Furthermore, cofactors facilitating SARS-CoV-2 infectivity are the transmembrane peptidase serine 2 (TMPRSS2), a clinically proven inhibitor of the cellular serine protease that modifies spike proteins in multiple virus to promote viral infection and spread, and which can block the host cell entry of SARS-CoV-2, and possibly the protease furin (Kimura et al., 2020; Ferastraoaru et al., 2021). The gene discussed is FURIN; the disease is viral infectious disease.