ACE2 and viral infectious disease: COVID‐19 patients had higher BMI and higher serum leptin than non‐COVID‐19 patients. Leptin levels correlate with BMI only in COVID‐19 patients. The authors propose that leptin is increased due to ACE2‐angiotensin II disruption due to the viral infection. In this context, inflammation is exacerbated in the lungs because of higher concentrations of leptin and angiotensin II.