“We show that vaccination of hamsters with recombinant VSV-ΔG-spike results in rapid and potent induction of neutralizing antibodies against SARS-CoV-2,” the Israeli scientists who are working on a vaccine against the Covid-19 virus reported Friday in the BioRXiv online magazine (A single dose of recombinant VSV-∆G-spike vaccine provides protection against SARS-CoV-2 challenge).
Should the Israeli Health Ministry permit the start of human trials of the new vaccine in the coming weeks, the vaccine could be ready for distribution by the end of this winter.
The team, working for the Israel Institute for Biological Research in Ness Ziona, who were using golden Syrian hamsters in their tests, noted: “Importantly, single-dose vaccination was able to protect hamsters against SARS-CoV-2 challenge, as demonstrated by the abrogation of body weight loss of the immunized hamsters compared to unvaccinated hamsters.”
“Furthermore, whereas lungs of infected hamsters displayed extensive tissue damage and high viral titers, immunized hamsters lungs showed only minor lung pathology, and no viral load,” the Israeli scientists reported, adding, “Taken together, we suggest recombinant VSV-ΔG-spike as a safe, efficacious and protective vaccine against SARS-CoV-2 infection.”
The lungs of the infected hamsters were removed at the end of the incubation period and analyzed for viral load and pathological changes. Lungs extracted from infected hamsters showed viral concentrations, whereas the viral presence in the lungs of vaccinated and then infected animals were below the limit of detection.
The unvaccinated infected hamsters revealed extensive lung damage including focal inflammation patches, pleural invagination and massive alveolar collapse, and edema, whereas the vaccinated hamsters demonstrated markedly ameliorated tissue damage. These results were further supported by tissue/air space analysis demonstrating significantly lower tissue/air space ratio in immunized hamsters compared to lungs of infected hamsters.
“We show that the VSV-∆G-spike vaccine is safe, well tolerated, elicits antibodies, is able to bind and neutralize SARSCoV-2 efficiently, and offers protection from high-dose SARS-CoV-2 challenge in concordance with viral clearance. Conversely, unimmunized hamsters display rapid deterioration, significant weight loss and lung damage,” the scientists reported.
The report’s authors are: Yfat Yahalom-Ronen, Hadas Tamir, Sharon Melamed, Boaz Politi, Ohad Shifman, Hagit Achdout, Einat B. Vitner, Ofir Israeli, Elad Milrot, Dana Stein, Inbar Cohen-Gihon, Shlomi Lazar, Hila Gutman, Itai Glinert, Lilach Cherry, Yaron Vagima, Shirley Lazar, Shay Weiss, Amir Ben-Shmuel, Roy Avraham, Reut Puni, Edith Lupu, Elad Bar David, Assa Sittner, Noam Erez, Ran Zichel, Emanuelle Mamroud, Ohad Mazor, Haim Levy, Orly Laskar, Shmuel Yitzhaki, Shmuel C. Shapira, Anat Zvi, Adi Beth-Din, Nir Paran, and Tomer Israely.