And 47% of the total population according to University of Cambridge research! It doesn't particularly surprise me, but didn't think it was quite that high!
www.mrc-bsu.cam.ac.uk/now-casting/nowcasting-and-forecasting-20th-october-2021/
Given how it's spread through schools over the past months and given these figures, I'd be surprised if things didn't die back down in schools in the run up to Christmas.