Could a human-derived protein help combat both COVID-19 and flu?

Trypstatin potently blocks TMPRSS2, a host protease used by many respiratory viruses to enter human cells. It inhibits entry of SARS-CoV-2, SARS-CoV-1, MERS-CoV, and influenza A/B viruses in vitro, and reduces viral loads and symptoms in SARS-CoV-2-infected hamsters after intranasal treatment—even in the presence of airway mucus.

The study can be found here and highlights Trypstatin’s potential as a broad-spectrum antiviral strategy targeting host entry factors.

Image: Rock-Paper-Scissors. TMPRSS2 (scissors) cleaves and activates viral glycoproteins (paper), but is inhibited by Trypstatin (rock); source: SharryX via https://commons.wikimedia.org/wiki/File:Rock-paper-scissors_Shapes.png;  Creative Commons Attribution-Share Alike 4.0 International license.