OBJECTIVES:

Clinical Practice Research Datalink (CPRD) Aurum contains primary care electronic health records, including vaccinations and nearly complete capture of SARS-CoV-2 PCR test results between August 2020-March 2022. Our objective was to build code lists to define a cohort of persons diagnosed with COVID in England using routinely collected health data.

METHODS:

Persons aged 1 year or older were indexed on first COVID diagnosis from August 1, 2020 - January 31, 2022. We developed SNOMED code lists to define high risk of severe disease: 1) National Health Service’s (NHS) list of highest risk conditions; 2) PANORAMIC trial inclusion criteria; 3) UK Health Security Agency (UKHSA) clinical risk groups. COVID vaccinations were defined as of December 1, 2021 using medical and product codes. Code lists were developed using wildcard search terms which were reviewed by multiple independent reviewers, and inclusion/exclusion was determined by consensus. All lists for diagnoses were reviewed by a UK physician.

RESULTS:

We identified 2,257,907 people diagnosed in primary care with COVID; 46% were male and mean age was 34 years, comparable to governmental data for the same period reporting 47% of cases in England were male and mean age was 34 years. We identified 12% at high risk of severe disease using the NHS definition, 31% using the PANORAMIC trial criteria, and 10% using the UKHSA clinical risk groups. Among adults, 86.1% had ≥1 and 80.2% had ≥2 COVID vaccine doses (2% and 0.2% lower than official reports, respectively).

CONCLUSIONS:

This cohort represented the age and sex distribution of COVID cases, and the COVID vaccination coverage, in England through January 2022. Definitions were built using reproducible methods that can be leveraged for future work. The high capture of COVID vaccinations supports the use of this cohort to examine clinical and societal benefits of COVID vaccination in England.