Two publications came to my attention recently. The first one is Shared B cell memory to coronaviruses and other pathogens varies in human age groups and tissues:

Notably, prepandemic children also had class-switched convergent clones to SARS-CoV-2 and its viral variants, but not EBOV, at higher frequencies than adults. We hypothesize that previous HCoV exposures may stimulate cross-reactive memory, and that such clonal responses may have their highest frequencies in childhood.

These findings suggest that encounters with coronaviruses in early life may produce cross-reactive memory B cell populations that contribute to divergent COVID-19 susceptibilities.

The second one is Mesenchymal Stem Cells: The Secret Children’s Weapons against the SARS-CoV-2 Lethal Infection. I don’t understand enough about this one, but the hypothesis here is twofold:

First, the integrity presence of a stable regenerative state of pediatric and young individuals, mainly based on the support of active circulating stem cells; and, secondly, the active presence of the adaptive immune system characterized by a continuous turn-over of lymphocytes, NK and B lymphocytes.

Both studies, however, agree that

The SARS-CoV-2 infection in children appears to be an unusual event. Despite the high number of affected adult and elderly, children and adolescents remained low in amounts, and marginally touched.

Overall children are unaffected personally by this virus, and pose no threat to others, as they are far from being the initially-claimed main vector of transmission.

This also means children do not need to be vaccinated at all, let alone undergo the risk of an experimental drug only authorised for emergency use, and with no safety data available in that age group, nor with any long-term side effects known.