Evaluation of the Gam-COVID-Vac and Vaccine-Induced Neutralizing Response Against SARS-CoV-2 Lineage P.1 (Manaus) Variant in an Argentinean Cohort

Background: The safety, efficacy and humoral immune-response to Sputnik-V were independently evaluated. Since SARS-CoV-2 lineage P.1 is rapidly spreading in Argentina and the neutralization of P.1 by Sputnik-V-elicited sera has not been determined yet, we evaluated efficacy of Sputnik-V-immunized humoral response faced to P.1. Methods: The safety/efficacy of Sputnik-V were assessed by monitoring self-reported adverse events and disease rate among Health-Care Workers (HCW) who received both doses, within 4 months. Immunogenicity of the vaccine was evaluated by measuring anti-Spike (S) IgG antibodies (Abs) and neutralizing antibodies (NAb) prior to, 14 and 42 days after-vaccination. To determine the effectiveness of pre-existing NAb against P.1, samples were analysed from individuals: A-recovered from SARS-CoV-2 wild type B.1 (WT) infection, B-recovered from WT infection and received one/two doses of Sputnik-V, and C-without previous infection and received one/two doses of Sputnik-V. Findings: A total of 285 HCW were recruited, all reporting good tolerance, without severe adverse events. Sputnik showed 97·60% efficacy against COVID-19 during the observation period. At day 42, 99·65% of the individuals had anti-S IgG; however, 23·15% had not detectable NAb. The NAb ability against the SARS-CoV-2 strains showed significantly higher neutralization levels against WT compared to P.1 (p<0·001), with only a few samples not able to neutralize P.1. Interpretation: We corroborated that Sputnik-V is safe and induces an efficient humoral immune response, although not all immunized subjects developed NAb. While few samples failed to neutralize P.1, the variant does not escape from Sputnik-V-elicited immunity neither from immunity by WT infection. Funding Information: This work was supported by the Fondo para la Investigacion Cientifica y Tecnologica (FONCyT) [PICT IP COVID 19-0464, 2020]; School of Medical Sciences, National University of Cordoba, Argentina and the Ministry of Health of Cordoba, Argentina. Declaration of Interests: The authors state that they have no conflicts of interest to declare. Ethics Approval Statement: This report has been performed in accordance with specific local regulations (provision number 32/2016, dated September 8, 2016, by the Council for the Ethical Evaluation of Health Research, Ministry of Health of Cordoba province, Argentina). The study observed the ethical standards established in the Declaration of Helsinki in 1964 and its subsequent modifications.