Safe supplies 2020: progress in a pandemic
Updated 21 December 2021
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This publication is available at https://www.gov.uk/government/publications/safe-supplies-annual-review/safe-supplies-2020-progress-in-a-pandemic
This report was produced jointly by NHS Blood and Transplant (NHSBT) and UK Health Security Agency (UKHSA).
The joint NHSBT and UKHSA Epidemiology Unit provides surveillance of infections in blood, plasma, tissue, cell and organ donors across the UK, and infections transmitted by blood transfusion. Blood donor surveillance started in the mid-1990s and has expanded as more screening tests have been added.
NHSBT is responsible for collecting and issuing blood, tissues and some stem cells in England and responsible for organ donation across the UK.
Other blood services across the UK and Ireland provide data to the unit, including:
- Welsh Blood Service
- Scottish National Blood Transfusion Service
- Northern Ireland Blood Transfusion Service
- Irish Blood Transfusion Service
All blood donations are screened for a range of mandatory tests including hepatitis B, C and E, HIV and syphilis and specific donations for human T-lymphotropic virus (HTLV).
In addition, there are a number of other tests that may be carried out if a donor declares an infection risk – for example, a test for malarial antibodies if the donor was born in (or has travelled to) a country where malaria is very common.
More detailed information is provided in the full 2020 report.
Blood donor demographics and positive blood donors
Blood donations which are reactive on screening are removed from the supply. Samples are sent for further testing and confirmation. If a donor has a positive donation testing result, they will be informed and arrangements made for them to see their general practitioner (GP) or to attend a sexual health clinic. The local health protection team will be informed of any notifiable infections.
In the UK in 2020 there was a slight decrease in whole blood donations of 7%. Looking at donors who made a whole blood donation in the UK in 2020, 44% of donors were male and 13% of donors were new. Due to the coronavirus (COVID-19) pandemic, collection patterns changed in part due to an intentional reliance on existing donors and a managed drop in supply to maintain stocks and meet reduced demand. Compared to 2019 these new donors gave approximately 7% of all donations, a decrease from 2019 when 10% of donations were made by new donors.
All of the UK blood services are keen to encourage more Black, Asian and minority ethnic donors to donate in order to more closely reflect the blood groups of patients needing multiple transfusions, such as patients with Sickle Cell Disease. While the number of donations decreased across all ethnic groups in 2020, the percentage of Black donors who gave a whole blood donation was maintained in England at 1%.
In 2020, over 1.7 million blood donations were screened across the UK. Of these, 176 (0.01%) donations confirmed positive for either hepatitis B virus, hepatitis C virus, HIV, HTLV or treponemal antibody (syphilis) were discarded. The majority of these were detected in donations from new donors (129, 73%) and these were mostly either past or chronic infections in the donor.
Only a small number of new infections, acquired within one year were identified. The majority of recent infections were due to syphilis (39), 2 were acute hepatitis B infections in repeat donors, 2 were hepatitis C infections in repeat donors and one was a recent HIV infection in a new donor. Additionally, 2 occult hepatitis B infections were detected in one new and one repeat donor. A further 458 donations tested positive for hepatitis E virus and were discarded.
All donors answer a series of questions at the time of donation on the Donation Safety Check – to both ensure the donor is safe to donate blood and ensure the safety to the recipient. Donor selection reduces the chance of a donor with a very early infection donating, and thus minimises the risk of an infection being missed on screening.
Of the 44 donors with recent infections, 12 did not fully disclose deferrable risks at the time of donation, 11 were repeat donors. These included 2 female donors, one with acute hepatitis B and one with hepatitis C, who had not declared a higher risk partner. The remaining 10 males included 6 who had not declared being treated for syphilis, three with syphilis who had not declared a male partner within 3 months and one who had not declared either syphilis or their male partner. To maintain safety, donors need to be encouraged to report past infection and think about current sexual activities before giving blood or plasma.
Convalescent plasma donation
In April 2020, the UK blood services began collection of convalescent plasma (CVP) to assess its effectiveness in clinical trials. Potential donors who had who had recovered from SARS-CoV-2 infection were targeted with male and hospitalised patients prioritised for the best chance of obtaining a donation with high antibody levels. In England, in contrast to whole blood donors, the majority of donations were given by males (86% vs 44%) and new donors (50% vs 7%) and increased percentage of Asian donors comprised 6% compared to 3%.
Between April and December 2020 in England, 33,301 CVP donations and 11,234 samples were collected with 46 confirmed positive (0.1%), 44 in new and 2 syphilis in lapsed donors. We saw higher but not significantly different rates of hepatitis B and C in CVP donations from new donors compared with new whole blood donations. These appeared to be longstanding infections.
Syphilis total rates were significantly higher in CVP donors but only 3 of 25 donors had a recent infection. Twelve or a quarter of positive donors had a known infection (9 syphilis and 3 hepatitis B or C) while one should have declared a higher risk partner.
Informing donor selection policy
A combination of donor selection and donation testing is used to maintain the safety of the blood supply – blood donor selection criteria are kept under review as the national epidemiology of infections and test sensitivity changes over time. SaBTO, the Department of Health and Social Care (DHSC) expert committee on the safety of blood, tissues and organs, is responsible for reviewing and making recommendations on certain donor selection criteria.
In November 2011, after a SaBTO review, the UK blood services removed their permanent deferral for men who have sex with men and reduced it to 12 months (Northern Ireland followed in 2016). In November 2017, after a further SaBTO review, the English, Welsh and Scottish blood services changed their donor selection criteria for donors with partners at increased risk, including men who have sex with men and commercial sex workers, to a 3-month deferral since the last time they had sex. The Northern Ireland blood service also switched to the 3-month deferral in June 2020.
In December 2020, following a further review by For the Assessment of Individualised Risk (FAIR) led by UK blood services, UKHSA, Nottingham University and a range of stakeholders including LGBT+ groups, UK ministers agreed the SaBTO recommendation to implement FAIR and switch to a more individualised blood donor selection policy.
The evidence has refined the behaviours and circumstances that are higher risk, triangulating evidence on higher risk from the general population, blood donors and acceptable and effective questions from socio-behavioural work. The same questions are now asked of all donors and allows anyone who has not had a new sexual partner in the last 3 months to give blood if other donation safety criteria are met.
There are new 3-month deferrals in place for gonorrhoea, use of drugs during sex known as chemsex and if new partner or multiple partners reported then donors are asked about anal sex with the partner(s) and deferred if yes. FAIR was implemented by the UK blood services in 2021 and active post implementation monitoring is in place.
Monitoring viral blood safety
A number of risk reduction strategies have been introduced to reduce the risk of viral transfusion-transmission infections (TTIs), including donor selection criteria and new tests such as the introduction of hepatitis E virus universal screening in 2017.
Blood safety is monitored in 2 ways. The chance of not detecting and releasing an infectious donation made by a donor who has very recently acquired hepatitis B, hepatitis C or HIV is estimated over a 3-year period each year. The current estimate remains at less than one in a million and a position statement is available on the Joint United Kingdom Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee (JPAC) website.
Of these 3 viruses, hepatitis B carries the highest risk of not being detected and released with potential for being transfusion-transmitted.
The chance, or residual risk, of not detecting and releasing a very recently acquired infection in a blood donor is used to monitor the impact of the changes in donor selection. Since 2012 the HIV and hepatitis C virus risk has declined, and the hepatitis B virus risk remained relatively stable.
The second way blood safety is monitored is by routine surveillance of reported suspected TTIs to the blood services for investigation. During 2020, 5 suspected viral TTIs were reported, a decrease of about 50% from previous years. Four were discounted by excluding infection in the donor or identifying another potential source of infection in the recipient.
One hepatitis B investigation was reported to Serious Hazards of Transfusion (SHOT) as probable transfusion-transmission. A suspected HEV investigation from 2019 was closed in 2020, also assigned as probable. More information is available in the SHOT report.
Bacterial screening of platelets and bacterial transfusion-transmitted infections
Although all blood donations are screened for the presence of certain viruses as well as syphilis, only platelet donations are routinely screened for the presence of bacteria because they are stored at 22°C – a temperature which may encourage the growth of bacteria.
Following screening, platelets have a shelf life of up to 7 days and any platelet packs reactive on screening are removed from the supply and further tested. The majority of bacteria detected on screening are unlikely to cause harm but sometimes more significant bacteria are detected such as those normally found in the gut. Donors are contacted if their platelet donation grows bacteria which may indicate an underlying illness, where appropriate donors will be referred to their GP for further investigations.
Bacterial screening is one of several strategies introduced to reduce the risk of bacterial TTIs. All suspected TTIs reported to the blood services are investigated. In 2020 no proven bacterial transmissions were reported to SHOT. Bacterial screening of platelets became universal in the UK in 2011, when England starting screening. Since then, there has been one confirmed bacterial TTI, a Staphylococcus aureus in 2015.
Emerging infections
Another role of the unit is in horizon-scanning for infectious diseases that could potentially affect the safety of the UK blood supply, particularly new and emerging infections. This work is carried out in conjunction with colleagues across UKHSA and with blood services around the world.
The Joint NHSBT UKHSA epidemiology unit produce a monthly emerging infections report for the UK blood services to assess risk and may result in additional tests or changes to donor selection criteria being implemented. 2020 was of course dominated by COVID-19 reports but in 2020 we also saw Usutu virus identified in birds in the UK, raising the public health risk to low but indicating the potential for West Nile virus transmission.
Tick-borne infections were also notable, with the first locally acquired babesia and the second locally acquired tick-borne encephalitis human cases recorded in the UK. In 2020 the blood services risk assessed COVID-19 with donor deferrals for any symptomatic individuals and after having a vaccine put in place as a precautionary measure since there was no evidence for transfusion transmission.
Donations were able to continue during the pandemic restrictions with extra safety precautions in place including social distancing and face coverings to protect staff and donors at session, recognised as COVID-secure by Public Health England (PHE). Additional testing for West Nile virus in donors returning from affected areas was extended to the Netherlands, Germany and the Andalucía region of Spain in 2020.
Tissue and cell donors
Over recent years there has been a planned reduction in the collection of bone from living surgical bone donors. During 2020, 260 living surgical bone donors were tested for donation by NHSBT. No markers of infection were detected. A range of tissues are collected from deceased donors, a significant percentage being corneas. Among 2,424 deceased tissue donors tested for donation, 5 donors had chronic hepatitis B, 3 hepatitis E, one for HTLV and 2 past syphilis.
In 2020, 3 hospitals in the London area collected cord blood from 141 pregnant women. The women were tested by NHSBT and none were found to be positive. Markers of infection are rarely identified in cord blood donors at the time of delivery as antenatal screening will usually detect HIV, hepatitis B or syphilis in these donors.
Deceased organ donors
Deaths increased in the UK during 2020 due to the impact of the COVID-19 pandemic, but the number of donors decreased by almost a third. During 2020, 1,644 people became consented potential donors with family consenting to donation. Around three quarters became actual donors with at least one organ retrieved for transplantation, and 95% became utilised with at least one organ transplanted.
More Black and Asian organ donors are needed for recipients; 7% of donors are from Black, Asian, mixed and minority ethnic communities compared with 14% of the general population. Testing of organ donors is carried out in local laboratories and reported as reactive or negative. It is not possible to get the same level of detail of confirmatory tests as for those samples tested within the UK blood services. Reference testing is carried out but not always reported to the surveillance system.
Of the 1,180 utilised donors, 11 were reactive for viral infections, 7 of which were hepatitis C. Hepatitis C is the most common virus among deceased organ donors. Nucleic acid testing (NAT) testing for increased risk donors such as people who have injected drugs can reduce hepatitis risk for recipients. Markers of infection are not necessarily barriers for transplantation.
Blood Borne Virus Unit
The NHSBT and UKHSA Epidemiology Unit and the UKHSA Blood Borne Virus Unit (BBVU) work together with scientific and clinical colleagues at NHSBT on several research projects to support blood, tissue and organ safety.
The unit undertakes surveillance, research and development activities for hepatitis A through to hepatitis E and also for other pathogens that impact on blood safety. In 2020, the unit worked on developing new genomic and serological methods for viral and viral strain detection, for example SARS-CoV-2 antibody assays, HTLV and HHV8 as well as supporting work to inform policy on screening and donor selection.
Data sources, methods and infographics from past years’ reports are available. Please contact epidemiology@nhsbt.nhs.uk for more information.