Epidemiology Unit

Monitoring infections in blood, tissue and organ donors, and transfusion recipients

Our latest annual review

Safe supplies 2022: monitoring safety in donors and recipients (PDF 12MB)

Please cite as: Safe supplies 2022: Monitoring safety in donors and recipients. Annual Review from the NHS Blood and Transplant and UK Health Security Agency Epidemiology Unit. London October 2023. Available at https://hospital.blood.co.uk/diagnostic-services/microbiology-services/epidemiology/

Key highlights from the 2022 review

The number of infections in all donors in the UK remains low, supporting good compliance with donor selection, and few infections were confirmed in transfusion recipients.
The FAIR donor selection policy allowing gay and bisexual men who have sex with men to give blood in the UK has not impacted on the safety of the UK blood supply. The chance of not detecting a recently acquired viral infection on routine screening remains below 1 in 1 million donations.
Routine blood donation screening for antibodies to hepatitis B core was rolled out across the UK, resulting in the increased detection of potentially transmissible hepatitis B virus from donors with occult hepatitis B.
Horizon scanning of potential emerging threats to blood safety picked up the mpox outbreak. This also informed a blood safety risk assessment, which found the risk to recipients was minimised through pre-donation information to donors and existing mitigation steps, including the FAIR donor selection policy.
Investigations identified the first confirmed transmission of hepatitis B from a donor with occult hepatitis B infection (OBI) to two recipients in the UK. The transfusions occurred in 2021, before the introduction of hepatitis B core antibody testing.
Evidence of Creutzfeldt-Jakob disease (CJD) transfusion-transmission has been gathered through the Transfusion Medicine Epidemiological Review (TMER) in collaboration with the National CJD Research and Surveillance Unit since 1997. Cases of variant CJD have been low in number and rarely linked to the blood supply, with no vCJD transfusion-transmission after the introduction of leucodepletion in 1999. In 2018, the risk was downgraded such that plasma collection for manufacturing in the UK could safely be restarted in 2021. The TMER continues to monitor sporadic CJD cases with no evidence of sporadic CJD transfusion-transmission to date.
We continue to recruit to the Human T-cell lymphotropic virus (HTLV) national register, in collaboration with Imperial College London. Health information reported by participants (mostly asymptomatic blood donors) showed onset of severe disease to be rare.

For more information, access the following links:

Who we are

The joint NHS Blood and Transplant (NHSBT) and UK Health Security Agency (UKHSA) Epidemiology Unit comprises a small team of epidemiologists and public health specialists working with scientific and clinical colleagues across both NHSBT and UKHSA (previously known as PHE).

The unit was established in 1995 to monitor infections in blood donors and transfusion recipients. The role of the unit has expanded over time and we are now responsible for monitoring infections in blood, tissue and organ donors, and transfusion recipients.

What we do

The Epidemiology Unit monitors infection in blood, tissue and organ donors, and transfusion recipients. The unit collates and reports national epidemiological data on:

Blood borne infections among donors
The associated risk of transmission through transfusion and transplant

Data from the 4 UK blood services (NHSBT, Welsh Blood Service, Northern Ireland Blood Transfusion Service and the Scottish National Blood Transfusion Service) is collated and analysed by the unit to produce surveillance reports and inform or evaluate policy changes relating to infection risk.

The unit manages a series of national surveillance schemes. Data from these schemes is used to assess and improve blood, tissue and organ safety. These schemes include:

Infections in blood donors: monitored through donation testing and the collection of information about identified infected donors.
Infections in tissue donors (including stem cell and cord blood donors): monitored in a similar way to blood donors.
Infections in deceased organ donors: monitored in a similar way to blood donors.
Reported post-transfusion infections: monitoring investigations among transfusion recipients from the four UK blood services, as the national infection co-ordinator as part of Serious Hazards of Transfusion (SHOT).
Emerging infections: relevant reports from various sources are collated and reported on a monthly basis or as necessary.
Transfusion Microbiology Epidemiology Review (TMER): looking for evidence of transmission of CJD via blood transfusion.

The unit manages the UK Blood Donor Surveys to help assess the impact of donor selection policy changes including FAIR. We also manage the HTLV National Register in collaboration with Imperial College Healthcare NHS Trust, consisting of donors with HTLV and HTLV specialist clinic attenders, to inform public health about onset and progression of HTLV associated disease.

What we work towards

Our work helps to maintain a safe supply of blood, tissues and organs by:

Informing donor selection criteria
Monitoring trends in infections
Following up any reported post-transfusion infections

Blood donors are a well characterised low risk group, with around 1.8 million donations screened in the UK each year for markers of HBV, HCV, HIV, HEV, syphilis, and HTLV in new donors.

The information we collect also contributes to our understanding of the epidemiology of blood borne infections, and there is potential for following up infected donors. This could provide additional information to public health specialists working to reduce infections in the general population, through prioritising population groups for interventions and delivery of care.

Annual review archive

2021

2020

Safe Supplies 2020: progress in a pandemic, published on the GOV.UK website or download here:

2015 to 2019

Contact us

epidemiology@nhsbt.nhs.uk