Protection against reinfection with D614- or G614-SARS-CoV-2 isolates in golden Syrian hamster

Reinfections with SARS-CoV-2 have already been documented in humans, although its real incidence is currently unknown. Besides having a great impact on public health, this phenomenon raises the question of immunity generated by a single infection is sufficient to provide sterilizing/protective immunity to a subsequent SARS-CoV-2 re-exposure. The Golden Syrian hamster is a manageable animal model to explore immunological mechanisms able to counteract COVID-19, as it recapitulates pathological aspects of mild to moderately affected patients. Here, we report that SARS-CoV-2-inoculated hamsters resolve infection in the upper and lower respiratory tracts within seven days upon inoculation with the Cat01 (G614) SARS-CoV-2 isolate. Three weeks after the primary challenge, and despite high titres of neutralizing antibodies, half of the animals were susceptible to reinfection by both identical (Cat01, G614) and variant (WA/1, D614) SARS-CoV-2 isolates. However, upon re-inoculation, only nasal tissues were transiently infected with much lower viral replication than those observed after the first inoculation. These data indicate that a primary SARS-CoV-2 infection is not sufficient to elicit a sterilizing immunity in hamster models but protects against lung disease.The CBIG Consortium (constituted by IRTA-CReSA, BSC, & IrsiCaixa) is supported by Grifols pharmaceutical. The authors also acknowledge the crowdfunding initiative of https://www.yomecorono.com.Peer Reviewed"Article signat per 19 autors/es: Marco Brustolin , Jordi Rodon , María Luisa Rodríguez de la Concepción , Carlos Ávila-Nieto , Guillermo Cantero , Mónica Pérez , Nigeer Te , Marc Noguera-Julián , Víctor Guallar , Alfonso Valencia, Núria Roca, Nuria Izquierdo-Useros, Julià Blanco, Bonaventura Clotet , Albert Bensaid , Jorge Carrillo , Júlia Vergara-Alert , Joaquim Segalés "Postprint (published version