Enhancing COVID-19 Vaccine Efficacy: Dual Adjuvant Strategies with TLR7/8 Agonists and Glycolipids.

The controlled release of immunostimulatory agents represents a promising strategy to enhance vaccine efficacy while minimizing side effects. This study aimed to improve the efficacy of the RBD-Fc-based COVID-19 vaccine through combining of an iNKT cell agonist and a TLR7/8 agonist using covalent conjugation and temporal delivery. We hypothesized that these combinations would yield a more balanced Th1/Th2 immune response.