Ah right, the 0.9% is after adjusting for the age distribution of Great Britain:
> These estimates were corrected for non-uniform attack
rates by age and when applied to the GB population result in an IFR of 0.9% with 4.4% of infections hospitalised (Table 1).
> These estimates were corrected for non-uniform attack rates by age and when applied to the GB population result in an IFR of 0.9% with 4.4% of infections hospitalised (Table 1).