COVID-19, SARS-CoV-2, Omicron variant, Neutralizing antibody, Surrogate neutralizing antibody test, spike protein receptor binding domain, Variants of Concern
COVID-19, SARS-CoV-2, older adults, vaccine booster, neutralizing antibody, T cell response, hybrid immunity
Phase-1, intranasal, DelNS1-nCoV-RBD LAIV, COVID-19
COVID-19 vaccine, SARS-CoV-2, Omicron variant, mucosal immunity, saliva, IgA