Groupings of variables by source
| Variable | Data source | |||
| England (OpenSAFELY) | Scotland (EAVE-II) | Wales (SAIL) | ||
| Demographics | Sex | TPP | EAVE-II | WDSD/WLGP |
| Age | TPP | EAVE-II | WDSD/WLGP | |
| Ethnicity | TPP | EAVE-II | CENW/NCCH | |
| Socioeconomic | IMD | TPP | EAVE-II | WDSD |
| Place of residence | Health board/STP, urban rural index | TPP | EAVE-II | WDSD |
| Accommodation type | Private or social housing | NA | EAVE-II | CENW |
| Comorbidities | Chronic childhood conditions | TPP, SUS APCS, SUS OPA, ISARIC | EAVE-II, SMR00/01/04/06, ISARIC | CYFI, BREC, WCSU, WLGP, PEDW |
| SARS-CoV-2 shielding list | TPP | EAVE-II | CVSP | |
| SARS-CoV-2 vaccination | Vaccine (type, date) | TPP | TVMT | CVVD |
| Laboratory tests | RT-PCR SARS-CoV-2 test (date and result) | SGSS | COVID-testing | PATD |
| Viral variant | SGSS | COG UK | CVSD/PATD | |
| Secondary care | ED contact | SUS ECDS | A+E Datamart | EDDD/EDDS |
| Outpatient clinic contact | SUS OPS | SMR00 | OPDW | |
| Hospital admission | SUS APCS | SMR01/04 | PEDW | |
| Admission ICD-10 code | SUS APCS | SMR | PEDW | |
| Level of care | SUS/ISARIC | SMR/ISARIC | PEDW/CCDS | |
| Length of stay | SUS/ISARIC | SMR/ISARIC | PEDW/CCDS | |
| PIMS-TS | SUS/ISARIC | SMR/ISARIC | PEDW/CCDS | |
| Primary care | In-hours contact | TPP | EAVE-II | WLGP |
| Community prescriptions | TPP | EAVE-II/PIS | WDDS | |
| Unscheduled care | NHS 111 contact | NA | NHS 24 | NHSO |
| Ambulance contact | NA | SAS | WASD/NHSO | |
| GP out of hours (OOH) contact | NA | GP OOH | NHSO | |
| Mortality | Death (all cause, COVID-19 main cause or <28 days of positive SARS-CoV-2 RT-PCR) | ONS deaths | NRS deaths | ONS deaths/ADDE |
| Symptoms | Presenting symptoms in CYP admitted with SARS-CoV-2 | ISARIC (subset only) | ISARIC (subset only) | ISARIC (subset only) |
ADDE, Annual District Death Extract; APCS, admitted patient care statistics; CCDS, Critical Care Data Source; CENW, Office of National Statistics Census; COG-UK, Centre of Genomics UK; CVSP, COVID-19 Shielded People; CVVD, COVID-19 Vaccine Data; EAVE-II, Early Pandemic Evaluation and Enhanced Surveillance of COVID-19; ECDS, emergency care datasets; ED, emergency department; EDDD, emergency department dataset daily; EDDS, Emergency Department Dataset; GP, general practitioner; ICD-10, International Classification of Diseases 10th Revision; IMD, Index of Multiple Deprivation; ISARIC, International Severe Acute Respiratory and emerging Infection Consortium; NA, not available; NCCH, National Community Child Health; NHS, National Health Service; NHSO, NHS 111 Call data; NRS, National Records of Scotland; ONS, Office for National Statistics; OPA, outpatient attendances; OPDW, Outpatient Dataset for Wales; PATD, Pathology Data (COVID-19 daily); PEDW, Patient Episode Database for Wales; PIMS-TS, paediatric multisystem inflammatory syndrome temporally associated ; PIS, Prescribing Information System; SAIL, Secure Anonymised Information Linkage; SAS, Scottish Ambulance Service; SGSS, Second Generation Surveillance System; SMR, Scottish Morbidity Record; STP, Sustainability and Transformation Partnership; SUS, Secondary Use Services; TPP, The Phoenix Partnership (GP group); WASD, Welsh Ambulance Service Dataset; WCSU, Welsh Cancer Incidence Surveillance Unit; WDDS, Welsh Dispensing Dataset; WDSD, Welsh Demographic Service Dataset; WLGP, Welsh Longitudinal General Practice.