So one of the main conclusions is that SARS-CoV-2 in children produces antibody responses to all the other human coronaviruses (this happens in adults too, but

So one of the main conclusions is that SARS-CoV-2 in children produces antibody responses to all the other human coronaviruses (this happens in adults too, but the effect is stronger in children) In the discussion section they speculate that maybe recent infection with these other coronaviruses could give some level of protection against SARS-CoV-2, and that this could possibly explain some of the unusual-ness of the age-severity relationship, I.e. that very young children are not hit as hard by SARS-CoV-2 as by other diseases like the flu (relatively). That would be really interesting to see investigated carefully