A panel of hepatitis C virus glycoproteins for the characterization of antibody responses using antibodies with diverse recognition and neutralization patterns.

A vaccine against Hepatitis C virus (HCV) is urgently needed to limit the spread of HCV. The large antigenic diversity of the HCV glycoprotein E1E2 makes it difficult to design a vaccine but also to fully understand the antibody response after infection or vaccination. Here we designed a panel of HCV pseudoparticles (HCVpps) that cover a wide range of genetically and antigenically diverse E1E2s. We validate our panel using neutralization and a binding antibody multiplex assay (BAMA). The panel of HCVpps includes E1E2 glycoproteins from acute and chronically infected cases in the Netherlands, as well as E1E2 glycoproteins from previously reported HCVs. Using eight monoclonal antibodies targeting multiple antigenic regions on E1E2, we could categorize four groups of neutralization sensitive viruses with viruses showing neutralization titers over a 100-fold range. One HCVpp (AMS0230) was extremely neutralization resistant and only neutralized by AR4-targeting antibodies. In addition, using binding antibody multiplex competition assay, we delineated mAb epitopes and their interactions. The binding and neutralization sensitivity of the HCVpps were confirmed using patient sera. At the end, eleven HCVpps with unique antibody binding and neutralization profiles were selected as the final panel for standardized HCV antibody assessments. In conclusion, this HCVpp panel can be used to evaluate antibody binding and neutralization breadth and potency as well as delineate the epitopes targeted in sera from patients or candidate vaccine trials. The HCVpp panel in combination with the established antibody competition assay present highly valuable tools for HCV vaccine development and evaluation.

SARS-CoV-2 vaccination uptake in six ethnic groups living in Amsterdam, the Netherlands: A registry-based study within the HELIUS cohort.

OBJECTIVE: Ethnic minority groups have experienced a disproportionate burden of COVID-19, and should therefore be especially encouraged to receive SARS-CoV-2 vaccination. This study compared first-dose uptake of the primary SARS-CoV-2 vaccination series across six ethnic groups in Amsterdam, the Netherlands in 2021. METHODS: We analyzed data from participants of the population-based HELIUS cohort. We linked their data to the SARS-CoV-2 vaccination registry data of the Public Health Service of Amsterdam. We included registry data from January 6, 2021 (the start of the Dutch vaccination campaign) until September 6, 2021 (a date by which all adults in the Netherlands could have received one or two vaccine doses). SARS-CoV-2 vaccination uptake was defined as having received at least one vaccine dose of the primary vaccination series. We examined the association between ethnicity and vaccination uptake using multivariable logistic regression, while accounting for the age and sex distribution of ethnic groups in Amsterdam. RESULTS: We included 19,006 participants (median age 53 years [interquartile range 41-62], 57% female). SARS-CoV-2 vaccination uptake was highest in the South-Asian Surinamese group (60.3%, 95%CI = 58.2-62.3%), followed by the Dutch (59.6%, 95%CI = 58.0-61.1%), Ghanaian (54.1%, 95%CI = 51.7-56.5%), Turkish (47.7%, 95%CI = 45.9-49.6%), African Surinamese (43.0%, 95%CI = 41.2-44.7%), and Moroccan (35.8%, 95%CI = 34.1-37.5%) groups. After adjusting for age, sex, perceived social support, and presence of relevant comorbidities, participants of African Surinamese, Ghanaian, Turkish and Moroccan origin were significantly less likely to be vaccinated than those of Dutch origin. CONCLUSIONS: Prevention strategies should continue tailoring to specific ethnic groups to encourage vaccination uptake and reduce barriers to vaccination.

Screening for Hepatitis C Virus Reinfection Using a Behaviour-Based Risk Score among Men Who Have Sex with Men with HIV: Results from a Case-Control Diagnostic Validation Study.

We assessed the predictive capacity of the HCV-MOSAIC risk score, originally developed for primary early HCV infection, as a screening tool for HCV reinfection in 103 men who have sex with men (MSM) with HIV using data from the MOSAIC cohort, including MSM with HIV/HCV-coinfection who became reinfected (cases, n = 27) or not (controls, n = 76) during follow-up. The overall predictive capacity of the score was assessed using the area under the receiver operating characteristic (AUROC) curve. The effects of covariates on the receiver operating characteristic (ROC) curve were assessed using parametric ROC regression. The score cut-off validated for primary early infection (≥2.0) was used, from which the sensitivity and specificity were calculated. The AUROC was 0.74 (95% confidence interval (CI) = 0.63-0.84). Group sex significantly increased the predictive capacity. Using the validated cut-off, sensitivity was 70.4% (95%CI = 49.8-86.2%) and specificity was 59.2% (95%CI: 47.3-70.4%). External validation from a cohort of 25 cases and 111 controls, all MSM with HIV, resulted in a sensitivity of 44.0% (95%CI = 24.4-65.1) and specificity of 71.2% (95%CI = 61.8-79.4). The HCV-MOSAIC risk score may be useful for identifying individuals at risk of HCV reinfection. In sexual health or HIV-care settings, this score could help guide HCV-RNA testing in MSM with a prior HCV infection.

Signatures of VH1-69-derived hepatitis C virus neutralizing antibody precursors defined by binding to envelope glycoproteins.

An effective preventive vaccine for hepatitis C virus (HCV) remains a major unmet need. Antigenic region 3 (AR3) on the E1E2 envelope glycoprotein complex overlaps with the CD81 receptor binding site and represents an important epitope for broadly neutralizing antibodies (bNAbs) and is therefore important for HCV vaccine design. Most AR3 bNAbs utilize the VH1-69 gene and share structural features that define the AR3C-class of HCV bNAbs. In this work, we identify recombinant HCV glycoproteins based on a permuted E2E1 trimer design that bind to the inferred VH1-69 germline precursors of AR3C-class bNAbs. When presented on nanoparticles, these recombinant E2E1 glycoproteins efficiently activate B cells expressing inferred germline AR3C-class bNAb precursors as B cell receptors. Furthermore, we identify critical signatures in three AR3C-class bNAbs that represent two subclasses of AR3C-class bNAbs that will allow refined protein design. These results provide a framework for germline-targeting vaccine design strategies against HCV.

Optimal Dosing and Timing of High-Dose Corticosteroid Therapy in Hospitalized Patients With COVID-19: Study Protocol for a Retrospective Observational Multicenter Study (SELECT).

BACKGROUND: In hospitalized patients with COVID-19, the dosing and timing of corticosteroids vary widely. Low-dose dexamethasone therapy reduces mortality in patients requiring respiratory support, but it remains unclear how to treat patients when this therapy fails. In critically ill patients, high-dose corticosteroids are often administered as salvage late in the disease course, whereas earlier administration may be more beneficial in preventing disease progression. Previous research has revealed that increased levels of various biomarkers are associated with mortality, and whole blood transcriptome sequencing has the ability to identify host factors predisposing to critical illness in patients with COVID-19. OBJECTIVE: Our goal is to determine the most optimal dosing and timing of corticosteroid therapy and to provide a basis for personalized corticosteroid treatment regimens to reduce morbidity and mortality in hospitalized patients with COVID-19. METHODS: This is a retrospective, observational, multicenter study that includes adult patients who were hospitalized due to COVID-19 in the Netherlands. We will use the differences in therapeutic strategies between hospitals (per protocol high-dose corticosteroids or not) over time to determine whether high-dose corticosteroids have an effect on the following outcome measures: mechanical ventilation or high-flow nasal cannula therapy, in-hospital mortality, and 28-day survival. We will also explore biomarker profiles in serum and bronchoalveolar lavage fluid and use whole blood transcriptome analysis to determine factors that influence the relationship between high-dose corticosteroids and outcome. Existing databases that contain routinely collected electronic data during ward and intensive care admissions, as well as existing biobanks, will be used. We will apply longitudinal modeling appropriate for each data structure to answer the research questions at hand. RESULTS: As of April 2023, data have been collected for a total of 1500 patients, with data collection anticipated to be completed by December 2023. We expect the first results to be available in early 2024. CONCLUSIONS: This study protocol presents a strategy to investigate the effect of high-dose corticosteroids throughout the entire clinical course of hospitalized patients with COVID-19, from hospital admission to the ward or intensive care unit until hospital discharge. Moreover, our exploration of biomarker and gene expression profiles for targeted corticosteroid therapy represents a first step towards personalized COVID-19 corticosteroid treatment. TRIAL REGISTRATION: ClinicalTrials.gov NCT05403359; https://clinicaltrials.gov/ct2/show/NCT05403359. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/48183.

Hepatitis C virus transmission between eight high-income countries among men who have sex with men: a whole-genome analysis.

BACKGROUND: Microelimination of the hepatitis C virus (HCV) among men who have sex with men (MSM) could be complicated by continuous external introductions and the emergence of phylogenetic clusters harbouring clinically significant resistance-associated substitutions (RAS). To investigate international clustering and the prevalence and transmission of RAS, we aimed to analyse whole-genome HCV sequences from MSM with a recently acquired infection who participated in a large, international HCV treatment trial. METHODS: For this whole-genome analysis, we obtained HCV sequences from 128 MSM who had acquired HCV within the past 12 months and were participating in the REACT trial. The participants from whom sequences were obtained were recruited at 24 sites in eight countries. We inferred maximum-likelihood phylogenies and identified transmission clusters for HCV genotypes separately. We constructed time-scaled phylogenies to estimate cluster introduction dates and used a Bayesian Skygrid approach to estimate the effective population size over the past 50 years. We calculated the prevalence of RAS and the extent of RAS transmission in the study population. FINDINGS: The majority of recent HCV infections were part of international networks that arose in the late 1990s and early 2000s. Sequences obtained in the same country clustered frequently, and in 36% of subclusters since 2015 we found evidence of international transmission. European MSM were more likely than non-European MSM to be in a cluster (odds ratio 11·9 [95% CI 3·6-43·4], p<0·0001). The effective population size decreased rapidly since around 2015 in Europe. RAS associated with substantially diminished cure rates were infrequently detected and transmission of highly resistant viruses was not observed. INTERPRETATION: Despite antiviral treatment becoming widely available, international transmission of HCV among MSM has still occurred over the past 8 years, which could complicate microelimination of the virus in this population. RAS-enriched clusters and widespread RAS transmission are currently not a threat to elimination goals. These findings support an international approach for HCV microelimination among MSM. FUNDING: National Institutes of Health and Dr. C.J. Vaillant Fonds.

Bispecific antibodies combine breadth, potency, and avidity of parental antibodies to neutralize sarbecoviruses.

SARS-CoV-2 variants evade current monoclonal antibody therapies. Bispecific antibodies (bsAbs) combine the specificities of two distinct antibodies taking advantage of the avidity and synergy provided by targeting different epitopes. Here we used controlled Fab-arm exchange to produce bsAbs that neutralize SARS-CoV and SARS-CoV-2 variants, including Omicron and its subvariants, by combining potent SARS-CoV-2-specific neutralizing antibodies with broader antibodies that also neutralize SARS-CoV. We demonstrated that the parental antibodies rely on avidity for neutralization using bsAbs containing one irrelevant Fab arm. Using mass photometry to measure the formation of antibody:spike complexes, we determined that bsAbs increase binding stoichiometry compared to corresponding cocktails, without a loss of binding affinity. The heterogeneous binding pattern of bsAbs to spike, observed by negative-stain electron microscopy and mass photometry provided evidence for both intra- and inter-spike crosslinking. This study highlights the utility of cross-neutralizing antibodies for designing bivalent agents to combat circulating and future SARS-like coronaviruses.

Evaluating interventions to reduce behaviour associated with HCV reinfection in men who have sex with men: study protocol for a non-blinded, phase 2, randomised trial.

BACKGROUND: As highly effective therapy against hepatitis C virus (HCV) infection is available with rapid uptake, there is newfound optimism for HCV elimination. Nevertheless, certain key populations have a high risk of HCV reinfection, in particular men who have sex with men (MSM) in Western European countries. Modelling data indicate that HCV elimination will not be feasible without reduction in risk behaviour, thus supporting the need for effective interventions aimed at reducing risk behaviour and preventing reinfections in MSM. METHODS: The ICECREAM study is an international, multi-centred, phase 2, 3-arm randomised trial comparing run-in and intervention periods enrolling MSM with a history of a cured or spontaneously cleared HCV infection. Individuals are followed in routine care for 6 months (i.e. run-in period) and then randomly allocated (1:1:1) to one of the following: a tailored, interactive online risk-reduction behavioural intervention, a validated home-based HCV-RNA self-sampling test service using dried blood spots, or a combination of both. After randomisation, individuals are followed every 6 months until 18 months (i.e. intervention period). Interventions are delivered in addition to standard of care. Online questionnaire measuring risk behaviour over the past 6 months is administered at every visit. The primary outcome is the proportion at risk of HCV infection during run-in versus intervention periods assessed by using the HCV-MOSAIC risk score. The risk score consists of six self-reported HCV-related risk behaviours. Secondary outcomes include incidence of HCV reinfection, changes in the individual risk behaviour items and changes in sexual well-being since changes in sexual behaviour may have an impact on sexual experience. Two hundred forty-six MSM aged 18 years or older will be invited to participate. DISCUSSION: The ICECREAM study is a trial aimed at establishing interventions that could effectively decrease the incidence of HCV re-infection in MSM with a previous HCV infection. By offering an online behavioural risk-reduction intervention and HCV-RNA self-sampling, both of which are aimed to influence risk behaviour, we are able to provide products to at-risk MSM that could further reduce population-level HCV incidence and ultimately help reach HCV micro-elimination. TRIAL REGISTRATION: ClinicalTrials.gov NCT04156945. Registered on November 8, 2019.

Reasons for not commencing direct-acting antiviral treatment despite unrestricted access for individuals with HIV and hepatitis C virus: a multinational, prospective cohort study.

BACKGROUND: Individuals with HIV and hepatitis C virus (HCV) who remain untreated with direct-acting antivirals can contribute to HCV transmission and HCV-related mortality. We aimed to compare rates of uptake of direct-acting antivirals following unrestricted access to this treatment in high-income countries and examine factors associated with remaining untreated. METHODS: This multinational, prospective cohort study used data from the International Collaboration on Hepatitis C Elimination in HIV Cohorts (InCHEHC). We analysed data from nine observational cohorts participating in the InCHEHC, including data from six high-income countries (Australia, Canada, France, the Netherlands, Spain, and Switzerland). We included individuals aged 18 years and older, with HIV and HCV (ie, HCV-RNA positive without evidence of spontaneous clearance) during unrestricted access to interferon-free direct-acting antiviral treatment in each country. We calculated the cumulative proportion of participants who remained untreated with direct-acting antivirals, with follow-up starting after the date of unrestricted access or cohort inclusion, whichever occurred most recently. Factors associated with the commencement rate of direct-acting antiviral treatment were assessed using competing-risks regression with the Fine-Gray method. FINDINGS: The date of unrestricted access to direct-acting antiviral treatment for people with HIV ranged from Nov 1, 2014, in France to Nov 1, 2017, in Switzerland. We included 4552 individuals with HIV-HCV, mainly men who have sex with men (MSM; n=2156 [47%]) and people who inject or have injected drugs (n=1453 [32%]). 1365 (30%) of 4552 participants remained untreated with direct-acting antivirals. For individuals treated with direct-acting antivirals, median time from start of follow-up to treatment was 5 months (IQR 2-12). For individuals who were not treated with direct-acting antivirals, median follow-up was 22 months (8-30). Being linked to care in Australia, France, or the Netherlands, on antiretroviral therapy, having undetectable HIV RNA, and shorter duration since first positive HCV test were independently associated with higher commencement rate of direct-acting antiviral treatment. Compared with MSM, male heterosexuals and females with unknown or other routes of HIV transmission (ie, neither injection drug use nor heterosexual transmission) had lower rates of commencement. INTERPRETATION: Despite unrestricted access, almost a third of individuals with HIV-HCV remained untreated with direct-acting antivirals during follow-up, with variation in commencement rate of HCV treatment between countries and key populations. Increased efforts are required to reach the remaining individuals with HIV who are HCV-viraemic to achieve HIV-HCV micro-elimination. FUNDING: None.

Intent to vaccinate against SARS-CoV-2 and its determinants across six ethnic groups living in Amsterdam, the Netherlands: A cross-sectional analysis of the HELIUS study.

BACKGROUND: Ethnic minority groups experience a disproportionately high burden of infections, hospitalizations and mortality due to COVID-19, and therefore should be especially encouraged to receive SARS-CoV-2 vaccination. This study aimed to investigate the intent to vaccinate against SARS-CoV-2, along with its determinants, in six ethnic groups residing in Amsterdam, the Netherlands. METHODS: We analyzed data of participants enrolled in the population-based multi-ethnic HELIUS cohort, aged 24 to 79 years, who were tested for SARS-CoV-2 antibodies and answered questions on vaccination intent from November 23, 2020 to March 31, 2021. During the study period, SARS-CoV-2 vaccination in the Netherlands became available to individuals working in healthcare or > 75 years old. Vaccination intent was measured by two statements on a 7-point Likert scale and categorized into low, medium, and high. Using ordinal logistic regression, we examined the association between ethnicity and lower vaccination intent. We also assessed determinants of lower vaccination intent per ethnic group. RESULTS: A total of 2,068 participants were included (median age 56 years, interquartile range 46-63). High intent to vaccinate was most common in the Dutch ethnic origin group (369/466, 79.2%), followed by the Ghanaian (111/213, 52.1%), South-Asian Surinamese (186/391, 47.6%), Turkish (153/325, 47.1%), African Surinamese (156/362, 43.1%), and Moroccan ethnic groups (92/311, 29.6%). Lower intent to vaccinate was more common in all groups other than the Dutch group (P < 0.001). Being female, believing that COVID-19 is exaggerated in the media, and being < 45 years of age were common determinants of lower SARS-CoV-2 vaccination intent across most ethnic groups. Other identified determinants were specific to certain ethnic groups. CONCLUSIONS: Lower intent to vaccinate against SARS-CoV-2 in the largest ethnic minority groups of Amsterdam is a major public health concern. The ethnic-specific and general determinants of lower vaccination intent observed in this study could help shape vaccination interventions and campaigns.

Dengue, chikungunya and Zika virus infections among Dutch travellers to Suriname: a prospective study during the introduction of chikungunya and Zika virus, 2014 to 2017.

BackgroundSuriname, a country endemic for dengue virus (DENV), is a popular destination for Dutch travellers visiting friends and relatives and tourist travellers. Chikungunya and Zika virus (CHIKV, ZIKV) were introduced in 2014 and 2015, respectively. Data on infection risks among travellers are limited.AimWe aimed to prospectively study incidence rate (IR) and determinants for DENV, ZIKV and CHIKV infection in adult travellers to Suriname from 2014 through 2017.MethodsParticipants kept a travel diary and were tested for anti-DENV, anti-ZIKV and anti-CHIKV IgG antibodies (Euroimmun). Selected samples were subjected to an in-house DENV and ZIKV PRNT50. The IR (infections/1,000 person-months of travel) and IR ratio and determinants for infection were calculated.ResultsTravel-acquired infections were found in 21 of 481 participants: 18 DENV, four ZIKV and two CHIKV, yielding an IRDENV of 47.0 (95% CI: 29.6-74.6), IRZIKV of 11.6 (95% CI: 4.4-31.0) and IRCHIKV of 5.6 (95% CI: 1.4-22.2)/1,000 person-months. In nine DENV and three ZIKV infected participants, infections were PRNT50-confirmed, yielding a lower IRDENV of 23.3 (95% CI: 12.1-44.8) and an IRZIKV of 8.4 (95% CI: 2.7-26.1) per 1,000 person-months. Tourist travel was associated with DENV infection. ZIKV and CHIKV infections occurred soon after their reported introductions.ConclusionsDespite an overestimation of serologically confirmed infections, Dutch travellers to Suriname, especially tourists, are at substantial risk of DENV infection. As expected, the risk of contracting ZIKV and CHIKV was highest during outbreaks. Cross-reaction and potential cross-protection of anti-DENV and -ZIKV antibodies should be further explored.

Low Risk of Failing Direct-Acting Antivirals in People With Human Immunodeficiency Virus/Hepatitis C Virus From Sub-Saharan Africa or Southeastern Asia: A European Cross-Sectional Study.

Background: Several studies have reported suboptimal efficacy of direct-acting antivirals (DAAs) to treat hepatitis C virus (HCV) subtypes endemic to sub-Saharan Africa (SSA) and Southeastern Asia (SEA). The extent of this issue in individuals with human immunodeficiency virus (HIV)/HCV from SSA or SEA residing in Europe is unknown. Methods: We retrospectively analyzed data from several prospective European cohorts of people living with HIV. We included individuals with HIV/HCV who originated from SSA or SEA, were treated with interferon-free DAAs, and had an available HCV RNA result ≥12 weeks after the end of treatment. The primary outcome was sustained virological response at least 12 weeks after the end of treatment (SVR12). Results: Of the 3293 individuals with HIV/HCV treated with DAA and with available SVR12 data, 142 were from SSA (n = 64) and SEA (n = 78). SVR12 was achieved by 60 (94% [95% confidence interval {CI}, 86%-98%]) individuals from SSA and 76 (97% [95% CI, 92%-99%]) from SEA. The genotypes of the 6 individuals failing DAA treatment were 2, 3a, 3h, 4a, 4c, and 6j. For 2 of the 4 unsuccessfully treated individuals with available sequence data at treatment failure, NS5A resistance-associated substitutions were present (30R/93S in an individual with genotype 4c and 31M in an individual with genotype 6j). Conclusions: SVR12 rates were high in individuals with HIV/HCV residing in Europe and originating from regions where intrinsically NS5A-resistant HCV strains are endemic. HCV elimination for this population in Europe is unlikely to be hampered by suboptimal DAA efficacy.

Induction of cross-neutralizing antibodies by a permuted hepatitis C virus glycoprotein nanoparticle vaccine candidate.

Hepatitis C virus (HCV) infection affects approximately 58 million people and causes ~300,000 deaths yearly. The only target for HCV neutralizing antibodies is the highly sequence diverse E1E2 glycoprotein. Eliciting broadly neutralizing antibodies that recognize conserved cross-neutralizing epitopes is important for an effective HCV vaccine. However, most recombinant HCV glycoprotein vaccines, which usually include only E2, induce only weak neutralizing antibody responses. Here, we describe recombinant soluble E1E2 immunogens that were generated by permutation of the E1 and E2 subunits. We displayed the E2E1 immunogens on two-component nanoparticles and these nanoparticles induce significantly more potent neutralizing antibody responses than E2. Next, we generated mosaic nanoparticles co-displaying six different E2E1 immunogens. These mosaic E2E1 nanoparticles elicit significantly improved neutralization compared to monovalent E2E1 nanoparticles. These results provide a roadmap for the generation of an HCV vaccine that induces potent and broad neutralization.

Optimization of the pseudoparticle system for standardized assessments of neutralizing antibodies against hepatitis C virus.

A better understanding of the antibody response during natural infection and the effect on disease progression and reinfection is necessary for the development of a protective hepatitis C virus (HCV) vaccine. The HCV pseudoparticle (HCVpp) system enables the study of viral entry and inhibition by antibody neutralization. A robust and comparable neutralization assay is crucial for the development and evaluation of experimental vaccines.With the aim of optimizing the HCVpp-murine leukaemia virus (MLV) system, we tested the neutralization of HCVpp-harbouring E1E2 from 21 HCV isolates representing 6 different genotypes by several monoclonal antibodies (mAbs). HCVpps are generated by expressing functional envelope glycoproteins (E1E2) onto pseudoparticles derived from env-deleted MLV. Adjustments of E1E2, gag-pol and luciferase plasmid ratios resulted in increased yields for most HCVpps and recovery of one non-infectious HCVpp. We simplified and improved the protocol to achieve higher signal/noise ratios and minimized the amount of HCVpps and mAbs needed for the detection of neutralization. Using our optimized protocol, we demonstrated comparable results to previously reported data with both diluted and freeze-thawed HCVpps.In conclusion, we successfully established a simplified and reproducible HCVpp neutralization protocol for studying a wide range of HCV variants. This simplified protocol provides highly consistent results and could be easily adopted by others to evaluate precious biological material. This will contribute to a better understanding of the antibody response during natural infection and help evaluate experimental HCV vaccines.

[Monkeypox, a new pandemic?] / Uitbraak van monkeypox: een nieuwe pandemie?

Monkeypox (MPX) is a disease caused by the monkeypox virus. It is a viral zoonotic disease, endemic in Central and West Africa. Human-to-human spread also occurs and is a feature of the current global outbreak. As far as we know, exponential transmission during this outbreak is not related to changed viral characteristics but due to multiple high-risk contacts in a subset of people that have contracted the virus, so far almost exclusively affecting men who have sex with men (MSM). Appropriate public health measures and increased alertness of all health care providers is needed to increase case-finding and decrease transmission. There is a real chance of MPX to become endemic in large parts of the world.

Structure of the hepatitis C virus E1E2 glycoprotein complex.

Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma in humans and afflicts more than 58 million people worldwide. The HCV envelope E1 and E2 glycoproteins are essential for viral entry and comprise the primary antigenic target for neutralizing antibody responses. The molecular mechanisms of E1E2 assembly, as well as how the E1E2 heterodimer binds broadly neutralizing antibodies, remain elusive. Here, we present the cryo-electron microscopy structure of the membrane-extracted full-length E1E2 heterodimer in complex with three broadly neutralizing antibodies-AR4A, AT1209, and IGH505-at ~3.5-angstrom resolution. We resolve the interface between the E1 and E2 ectodomains and deliver a blueprint for the rational design of vaccine immunogens and antiviral drugs.

Internet-guided HCV-RNA testing: A promising tool to achieve hepatitis C micro-elimination among men who have sex with men.

In the Netherlands, hepatitis C virus (HCV) transmission occurs primarily in men who have sex with men (MSM). By early diagnosis and immediate treatment of acute HCV infections, HCV micro-elimination in MSM is within reach. In cooperation with the community affected, we developed an online HCV-RNA home-based self-sampling test service. This service combined online HCV self-risk assessment with the possibility to test anonymously for HCV-RNA. The service was available in the Netherlands from February 2018 till December 2020 and was promoted online on various dating sites and offline by community volunteers. Using website user data, test results and an online post-test user survey, we evaluated the service and user experiences. The website page with information about testing was visited by 3401 unique users, of whom 2250 used the HCV-risk assessment tool, 152 individuals purchased 194 HCV-RNA tests, and 104 tests were used, of which 101 gave a conclusive result. The target population of MSM at risk was successfully reached with 44.1% of users receiving the advice to test. The test service had a satisfactory uptake (6.8%, 152/2250), a very high HCV-RNA positivity rate (10.9%, 11/101) and was considered acceptable and easy to use by most MSM. We demonstrate that an HCV-RNA home-based self-sampling test service is successful in diagnosing HCV infections among MSM. This service could be a valuable addition to existing sexual healthcare services as it may reach men who are otherwise not tested.

Epidemiologic and Genomic Analysis of SARS-CoV-2 Delta Variant Superspreading Event in Nightclub, the Netherlands, June 2021.

We report a severe acute respiratory syndrome coronavirus 2 superspreading event in the Netherlands after distancing rules were lifted in nightclubs, despite requiring a negative test or vaccination. This occurrence illustrates the potential for rapid dissemination of variants in largely unvaccinated populations under such conditions. We detected subsequent community transmission of this strain.