Contrary to expectations, statistical data showed lower rates of COVID-19 in adolescents and children compared to adults, possibly due to an association between the lower expression of angiotensin-converting enzyme 2 (ACE2) receptors in the respiratory epithelium and more frequent exposure to a high variety of pathogens, leading to immunity to common coronaviruses [117,118]. The gene discussed is ACE2; the disease is COVID-19.