Pulmonary immune response after a single-dose immunization of inhalable SARS-CoV-2 vaccine

The ongoing COVID-19 pandemic has fostered major advances in vaccination technologies, yet it is notable that all of the COVID-19 vaccines approved to date are based on intramuscular injections, and require multiple doses to achieve a protective immune response. Here, we developed a single-dose inhalable SARS-CoV-2 vaccine that induces potent systemic and mucosal immune responses. Our vaccine encapsulates proteinaceous cholera toxin B subunit (CTB)-assembled nanoparticles evenly displaying the SARS-CoV-2 RBD antigen (R-CNP) within microcapsules of optimal aerodiameter (aerodynamic particle size) for efficient delivery to alveoli-the tiny, immune-cell-laden air sacs positioned at the end of the bronchioles in lungs, and the known site of SARS-CoV-2 infection.