Remember this key study early in 2020 on children not being primary spreader of COVID: "Children are unlikely to have been the primary source of household SARS-CoV-2 infections" by Zhu & Short et al.

Whilst SARS-CoV-2 can cause mild disease in children, the data available to date suggests that children have not played a substantive role in the intra-household transmission of SARS-CoV-2.

SOURCE:

https://www.medrxiv.org/content/10.1101/2020.03.26.20044826v1

Drawing on studies from China, Singapore, South Korea, Japan, and Iran a broad range of clinical symptoms were observed in children. These ranged from asymptomatic to severe disease. Of the 31 household transmission clusters that were identified…the data available to date suggests that children have not played a substantive role in the intra-household transmission of SARS-CoV-2.”