covid-19 in children: do they have a lower risk of severe infection than adults?

The novel coronavirus disease 2019 (covid-19), which was first identified inwuhan, china, in late 2019, has now spread around the world. it significantly affects the lower respiratory tract, and pneumonia is always present in patients with the severe form of the disease. many studies have shown that the severity of covid-19 is lower in pediatric populations. it is important to determine why infants and young children are not severely affected by covid-19. by increasing our awareness of this disease, we can prioritize our limited health resources. several theories have been proposed to explain such significant differences between the pediatric and adult populations with covid-19. some of them are: (1) the role of angiotensin-converting enzyme 2 (ace2); (2) cross-immunity with other severe acute respiratory syndrome (sars)-like viruses; (3) obtunded systemic inflammatory response in children; (4) more efficient t cells in them; (5) interactions of sars-coronavirus-2 (sars-cov-2) with other viruses in the mucosa of the lungs and airways; and (6) a hypothesis that covid-19 proteins onslaught the heme on the β-1 chain of hemoglobin. the important thing to keep in mind is that the asymptomatic and mildly symptomatic pediatrics are crucial in the spread of covid-19.