AN HETEROLOGOUS PLATFORM BOOSTER ELICITS A HIGHER HUMORAL RESPONSE AMONG HEALTHCARE- WORKERS WITH COMPLETE SPUTNIK V

REYES, NOELIA SOLEDAD; SCHWALD ISABEL; HERMIDA ELIANA; RODRIGUEZ PAMELA ELIZABETH; RICARTE CARMEN; ECHAVARRIA MARCELA; JARA RAQUEL; DIAZ VICTORIA; STRYJEWSKI, MARTIN E.

Congreso; XII Congreso SADI 2022.; 2022

IntroductionSARS-CoV-2 vaccination showed to be effective in avoiding severe disease. Different platform vaccinesinclude adenoviral vectors, attenuated virus, mRNA and viral-like particles. Humoral response afterboostering subjects with complete Sputnik V using a different platform vaccine is poorly described.ObjectivesTo evaluate humoral response with Sputnik V vaccine in health care workers (HCW). To compare humoralresponse in HCW with complete Sputnik V vaccine followed by homologous or heterologous platformbooster.Materials and MethodsA prospective observational cohort study in HCW with complete Sputnik V vaccine (2 doses) wasconducted from February-2021 to June-2022.Adenoviral vector based vaccines included Sputnik V, AstraZeneca and Janssen while mRNA vaccinesincluded Pfizer and Moderna. Combination of these approaches was considered an “heterologousplatform” booster.Sera were collected on day 21, 90, 180, 270 and 360 after each vaccine dose. SARS-CoV-2 IgG anti-spikeantibodies were quantified using a manual enzyme-linked immuno assay (ELISA) (COVIDAR) with a WHOinternational standard.Mann-Whitney method was used to compare antibody levels. Data was analyzed using GraphPad Prismsoftware (version 5; GraphPad software, La Jolla, CA, USA).ResultsSerum samples (n=634) from 134 HCWs were evaluated. HCW median age was 40 years old, 65% werefemale and none was immunocompromised. Most HCW (77 %) were naive of SARS-CoV-2 infection atenrollment.All HCWs seroconverted after complete scheme with Sputnik V although naïve HCW showed a significantlower IgG level (616 UI/mL) compared to HCW previously infected with SARS-CoV-2 (2335 UI/mL)(p=0.004).Half of HCW (51%) received a third dose (booster), 79% with homologous platform booster and 21% withheterologous platform booster. Median IgG level among HCW with a heterologous platform booster wassignificantly higher (7286 UI/mL) than in HCW who received an homologous platform booster (758 UI/mL)(p=0.006).ConclusionsComplete Sputnik V scheme was highly immunogenic eliciting 100% seroconversion among our HCW.Heterologous platform booster elicited significantly higher humoral response than homologous platformbooster among HCW with complete Sputnik V.