ACE2 and viral infectious disease: Furthermore, the latest findings in the current field of viral immunology confirm naltrexone as a potential candidate for COVID-19 treatment, as it has the ability to inhibit viral infection at the level of (i) virus entry into the cell due to its molecular entities, being able to interfere with binding of the SARS-CoV-2 spike protein to ACE2, or (ii) damping the hyperinflammatory cytokine storm along with viral infectivity, by confirming its potential in this regard by suppressing LPS-induced cytokine release from pro-inflammatory macrophages [51].