Development of COVID-19 vaccine using a dual Toll-like receptor ligand liposome adjuvant.

We developed a SARS-CoV-2 spike subunit vaccine formulation containing dual TLR ligand liposome adjuvant. The vaccine-induced robust systemic neutralizing antibodies and completely protected mice from a lethal challenge. Two immunizations protected against lung injury and cleared the virus from lungs upon challenge. The adjuvanted vaccine also elicited systemic and local anti-Spike IgA which can be an important feature for a COVID-19 vaccine.