HP and COVID-19: Recently, we adopted the drug repurposing approach [14] as suitable strategy to give fast response to global COVID-19 epidemic, by demonstrating that the zonulin octapeptide inhibitor AT1001 (Larazotide acetate) [15], currently in phase 3 trials in celiac disease, binds Mpro catalytic domain by means of an integrated approach of molecular modeling and fluorescence resonance energy transfer (FRET) assay [16].