> I have doubts about this measurement - that level (83.3% with antibodies!) should have been enough for herd immunity in May 2021, yet we don't see it in the U

> I have doubts about this measurement - that level (83.3% with antibodies!) should have been enough for herd immunity in May 2021, yet we don't see it in the US, cases being broadly static in the last month The 83% includes immunity from vaccination which, as we know now, is not sufficient for herd immunity. Natural immunity may not be sufficient either. > School closures, remote learning, masks even at that age. Obviously there have been (arguably way overzealous) efforts at controlling COVID even at the youngest ages. In many cases, schools didn't get closed during much of the Delta wave and incidence in the young population was particularly high. As for masks: They have a modest effect at best (20% risk reduction). https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7021e1-H.pdf https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7021e1-H.pdf