In addition, through in vivo comparative analysis of immunopathological phenotypes in IAV-infected wild-type versus Ninj1-/- mice and single-cell profiling of lung tissues from IAV-infected mice and BALF samples from COVID-19 patients, we provided preliminary insight into its potential as a therapeutic target and severity biomarker in influenza and COVID-19. This evidence concerns the gene NINJ1 and COVID-19.