Thread by @peterdonaghy

I was looking into recent UK COVID-19 data, and I think it's reasonable to conclude:

Case fatality rate has fallen by around 86%, from 1.1% in winter to 0.15% now

Case hospitalization rate has fallen by 63%

This pattern is evident in areas where the Delta variant dominant
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Hospitalization and deaths from COVID-19 lag behind cases. From trial and error, it looks like the best lag to use for hospitalizations is the 31 day period after a confirmed positive test. For deaths, cases over a 14 day period starting 28 days ago seems to work best.

The charts below show the correlation between weekly deaths and cases since October 2020, and the number of hospital inpatients and cases, compared with the lagged case numbers.

You can then use these values to work out case fatality and case hospitalization rates. The hospitalization rate is defined as the % of all cases over the previous 31 days that are in hospital on any given day, and the fatality rate deaths divided by lagged 14 day case numbers.

Weighted by the number of cases, the average case fatality rate was 1.1% from October 2020 to February 2021, and the hospitalization rate was 2.7% over the same period. As of the 6th of June, the fatality rate has fallen to 0.15% and hospitalization rate to 1.0%.

The hospitalization rate appears to be still falling, and the fatality rate seems to have plateaued over the last couple of weeks at around 0.15%.

Split by nation and English region, the same pattern can be seen, even in areas such as the North West and London where the Delta variant has been dominant for longer than 4 weeks.

Testing levels now are similar to what they were last autumn, so the recent declines in the hospitalization and fatality rates aren't being caused by an increase in testing. (ends)