Of note, α1AT may not only be beneficial in COVID-19 therapy because of its direct antiviral effect by targeting TMPRSS2-mediated SARS-CoV-2 entry, but also by inhibiting neutrophil elastase, which has been proposed to act as alternative spike priming protease41,42 and might contribute to pulmonary inflammation in COVID-1943,44. Here, TMPRSS2 is linked to COVID-19.