Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to significant morbidity and mortality in elderly individuals. Children typically have mild illness with rare mortalities. Age and co-morbid medical conditions are the most important determinant of the infection outcome. Currently there is no clear explanation for the difference in disease severity and outcome in different age groups. Based on evolutionary biology and translational research this review suggests that the high antioxidant capacity of children leading to a balanced redox state is the key factor for mild SARS-CoV-2 infections in this age group. On the other hand, elderly individuals with low antioxidant capacity and low angiotensin-converting enzyme 2 expression are prone to severe infections by redox-sensitive immune modulation.
Mild SARS-CoV-2 infections in children might be based on evolutionary biology and linked with host reactive oxidative stress and antioxidant capabilities