Research and analysis

HPR volume 18 issue 7: news (29 August)

Updated 26 September 2024

New UK RSV vaccination programmes

Following the advice from the JCVI in June 2023, the NHS is introducing 2 new immunisation programmes across the UK ahead of this winter to protect neonates/infants through maternal vaccine and for direct protection of older adults from respiratory syncytial virus (RSV) disease.

RSV is a common infection in infancy or early childhood and causes over 20,000 infants to be admitted to hospital in the UK each year for conditions like bronchiolitis. Significant morbidity and mortality has also been recorded in older adults with recent estimates from enhanced surveillance suggesting over 2000 deaths annually in the UK.

Pfizer’s RSV vaccine, Abrysvo®, has been selected for both the programmes. In the case of the infants or newborns programme, protection will be achieved through maternal vaccination and ‘passive’ protection of neonates by transplacental antibody transfer and other indirect effects. Direct vaccination of infants is not approved nor considered appropriate in their first months of life due the immaturity of the immune system. To date, the only immunisation available against RSV has been a high-cost monoclonal antibody, which was limited to the most medically vulnerable infants as the only group in which it was cost-effective. This will continue to be available to provide direct protection for these high-risk children additional to protection they might get from maternal vaccination.

Healthcare practitioner information and guidance to support the 2 programmes are available via the UKHSA’s RSV immunisation collection webpage at RSV vaccination of pregnant women for infant protection: information for healthcare practitioners and RSV vaccination of older adults: information for healthcare practitioners. Separate core training slide sets, for healthcare practitioners, for each programme, can be downloaded from the collection webpage.

Detailed information on RSV and clinical guidance on RSV immunisation is contained in chapter 27a of Immunisation Against Infectious Disease (the Green Book).

Joint NHSBT and UKHSA Epidemiology Unit annual report in summary

The latest annual report of the joint NHS Blood and Transplant (NHSBT) and UK Health Security Agency (UKHSA) Epidemiology Unit, Safe supplies 2023: Close monitoring of blood donations, has been published.

The unit was established in 1995 and comprises a small team of epidemiologists and public health specialists working with scientific and clinical colleagues across both NHSBT and UKHSA. This year’s report has 6 infographics focusing on the unit’s work relating to the surveillance of infections in blood donors and transfusion recipients across the UK providing assurance of the safety of the blood supply for recipients today.

Figure 1. Safe Supplies 2023: close monitoring of blood donations

Blood donor selection rules aim to allow as many donors as possible to give blood while maintaining the safety of the supply. In 2023, approximately 950,000 volunteer blood donors aged 17 and above gave a whole blood donation in the UK, 54% were made by women. Of the 140,000 donors giving for the first time, 8% were Asian and 4% Black (Figure 1). Among almost 1.8 million blood and apheresis donations screened, 287 donations (1 in 6,224) had evidence of infection including 7 HIV, 29 hepatitis C (HCV), 4 acute, 61 chronic and 16 occult hepatitis B (HBV), 10 Human T-lymphotropic virus (HTLV), and 162 syphilis (46 syphilis likely acquired within 1 year). Most positive donations came from first-time donors (72%), males (75%) and people of White ethnicity (59%).  During 2023 there was an increase in detections of syphilis in repeat donors in England due to switching to a more sensitive assay picking up previously undetected longstanding or treated syphilis.

Additionally, there were 429 (one in 4,164) donations confirmed positive for hepatitis E virus (HEV) and discarded. While this is higher number than all other viruses detected, there are no specific donor selection rules to exclude those at risk for HEV as locally acquired cases in the UK are mainly foodborne. HEV positive donors can return to donate after recovery.

Sixty-three (22%) of the 287 donors confirmed with HBV, HCV, HIV, HTLV or syphilis, later gave the blood services’ clinical team information which they had not disclosed before donating which would have resulted in them being deferred: 46 had been treated for syphilis, 7 had anal sex with new or multiple partners, 3 knew they had hepatitis, 2 injected drugs in the past, 2 injected drugs in the past and also knew they had hepatitis, one had been treated for syphilis and was taking preventive HIV medication, and one had undergone recent surgery (unrelated to their positive donation). One regular apheresis donor who seroconverted with early HIV infection should not have donated as their partner may have injected drugs but had not been able to disclose this information before donation. This data serves as a reminder that it is important to prompt regular donors about any changes in their behaviours or history since their last donation which may impact on recipient safety.  

Blood donor selection rules keep numbers of recently acquired HIV, HCV or HBV infections in donors low, resulting in a low risk of not detecting a very early infection.  In 2023, one acute HBV was identified in a first-time donor​​ while 5 repeat donors had seroconverted; that is: were negative for infectious markers at their previous donation, 2 HIV and 3 HBV ​compared with 4 seroconverters in 2022. One was not able to disclose information (as described above) while 5 of 6 were compliant, reporting sex between men and women, 4 with regular partners, one with a new partner without anal sex. Recent HIV, HCV or HBV detections (and discard of the donations) have allowed an estimate to be made of the chance of not detecting ​​a very early HIV, HCV or HBV infection. This has remained ​​below 1 in 1 million donations​​ for the last 10 years.

The unit continues to support the blood services work towards a more diverse and inclusive donor population to help address inequities in donation. The ‘For the Assessment of Individualised Risk’ (FAIR) policy is a more individualised approach to donor selection introduced from June 2021. Close monitoring throughout 2023 shows FAIR questions helped maintain safety. Numbers of recent HIV, HCV, and HBV infections remain low, there was little impact on donor deferral at donation and there were no reported viral transmissions associated with this policy change. There was some evidence of non-disclosure of information among positive donors, mainly related to past, treated syphilis which is detected on screening. Research is ongoing to improve the questions asked during pre-donation checks and support donors in disclosing any relevant information pre-donation.  

Hepatitis B core antibody (anti-HBc) screening was introduced to mitigate risk of HBV transfusion-transmission from donors with occult hepatitis B infection (OBI) in 2022 following ministers’ acceptance of a recommendation from the Advisory Committee on the Safety of Blood Tissues and Organs (SaBTO). This has significantly improved safety for recipients, identifying and discarding 14 additional OBI cases in donors in 2023 that were not detected on pooled Nucleic Acid Amplification Testing (NAT) screening alone.  

The unit also undertakes horizon scanning to enable risk assessment of potential emerging infection threats. In 2023, this resulted in actions taken by the Joint UK Blood Transfusion and Tissue Transplantation Service Professional Advisory Committee (JPAC) regarding the global spread of arboviruses, ​including local transmission of dengue and West Nile virus (WNV) in Europe.  

All suspected transfusion-transmitted infections (TTIs) investigated by the UK blood services are reported to the NHSBT and UKHSA Epidemiology Unit for monitoring and have formed part of the Serious Hazards of Transfusion (SHOT) haemovigilance scheme since 1996. While TTIs are rare, it is important to highlight to recipients the small but potential chance of infection. In 2023, 140 suspected transfusion-transmitted infections were investigated, leading to one confirmed case each of malaria and hepatitis A transmission in 2023, and one probable case each of HEV and HBV transmission in 2022. Details of the 2023 SHOT Annual Report, published in July 2024 on the SHOT Annual Reports and Summaries – Serious Hazards of Transfusion webpages, are presented in the following news item.

During 2023, the Infected Blood Inquiry heard final submissions and concluded with a report on 20 May, 2024. The blood services apologised for past suffering and acknowledged improvements in donor selection, testing, and infection surveillance. The Unit continues to support the blood services in providing evidence of the effectiveness of current processes. Over 27 years of surveillance, the Unit has shown how significant advancements in screening and infection prevention have reduced the risk of undiagnosed infections entering the blood supply. 

More information about the NHSBT/UKHSA Epidemiology Unit can be found at Epidemiology – Hospitals and Science – NHSBT.

Transfusion transmitted infections (UK): 2023 annual report in summary

Transfusion-transmitted infections (TTIs) remain extremely rare in the UK due to risk reduction strategies including donor selection and rigorous testing of blood donations. All suspected TTIs investigated by the UK blood services are reported to the joint NHS Blood and Transplant (NHSBT) and UKHSA Epidemiology Unit for monitoring and form part of the Serious Hazards of Transfusion (SHOT) haemovigilance scheme.

This news report summarises the findings of the Annual SHOT Report for 2023.

During 2023, the UK blood services investigated 113 suspected bacterial cases, one suspected parasitic incident and 26 suspected viral incidents. One confirmed malaria and one confirmed Hepatitis A virus (HAV) TTI were reported, as well as 2 probable TTIs (one Hepatitis B virus [HBV] and one Hepatitis E virus [HEV]). Both patients with confirmed TTIs were reporting as recovering from their infection, and there were no near misses reported in 2023.

Viral transmissions are extremely rare in the UK, with only 33 confirmed transfusion-transmitted viral infections documented in the UK since 1996. Among these, HBV (n=11) and HEV (n=12) were the most commonly reported, proven, viral TTIs. For recently acquired HBV, this is partly because the ‘window period’ – during which an infectious donation from a recently infected donor cannot be detected by the screening tests – is longer than for Hepatitis C virus (HCV) or human immunodeficiency virus (HIV). For HEV, all except 2 transmissions were reported before routine HEV RNA screening was introduced in April 2017 in the UK.

All of the suspected bacterial cases were concluded to be either a post-transfusion reaction with no evidence of bacteria in the implicated or associated products or in the recipient, or not a TTI, with evidence of bacteria in either the products or the recipient(s) but not both. In all cases where patient blood cultures were positive, the likely source was the patient’s underlying condition. Since 2011, all four UK Blood Services have used the BacT/ALERT system for bacterial screening which has been successful in reducing the risk of bacterial TTI, together with diversion and arm cleansing. The last confirmed bacterial TTI – a Staphylococcus aureus transmission – was reported in 2015.

Lookback investigations

Lookback investigations are initiated when regular donors are found to be newly positive for a marker of infection, either through seroconversion, post-donation information or introduction of new test. Following the introduction of a new test for hepatitis B core antibody (anti-HBc) lookback was initiated for some donors depending on hepatitis B markers. Lookback investigations are initiated by the blood services whereas potential TTIs are usually reported either by the clinical team looking after the patient with an infection, or by the centre where they received their transfusion.  

For lookbacks, where possible, archive samples from previous donations are retrospectively retested and, regardless of archive availability, associated components are traced. The blood services – working with the clinical team – look after the recipient to ensure that they are fully informed and are given advice regarding follow-up and testing.

During 2023, NHSBT initiated investigations prompted by 20 donors in England with newly detected markers of infection known to have previously donated.  Archive samples were available for testing for 11 donors (3 HEV [2 associated with TTI investigations], 4 occult Hepatitis B (OBI) and 4 syphilis) but for 4 donors the most recent negative donation had been given more than 3 years ago and therefore no archive was available for testing (one Epstein-Barr virus and 3 syphilis).

Investigations involved 30 previous donations, with 40 of 45 components issued known to be transfused. Of the 40 recipients identified, 19 were alive and 17 were tested with none found to have evidence of transmission. In addition, lookback was commenced for two donors with Human T-cell lymphotropic virus (HTLV) infection with a history of donating in the 1990’s, prior to leucodepletion and before anti-HTLV screening was implemented. Although NHSBT was able to identify which hospital these units had been issued to, hospitals have not been able to identify the possible recipients despite their best efforts to date. In addition, there were 2 malaria and one HIV lookbacks initiated, information from these investigations is awaited.

Further information about these cases is available in the TTI chapter of the annual SHOT report. The TTI chapter delivers the following 6 key messages:

1. Any suspected TTI should be reported to the appropriate blood service to allow investigation. However, it should be noted that confirmed or probable TTIs are rare.
2. SHOT data is used to inform policy and change it when necessary. Additional anti-HBc testing has been introduced to reduce the risk of hepatitis B transmission from donors with OBI where viral levels may be below the level of detection by the previous routine screening assays.
3. Suspected TTIs should be discussed with the consultant microbiologist, virologist and/or other infection diseases expert to confirm the diagnosis and following that, reported to the appropriate UK Blood Service for further investigations.
4. The UK blood services store a sample from every blood donation for at least 3 years – testing can be done on these samples during this time if a TTI is suspected.
5. It is important that all healthcare professionals consenting patients for blood transfusion have up-to-date knowledge of blood donation testing, and the extremely small but potential risk of routine testing not detecting an infection in a donor that may enter the blood supply. For acute HBV, HCV, and HIV infections this has been estimated to be less than one in one million donations tested and confirmed and probable transmissions remain rare with very few numbers each year.
6. The UK blood services continue to monitor rates of infection in donors to sustain a safe supply of blood components.

Further information about UK TTI surveillance is available from the NHSBT and UKHSA Epidemiology Unit: epidemiology@nhsbt.nhs.uk

Vaccine coverage reports in this issue

Shingrix® vaccine uptake report (adults eligible from September 2023 to February 2024 and vaccinated to the end of April 2024): England

Infection reports

Meningococcal disease (England): July to September 2024

Meningococcal disease: laboratory-confirmed cases in England in 2022 to 2023

Laboratory reports of Haemophilus influenzae by age group and serotype, England: annual 2023 (and 2022)

Diphtheria in England: 2023