NVX-CoV2515 + NVX-CoV2540

NVX-CoV2515 + NVX-CoV2540 is an investigational **bivalent recombinant protein-based COVID-19 vaccine** targeting the Omicron subvariants BA.1 (NVX-CoV2515) and BA.5 (NVX-CoV2540) spike proteins. Each component consists of a SARS-CoV-2 recombinant spike protein (produced in insect cells) specific for one Omicron subvariant, formulated together with the Matrix-M adjuvant (a saponin-based adjuvant). The vaccine is designed for use as a heterologous booster following primary mRNA vaccination, aiming to elicit broader and stronger immune responses against Omicron lineage variants compared to monovalent or ancestral strain vaccines. Preclinical and phase 3 trial data indicate that, when administered together as a bivalent vaccine, NVX-CoV2515 + NVX-CoV2540 increases neutralizing antibody titers against Omicron BA.1, BA.5, and ancestral SARS-CoV-2, with a safety and reactogenicity profile similar to earlier Novavax vaccines[2][3][1][4]. Developed and trialed by Novavax, this combination is not yet approved as a marketed product but studied for use in adults as a booster.