An enveloped virus-like particle vaccine expressing a stabilized prefusion form of the SARS-CoV-2 spike protein elicits highly potent immunity

We evaluated enveloped virus-like particles (eVLPs) expressing various forms of the Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein and several adjuvants in an effort to identify a highly potent Coronavirus disease 2019 (COVID-19) vaccine candidate. eVLPs expressing a modified pre fusion form of SARS-CoV-2 spike protein were selected as they induced high antibody binding titers and neutralizing activity after a single injection in mice. Formulation of SARS-CoV-2 S eVLPs with aluminum phosphate resulted in balanced induction of IgG2 and IgG1 isotypes and antibody binding and neutralization titers were undiminished for more than 3 months after a single immunization. A single dose of this candidate, named VBI-2902a, protected Syrian golden hamsters from challenge with SARS-CoV-2 and supports the on-going clinical evaluation of VBI-2902a as a highly potent vaccine against COVID-19. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The study evaluated enveloped virus-like particles (eVLPs) expressing different forms of the SARS-CoV-2 spike protein and various adjuvants to identify a highly effective COVID-19 vaccine candidate. The selected eVLPs expressing a modified pre-fusion form of the spike protein induced high antibody binding titers and neutralizing activity in mice. The candidate vaccine, named VBI-2902a, provided protection against SARS-CoV-2 challenge in Syrian golden hamsters and is being clinically evaluated as a potent vaccine against COVID-19.