The COVID-19 outbreak and the angiotensin-converting enzyme 2: too little or too much?

Abstract
The current outbreak of coronavirus disease 2019 (COVID-19) constitutes a major challenge for the world’s medical systems. None of the available antiviral drugs has proven efficacy in controlling this viral disease. The mortality rate is especially high in patients with risk factors, e.g. older age, male gender, cardiovascular comorbidities, high blood pressure and diabetes.