ABSTRACT
Furin is a protease that is ubiquitous in mammalian metabolism. One of the innovations that make sudden acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) more infectious than its ancestor viruses is the addition of a furin cleavage site. Conditions associated with elevated furin levels, including diabetes, obesity, and hypertension, overlap greatly with vulnerability to the severe form of coronavirus disease 2019 (COVID-19). We suggest that diet and lifestyle modifications that reduce the associated comorbidities may prevent the development of severe COVID-19 by, in part, lowering circulating furin levels. Likewise, natural and pharmaceutical inhibitors of furin may be candidate prophylactic interventions or, if used early in the COVID-19, may prevent the development of critical symptoms.