**13. Recombinant protein based vaccine (Novavax)**

Novavax vaccine is composed of an engineered baculovirus with a modified spike gene. Then the baculovirus transfects the Sf9 moth cell lines, which produce and display the spike protein on their cell membranes. The spike proteins are then extracted and assembled onto a synthetic lipid nanoparticle [59]. Novavax's unique nanoparticle technology used an adjuvants called Matrix-M, to boost immune system and induce high levels of neutralizing antibodies [60]. In Phase 1–2 clinical trial of a Novavax vaccine, the immunological responses produced by NVX-CoV2373 appeared to be higher than those seen in COVID-19 serum [61]. The Matrix-M1 adjuvant elicited CD4+ T cell responses with a Th1 phenotypic bias.
