The coronavirus can stay in the noses and throats of children for weeks altogether even if they dont show any symptoms, suggests a study from South Korea. This might explain the silent spread of the virus.

The study included data on 91 asymptomatic, presymptomatic and symptomatic children diagnosed with COVID-19 from February 18 to March 31. Around 22% of these patients did not have any apparent symptoms and remained asymptomatic throughout the study period. About 20% were presymptomatic, i.e., they did not appear or feel sick at the time but developed symptoms later. Nearly 78% exhibited symptoms. Just 8.5% of the patients with symptoms were diagnosed with COVID-19 at the time their symptoms started. About 66.2% of the patients with symptoms had symptoms that were not recognized before they were diagnosed, and 25.4% developed symptoms after diagnosis.

Therefore, it appears that children with COVID-19 infection might go unnoticed either with or without symptoms, which could facilitate viral circulation within the community… (CNN, August 30, 2020)