Nucleos/tide analogue (NA) drugs are used for long-term treatment of chronic hepatitis B virus (HBV) infection, with treatment eligibility criteria changing rapidly amidst globally evolving clinical guidelines. We aimed to quantify the prescription of NA drugs to date, and to undertake a preliminary assessment of the impact of relaxing treatment eligibility thresholds, leveraging a unique large real-world secondary care dataset. We assimilated longitudinal clinical data, collected between February 1997 and April 2023 from adults with chronic HBV infection from six centres in England through the UK NIHR Health Informatics Collaborative (HIC) Viral Hepatitis and Liver Disease theme. We describe factors currently associated with the receipt of NA treatment and determine the proportion of the population who would become treatment eligible as thresholds change. Across 7558 adults with a mean follow-up of 4.0 years (SD 3.9), NA treatment was prescribed in 2014/7558 (26.6%), and as expected according to guidelines at the time, was associated with HBV e-antigen (HBeAg) positivity and alanine transferase (ALT) above the upper limit of normal (> ULN). Treatment was more likely in males, older adults, in Asian and Other ethnicities (compared to White), and less likely in socioeconomically deprived individuals. The proportion of treatment-eligible individuals was 32.3% based on 2 records of ALT > ULN over 6-12 months, 41.7% based on ALT > ULN and viral load (VL) > 2000 IU/mL, and 95.1% based on detectable VL and either ALT > ULN or age > 30 years. Evolving clinical guidelines will lead to substantial increases in the proportion of individuals living with HBV who are eligible for treatment, underlining the need for services to adapt rapidly to the changing clinical environment.

Analysis of viral genetic data has previously revealed distinct within-host population structures in both untreated and interferon-treated chronic hepatitis C virus (HCV) infections. While multiple subpopulations persisted during the infection, each subpopulation was observed only intermittently. However, it was unknown whether similar patterns were also present after Direct-Acting Antiviral (DAA) treatment, where viral populations were often assumed to go through narrow bottlenecks. Here we tested for the maintenance of population structure after DAA treatment failure, and whether there were different evolutionary rates along distinct lineages where they were observed. We analysed whole-genome next-generation sequencing data generated from a randomised study using DAAs (the BOSON study). We focused on samples collected from patients (N=84) who did not achieve sustained virological response (i.e., treatment failure) and had sequenced virus from multiple timepoints. Given the short-read nature of the data, we used a number of methods to identify distinct within-host lineages including tracking concordance in intra-host nucleotide variant (iSNV) frequencies, applying sequenced-based and tree-based clustering algorithms to sliding windows along the genome, and haplotype reconstruction. Distinct viral subpopulations were maintained among a high proportion of individuals post DAA treatment failure. Using maximum likelihood modelling and model comparison, we found an overdispersion of viral evolutionary rates among individuals, and significant differences in evolutionary rates between lineages within individuals. These results suggest the virus is compartmentalised within individuals, with the varying evolutionary rates due to different viral replication rates and/or different selection pressures. We endorse lineage awareness in future analyses of HCV evolution and infections to avoid conflating patterns from distinct lineages, and to recognise the likely existence of unsampled subpopulations.

Adenoviral (Ad) vectors and mRNA vaccines exhibit distinct patterns of immune responses and reactogenicity, but underpinning mechanisms remain unclear. We longitudinally compared homologous ChAdOx1 nCoV-19 and BNT162b2 vaccination, focusing on cytokine-responsive innate-like lymphocytes-mucosal-associated invariant T (MAIT) cells and Vδ2+ γδ T cells-which sense and tune innate-adaptive cross-talk. Ad priming elicited robust type I interferon (IFN)-mediated innate-like T cell activation, augmenting T cell responses (innate-to-adaptive signaling), which was dampened at boost by antivector immunity. Conversely, mRNA boosting enhanced innate-like responses, driven by prime-induced spike-specific memory T cell-derived IFN-γ (adaptive-to-innate signaling). Extending the dosing interval dampened inflammation at boost because of waning T cell memory. In a separate vaccine trial, preboost spike-specific T cells predicted severe mRNA reactogenicity regardless of the priming platform or interval. Overall, bidirectional innate-like and adaptive cross-talk, and IFN-γ-licensed innate-like T cells, orchestrate interval-dependent early vaccine responses, suggesting modifiable targets for safer, more effective regimens.

BACKGROUND & AIMS:Chronic hepatitis B (CHB) and metabolic dysfunction-associated steatotic liver disease (MASLD) commonly co-exist, with conflicting data in prevalence and disease severity. We aimed to investigate these discrepancies. METHODS:This multicenter study included consecutive patients with CHB from 19 European centers. A survey on standard of care for MASLD screening in CHB was circulated. RESULTS:A total of 1709 patients with CHB were included; median age, 53 years (interquartile range [IQR], 42-64); males, 60.7%; body mass index (BMI), 25.6 kg/m2 (IQR, 14-63 kg/m2); and 57.3% White. MASLD prevalence (1510 consecutive patients) was 42.3%. BMI (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.19-1.36), ferritin (OR, 1.00; 95% CI, 1.00-1.00) and type 2 diabetes (OR, 2.60; 95% CI, 1.12-6.02) were independently associated with MASLD. The prevalence of advanced fibrosis was 18% (255/1420) in the whole cohort, 25.4% (162/639) among patients with CHB with MASLD, and 13.7% in those without MASLD. Independent predictors of advanced fibrosis were MASLD (OR, 2.76; 95% CI, 1.50-5.05), BMI (OR, 1.08; 95% CI, 1.02-1.15), alanine transaminase (OR, 1.01; 95% CI, 1.00-1.03), lower platelets (OR, 0.99; 95% CI, 0.98-0.99), insulin treatment (OR, 13.88; 95% CI, 2.95-65.28), and long-term antivirals (OR, 4.86; 95% CI, 2.40-9.85). During follow-up (48 months), only patients without MASLD showed significant liver stiffness measurement improvement over time (P < .001). Among patients with MASLD, Fibrosis-4 and liver stiffness measurement performed moderately at predicting advanced fibrosis (area under the receiver operating characteristic curve = 0.71 vs 0.70; P = .38) against histology. As standard of care, 68.4% of centers screened all patients with CHB for MASLD; 52.6% followed the same treatment indication in those with CHB and MASLD vs CHB only. CONCLUSIONS:In this large European cohort, MASLD and fibrosis were highly prevalent among patients with CHB, whereas MASLD aggravated liver fibrosis. Though screening strategies remain inconsistent, ferritin levels, increased BMI, and type 2 diabetes may inform on the presence of MASLD. Biomarkers showed modest performance in predicting fibrosis.

Introduction Despite repeated vaccinations against SARS-CoV-2 virus, patients who are immunocompromised remain at very high risk of catching SARS-CoV-2 virus and becoming unwell. AZD7442 (Evusheld) is a long-acting monoclonal antibody treatment that has been shown in clinical trials to prevent SARS-CoV-2 infection for up to a year after a single dose. Vaccines require a healthy immune system to generate protective immunity. AZD7442 may prevent SARS-CoV-2 infection in immunocompromised individuals that may not have responded to repeated vaccinations against SARS-CoV-2 virus. Unlike vaccinations, AZD7442 reaches effective levels within the body a few hours after a single dose. The RAPID-PROTECTION trial will determine the levels of immune protection that AZD7442 offers patients at the very highest risk of SARS-CoV-2 infection and whether this protection can be further enhanced by repeated vaccination against SARS-CoV-2 virus.Methods RAPID-PROTECTION is a multicentre, interventional and open-label adaptive platform trial that aims to recruit 350 immunocompromised participants across five UK centres. Participants will be administered AZD7442 on day 0 followed by a SARS-CoV-2 vaccination 28 days later. Participants will be randomised (1:1) to the Moderna vaccine or Pfizer/BioNTech vaccine. Participant samples will be taken at baseline and at multiple timepoints after the administration of AZD7442.Analysis The participant samples will be analysed to measure the function and magnitude of SARS-CoV-2 specific antibody and T-cell responses at baseline and at multiple timepoints after the administration of AZD7442. The immunological effect of the study interventions will be determined by comparison of the results of immunological assessments at baseline and subsequent timepoints.Ethics and dissemination The trial protocol was approved by the research ethics committee of the National Health Service (reference 22/HRA/0359), Health Research Authority and Health and Care Research Wales on 25 July 2022. Findings will be disseminated through peer-reviewed journals and presented at scientific conferences.Trial registration number ISRCTN53507177.

Hepatitis B virus (HBV) whole genome sequencing (WGS) is currently limited as the DNA viral loads (VL) of many clinical samples are below the threshold required to generate full genomes using current sequencing methods. We developed two pan-genotypic viral enrichment methods, using probe-based capture and tiled amplicon PCR (HEP-TILE) for HBV WGS. We demonstrate using mock samples that both enrichment methods are pan-genotypic (genotypes A-J). Using clinical samples, we demonstrate that HEP-TILE amplification successfully amplifies full genomes at the lowest HBV VL tested (30 IU/ml), and the PCR products can be sequenced using both Nanopore and Illumina platforms. Probe-based capture with Illumina sequencing required VL > 300,000 IU/ml to generate full length HBV genomes. The capture-Illumina and HEP-TILE-Nanopore pipelines had consensus sequencing accuracy of 100% in mock samples with known DNA sequences. Together, these protocols will facilitate the generation of HBV sequence data, enabling a more accurate and representative picture of HBV molecular epidemiology, cast light on persistence and pathogenesis, and enhance understanding of the outcomes of infection and its treatment.

With the continued emergence of SARS-CoV-2 variants and concerns of waning immunity, there is a need for better defined correlates of protection to aid future vaccine and therapeutic developments. Whilst neutralising antibody titres are associated with protection, these are typically determined in the absence of the complement system, which has the potential to enhance neutralisation titres and strengthen correlates with protection in vivo. Here we show that replenishment of the complement system in neutralisation assays can significantly enhance neutralisation titres, with up to an ~83-fold increase in neutralisation of the BA.1.1.529 strain using cross-reactive sera from vaccination against the ancestral strain. The magnitude of enhancement significantly varies between individuals, viral strains (wild-type/VIC01 and Omicron/BA.1), and cell lines (Vero E6 and Calu-3), and is abrogated following heat-inactivation of the complement source. Utilising ACE2 competition assays, we show that the mechanism of action is partially mediated by reducing ACE2-spike interactions. Through the addition of compstatin (a C3 inhibitor) to live virus neutralisation assays, the complement protein C3 is shown to be required for maximum efficiency. These findings further our understanding of SARS-CoV-2 immunity and neutralisation, with implications for protection against emerging variants and assessing future vaccine and therapeutic developments.

Background & Aims: The dynamics of HBV viral load (VL) in patients with chronic hepatitis B (CHB) on nucleos(t)ide analogue (NA) treatment and its relationship with liver disease are poorly understood. We aimed to study longitudinal VL patterns and their associations with CHB clinical outcomes. Methods: Utilising large scale, routinely collected electronic health records from six centres in England, collated by the National Institute for Health and Care Research Health Informatics Collaborative (NIHR HIC), we applied latent class mixed models to investigate VL trajectory patterns in adults receiving NA treatment. We assessed associations of VL trajectory with alanine transaminase, and with liver fibrosis/cirrhosis. Results: We retrieved data from 1,885 adults on NA treatment (median follow-up 6.2 years, IQR 3.7-9.3 years), with 21,691 VL measurements (median 10 per patient, IQR 5-17). Five VL classes were identified from the derivation cohort (n = 1,367, discrimination: 0.93, entropy: 0.90): class 1 'long term suppression' (n = 827, 60.5%), class 2 'timely virological suppression' (n = 254, 18.6%), class 3 'persistent moderate viraemia' (n = 140, 10.2%), class 4 'persistent high-level viraemia' (n = 44, 3.2%), and class 5 'slow virological suppression' (n =102, 7.5%). The model demonstrated a discrimination of 0.93 and entropy of 0.88 for the validation cohort (n = 518). Alanine transaminase decreased variably over time in VL-suppressed groups (classes 1, 2, 5; all p <0.001), but did not significantly improve in those with persistent viraemia (classes 3, 4). Patients in class 5 had twofold increased hazards of fibrosis/cirrhosis compared with class 1 (adjusted hazard ratio, 2.00; 95% CI, 1.33-3.02). Conclusions: Heterogeneity exists in virological response to NA therapy in CHB patients, with over 20% showing potentially suboptimal responses. Slow virological suppression is associated with liver disease progression. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

OBJECTIVES:We set out to evaluate Hepatitis B core-related antigen (HBcrAg) as a proxy for hepatitis B (HBV) viral load (VL) and liver disease in two different population settings. METHODS:We undertook a cross-sectional retrospective observational study using samples and data from adults living with chronic HBV infection from the United Kingdom (UK, n=142) and South Africa (SA, n=211). We assessed HBcrAg distribution, relationship with other biomarkers, and risk stratification performance, applying point of care test (POCT) thresholds. RESULTS:SA and UK cohorts differed by ethnicity, HIV coinfection, HBeAg-positivity and proportion with HBV VL >200,000 IU/ml (all p<0.001). HBcrAg positively correlated with alanine aminotransferase (ALT) (in both settings p<0.01), and fibrosis/cirrhosis by APRI score (p=0.03 in UK, p=0.008 in SA), but not with elastography or FIB-4 scores. HBcrAg ≥4.3 log10U/ml (POCT threshold) was 100% sensitive and 92% specific for predicting VL >200,000 IU/ml in the UK cohort, compared to 94% sensitive and 86% specific in the SA population. CONCLUSIONS:HBcrAg correlated with VL, but less so with liver disease. Use of this biomarker needs tailoring for use in diverse populations.

Functional T cell responses are crucial for protective immunity induced by COVID-19 vaccination, but factors influencing the quality of these responses are incompletely understood. We used an activation-induced marker (AIM) assay and single-cell transcriptomic sequencing to analyze SARS-CoV-2 spike-responsive T cells after mild SARS-CoV-2 infection or after one or two doses of mRNA-lipid nanoparticle (mRNA-LNP) or adenoviral-vectored COVID-19 vaccines. Our findings revealed broad functional and clonal heterogeneity in T cells generated by vaccination or infection, including multiple distinct effector populations. T cell function was largely conserved between COVID-19 vaccine platforms but was distinct compared with SARS-CoV-2 infection. Notably, the dosing interval greatly influenced the quality of T cells after two vaccine doses, particularly after mRNA-LNP vaccination, where a longer interval led to reduced inflammatory signaling and increased secondary proliferation. These insights enhance our understanding of SARS-CoV-2-specific T cells and inform the optimization of mRNA vaccination regimens.

The COVID-19 pandemic response demonstrated the effectiveness of adenovirus vector vaccines in inducing protective cellular and antibody responses. However, we still lack mechanistic understanding of the factors regulating immunity induced by this platform, especially innate pathways. We utilized a human tonsil organoid model to study the regulation of adaptive responses to ChAdOx1 nCoV-19. Innate activation and cytokine release occurred within 24 hours and T and B cell activation and antigen-specific antibody secretion occurred during the ensuing 14-day culture. Among the immune cell populations, plasmacytoid dendritic cells (pDCs) exhibited the highest ChAdOx1 transduction levels. pDC-derived IFN-ɑ was critical for humoral responses, but production of antigen in pDCs was dispensable. Furthermore, IL-6 enhanced humoral responses in both IFN-ɑ-dependent and independent manners, indicating intricate signaling interplay. IFN-ɑ and IL-6 also regulated the function of vaccine-activated CD4+ T cells, including TFH. These data provide key insights into innate pathways regulating ChAdOx1-induced immunity and highlights the promise of this model for vaccine platform mechanistic studies.

BACKGROUND:The use of measured immune responses in informing risk of breakthrough COVID-19 infection and infection outcomes after vaccination against SARS-CoV-2 in clinically vulnerable patients has not been applied clinically. OBJECTIVES:The aim of this study was to investigate the association between measured vaccine immunogenicity and vaccine effectiveness in clinically vulnerable populations. DATA SOURCES:PubMed, MEDLINE, EMBASE, and Cochrane Library. STUDY ELIGIBILITY CRITERIA:Studies published between March 2020 and January 2025, which reported data on COVID-19 vaccine immunogenicity (antibody and T-cell) and subsequent infection outcomes. PARTICIPANTS:Patients defined as clinically vulnerable by QCOVID criteria, who had received at least the primary course of COVID-19 vaccination. ASSESSMENT OF RISK OF BIAS:The Newcastle-Ottawa Quality Assessment Scale was used to assess the risk of bias. METHODS OF DATA SYNTHESIS:A random effects meta-analysis model was used to pool relative risks of COVID-19 breakthrough infection (BTI), hospitalization, and death. Unadjusted data were used for the primary analysis due to the lack of adjusted data available in individual studies. RESULTS:We identified 3305 articles, of which 45 observational studies were included in the review. Negative antibody response following COVID-19 vaccination was associated with higher risks of BTI (Relative Risk (RR), 1.82 (1.45-2.29), p < 0.01, I2 = 84.03%), COVID-19-related hospitalization (RR, 5.88 (4.08-8.47), p < 0.01, I2 = 25.59%) and death (RR, 3.66 (1.87-7.15), p < 0.01), I2 = 0%). Lack of T-cell response was associated with a higher risk of BTI (RR, 2.08 (1.08-4.04), p 0.03, I2 = 65.99). Using the Newcastle-Ottawa Quality Assessment Scale, 5 (11%) studies were of good quality, 2 (7%) of fair quality, and 37 (82%) of poor quality. CONCLUSIONS:Within the methodological limitations, this study has shown that lack of antispike antibody responses was associated with BTI and severe infection outcomes in clinically vulnerable populations. Further research is required to investigate the current utility of testing to inform the ongoing management of clinically vulnerable persons, such as vaccine booster schedules.

Hepatitis C virus (HCV) exhibits significant genetic diversity and is a cause of severe liver complications. The viral envelope glycoproteins E1 and E2, key targets for neutralizing antibodies, are highly variable. To understand how host and viral genetic factors modulate antibody responses, we analyze genetic and antibody binding and neutralization data from 54 patients infected with HCV genotype 3a. We find that host polymorphisms in IFNL4 gene (IFNλ4-P70 generating haplotype) are associated with reduced antibody binding. Within the virus, variations at three specific E1/E2 amino acid positions and three N-glycosylation sites (including one site common to both analyses) significantly correlate with antibody binding and/or neutralization sensitivity. Furthermore, greater intra-patient diversity within the E2 hypervariable region 1 is associated with stronger antibody binding. These results identify specific host and viral genetic features that shape humoral immunity against HCV genotype 3a, providing insights crucial for designing broadly effective vaccines.

There are varying data concerning the effect of prior anti-vector immunity on the T-cell response induced by immunisation with an identical vectored vaccine containing a heterologous antigen insert. To determine whether prior exposure to ChAdOx1-SARS-CoV2 immunisation (Vaxzevria®) impacts magnitudes of antigen-specific T-cell responses elicited by subsequent administration of the same viral vector (encoding HBV antigens, ChAdOx1-HBV), healthy volunteers that had received Vaxzevria® (n = 15) or the Pfizer or Moderna mRNA COVID-19 vaccine (n = 11) between 10 and 18 weeks prior were recruited to receive a single intramuscular injection of ChAdOx1-HBV. Anti-ChAdOx1-neutralising antibody titers were determined, and vector or insert-specific T-cell responses were measured by a gamma-interferon ELISpot and intracellular cytokine staining (ICS) assay using multiparameter flow cytometry. Participants were followed for three months after the ChAdOx1-HBV injection, which was well-tolerated, and no dropouts occurred. The baseline ChAdOx1 neutralisation titers were higher in the Vaxzevria® cohort (median of 848) than in the mRNA cohort (median of 25). T-cell responses to HBV antigens, measured by ELISpot, were higher on day 28 in the mRNA group (p = 0.013) but were similar between groups on day 84 (p = 0.441). By ICS, these differences persisted at the last time point. There was no clear correlation between the baseline responses to the adenoviral hexon and the subsequent ELISpot responses. As vaccination within 3 months using the same viral vector backbone affected the insert-specific T-cell responses, a greater interval after prior adenoviral immunisation using heterologous antigens may be warranted in settings in which these cells play critical roles.