Biomarkers of transfusion transmitted occult hepatitis B virus infection: Where are we and what next?

Blood transfusion is a vital procedure, where transfusion-transmitted infection of hepatitis B virus (HBV) remains an important issue, especially from blood donors with occult hepatitis B virus infection (OBI). Occult hepatitis B virus infection is a complex entity to detect using surrogate blood biomarkers for intrahepatic viral transcriptional activity, requiring a continually refined battery of tests utilised for screening. This review aims to critically evaluate the latest advances in the current blood biomarkers to guide the identification of OBI donors and discuss novel HBV markers that could be introduced in future diagnostic practice. Challenges in detecting low HBV surface antigen levels, mutants, and complexes necessitate ultrasensitive multivalent dissociation assays, whilst HBV DNA testing requires improved sensitivity but worsens inaccessibility. Anti-core antibody assays defer almost all potentially infectious donations but have low specificity, and titres of anti-surface antibodies that prevent infectivity are poorly defined with suboptimal sensitivity. The challenges associated with these traditional blood HBV markers create an urgent need for alternative biomarkers that would help us better understand the OBI. Emerging viral biomarkers, such as pre-genomic RNA and HBV core-related antigen, immunological HBV biomarkers of T-cell reactivity and cytokine levels, and host biomarkers of microRNA and human leucocyte antigen molecules, present potential advances to gauge intrahepatic activity more accurately. Further studies on these markers may uncover an optimal diagnostic algorithm for OBI using quantification of various novel and traditional blood HBV markers. Addressing critical knowledge gaps identified in this review would decrease the residual risk of transfusion-transmitted HBV infection without compromising the sustainability of blood supplies

A blood safety perspective on emerging arboviral infections in the United Kingdom

A core focus of the blood services is to maintain the blood supply whilst simultaneously being vigilant for potential threats to blood safety. At present, West Nile virus (WNV), Usutu virus (USUV), Dengue virus (DENV) and Tick‐borne encephalitis virus (TBEV) are considered primary arboviral threats to blood safety in the UK and Northern Europe. Climate change and globalisation have enhanced the frequency of WNV and DENV cases being reported in Europe, furthering the likelihood of their spread to the UK. Furthermore, both TBEV and USUV have already been identified in reservoir hosts in England and the first human cases of TBEV infections acquired in England have been recently documented. Existing policy to protect the blood supply against emerging viral risks is based on donor deferral or nucleic acid test (NAT) screening for those recently returning from WNV endemic areas, only. Constant evaluation of the current policy is necessary to assess the feasibility of donor deferral if the case numbers within Europe continue to increase, and to determine if selective screening for these viruses is needed. Regardless of the testing and prevention strategies decided upon by the blood services, frequent review of these policies will be necessary to reflect the national and wider disease epidemiology of these arboviral infections

Sustained circulation of enterovirus D68 in Europe in 2023 and the continued evolution of enterovirus D68 B3-lineages associated with distinct amino acid substitutions in VP1 protein

Background: Enterovirus D68 (EV-D68) causes respiratory disease ranging from mild to severe and in rare cases a paralytic syndrome, called acute flaccid myelitis (AFM). Since the global EV-D68 outbreak in 2014, the virus has mainly circulated in biennial epidemic cycles with peaks detected during even years. However, following the COVID-19 pandemic, the seasonal pattern of EV-D68 has been characterized by large yearly upsurges. Here, we describe the circulation of EV-D68 in Europe in 2023 and track its genetic evolution. Study design: Data was compiled from members of the European Non-Polio Network (ENPEN). This included monthly data on the total number of EV samples tested, EV positive samples, EV-D68 positive samples and cases, and other EV positive samples detected in 2023. Information on sample types and surveillance system was recorded. Sequence data from the VP1 gene was used for phylogenetic and amino acid sequence analysis. Results: EV was detected in 13,585 out of 203,622 diagnostic samples tested (6.7 %), of which 402 (3.0 %) were determined as EV-D68, representing 386 cases. EV-D68 infections peaked in October 2023 (136/386; 35.2 %). 267/386 (69.2 %) of EV-D68 cases were captured through clinical EV surveillance, almost all of which (202/204 of positive samples with sample type information) were detected in respiratory specimens. Phylogenetic analysis performed on 99 VP1 sequences revealed a distinct B3-derived lineage with a previously undescribed residue change, D554E, in Europe. Conclusions: The study documents sustained circulation of EV-D68 in Europe in 2023, the evolution of B3-derived lineages, and appearance of previously undescribed amino acid substitutions in Europe. This stresses the need for continuous EV-D68 surveillance and harmonization of EV-D68 detection practices towards better data comparability across countries

Genetic characterisation of human Coxsackievirus A6 variants associated with atypical hand, foot and mouth disease; a potential role of recombination in emergence and pathogenicity

Human coxsackievirus A6 (CVA6) is an enterically transmitted enterovirus. Until recently, CVA6 infections were considered as being of minor clinical significance, and only rarely aetiologically linked with hand, foot and mouth disease (HFMD) associated with other species A enteroviruses (particularly EV71 and CVA16). From 2008 onwards, however, CVA6 infections have been associated with several outbreaks worldwide of atypical HFMD (aHFMD) accompanied by a varicelliform rash. We recently reported CVA6-associated eczema herpeticum occurring predominantly in children and young adults in Edinburgh in January and February 2014. To investigate genetic determinants of novel clinical phenotypes of CVA6, we genetically characterized and analysed CVA6 variants associated with eczema herpeticum in Edinburgh in 2014 and those with aHFMD in CAV isolates collected from 2008. A total of eight recombinant forms (RFs) have circulated worldwide over the past 10 years, with the particularly recent appearance of RF-H associated with eczema herpeticum cases in Edinburgh in 2014. Comparison of phylogenies and divergence of complete genome sequences of CVA6 identified recombination breakpoints in 2A–2C, within VP3, and between 5′ untranslated region and VP1. A Bayesian temporal reconstruction of CVA6 evolution since 2004 provided estimates of dates and the actual recombination events that generated more recently appearing recombination groups (RF-E, -F, -G and -H). Associations were observed between recombination groups and clinical presentations of herpangina, aHFMD and eczema herpeticum, but not with VP1 or other structural genes. These observations provided evidence that NS gene regions may potentially contribute to clinical phenotypes and outcomes of CVA6 infection

Absence of detectable monkeypox virus DNA in 11,000 English blood donations during the 2022 outbreak

BACKGROUND: A large, worldwide outbreak of mpox (formerly referred to as monkeypox) involving mainly men who have sex with men commenced in May 2022. We evaluated the frequency of positivity for the causative agent, monkeypox virus (MPXV), in blood donations collected in August 2022, during the outbreak period in Southern England. METHODS/MATERIALS: The sensitivity and specificity of an MPXV-specific PCR and a generic non-variola orthopoxvirus (NVO) PCR were evaluated using samples from mpox cases and synthetic DNA standards. Residual minipools from nucleic acid testing were obtained from 10,896 blood donors in Southern England, with 21% from London. RESULTS: MPXV and NVO PCRs were both capable of detection of single copies of target sequence with calculated limits of detection (LOD)90  s of 2.3 and 2.1 DNA copies and analytical sample sensitivities of 46 and 42 MPXV DNA copies/ml, respectively. 454 minipools produced from 10,896 unique donors were assayed for MPXV DNA by both methods. No positive minipools were detected by either PCR. CONCLUSIONS: Although blood donors are unrepresentative of the UK population in terms of MPXV infection risk, the uniformly negative MPXV DNA testing results provide reassurance that MPXV viraemia and potential transmission risk were rare or absent in donors during the outbreak period. Minipools from blood donors allow rapid implementation of large-scale population-based screening for emerging pathogens and represent an important resource for pandemic preparedness

Poliovirus circulation in the WHO European region, 2015-2022: a review of data from WHO's three core poliovirus surveillance systems

BackgroundThe Global Polio Eradication Initiative (GPEI) has drastically reduced the global incidence of poliomyelitis since its launch in 1988 thanks to effective vaccines and strong global surveillance systems. However, detections of wild-type as well as vaccine-derived poliovirus (VDPV) still occur, also in the WHO European Region. This study aims to describe the poliovirus detection via the acute flaccid paralysis (AFP), clinical enterovirus, and environmental surveillance systems.MethodsIn this study, we review data from annual reports from 2015 to 2022 from the World Health Organization (WHO)'s three core poliovirus surveillance systems in place in the WHO European Region: AFP, clinical enterovirus, and environmental surveillance systems.FindingsA total of 4324 reported samples were found positive for poliovirus: 477 from AFP surveillance, 394 from clinical surveillance and 3453 from environmental surveillance. Of these, 366 were VDPV, 3952 vaccine strains, and 6 were wild-type poliovirus. 709 were identified as type 1, 399 as type 2, and 1944 type 3, while 1272 samples contained more than one type. Temporal and spatial association of positive environmental samples with positive samples from AFP or clinical enterovirus surveillance was found in only eight countries.InterpretationAnalysis of poliovirus-positive samples from AFP, clinical enterovirus, and environmental surveillance revealed that type 3 poliovirus was the most prevalent type detected. Most poliovirus-positive samples were identified as vaccine strains. No information on sequences was available.FundingThis study was funded by WHO Regional Office for Europe and received financial support from the Bill and Melinda Gates Foundation

Quality of life in patients with HBV infection: a systematic review and meta-analysis

Background & Aims: Despite nearly 250 million people worldwide estimated to have chronic HBV infection, health-related quality of life (HRQOL) in HBV-related disease has not been well characterised. Here, we summarise existing data on HBV-related HRQOL and quantify summary utility values by stage of disease. Methods: Embase, Global Health, PubMed, and Web of Science were searched for articles investigating HBV HRQOL. Meta-analyses for utility scores were pooled by stage of disease and utility instrument; meta-regression was further adjusted for the effect of current health expenditure as a percentage of gross domestic product (CHE/GDP), as a proxy of the importance of healthcare perceived by different countries. Results: Twenty-two articles from 19 studies, comprising 10,311 patients, were included. Of these studies, 74% were performed in the Western Pacific Region, and 47% used the EuroQoL-5D-3L instrument. HRQOL was found to decrease with advancing stages of HBV-related disease. Meta-regression showed the following predicted mean utility scores for the different stages of chronic HBV infection: non-cirrhotic, 0.842; compensated cirrhosis, 0.820 (p = 0.474 compared with non-cirrhotic); decompensated cirrhosis, 0.722 (p = 0.001); and hepatocellular carcinoma, 0.749 (p = 0.008). The type of tool affected HRQOL and populations with a higher CHE/GDP were associated with higher predicted utility values. Conclusions: Chronic HBV infection impairs the HRQOL of patients, even when there is no evidence of cirrhosis. HRQOL is particularly impaired in the advanced stages of decompensated cirrhosis and hepatocellular carcinoma. These results have important implications for global hepatitis elimination efforts and are useful for economic analyses. However, further research is needed, particularly in high-burden, low-income settings where data are lacking. Impact and implications: This study, based on 22 articles and 10,311 patients, provides a comprehensive synthesis of data on the impact of chronic hepatitis B virus (HBV) infection on patients’ health-related quality of life (HRQOL) worldwide. These findings, of how HRQOL is affected in people living with HBV, highlight the importance of patient-centred care and holistic approaches to management, even at the early stages of disease. These results are useful for cost-effectiveness analyses and may help inform decision-making in improving public health policy towards the elimination of viral hepatitis. The study also underscores the need for further data from low-to middle-income settings, and on the effects of treatment on HRQOL

Recommendations for enterovirus diagnostics and characterisation within and beyond Europe.

Enteroviruses (EV) can cause severe neurological and respiratory infections, and occasionally lead to devastating outbreaks as previously demonstrated with EV-A71 and EV-D68 in Europe. However, these infections are still often underdiagnosed and EV typing data is not currently collected at European level. In order to improve EV diagnostics, collate data on severe EV infections and monitor the circulation of EV types, we have established European non-polio enterovirus network (ENPEN). First task of this cross-border network has been to ensure prompt and adequate diagnosis of these infections in Europe, and hence we present recommendations for non-polio EV detection and typing based on the consensus view of this multidisciplinary team including experts from over 20 European countries. We recommend that respiratory and stool samples in addition to cerebrospinal fluid (CSF) and blood samples are submitted for EV testing from patients with suspected neurological infections. This is vital since viruses like EV-D68 are rarely detectable in CSF or stool samples. Furthermore, reverse transcriptase PCR (RT-PCR) targeting the 5'noncoding regions (5'NCR) should be used for diagnosis of EVs due to their sensitivity, specificity and short turnaround time. Sequencing of the VP1 capsid protein gene is recommended for EV typing; EV typing cannot be based on the 5'NCR sequences due to frequent recombination events and should not rely on virus isolation. Effective and standardized laboratory diagnostics and characterisation of circulating virus strains are the first step towards effective and continuous surveillance activities, which in turn will be used to provide better estimation on EV disease burden