Scientists are urgently investigating hints the new variant of coronavirus spreads more easily in children. Children almost universally shrug off the virus, but the variant could alter the role they, and schools, play in spreading the virus.
Earlier strains of coronavirus found it harder to infect children than adults. Source : BBC

One explanation is children have fewer of the doorways (the ACE2 receptor) the virus uses to enter our body’s cells. The R number - the average number of people each infected person passes the virus onto - for this variant during the tight restrictions has been estimated at 1.2, which meant cases were increasing.