Abstract
Development of efficacious single dose vaccines would substantially aid efforts to stop the uncontrolled spread of the COVID-19 pandemic. We evaluated enveloped virus-like particles (eVLPs) expressing various forms of the SARS-CoV-2 spike protein and several adjuvants in an effort to identify a COVID-19 vaccine candidate efficacious after a single dose. The eVLPs expressing a modified prefusion form of SARS-CoV-2 spike protein were selected as they induced the highest 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, VBI-2902a (prefusion S eVLPs formulated with aluminum phosphate), protected Syrian golden hamsters from challenge with SARS-CoV-2 and supports the on-going clinical evaluation of VBI-2902a as a potential single dose vaccine against COVID-19.
Highlights
VBI-2902a is a VLP-based vaccine candidate against SARS-COV-2
VBI-2902a contains VLPs pseudotyped with a modified prefusion SARS-COV-2 S in Alum.
VBI-2902a induces robust neutralization antibody response against SARS-COV-2 S
VBI-2902a protects hamsters from SARS-CoV-2 induced lung inflammation
A single dose of VBI-2902a provides protective benefit in hamsters
Competing Interest Statement
All authors and co-authors are employees (B.O., J.B., A.D., T.A., T.B., F.D.M., D.E.A., C.S.), collaborators (A.T., D.D., M.McC. from NRC and L.M. from VIDO) or scientific advisors (A-C.F.) of VBI vaccines who funded this work.
Abbreviations
- eVLP,
- enveloped virus-like particules;
- CoV,
- coronavirus;
- RBD,
- receptor binding domain;
- TMCTD,
- transmembrane cytoplasmic terminal domain;
- Ab,
- antibody;
- nAb,
- neutralizing antibody;
- MLV,
- murine leukemia virus;
- ELISA,
- enzyme-linked-immuno-sorbent-assay;
- PRNT,
- plaque reduction neutralization test;
- EPT,
- end-point titer; Alum, aluminum;
- ELISPOT,
- Enzyme Linked ImmunoSpot Test;
- IP,
- IntraPeritoneal;
- IM,
- IntraMuscular;
- NRC,
- National Research Council Canada;
- VIDO,
- Vaccine and Infectious Disease Organization