DPP9 and COVID-19: Another factor that connects COVID-19 and IPF is a genetic overlap: recently, Allen et al. demonstrated a positive genome-wide genetic correlation between IPF and severe COVID-19 risk using large genome-wide association studies (GWASs); they showed for the first time the same underlying causal variant to the genetic association signals of MUC5B, DPP9, and ATP11A [51].