At the beginning of Covid-19 pandemic, we proposed to use hydroxychloroquine (HCQ) and intranasal interferon (IFN) a-2b spray to prevent SARS-CoV-2. Since then, clinical trials testing these two drugs separately for the treatment and prophylaxis have been reported. A consensus is forming that HCQ and IFNs are not effective in treating severe Covid-19. However, the pathogenesis of Covid-19 suggests that early intervention could reduce the infection and prevent the progression from mild to severe Covid-19. This commentary will focus on discussion regarding the prophylaxis and early treatment of SARS-CoV-2 infection. After review and reanalysis of the two randomized clinical trials (RCTs) using HCQ for postexposure prophylaxis, we concluded that HCQ is beneficial for the prophylaxis of SARS-CoV-2. The side effects of HCQ are mild, and severe side effects such as life-threatening arrhythmia are rare. Thus, risk-benefit ratio strongly suggests that the use of HCQ for pre-exposure prophylaxis should be available, especially among high risk population with no known cardiovascular diseases. The risk-benefit ratio for postexposure prophylaxis is even better for Covid-19 with a medium infection fatality rate of 0.27%. Clinical trials using type I IFN (IFN I) for prophylaxis are still ongoing. Clinical studies using IFN Is for early or in mild Covid-19 hospitalized patients suggest that IFN a-2b may be beneficial. Clinical trials testing the combination of HCQ and IFN Is in the prophylaxis and early treatment of SARS-CoV-2 are still needed to test if the combination improves monotherapy treatment.

Covid-19, Hydroxychloroquine, Interferon, Prophylaxis