Version 1: Immunogenicity of virus-like particle vaccine candidates against SARS-CoV-2 infection

SARS-CoV-2 variants could become more virulent and transmissible due primarily to the mutations of the viral spike protein, rendering currently approved vaccines less effective. More effective vaccines are needed as vaccination is by far the best strategy against this virus. We have produced two SARS-CoV-2 virus-like particles (VLPs) using a baculovirus BacMam expression platform and examined their immunogenicity in mice. VLP1 contains the spike protein from the Wuhan strain whereas VLP2 contains that of an Omicron variant. Mice immunized with VLP1 and boosted with VLP2 developed significantly higher antibodies in the sera, and more IFNγ secreting cells than the control group. Furthermore, both VLPs induced virus neutralization antibodies against the ancestral Wuhan and an Omicron variant. In conclusion, our study warrants further development of VLPs as effective vaccines against emerging variants of SARS-CoV-2.