The accumulated research on COVID-19 has demonstrated that two prominent proteins might serve as potential targets to develop possible treatments for COVID-19: the SARS-CoV-2 main protease, which is a viral protein involved in the replication of the virus, and the transmembrane serine protease 2 (TMPRSS2), which is a human protein responsible for viral entry into the host cells and, hence, viral infection. Here, TMPRSS2 is linked to viral infectious disease.