Numbers of patients in line for vaccination against COVID-19 - and the proportion of the population in different areas in the first eligible group - vary hugely between CCGs.
The first-wave rollout of vaccination in primary care is focused on patients aged over 80. Across England as a whole, there are around 2.87m patients registered with GP practices in this age bracket - just over half a million of whom are aged over 90.
Analysis by GPonline of data from NHS Digital shows that in some CCG areas as many as 8% of the total registered patient population are aged over 80 - and at primary care network (PCN) level this rises to 11%.
In terms of sheer numbers, Kent and Medway CCG tops the list - with 99,502 patients aged over 80. The CCG is one of the largest in the country, however, with 200 GP practices covering 1.9m patients, and over 80s make up just 5% of the total.
In Southport and Formby CCG, 8% of patients are aged over 80 years old - the highest proportion of any CCG area in England. The area has just 17 GP practices covering 125,344 patients in total, 9,957 of whom are over 80 years old - meaning these practices will have to administer 10 of the 975-dose boxes of Pfizer/BioNTech vaccine just to cover this age group.
In just a week from the point when 91-year-old Margaret Keenan became on 8 December the first person to receive the Pfizer/BioNTech vaccine outside of a clinical trial, nearly 140,000 doses had been administered at hospital hubs and GP-led sites.
Delivering the vaccine will be complicated by the fact that around 400,000 older patients are thought to live in care homes, according to figures cited by charity care provider MHA. This cohort is the first in line for vaccination based on the priority list set out by the Joint Committee on Vaccination and Immunisation (JCVI) - but the fragility of the only vaccine approved for use to date means delivery in care homes is complex.
However, after a trial involving seven PCN sites last week, primary care vaccination sites from the first three waves of the programme were due to start delivering the vaccine in care homes in England this week.