SIREN study

The SARS-CoV2 immunity and reinfection evaluation (SIREN) study is a unique, large-scale partnership with NHS healthcare workers providing an agile response to an evolving pandemic. It is one of the national core studies established in response to COVID-19 and a National Institute for Health Research (NIHR) urgent priority study, providing vital research into immunity and vaccine effectiveness.

The SIREN study was established early in the pandemic with participants undergoing regular testing for up to 2 years. Analysis of these testing samples helps the UK to evaluate the immune response to COVID-19, build understanding of the protection offered by vaccines and provide insight into COVID-19 reinfections.

Healthcare workers are enrolled in the study via the hospital site they work at. A total of 135 sites have participated in the study involving almost 45,000 participants, making SIREN the largest study of its kind globally. The SIREN study is UK-wide, running in partnership with the Public Health Agency Northern Ireland, Public Health Scotland and Public Health Wales.

The SIREN study is registered with ISRCTN.

Our story:

The SIREN Study: Our story - YouTube

Hear from SIREN study research teams:

The SIREN Study: Hear from our research teams - YouTube

Hear from SIREN study participants:

The SIREN Study: Hear from our participants - YouTube

Hear from the SIREN study team:

The SIREN Study: Hear from the SIREN study team - YouTube

Locations

One-hundred-and-thirty-five sites across the UK contributed to the first year of the SIREN study, with 87 sites contributing to the second-year extension – see locations list here.

Findings

The SIREN study has provided valuable evidence on immunity following SARS-CoV-2 infection and COVID-19 vaccination and provided surveillance data on infection and emerging variants. This evidence has played a critical role in informing the national COVID-19 response.

In January 2021 the SIREN study published its first analysis of protection following SARS-CoV-2 infection. Crucially the analysis showed that reinfection was possible and could occur, but that there was an over 80% reduction in infection among people who had previously contracted COVID-19 compared to those who had not.

In spring 2021 when the Alpha variant was dominant in the UK the SIREN study published its first analysis on the effectiveness of COVID-19 vaccines, focusing primarily on the Pfizer vaccine. The analysis showed that short-term vaccine effectiveness against infection 21 days after the first dose was 70% in the study population of healthcare workers and rose to 85%, 7 days after the second dose was received.

In February 2022 a later publication by the SIREN study looked at protection against SARS-CoV-2 infection following both previous infection and vaccination. It found that in previously uninfected individuals, 2 doses of the Pfizer vaccine were associated with high short-term protection against SARS-CoV-2 infection but that this protection reduced considerably after 6 months. Among those with a previous infection vaccination appeared to boost their immunity, providing strong and longer lasting protection. This provided important insights for COVID-19 vaccination programmes.

The SIREN study has published several articles to share its findings.

Examples include:

• The New England Journal of Medicine (February 2022): Protection against SARS-CoV-2 after COVID-19 vaccination and previous infection

• The Lancet (April 2021): COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study

• The Lancet (April 2021): SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN)

• medRxiv (April 2022): Determinants of SARS-CoV-2 anti-spike antibody 2 levels following BNT162b2 vaccination: cross3 sectional analysis of 6,000 SIREN study participants

• Journal of Infection (February 2022): Serological profile of first SARS-CoV-2 reinfection cases detected within the SIREN study

• The British Medical Journal (July 2022): Burden of SARS-CoV-2 infection in healthcare workers during second wave in England and impact of vaccines: prospective multicentre cohort study (SIREN) and mathematical model

• The Journal of Infection (September 2022): A nested case-control within the SIREN study

Partners

The UK Health Security Agency (UKHSA) runs the SIREN study in partnership with NHS sites, the Public Health Agency Northern Ireland, Public Health Scotland and Public Health Wales.

The SIREN study works with a number of academic partners. The SIREN Consortium was established in August 2021 and was successfully awarded a £1.57 million research grant by UK Research and Innovation (UKRI).

SIREN Consortium members include:

• Protective Immunity from T cells to COVID-19 in Health workers (PITCH):
  • University of Oxford
  • University of Liverpool
  • University of Sheffield
  • Newcastle University
  • University of Birmingham
• The Francis Crick Institute
• Humoral Immune Correlates for COVID-19 (HICC)
• Imperial College London
• University of Glasgow
• British Society for Immunology
• GenOMICC

Contributors

Staff across the 135 sites have helped with the running of the study – download a study contributors list here (ODS, 26.9 KB).

Funding

The SIREN study is funded by UKHSA, the Department of Health and Social Care and NIHR, with contributions from the Scottish, Welsh and Northern Irish governments and funding awarded through research grants.

Further information

The SIREN study: answering the big questions.

SIREN: One year on.

SIREN: Two years on.

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Site list

Key

SeeActive list= ofActive SIREN testing
Closed = Active SIREN testing stopped

SIREN study site	Year 1	Year 2
England
St George’s University Hospitals NHS Foundation Trust	Active	Active
University Hospitals Of Leicester NHS Trust	Active	Active
University Hospitals Plymouth NHS Trust	Active	Active
Leeds Teaching Hospitals NHS Trust	Active	Active
Mid Essex Hospital Services NHS Trust	Active	Active
North Middlesex University Hospital NHS Trust	Active	Active
Liverpool University Hospitals NHS Foundation Trust	Active	Active
West Suffolk NHS Foundation Trust	Active	Active
Sheffield Teaching Hospitals NHS Foundation Trust	Active	Active
University Hospitals of Morecambe Bay NHS Foundation Trust	Active	Active
Southend University Hospital NHS Foundation Trust	Active	Active
University Hospitals Bristol and Weston NHS Foundation Trust	Active	Active
King’s College Hospital NHS Foundation Trust	Active	Active
The Dudley Group NHS Foundation Trust	Active	Active
Royal Devon and Exeter NHS Foundation Trust	Active	Active
North Cumbria Integrated Care NHS Foundation Trust	Active	Active
St Helens and Knowsley Teaching Hospitals NHS Trust	Active	Active
Lewisham and Greenwich NHS Trust	Active	Active
The Newcastle Upon Tyne Hospitals NHS Foundation Trust	Active	Active
The Princess Alexandra Hospital NHS Trust	Active	Active
Imperial College Healthcare NHS Trust	Active	Active
Blackpool Teaching Hospitals NHS Foundation Trust	Active	Active
East Suffolk and North Essex NHS Foundation Trust	Active	Active
Hampshire Hospitals NHS Foundation Trust	Active	Active
James Paget University Hospitals NHS Foundation Trust	Active	Active
Buckinghamshire Healthcare NHS Trust	Active	Active
Sheffield Children’s NHS Foundation Trust	Active	Active
Basildon and Thurrock University Hospitals NHS Foundation Trust	Active	Active
Frimley Health NHS Foundation Trust	Active	Active
Calderdale and Huddersfield NHS Foundation Trust	Active	Active
United Lincolnshire Hospitals NHS Trust	Active	Active
Isle Of Wight NHS Trust	Active	Active
Warrington and Halton Teaching Hospitals NHS Foundation Trust	Active	Active
Royal Free London NHS Foundation Trust	Active	Active
Whittington Health NHS Trust	Active	Active
The Clatterbridge Cancer Centre NHS Foundation Trust	Active	Active
University Hospitals Of North Midlands NHS Trust	Active	Active
Royal Papworth Hospital NHS Foundation Trust	Active	Active
Shrewsbury and Telford Hospital NHS Trust	Active	Active
Devon Partnership NHS Trust	Active	Active
The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust	Active	Active
London North West University Healthcare NHS Trust	Active	Active
Croydon Health Services NHS Trust	Active	Active
Nottingham University Hospitals NHS Trust	Active	Active
Mid Cheshire Hospitals NHS Foundation Trust	Active	Active
Dartford and Gravesham NHS Trust	Active	Active
Lancashire Teaching Hospitals NHS Foundation Trust	Active	Active
Bedfordshire Hospitals NHS Foundation Trust	Active	Active
Shropshire Community Health NHS Trust	Active	Active
Royal National Orthopaedic Hospital NHS Trust	Active	Active
Stockport NHS Foundation Trust	Active	Active
Hounslow and Richmond Community Healthcare NHS Trust	Active	Active
Salisbury NHS Foundation Trust	Active	Active
Derbyshire Healthcare NHS Foundation Trust	Active	Active
Birmingham and Solihull Mental Health NHS Foundation Trust	Active	Active
Black Country Healthcare NHS Foundation Trust	Active	Active
Solent NHS Trust	Active	Active
Southern Health NHS Foundation Trust	Active	Active
George Eliot Hospital NHS Trust	Active	Active
Lincolnshire Partnership NHS Foundation Trust	Active	Active
The Hillingdon Hospitals NHS Foundation Trust	Active	Active
Central and North West London NHS Foundation Trust	Active	Active
Lancashire and South Cumbria NHS Foundation Trust	Active	Active
Doncaster and Bassetlaw Teaching Hospitals NHS Foundation Trust	Active	Active
Bolton NHS Foundation Trust	Active	Active
Southport and Ormskirk Hospital NHS Trust	Active	Active
Norfolk and Norwich University Hospitals NHS Foundation Trust	Active	Active
Mid Yorkshire Hospitals NHS Trust	Active	Active
Somerset NHS Foundation Trust	Active	Closed
University Hospitals Of Derby and Burton NHS Foundation Trust	Active	Closed
Sherwood Forest Hospitals NHS Foundation Trust	Active	Closed
Gloucestershire Hospitals NHS Foundation Trust	Active	Closed
Hull University Teaching Hospitals NHS Trust	Active	Closed
Yeovil District Hospital NHS Foundation Trust	Active	Closed
Sandwell and West Birmingham Hospitals NHS Trust	Active	Closed
Royal Cornwall Hospitals NHS Trust	Active	Closed
Moorfields Eye Hospital NHS Foundation Trust	Active	Closed
Torbay and South Devon NHS Foundation Trust	Active	Closed
Ashford and St Peter’s Hospitals NHS Foundation Trust	Active	Closed
York Teaching Hospital NHS Foundation Trust	Active	Closed
Northern Devon Healthcare NHS Trust	Active	Closed
Countess Of Chester Hospital NHS Foundation Trust	Active	Closed
Portsmouth Hospitals NHS Trust	Active	Closed
Walsall Healthcare NHS Trust	Active	Closed
Royal Surrey County Hospital NHS Foundation Trust	Active	Closed
University Hospital Southampton NHS Foundation Trust	Active	Closed
Manchester University NHS Foundation Trust	Active	Closed
North West Anglia NHS Foundation Trust	Active	Closed
Royal United Hospitals Bath NHS Foundation Trust	Active	Closed
Surrey and Sussex Healthcare NHS Trust	Active	Closed
Great Western Hospitals NHS Foundation Trust	Active	Closed
Epsom and St Helier University Hospitals NHS Trust	Active	Closed
University Hospitals Coventry and Warwickshire NHS Trust	Active	Closed
Western Sussex Hospitals NHS Foundation Trust	Active	Closed
The Royal Wolverhampton NHS Trust	Active	Closed
Chesterfield Royal Hospital NHS Foundation Trust	Active	Closed
Brighton and Sussex University Hospitals NHS Trust	Active	Closed
Wye Valley NHS Trust	Active	Closed
Wirral University Teaching Hospital NHS Foundation Trust	Active	Closed
East Sussex Healthcare NHS Trust	Active	Closed
Maidstone and Tunbridge Wells NHS Trust	Active	Closed
Queen Victoria Hospital NHS Foundation Trust	Active	Closed
Cornwall Partnership NHS Foundation Trust	Active	Closed
The Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust	Active	Closed
Poole Hospital NHS Foundation Trust	Active	Closed
Northern Lincolnshire and Goole NHS Foundation Trust	Active	Closed
Leicestershire Partnership NHS Trust	Active	Closed
Birmingham Community Healthcare NHS Foundation Trust	Active	Closed
Dorset County Hospital NHS Foundation Trust	Active	Closed
Alder Hey Children’s NHS Foundation Trust	Active	Closed
Royal Berkshire NHS Foundation Trust	Active	Closed
Dorset Healthcare University NHS Foundation Trust	Active	Closed
Derbyshire Community Health Services NHS Foundation Trust	Active	Closed
Northern Ireland
Southern Health and Social Care Trust	Active	Active
South Eastern Health and Social Care	Active	Active
Belfast Health and Social Care Trust	Active	Active
Western Health and Social Care Trust	Active	Active
Northern Heath and Social Care Trust	Active	Active
Scotland
NHS Lothian	Active	Active
NHS Greater Glasgow and Clyde	Active	Active
NHS Lanarkshire	Active	Active
NHS Grampian	Active	Active
NHS Highland	Active	Active
NHS Fife	Active	Active
NHS Forth Valley	Active	Active
Golden Jubilee National Hospital	Active	Active
NHS Western Isles	Active	Active
NHS Borders	Active	Active
Wales
Aneurin Bevan University LHB	Active	Active
Swansea Bay University LHB	Active	Active
Cwm Taf Morgannwg University LHB	Active	Active
Hywel Dda University LHB	Active	Active
Velindre NHS Trust	Active	Closed
Betsi Cadwaladr University LHB	Active	Closed
Powys Teaching LHB	Active	Closed