Pereson, Matías JAmaya, LucasNeukam, KarinBaré, PatriciaEchegoyen, NataliaBadano, María NoelLucero, AliciaMartelli, AntonellaGarcia, Gabriel HVidela, CristinaMartínez, Alfredo PDi Lello, Federico A2023-05-032023-05-032022-05-17http://hdl.handle.net/10668/22131To compare the homologous prime-boost vaccination scheme of Gam-COVID-Vac (Sputnik V (SpV)) to its heterologous combination with mRNA-1273 (Moderna (Mod)) vaccine. SARS-CoV-2 anti-spike (S)-receptor binding domain (RBD) IgG concentration was assessed three to seven weeks after complete vaccination. Reactogenicity was evaluated by declared side events and medical assistance required until day 7 post boost. Of 190 participants enrolled, 105 received homologous SpV/SpV and the remaining heterologous SpV/Mod vaccination scheme, respectively. Median (interquartile range (IQR)) age was 54 (37-63) years, 132 out of 190 (69.5%) were female, and 46 out of 190 (24.2%) individuals had a prior confirmed COVID-19. Anti-S-RBD IgG median (IQR) titers were significantly higher for SpV/Mod (2511 (1476-3992) binding antibody units (BAU)/mL) than for SpV/SpV (582 (209-1609) BAU/mL; p  The heterologous SpV/Mod combination against SARS-CoV-2 is well tolerated and significantly increases humoral immune response as compared to the homologous SpV/SpV immunization.enGam-COVID-VacHeterologous schemeSARS-CoV-2VaccinemRNA-12732019-nCoV Vaccine mRNA-1273Antibodies, ViralCOVID-19COVID-19 VaccinesData AnalysisFemaleHumansImmunoglobulin GMaleMiddle AgedSARS-CoV-2research article35595128open access10.1016/j.cmi.2022.05.0091469-0691PMC9112602https://digital.csic.es/bitstream/10261/279785/1/Heterologous%20gam-COVID-vac.pdfhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC9112602/pdf