NHS England COVID-19 datasets

Last modified: 05 Feb 2025

Introduction

NHS England flows extracts of six COVID-19 datasets into the UK LLC TRE - see Table 1.
Researchers are permitted access to these six datasets provided that their research is related to COVID-19. This is a specific term set by NHS England. (For examples of research purposes acceptable to NHS England see the COVID-19 Public Health Directions 2020.)

NHS England introduced new dm+d and SNOMED codes during the COVID-19 pandemic, which were mapped to the World Health Organization’s Emergency use ICD codes for COVID-19 disease outbreak. Primarily, SNOMED codes are used in the COVID-19 datasets - see the Coded variables guide for further details.

Coverage of COVID-19 datasets

Table 1 summarises the temporal and geographical coverage of each of the six COVID-19 datasets.

As explained in the overarching NHS England datasets guide, the UK LLC Data Team does not change the names of the datasets when they are ingested to the UK LLC TRE, apart from SGSS where we added COVID in front of it to distinguish it from the UK Health Security Agency’s (UKHSA’s) generalised Second Generation Surveillance System (SGSS).

Some datasets have been renamed by NHS England, e.g. CHESS is now called the Severe Acute Respiratory Infection (SARI-Watch) surveillance system dataset and some datasets have alternative names, e.g. NPEX is also called the Covid-19 UK Non-hospital Antigen Testing Results dataset. We receive the data from NHS England as the CHESS and NPEX datasets and these are the names researchers will see in the UK LLC TRE. Therefore, we refer to them by these names in our documentation.

Table 1 Names, coverage, availability and ownership of COVID-19 datasets in the UK LLC TRE (the dataset in italics is retired)

Name in TRE	Full name	Other name	Domain	Coverage	From	Data available in TRE1	Owner
COVIDSGSS	COVID-19 Second Generation Surveillance System	N/A	Testing (Pillars 1, 2, 42)	England	06/04/2020 to Feb 2024	06/04/2020 to Feb 2024	NHSE
IELISA	Enzyme-Linked Immunosorbent Assay	Covid-19 UK Non-hospital Antibody Testing Results	Testing (Pillars 3, 42)	UK	01/09/2020 to July 2022	01/09/2020 to July 2022	DHSC
NPEX	National Pathology Exchange	Covid-19 UK Non-hospital Antigen Testing Results	Testing (Pillars 2, 42)	UK	17/04/2020 to Feb 2024	17/04/2020 to Feb 2024	DHSC
CHESS	COVID-19 Hospitalisation in England Surveillance System	Severe Acute Respiratory Infection (SARI-Watch) surveillance system	Hospital	England	12/03/2020 to Oct 2022	12/03/2020 to Oct 2022	NHSE
CVS	COVID-19 Vaccination Status	N/A	Vaccination	England	08/12/2020 onwards	08/12/2020 onwards	NHSE
CVAR	COVID-19 Vaccination Adverse Reactions	N/A	Vaccination	England	08/12/2020 to Sept 2023	08/12/2020 to Sept 2023	NHSE

DHSC: Department of Health and Social Care
¹As documented in the data sharing agreement.
²As explained in the DHSC’s COVID-19 Scaling up our testing programmes, four pillars comprised the UK government’s approach to testing for SARS-CoV-2.
Pillar 1 quantified the number of people with a clinical need, and health and care workers, who returned positive swab (antigen) tests (processed in PHE labs and NHS hospitals).
Pillar 2 quantified the number of people in the wider community who returned positive swab (antigen) tests (processed in commercial labs).
Pillar 3 quantified the number of people who returned positive serology (antibody) tests to detect immunity and to understand the efficacy of the different testing methods.
Pillar 4 quantified the number of people who returned positive serology (antibody) and swab (antigen) tests to detect immunity and to understand the efficacy of the different testing methods.
For further details see the DHSC’s COVID-19 testing data: methodology note.