COVID-19 caused by SARS-CoV-2 has spread worldwide and significantly affected human lives. To cope with this disease, we have developed a combined system for the detection and vaccination of this notorious disease. We have displayed both the spike (S) and nucleocapsid (N) proteins from SARS-CoV-2 on the envelope of baculovirus or the membrane of the insect cell. We have used insect cells displaying S or N to generate a novel cell-based ELISA (C-ELISA), and C-ELISA has been used to detect COVID-19 patient sera with high accuracy. Also, baculovirus presenting S (S-Bac) or N (N-Bac) can become vector vaccines, and proved to be effective in preventing viral diseases. Since this combined platform avoids the protein purification process, also, the S and N displayed on membranes can adequately maintain their conformations, thus ensuring better quality in serum detection and vaccine application. Therefore, this system can become an innovative breakthrough in controlling COVID-19.

The integrated virus detection and vaccination system is a novel concept for the prevention of viral diseases. The same recombinant baculoviruses can display virus antigens on the cells (C-ELISA) for patient sera detection, and likewise, on the baculovirus (S-Bac) to be used as an immediate vaccine. No tedious protein purification needed is another breakthrough. The antigens can be displayed in their natural states on cells allowing better antibody recognition, or on baculovirus envelope generating protective neutralizing antibodies. Baculovirus itself can be used as an adjuvant to stimulate effective vaccination. This system can be used not only to detect and prevent COVID-19, but also for other virus infections in the future.

Our integrated system provides two products simultaneously: COVID-19 detection reagents and vaccine. Our C-ELISA is particularly suitable for high throughput screening in response to the pandemic. The C-ELISA is different from the conventional ELISA system and does not require protein purification, and thus greatly reduces production cost and can compete with current commercial ELISA products on the market. For vaccines, S-Bac and N-Bac are novel vaccines. Since protein purification is also not needed, our vaccine is easy to prepare. The antigen-fused baculovirus can serve as an adjuvant, making the product very cheap and easy for large scale production. Furthermore, this system is also applicable to diseases resulting from other viral pathogens.