Epidemiology Unit: annual review
Our latest annual review is Safe Supplies 2024: Collaborating for safety (PDF 2MB).
Download supplementary material below:
Please cite as: Safe Supplies 2024: Collaborating for safety. Annual Review from the NHS Blood and Transplant and UK Health Security Agency Epidemiology Unit. London October 2025. Available at https://hospital.blood.co.uk/diagnostic-services/microbiology-services/epidemiology/annual-review
Key highlights
Key message:
- Donor selection helped keep the number of UK blood donors with markers of infection low in 2024, and no transfusion-transmitted infections were identified following investigations. However, continued vigilance is essential, especially with challenges faced by emerging threats like arboviruses and the potential for rare cases of early viral infections which could potentially go undetected. Collaboration across services ensures donors are supported and recipients protected.
Key highlights from this review include:
- In 2024, there were 1.8 million blood donations made by 964,000 UK blood donors, selected to be at low risk of blood borne infection. Just 287 gave a donation which was confirmed positive for either chronic, occult or acute hepatitis B, hepatitis C, HIV, HTLV or syphilis and removed from the supply. Only 10 repeat donors had markers of recent infection, but 6 were recent HIV including 1 early HIV detected only on NAT with negative serology.
- The chance that blood donation screening did not detect a marker of HBV, HCV or HIV due to a window period donation remained around 1 in 1 million whole blood donations tested. However, the small chance of not detecting a donation from a donor with very early HIV increased from previous estimate of 0.05 in 1 million to 0.1 in 1 million, or 1 in up to 6 years.
- There were no transfusion-transmitted infections identified after 136 investigations of potential transmissions requested by hospitals, and 11 lookbacks in England on repeat donors with markers of infection. But hospital engagement and collaboration are key to ensure those affected are promptly identified, tested and referred for appropriate care. For more information access annual reports on the Serious Hazards of Transfusion (SHOT) website.
- Collaborative CJD surveillance between the National CJD Research and Surveillance Unit and the UK blood services since 1997 linked information to identify transfusion-transmission of variant CJD to 4 recipients before leucodepletion began in 1999. There is no evidence of sporadic CJD transfusion transmission to date, despite continuing searches in 2024.
- There is a clear process for horizon scanning for emerging infections that may impact the safety or sufficiency of the blood supply that relies on close links with public health and One Health surveillance. In 2024, 952 entries in the Emerging Infection Report were reviewed with spread of arboviruses, mpox and avian influenza accounting for a significant proportion of activity.
- Since the 2020 FAIR policy review, allowing more GBMSM to donate from June 2021, the unit has monitored its impact. This included a 2024 survey in partnership with the University of Nottingham with 23,861 UK donor responses, including LGBTQ+ and gender-diverse individuals. Most responders told us they had donated while eligible to the FAIR policy.
- Partnerships with UKHSA, Imperial College London, and the University of Nottingham continued by contributing data to national infection surveillance, managing the HTLV National Register, and exploring donor disclosure through the PROMPT study.
- The Unit also carry out surveillance of infection markers in other donor groups on behalf of NHSBT, including organ donors, and living and deceased tissue donors and cord blood donors, and an update on markers of infection in these donors is included.
For more information about blood donation safety, including adverse events and reactions that have been reported, access annual reports on the Serious Hazards of Transfusion (SHOT) website.