycoprotein S of the Omicron XBB variant and neutralization assay with viable SARS-CoV-2 virus Omicron ХВВ.1.5, ХВВ.1.9.1, ХВВ.1.16, EG.5.1, ВА.2.86, JN.1, KS.1, XFG.3, NY.2 and PY.2 variants. Results Safety profile of the Sputnik V XBB vaccine was consistent with the previous formulation, and no new safety concerns were reported. There were no cases of serious AEs. Seroconversion of antigen-specific IgG on day 42 was 100% in adults and 87.5% in adolescents. We showed robust NtAb response to circulating SARS-CoV-2 variants (ХВВ.1.5, ХВВ.1.9.1, ХВВ.1.16, EG.5.1, ВА.2.86, JN.1, KS.1, XFG.3, NY.2 and PY.2) in vaccinated adults and adolescents, seroconversion rate of NtAb against any circulating variant was 96% in adults and 94% in adolescents. Conclusion The results of the clinical trials demonstrated a favorable safety profile and a high level of immunogenicity of Sputnik V XBB in adults and adolescents. Clinical Trial Registration ClinicalTrials.gov , identifiers NCT06068569 and NCT06068556.