A list of key dates:
mortality_updated - the last time the NHS mortality data was extracted and added to AvonCAP
min_alpha - earliest observation of the alpha variant
max_wuhan - last observation of the wuhan variant
min_delta - earliest observation of the delta variant
max_alpha - last observation of the alpha variant
min_omicron - earliest observation of the omicron variant
max_delta - last observation of the delta variant
The default catchment population for AvonCAP is limited to the Bristol, North Somerset and South Gloucestershire Integrated Care Board (BNSSG ICB). This list is the list of GP surgeries considered part of the denominator.