A Review of Protein-Based COVID-19 Vaccines: From Monovalent to Multivalent Formulations

The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulting in the COVID-19 pandemic, has profoundly impacted global healthcare systems and the trajectory of economic advancement. As nations grapple with the far-reaching consequences of this unprecedented health crisis, the administration of COVID-19 vaccines has proven to be a pivotal strategy in managing this crisis. Protein-based vaccines have garnered significant attention owing to their commendable safety profile and precise immune targeting advantages. Nonetheless, the unpredictable mutations and widespread transmission of SARS-CoV-2 have posed challenges for vaccine developers and governments worldwide. Monovalent and multivalent vaccines represent two strategies in COVID-19 vaccine development, with ongoing controversy surrounding their efficacy. This review concentrates on the development of protein-based COVID-19 vaccines, specifically addressing the transition from monovalent to multivalent formulations, and synthesizes data on vaccine manufacturers, antigen composition, pivotal clinical study findings, and other features that shape their distinct profiles and overall effectiveness. Our hypothesis is that multivalent vaccine strategies for COVID-19 could offer enhanced capability with broad-spectrum protection.