SUMMARY
There is an urgent need to develop efficacious vaccines against SARS-CoV-2 that also address the issues of deployment, equitable access, and vaccine acceptance. Ideally, the vaccine would prevent virus infection and transmission as well as preventing COVID-19 disease. We previously developed an oral adenovirus-based vaccine technology that induces both mucosal and systemic immunity in humans. Here we investigate the immunogenicity of a range of candidate adenovirusbased vaccines, expressing full or partial sequences of the spike and nucleocapsid proteins, in mice. We demonstrate that, compared to expression of the S1 domain or a stabilized spike antigen, the full length, wild-type spike antigen induces significantly higher neutralizing antibodies in the periphery and in the lungs, when the vaccine is administered mucosally. Antigen-specific CD4+ and CD8+ T cells were induced by this leading vaccine candidate at low and high doses. This fulllength spike antigen plus nucleocapsid adenovirus construct has been prioritized for further clinical development.
Competing Interest Statement
EGD, ND, KPT, KLM MC and SNT are current employees and/or own stock options in Vaxart, the sponsor of the studies. EGD and SNT are named as inventors covering a SARS-CoV-2 (nCoV-19) vaccine. SNT is named as an inventor on patents covering the vaccine platform. ACM declares no competing interest.
