Someone linked to this earlier:
www.theguardian.com/world/2020/may/13/are-children-less-susceptible-to-coronavirus
However, it is not yet clear whether they have a lower chance of catching Covid-19. Although fewer children have been picked up in national testing programmes, this could be due to fewer being tested. During the early phase of the epidemic in Europe, adult travellers played a dominant role in seeding infections, which also meant, purely for circumstantial reasons, that children would have played a less significant role in spreading infections.
Studies on this question give a mixed picture. One analysis, in the Lancet Infectious Diseases, of households with confirmed Covid-19 in Shenzhen, China, found that children younger than ten were just as likely as adults to get infected. However, there is other evidence from South Korea, Italy and Iceland suggesting lower infection rates among children. Some of the difference could also be down to differences in social mixing.
I'd hazard a guess that one reason children haven't been getting it is that schools have been closed.
Also this one:
www.theguardian.com/education/2020/may/13/opening-schools-could-fuel-coronavirus-spread-dfe-adviser-admits
Rahman told the committee there was little evidence to suggest children transmit the virus any differently from adults. “There are some studies which suggest that they might transmit it less than adults, but this evidence is mixed, it’s quite early, and so there is a low degree of confidence among Sage [the Scientific Advisory Group for Emergencies] currently in the evidence which suggests that they might transmit it less.”