mRNA-based vaccines are currently the most widely used vaccines for COVID-19. Challenges surrounding these novel vaccines such as mRNA-based vaccine hesitancy, production costs and demand, delivery, and unknown longevity of protection have highlighted the need for alternative vaccine strategies.

In this preprint, not yet per-reviewed, the research team outlines how they recently developed an alternative vaccine that uses a safe vesicular stomatitis virus-based vaccine that delivers a key SARS-CoV-2 protein to our immune system to train it to recognize and prevent SARS-CoV-2 infection. They report the development of modifications to this vaccine to allow for the targeting of SARS-CoV-2 variants. This modified vaccine delivers the Spike protein from the original SARS-CoV-2 isolate, Beta variant, Delta variant or a combination of all three variants (“trivalent”).

They showed that mice vaccinated with these vaccines, and especially the trivalent vaccine, induced antibodies that potently neutralized SARS-CoV-2 viruses including the Omicron variant. In addition, these vaccines all induced a strong cellular response to the virus, which is critical for destroying infected cells in the body. This work identifies VSV-based vaccines as an important viable alternative to mRNA-based vaccines for COVID-19.

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Kate A. Parham, Gyoung Nyoun Kim, Nasrin Saeedian, Marina Ninkov, Connor G. Richer, Yue Li, Kunyu Wu, Rasheduzzaman Rashu, Stephen D. Barr, Eric J. Arts, S.M. Mansour Haeryfar, C. Yong Kang, Ryan M. Troyer. Monovalent and trivalent VSV-based COVID-19 vaccines elicit potent neutralizing antibodies and immunodominant CD8+ T cells against diverse SARS-CoV-2 variants. bioRxiv 2022.07.19.500626;