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Objectives: Following clearance of incident hepatitis C virus (HCV) infections, HCV antibody levels may decline, resulting in seroreversion. It is unclear to what extent HCV antibody level trajectories differ between patients with treatment‐induced sustained virological response (SVR), those with spontaneous clearance and those with untreated replicating HCV infection. We investigated HCV antibody level dynamics in HIV‐infected MSM with different clinical outcomes. Methods: We investigated anti‐HCV antibody level dynamics following an incident HCV infection in 67 HIV‐infected men who have sex with men (MSM) with different clinical outcomes: SVR (n = 33), spontaneous clearance (n = 12), and untreated replicating infection (n = 22). Antibody levels were measured at the time of HCV diagnosis, and at yearly intervals for 3 years thereafter. Results: At baseline, median HCV antibody levels were similar in the three groups: 13.4, 13.8 and 13.5 sample to cut‐off (S/CO) for SVR, spontaneous clearance and untreated infection, respectively. Over 3 years of follow‐up, SVR was associated with a more pronounced decrease in anti‐HCV levels compared with spontaneous clearance and untreated infection [median decline 71% [interquartile range (IQR: 43–87%), 38% (IQR: 29–60%) and 12% (IQR: 9–22%), respectively; P < 0.001]. Seroreversions occurred in five of 33 (15%) patients with SVR and in one of 12 (8%) with spontaneous clearance. A shorter delay between time of infection and treatment start correlated with higher rates of decline in antibody levels. Seven patients experienced a reinfection. Conclusions: Treatment‐induced HCV clearance was associated with a more pronounced decline in anti‐HCV antibody levels and with higher rates of seroreversion compared with spontaneous clearance or untreated replicating HCV infection among HIV‐infected MSM with incident HCV infections. Rapid clearance of HCV RNA following early HCV treatment might impair the development of persistent antibody titres. [ABSTRACT FROM AUTHOR]

Background: We evaluated long-term trajectories of circulating hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg) in persons with and without hepatitis B surface antigen (HBsAg) loss during tenofovir therapy in the Swiss HIV Cohort Study., Methods: We included 29 persons with HIV with HBsAg loss and 29 matched persons with HIV without HBsAg loss. We compared HBV RNA and HBcrAg decline and assessed the cumulative proportions with undetectable HBV RNA and HBcrAg levels during tenofovir therapy using Kaplan-Meier estimates., Results: HBsAg loss occurred after a median of 4 years (IQR, 1-8). All participants with HBsAg loss achieved suppressed HBV DNA and undetectable HBV RNA preceding undetectable quantitative HBsAg levels, whereas 79% achieved negative HBcrAg. In comparison, 79% of participants without HBsAg loss achieved undetectable HBV-RNA and 48% negative HBcrAg. After 2 years of tenofovir therapy, an HBV RNA decline ≥1 log10 copies/mL had 100% sensitivity and 36.4% specificity for HBsAg loss, whereas an HBcrAg decline ≥1 log10 U/mL had 91.0% sensitivity and 64.5% specificity., Conclusions: HBV RNA suppression preceded undetectable quantitative HBsAg levels and had high sensitivity but low specificity for HBsAg loss during tenofovir therapy in persons with HIV. HBcrAg remained detectable in approximately 20% of persons with HBsAg loss and 50% of persons without HBsAg loss., Competing Interests: Potential conflicts of interest. L. B. reports support for travel and conference participation from the CROI Foundation and the SAFE-ID Foundation. A. B. has received speaker honoraria from Gilead unrelated to this work. M.-L. P. reported support for the present article from the CirB-RNA-RHU program paid to her institution. B. T. has received honoraria for lectures from Gilead Sciences France, Hopital Vall D’Hebron, and the Belgian Association for the Study of the Liver and payment for expert testimony and travel support from the International Hepatology Education Program. L. S.-V. has received honoraria for consulting from Gilead paid to her institution and unrelated to this work. F. S.-R. reports no potential conflicts. C. S. received speaker honoraria and travel support from Gilead and a grant from Roche Diagnostics paid to her institution and unrelated to this work. C. B. has received advisory board membership fees from Gilead paid to his institution. J. K. R. has received honoraria for consulting or speaking at educational events from Boehringer, Gilead, Merck, Janssen, and ViiV. H. F. G. has received unrestricted research grants from Gilead Sciences; fees for data and safety monitoring board membership from Merck; consulting/advisory board membership fees from Gilead Sciences, Merck, Johnson & Johnson, Janssen, GSK, Novartis, and ViiV Healthcare; and grants from the Swiss National Science Foundation, the Bill & Melinda Gates Foundation, the Yvonne Jacob Foundation, Gilead, ViiV, and the National Institutes of Health. A. C. reported unrestricted educational grants from ViiV, Gilead, and MSD and industry-sponsored clinical trials at her HIV unit. M. C.'s institution received research grants from Gilead, MSD, and ViiV and financial compensation for expert opinion given to Gilead, MSD, and ViiV. H. H. H. received grant support from Moderna paid to his institution and honoraria for consulting or speaking at educational events from AICuris, Allovir, Moderna, VeraTx, Roche, Takeda, Biotest, and Gilead. P.S.'s institution has received travel grants and congress/advisory fees from Gilead and ViiV unrelated to this work. The institution of E. B. received grants from MSD; consulting fees from Moderna; speaker fees from Pfizer AG Switzerland; and payments for the participation of E. B. to advisory boards or travel grants from Gilead Sciences, ViiV Healthcare, MSD, Pfizer AG Switzerland, Moderna, Astra Zeneca, Eli Lilly, and Abbvie. M. L. has received lecture and presentation fees from Abbvie and Gilead and coverage and reimbursement of travel expenses from Abbvie, Gilead, Inventiva, Madrigal, and MSD. G. W. received unrestricted research grants from Gilead Sciences and Roche Diagnostics and lecture/advisory board membership fees from Gilead Sciences, MSD, and ViiV Healthcare, all paid to his institution. F. Z. has received speaker fees from Gilead; consulting fees from Aligos, Assembly, Blue Jay, and GSK; and research grants through INSERM from Assembly, Beam, Blue Jay, and Janssen. A. R. reports support to his institution for advisory boards and/or travel grants from MSD, Gilead Sciences, Pfizer, and Moderna and an investigator-initiated trial grant from Gilead Sciences. All remuneration went to his home institution and not to A. R. personally, and all remuneration was provided outside the submitted work. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Objectives: Improving the understanding of the patterns of quantitative hepatitis B surface antigen (qHBsAg) trajectories associated with HBsAg loss is important in light of novel anti-hepatitis B virus agents being developed. We evaluated long-term qHBsAg trajectories in persons with HIV and HBV during tenofovir-containing antiretroviral therapy in the Swiss HIV Cohort Study., Methods: We included 29 participants with and 29 without HBsAg loss, defined as qHBsAg <0.05 IU/mL. We assessed qHBsAg decline during therapy in both groups and used agglomerative hierarchical clustering to identify different qHBsAg trajectory profiles in persons with HBsAg loss., Results: The median follow-up time was 11.9 years (IQR 8.4-14.1), and the median time to HBsAg loss was 48 months (IQR 12-96). Among participants with HBsAg loss, 79% had a qHBsAg decline ≥1 log 10 IU/mL 2 years after starting tenofovir. The trajectories in qHBsAg levels during tenofovir therapy were heterogeneous, characterized by five distinct profiles. Among participants without HBsAg loss, only 7% had a qHBsAg decline ≥1 log 10 IU/ml after 2 years., Conclusions: Most persons with HIV who experienced HBsAg loss had an early decline in qHBsAg levels, with diverse trajectories during long-term tenofovir therapy. In persons without HBsAg loss, qHBsAg levels remained remarkably stable over time., (© 2023 The Authors. HIV Medicine published by John Wiley & Sons Ltd on behalf of British HIV Association.)

Despite decreased numbers of sexual partners, the COVID-19 pandemic had limited impact on the prevalence of attending private sex parties, traveling for sex within Switzerland, and practicing chemsex in men with HIV who have sex with men. COVID-19 risk perception was low, and STI-diagnosis incidence rates remained stable over time., Competing Interests: Potential conflicts of interest. None of the authors has declared a possible conflict of interest related to this study. AH's institution has received travel grants, congress and advisory fees from MSD, Viiv and Gilead, unrelated to this work. AR reports support to his institution for advisory boards and/or travel grants from MSD, Gilead Sciences, Pfizer and Moderna, and an investigator initiated trial (IIT) grant from Gilead Sciences. All remuneration went to his home institution and not to AR personally, and all remuneration was provided outside the submitted work. AC reported unrestricted Education grants from Gilead Sciences, MSD and ViiV; research grant from MSD. DLB reported honoraria payed to himself for advisory boards from the companies Gilead, MSD and ViiV outside of the submitted work. EB's institution has received travel grants and advisory fees from MSD, ViiV Healthcare, Gilead Sciences, Pfizer, Astra Zeneca, Ely Lilly, and Moderna, unrelated to this work. MC's institution received research grants and expert opinion honoraria from Gilead, MSD and Viiv outside of the submitted work. RDK reports research grants from Gilead Sciences, unrelated to this work., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

We followed adolescents and adults living with HIV aged older than 15 years who enrolled in a South African private-sector HIV programme to examine adherence and viral non-suppression (viral load > 400 copies/mL) of participants with (20,743, 38%) and without (33,635, 62%) mental health diagnoses. Mental health diagnoses were associated with unfavourable adherence patterns. The risk of viral non-suppression was higher among patients with organic mental disorders [adjusted risk ratio (aRR) 1.55, 95% confidence interval (CI) 1.22-1.96], substance use disorders (aRR 1.53, 95% CI 1.19-1.97), serious mental disorders (aRR 1.30, 95% CI 1.09-1.54), and depression (aRR 1.19, 95% CI 1.10-1.28) when compared with patients without mental health diagnoses. The risk of viral non-suppression was also higher among males, adolescents (15-19 years), and young adults (20-24 years). Our study highlights the need for psychosocial interventions to improve HIV treatment outcomes-particularly of adolescents and young adults-and supports strengthening mental health services in HIV treatment programmes., (© 2022. The Author(s).)

Objective: From January 1, 2018, until July 31, 2020, our hospital network experienced an outbreak of vancomycin-resistant enterococci (VRE). The goal of our study was to improve existing processes by applying machine-learning and graph-theoretical methods to a nosocomial outbreak investigation., Methods: We assembled medical records generated during the first 2 years of the outbreak period (January 2018 through December 2019). We identified risk factors for VRE colonization using standard statistical methods, and we extended these with a decision-tree machine-learning approach. We then elicited possible transmission pathways by detecting commonalities between VRE cases using a graph theoretical network analysis approach., Results: We compared 560 VRE patients to 86,684 controls. Logistic models revealed predictors of VRE colonization as age (aOR, 1.4 (per 10 years), with 95% confidence interval [CI], 1.3-1.5; P < .001), ICU admission during stay (aOR, 1.5; 95% CI, 1.2-1.9; P < .001), Charlson comorbidity score (aOR, 1.1; 95% CI, 1.1-1.2; P < .001), the number of different prescribed antibiotics (aOR, 1.6; 95% CI, 1.5-1.7; P < .001), and the number of rooms the patient stayed in during their hospitalization(s) (aOR, 1.1; 95% CI, 1.1-1.2; P < .001). The decision-tree machine-learning method confirmed these findings. Graph network analysis established 3 main pathways by which the VRE cases were connected: healthcare personnel, medical devices, and patient rooms., Conclusions: We identified risk factors for being a VRE carrier, along with 3 important links with VRE (healthcare personnel, medical devices, patient rooms). Data science is likely to provide a better understanding of outbreaks, but interpretations require data maturity, and potential confounding factors must be considered.

We assessed changes in sexual behavior among people with human immunodeficiency virus (HIV) over 20 years. Condom use with stable partners steadily declined from over 90 to 29 since the Swiss U U statement, with similar trajectories between men who have sex with men (MSM) and heterosexuals. Occasional partnership remained higher among MSM compared to heterosexuals even during coronavirus disease 2019 (COVID-19) social distancing., (The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Machine learning is increasingly introduced into medical fields, yet there is limited evidence for its benefit over more commonly used statistical methods in epidemiological studies. We introduce an unsupervised machine learning framework for longitudinal features and evaluate it using sexual behaviour data from the last 20 years from over 3'700 participants in the Swiss HIV Cohort Study (SHCS). We use hierarchical clustering to find subgroups of men who have sex with men in the SHCS with similar sexual behaviour up to May 2017, and apply regression to test whether these clusters enhance predictions of sexual behaviour or sexually transmitted diseases (STIs) after May 2017 beyond what can be predicted with conventional parameters. We find that behavioural clusters enhance model performance according to likelihood ratio test, Akaike information criterion and area under the receiver operator characteristic curve for all outcomes studied, and according to Bayesian information criterion for five out of ten outcomes, with particularly good performance for predicting future sexual behaviour and recurrent STIs. We thus assess a methodology that can be used as an alternative means for creating exposure categories from longitudinal data in epidemiological models, and can contribute to the understanding of time-varying risk factors., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: DLB reports honoraria and travel grants outside of the submitted work from Gilead, ViiV and Merck. HFG, outside of this study, reports grants from Swiss HIV Cohort Study, grants from Swiss National Science Foundation, during the conduct of the study; grants from Swiss HIV Cohort Study, grants from Swiss National Science Foundation, grants from NIH, grants from Gilead unrestricted research grant, personal fees from Advisor/consultant for Merck, ViiV healthcare and Gilead sciences and member of DSMB for Merck, grants from Yvonne Jacob Foundation. KEAD’s institution has received research funding unrelated to this publication from Gilead and sponsorship to specialist meetings from MSD. AR reports fees for sitting on advisory boards from Merck Sharp & Dohme and Gilead Sciences; travel grants from Gilead Sciences, Pfizer, and AbbVie; and a research grant from Gilead Sciences, outside of the submitted work. All fees were paid to AR’s institution and not to AR personally., (Copyright: © 2022 Andresen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Future prevalence of colonization with extended-spectrum betalactamase (ESBL-) producing K. pneumoniae in humans and the potential of public health interventions against the spread of these resistant bacteria remain uncertain., Methods: Based on antimicrobial consumption and susceptibility data recorded during > 13 years in a Swiss region, we developed a mathematical model to assess the comparative effect of different interventions on the prevalence of colonization., Results: Simulated prevalence stabilized in the near future when rates of antimicrobial consumption and in-hospital transmission were assumed to remain stable (2025 prevalence: 6.8% (95CI%:5.4-8.8%) in hospitals, 3.5% (2.5-5.0%) in the community versus 6.1% (5.0-7.5%) and 3.2% (2.3-4.2%) in 2019, respectively). When overall antimicrobial consumption was set to decrease by 50%, 2025 prevalence declined by 75% in hospitals and by 64% in the community. A 50% decline in in-hospital transmission rate led to a reduction in 2025 prevalence of 31% in hospitals and no reduction in the community. The best model fit estimated that 49% (6-100%) of observed colonizations could be attributable to sources other than human-to-human transmission within the geographical setting., Conclusions: Projections suggests that overall antimicrobial consumption will be, by far, the most powerful driver of prevalence and that a large fraction of colonizations could be attributed to non-local transmissions., (© 2022. The Author(s).)

We hypothesize that patterns of sexual behavior play a role in the conformation of transmission networks, i.e., the way you behave might influence whom you have sex with. If that was the case, behavioral grouping might in turn correlate with, and potentially predict transmission networking, e.g., proximity in a viral phylogeny. We rigorously present an intuitive approach to address this hypothesis by quantifying mapped interactions between groups defined by similarities in sexual behavior along a virus phylogeny while discussing power and sample size considerations. Data from the Swiss HIV Cohort Study on condom use and hepatitis C virus (HCV) sequences served as proof-of-concept. In this case, a strict inclusion criteria contrasting with low HCV prevalence hindered our possibilities to identify significant relationships. This manuscript serves as guide for studies aimed at characterizing interactions between behavioral patterns and transmission networks. Large transmission networks such as those of HIV or COVID-19 are prime candidates for applying this methodological approach.

Over the last decade, syphilis diagnoses among men-who-have-sex-with-men (MSM) have strongly increased in Europe. Understanding the drivers of the ongoing epidemic may aid to curb transmissions. In order to identify the drivers of syphilis transmission in MSM in Switzerland between 2006 and 2017 as well as the effect of potential interventions, we set up an epidemiological model stratified by syphilis stage, HIV-diagnosis, and behavioral factors to account for syphilis infectiousness and risk for transmission. In the main model, we used 'reported non-steady partners' (nsP) as the main proxy for sexual risk. We parameterized the model using data from the Swiss HIV Cohort Study, Swiss Voluntary Counselling and Testing center, cross-sectional surveys among the Swiss MSM population, and published syphilis notifications from the Federal Office of Public Health. The main model reproduced the increase in syphilis diagnoses from 168 cases in 2006 to 418 cases in 2017. It estimated that between 2006 and 2017, MSM with HIV diagnosis had 45.9 times the median syphilis incidence of MSM without HIV diagnosis. Defining risk as condomless anal intercourse with nsP decreased model accuracy (sum of squared weighted residuals, 378.8 vs. 148.3). Counterfactual scenarios suggested that increasing screening of MSM without HIV diagnosis and with nsP from once every two years to twice per year may reduce syphilis incidence (at most 12.8% reduction by 2017). Whereas, increasing screening among MSM with HIV diagnosis and with nsP from once per year to twice per year may substantially reduce syphilis incidence over time (at least 63.5% reduction by 2017). The model suggests that reporting nsP regardless of condom use is suitable for risk stratification when modelling syphilis transmission. More frequent screening of MSM with HIV diagnosis, particularly those with nsP may aid to curb syphilis transmission., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: HFG, outside of this study, report grants from Swiss HIV Cohort Study, grants from Swiss National Science Foundation, grants from NIH, grants from Gilead unrestricted research grant, personal fees from Advisor/consultant for Merck, ViiV healthcare and Gilead Sciences and member of DSMB for Merck, grants from Yvonne Jacob Foundation. The institution of MC received research grants from Gilead, ViiV and MSD. All other authors declare no competing interests.

Background: In 2016, the World Health Organization (WHO) introduced global targets for the elimination of hepatitis C virus (HCV) by 2030. We conducted a nationwide HCV micro-elimination program among men who have sex with men (MSM) living with human immunodeficiency virus (HIV) from the Swiss HIV Cohort Study (SHCS) to test whether the WHO goals are achievable in this population., Methods: During phase A (10/2015-06/2016), we performed a population-based and systematic screening for HCV-RNA among MSM from the SHCS. During phase B (06/2016-02/2017) we offered treatment with HCV direct-acting antiviral (DAA) agents to MSM identified with a replicating HCV infection. During phase C (03/2017-11/2017), we offered rescreening to all MSM for HCV-RNA and initiated DAA treatment in MSM with replicating infections., Results: We screened 3715/4640 (80%) MSM and identified 177 with replicating HCV infections (4.8%); 150 (85%) of whom started DAA treatment and 149 (99.3%) were cured. We rescreened 2930/3538 (83%) MSM with a prior negative HCV-RNA and identified 13 (0.4%) with a new HCV infection. At the end of the micro-elimination program, 176/190 MSM (93%) were cured, and the HCV incidence rate declined from .53 per 100 patient-years (95% CI, .35-.83) prior to the intervention to .12 (95% CI, .03-.49) by the end of 2019., Conclusions: A systematic, population-based HCV micro-elimination program among MSM living with HIV was feasible and resulted in a strong decline in HCV incidence and prevalence. Our study can serve as a model for other countries aiming to achieve the WHO HCV elimination targets., Clinical Trials Registration: NCT02785666., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Beta-lactam- and in particular carbapenem-resistant Enterobacteriaceae represent a major public health threat. Despite strong variation of resistance across geographical settings, there is limited understanding of the underlying drivers. To assess these drivers, we developed a transmission model of cephalosporin- and carbapenem-resistant Klebsiella pneumoniae. The model is parameterized using antibiotic consumption and demographic data from eleven European countries and fitted to the resistance rates for Klebsiella pneumoniae for these settings. The impact of potential drivers of resistance is then assessed in counterfactual analyses. Based on reported consumption data, the model could simultaneously fit the prevalence of extended-spectrum beta-lactamase-producing and carbapenem-resistant Klebsiella pneumoniae (ESBL and CRK) across eleven European countries over eleven years. The fit could explain the large between-country variability of resistance in terms of consumption patterns and fitted differences in hospital transmission rates. Based on this fit, a counterfactual analysis found that reducing nosocomial transmission and antibiotic consumption in the hospital had the strongest impact on ESBL and CRK prevalence. Antibiotic consumption in the community also affected ESBL prevalence but its relative impact was weaker than inpatient consumption. Finally, we used the model to estimate a moderate fitness cost of CRK and ESBL at the population level. This work highlights the disproportionate role of antibiotic consumption in the hospital and of nosocomial transmission for resistance in gram-negative bacteria at a European level. This indicates that infection control and antibiotic stewardship measures should play a major role in limiting resistance even at the national or regional level., Competing Interests: The authors have declared that no competing interests exist.

HIV-1 genetic diversity can be used to infer time since infection (TSI) and infection recency. We adapted this approach for HCV and identified genomic regions with informative diversity. We included 72 HCV/HIV-1 coinfected participants of the Swiss HIV Cohort Study, for whom reliable estimates of infection date and viral sequences were available. Average pairwise diversity (APD) was calculated over each codon position for the entire open reading frame of HCV. Utilizing cross validation, we evaluated the correlation of APD with TSI, and its ability to infer TSI via a linear model. We additionally studied the ability of diversity to classify infections as recent (infected for <1 year) or chronic, using receiver-operator-characteristic area under the curve (ROC-AUC) in 50 patients whose infection could be unambiguously classified as either recent or chronic. Measuring HCV diversity over third or all codon positions gave similar performances, and notable improvement over first or second codon positions. APD calculated over the entire genome enabled classification of infection recency (ROC-AUC = 0.76). Additionally, APD correlated with TSI (R 2 = 0.33) and could predict TSI (mean absolute error = 1.67 years). Restricting the region over which APD was calculated to E2 - NS2 further improved accuracy (ROC-AUC = 0.85, R 2 = 0.54, mean absolute error = 1.38 years) . Genetic diversity in HCV correlates with TSI and is a proxy for infection recency and TSI, even several years post-infection.

Background: Self-reported neurocognitive impairment (SRNI) in people living with human immunodeficiency virus type 1 (HIV-1) infection is frequent. We use longitudinal information on SRNI in the Swiss HIV Cohort Study (SHCS) to identify and characterize groups of patients with persisting SRNI over time., Methods: We included all SHCS patients who were assessed for SRNI during at least 5 visits spanning at least 2.5 years in 2013-2017. We first compared patients with SRNI to those without SRNI over the whole study period. Second, we used a hierarchical cluster algorithm to identify groups of patients with similar changes of SRNI over time. In both analyses, we studied clinical and demographic factors potentially influencing SRNI., Results: In total, 79 683 questionnaires of 11 029 patients contained information about SRNI, and 8545 of 11 029 (77.5%) patients had longitudinal information. The overall percentage of patients with SRNI decreased from 19.6% in 2013 to 10.7% in 2017. Compared to patients in the cluster with low-level SRNI over time, patients in the cluster with high-level persisting SRNI more often had a prior opportunistic infection of the central nervous system (CNS) (odds ratio [OR], 3.7; P < .001), imperfect adherence to antiretroviral therapy (ART) (OR, 2.8; P < .001), and depression (OR, 1.9; P < .001)., Conclusions: Although overall SRNI is decreasing in the SHCS, there is a group of patients with persisting SRNI over time. Past opportunistic infections of the CNS, imperfect adherence to ART, and depression were associated most with persisting SRNI. Patients with these characteristics should be preferentially tested for neurocognitive impairment.Although overall self-reported neurocognitive impairment (SRNI) is decreasing in the Swiss HIV Cohort Study, there is a group of patients with persisting SRNI over time, characterized by more past opportunistic infections of the central nervous system, imperfect adherence to antiretroviral therapy, and depression., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Separately addressing specific groups of people who share patterns of behavioral change might increase the impact of behavioral interventions to prevent transmission of sexually transmitted infections. We propose a method based on machine learning to assist the identification of such groups among men who have sex with men (MSM)., Methods: By means of unsupervised learning, we inferred "behavioral clusters" based on the recognition of similarities and differences in longitudinal patterns of condomless anal intercourse with nonsteady partners (nsCAI) in the HIV Cohort Study over the last 18 years. We then used supervised learning to investigate whether sociodemographic variables could predict cluster membership., Results: We identified 4 behavioral clusters. The largest behavioral cluster (cluster 1) contained 53% of the study population and displayed the most stable behavior. Cluster 3 (17% of the study population) displayed consistently increasing nsCAI. Sociodemographic variables were predictive for both of these clusters. The other 2 clusters displayed more drastic changes: nsCAI frequency in cluster 2 (20% of the study population) was initially similar to that in cluster 3 but accelerated in 2010. Cluster 4 (10% of the study population) had significantly lower estimates of nsCAI than all other clusters until 2017, when it increased drastically, reaching 85% by the end of the study period., Conclusions: We identified highly dissimilar behavioral patterns across behavioral clusters, including drastic, atypical changes. The patterns suggest that the overall increase in the frequency of nsCAI is largely attributable to 2 clusters, accounting for a third of the population., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Human immunodeficiency virus (HIV)-positive gay and bisexual men (GBM) in Australia are well engaged in care. The World Health Organization's (WHO) hepatitis C virus (HCV) elimination target of an 80% reduction in incidence by 2030 may be reachable ahead of time in this population., Methods: We predicted the effect of treatment and behavioral changes on HCV incidence among HIV-positive GBM up to 2025 using a HCV transmission model parameterized with Australian data. We assessed the impact of changes in behavior that facilitate HCV transmission in the context of different rates of direct-acting antiviral (DAA) use., Results: HCV incidence in our model increased from 0.7 per 100 person-years in 2000 to 2.5 per 100 person-years in 2016 and had the same trajectory as previously reported clinical data. If the proportion of eligible (HCV RNA positive) patients using DAAs stays at 65% per year between 2016 and 2025, with high-risk sexual behavior and injecting drug use remaining at current levels, HCV incidence would drop to 0.4 per 100 person-years (85% decline from 2016). In the same treatment scenario but with substantial increases in risk behavior, HCV incidence would drop to 0.6 per 100 person-years (76% decline). If the proportion of eligible patients using DAAs dropped from 65% per year in 2016 to 20% per year in 2025 and risk behavior did not change, HCV incidence would drop to 0.7 per 100 person-years (70% reduction)., Conclusions: Reaching the WHO HCV elimination target by 2025 among HIV-positive GBM in Australia is achievable., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Scale-up of direct-acting antiviral therapy is expected to abate hepatitis C virus (HCV) incidence among human immunodeficiency virus (HIV)-positive men who have sex with men (MSM). International transmission could influence this process. We classified HCV infections in HIV-positive MSM as either domestically or internationally acquired, and estimated how this classification changed over time., Methods: HCV subtype 1a (the most frequent subtype among MSM) genomes from 99 persons enrolled in the Swiss HIV Cohort Study and diagnosed with replicating HCV infections, were sequenced. Sixty-six of these sequences were from MSM. We inferred maximum-likelihood phylogenetic trees and time trees containing a fragment of the NS5B region of these and 374 circulating strains. We inferred transmission clusters from these trees and used the country composition of such clusters to attribute infections to domestic or international transmission., Results: Of HCV transmissions, 50% to 80% were classified as domestic depending on the classification criterion. Between 2000 and 2007, the fraction attributable to domestic transmission was 54% (range 0-75%). It increased to 85% (range 67%-100%) between 2008 and 2016., Conclusions: International and domestic transmission have played major roles in this epidemic. While international transmission persists, local transmission has established as the main source of infections., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.)

In the Swiss HIV Cohort Study, the number of people who inject drugs with replicating hepatitis C virus (HCV) infection decreased substantially after the introduction of direct-acting antivirals (DAAs). Among men who have sex with men, the increase in DAA uptake and efficacy was counterbalanced by frequent incident HCV infections.

Hepatitis C virus reinfection rates among men who have sex with men are high. Factors associated with infection point to varied sexual and drug-related risks that could be targeted for interventions to prevent infection/reinfection. Modeling indicates that tackling increasing incidence and high reinfection rates requires high levels of hepatitis C virus treatment combined with behavioral interventions. Enhanced testing strategies and prompt retreating of reinfection may be required to promptly diagnosed reinfections. Behavioral interventions studies addressing reinfection are required. Other interventions include traditional harm reduction interventions, adapted behavioral interventions, and interventions to prevent harms related to ChemSex and other risk factors., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Antiretroviral therapy (ART) reduces HIV transmission, but treated patients may again become infectious. We used a mathematical model to determine whether ART as prevention is more effective if viral load (VL) is routinely monitored and patients lost to follow-up (LTFU) traced., Methods: We simulated ART cohorts to parameterize a deterministic transmission model calibrated to Malawi. We investigated the following strategies for improving treatment and retention: monitoring VL every 12 or 24 months, tracing patients LTFU, or a generic strategy leading to uninterrupted treatment. We tested 3 scenarios, where ART scale-up continues at current (Universal ART), reduced (Failed scale-up), or accelerated speed (Test&Treat)., Results: In the Universal ART scenario, between 2017 and 2020 (2050), monitoring VL every 24 months prevented 0.5% (0.9%), monitoring every 12 months prevented 0.8% (1.4%), tracing prevented 0.3% (0.5%), and uninterrupted treatment prevented 5.5% (9.9%) of HIV infections. Failed scale-up resulted in 25% more infections than the Universal ART scenarios, whereas Test&Treat resulted in 7%-8% less., Conclusions: Test&Treat reduces transmission of HIV, despite individual cases of treatment failure and ART interruption. Whereas viral load monitoring and tracing have only a minor impact on transmission, interventions that aim to minimize treatment interruptions can further increase the preventive effect of ART.

The incidence of hepatitis C virus (HCV) infections among human immunodeficiency virus (HIV)-infected men who have sex with men has increased in recent years and is associated with high-risk sexual behavior. Behavioral interventions that target high-risk behavior associated with HCV transmission and treatment with direct-acting antivirals may prevent further HCV infections. We predicted the effect of behavioral and treatment interventions on HCV incidence and prevalence among HIV-infected men who have sex with men up to 2030 using a HCV transmission model parameterized with data from the Swiss HIV Cohort Study. We assessed behavioral interventions associated with further increase, stabilization, and decrease in the size of the population with high-risk behavior. Treatment interventions included increase in treatment uptake and use of direct-acting antivirals. If we assumed that without behavioral interventions high-risk behavior spread further according to the trends observed over the last decade and that the treatment practice did not change, HCV incidence converged to 10.7/100 person-years. All assessed behavioral interventions alone resulted in reduced HCV transmissions. Stabilization of high-risk behavior combined with increased treatment uptake and the use of direct-acting antivirals reduced incidence by 77% (from 2.2 in 2015 to 0.5/100 person-years) and prevalence by 81% (from 4.8% in 2015 to 0.9%) over the next 15 years. Increasing treatment uptake was more effective than increasing treatment efficacy to reduce HCV incidence and prevalence. A decrease in high-risk behavior led to a rapid decline in HCV incidence, independent of treatment interventions., Conclusion: Treatment interventions to curb the HCV epidemic among HIV-infected men who have sex with men are effective if high-risk behavior does not increase as it has during the last decade; reducing high-risk behavior associated with HCV transmission would be the most effective intervention for controlling the HCV epidemic, even if this was not accompanied by an increase in treatment uptake or efficacy. (Hepatology 2016;64:1856-1869)., (© 2016 The Authors. Hepatology published by Wiley Periodicals, Inc., on behalf of the American Association for the Study of Liver Diseases.)

Background: Adherence to antiretroviral therapy (ART) is crucial to preventing mother-to-child transmission of human immunodeficiency virus (HIV) and ensuring the long-term effectiveness of ART, yet data are sparse from African routine care programs on maternal adherence to triple ART., Methods: We analyzed data from women who started ART at 13 large health facilities in Malawi between September 2011 and October 2013. We defined adherence as the percentage of days "covered" by pharmacy claims. Adherence of ≥90% was deemed adequate. We calculated inverse probability of censoring weights to adjust adherence estimates for informative censoring. We used descriptive statistics, survival analysis, and pooled logistic regression to compare adherence between pregnant and breastfeeding women eligible for ART under Option B+, and nonpregnant and nonbreastfeeding women who started ART with low CD4 cell counts or World Health Organization clinical stage 3/4 disease., Results: Adherence was adequate for 73% of the women during pregnancy, for 66% in the first 3 months post partum, and for about 75% during months 4-21 post partum. About 70% of women who started ART during pregnancy and breastfeeding adhered adequately during the first 2 years of ART, but only about 30% of them had maintained adequate adherence at every visit. Risk factors for inadequate adherence included starting ART with an Option B+ indication, at a younger age, or at a district hospital or health center., Conclusions: One-third of women retained in the Option B+ program adhered inadequately during pregnancy and breastfeeding, especially soon after delivery. Effective interventions to improve adherence among women in this program should be implemented., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background & Aims: Hepatitis C (HCV) is a leading cause of morbidity and mortality in people who live with HIV. In many countries, access to direct acting antiviral agents to treat HCV is restricted to individuals with advanced liver disease (METAVIR stage F3 or F4). Our goal was to estimate the long term impact of deferring HCV treatment for men who have sex with men (MSM) who are coinfected with HIV and often have multiple risk factors for liver disease progression., Methods: We developed an individual-based model of liver disease progression in HIV/HCV coinfected MSM. We estimated liver-related morbidity and mortality as well as the median time spent with replicating HCV infection when individuals were treated in liver fibrosis stages F0, F1, F2, F3 or F4 on the METAVIR scale., Results: The percentage of individuals who died of liver-related complications was 2% if treatment was initiated in F0 or F1. It increased to 3% if treatment was deferred until F2, 7% if it was deferred until F3 and 22% if deferred until F4. The median time individuals spent with replicating HCV increased from 5years if treatment was initiated in F2 to almost 15years if it was deferred until F4., Conclusions: Deferring HCV therapy until advanced liver fibrosis is established could increase liver-related morbidity and mortality in HIV/HCV coinfected individuals, and substantially prolong the time individuals spend with a replicating HCV infection., (Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Background: Tuberculosis (TB) is the leading cause of death in South Africa. The burden of disease varies by age, with peaks in TB notification rates in the HIV-negative population at ages 0-5, 20-24, and 45-49 years. There is little variation between age groups in the rates in the HIV-positive population. The drivers of this age pattern remain unknown., Methods: We developed an age-structured simulation model of Mycobacterium tuberculosis (Mtb) transmission in Cape Town, South Africa. We considered five states of TB progression: susceptible, infected (latent TB), active TB, treated TB, and treatment default. Latently infected individuals could be re-infected; a previous Mtb infection slowed progression to active disease. We further considered three states of HIV progression: HIV negative, HIV positive, on antiretroviral therapy. To parameterize the model, we analysed treatment outcomes from the Cape Town electronic TB register, social mixing patterns from a Cape Town community and used literature estimates for other parameters. To investigate the main drivers behind the age patterns, we conducted sensitivity analyses on all parameters related to the age structure., Results: The model replicated the age patterns in HIV-negative TB notification rates of Cape Town in 2009. Simulated TB notification rate in HIV-negative patients was 1000/100,000 person-years (pyrs) in children aged <5 years and decreased to 51/100,000 in children 5-15 years. The peak in early adulthood occurred at 25-29 years (463/100,000 pyrs). After a subsequent decline, simulated TB notification rates gradually increased from the age of 30 years. Sensitivity analyses showed that the dip after the early adult peak was due to the protective effect of latent TB and that retreatment TB was mainly responsible for the rise in TB notification rates from the age of 30 years., Conclusion: The protective effect of a first latent infection on subsequent infections and the faster progression in previously treated patients are the key determinants of the age-structure of TB notification rates in Cape Town., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: The number of patients in need of second-line antiretroviral drugs is increasing in sub-Saharan Africa. We aimed to project the need of second-line antiretroviral therapy in adults in sub-Saharan Africa up to 2030., Methods: We developed a simulation model for HIV and applied it to each sub-Saharan African country. We used the WHO country intelligence database to estimate the number of adult patients receiving antiretroviral therapy from 2005 to 2014. We fitted the number of adult patients receiving antiretroviral therapy to observed estimates, and predicted first-line and second-line needs between 2015 and 2030. We present results for sub-Saharan Africa, and eight selected countries. We present 18 scenarios, combining the availability of viral load monitoring, speed of antiretroviral scale-up, and rates of retention and switching to second-line. HIV transmission was not included., Findings: Depending on the scenario, 8·7-25·6 million people are expected to receive antiretroviral therapy in 2020, of whom 0·5-3·0 million will be receiving second-line antiretroviral therapy. The proportion of patients on treatment receiving second-line therapy was highest (15·6%) in the scenario with perfect retention and immediate switching, no further scale-up, and universal routine viral load monitoring. In 2030, the estimated range of patients receiving antiretroviral therapy will remain constant, but the number of patients receiving second-line antiretroviral therapy will increase to 0·8-4·6 million (6·6-19·6%). The need for second-line antiretroviral therapy was two to three times higher if routine viral load monitoring was implemented throughout the region, compared with a scenario of no further viral load monitoring scale-up. For each monitoring strategy, the future proportion of patients receiving second-line antiretroviral therapy differed only minimally between countries., Interpretation: Donors and countries in sub-Saharan Africa should prepare for a substantial increase in the need for second-line drugs during the next few years as access to viral load monitoring improves. An urgent need exists to decrease the costs of second-line drugs., Funding: World Health Organization, Swiss National Science Foundation, National Institutes of Health., (Copyright © 2016 World Health Organization. Published by Elsevier Ltd/Inc/BV. All rights reserved. Published by Elsevier Ltd.. All rights reserved.)

Background.  The hepatitis C virus (HCV) epidemic is evolving rapidly in patients infected with human immunodeficiency virus (HIV). We aimed to describe changes in treatment uptake and outcomes of incident HCV infections before and after 2006, the time-point at which major changes in HCV epidemic became apparent. Methods.  We included all adults with an incident HCV infection before June 2012 in the Swiss HIV Cohort Study, a prospective nationwide representative cohort of individuals infected with HIV. We assessed the following outcomes by time period: the proportion of patients starting an HCV therapy, the proportion of treated patients achieving a sustained virological response (SVR), and the proportion of patients with persistent HCV infection during follow-up. Results.  Of 193 patients with an HCV seroconversion, 106 were diagnosed before and 87 after January 2006. The proportion of men who have sex with men increased from 24% before to 85% after 2006 (P < .001). Hepatitis C virus treatment uptake increased from 33% before 2006 to 77% after 2006 (P < .001). Treatment was started during early infection in 22% of patients before and 91% after 2006 (P < .001). An SVR was achieved in 78% and 29% (P = .01) of patients treated during early and chronic HCV infection. The probability of having a detectable viral load 5 years after diagnosis was 0.67 (95% confidence interval [CI], 0.58-0.77) in the group diagnosed before 2006 and 0.24 (95% CI, 0.16-0.35) in the other group (P < .001). Conclusions.  In recent years, increased uptake and earlier initiation of HCV therapy among patients with incident infections significantly reduced the proportion of patients with replicating HCV.

Background: The cost-effectiveness of routine viral load (VL) monitoring of HIV-infected patients on antiretroviral therapy (ART) depends on various factors that differ between settings and across time. Low-cost point-of-care (POC) tests for VL are in development and may make routine VL monitoring affordable in resource-limited settings. We developed a software tool to study the cost-effectiveness of switching to second-line ART with different monitoring strategies, and focused on POC-VL monitoring., Methods: We used a mathematical model to simulate cohorts of patients from start of ART until death. We modeled 13 strategies (no 2nd-line, clinical, CD4 (with or without targeted VL), POC-VL, and laboratory-based VL monitoring, with different frequencies). We included a scenario with identical failure rates across strategies, and one in which routine VL monitoring reduces the risk of failure. We compared lifetime costs and averted disability-adjusted life-years (DALYs). We calculated incremental cost-effectiveness ratios (ICER). We developed an Excel tool to update the results of the model for varying unit costs and cohort characteristics, and conducted several sensitivity analyses varying the input costs., Results: Introducing 2nd-line ART had an ICER of US$1651-1766/DALY averted. Compared with clinical monitoring, the ICER of CD4 monitoring was US$1896-US$5488/DALY averted and VL monitoring US$951-US$5813/DALY averted. We found no difference between POC- and laboratory-based VL monitoring, except for the highest measurement frequency (every 6 months), where laboratory-based testing was more effective. Targeted VL monitoring was on the cost-effectiveness frontier only if the difference between 1st- and 2nd-line costs remained large, and if we assumed that routine VL monitoring does not prevent failure., Conclusion: Compared with the less expensive strategies, the cost-effectiveness of routine VL monitoring essentially depends on the cost of 2nd-line ART. Our Excel tool is useful for determining optimal monitoring strategies for specific settings, with specific sex-and age-distributions and unit costs.

Objectives: Many paediatric antiretroviral therapy (ART) programmes in Southern Africa rely on CD4⁺ to monitor ART. We assessed the benefit of replacing CD4⁺ by viral load monitoring., Design: A mathematical modelling study., Methods: A simulation model of HIV progression over 5 years in children on ART, parameterized by data from seven South African cohorts. We simulated treatment programmes with 6-monthly CD4⁺ or 6- or 12-monthly viral load monitoring. We compared mortality, second-line ART use, immunological failure and time spent on failing ART. In further analyses, we varied the rate of virological failure, and assumed that the rate is higher with CD4⁺ than with viral load monitoring., Results: About 7% of children were predicted to die within 5 years, independent of the monitoring strategy. Compared with CD4⁺ monitoring, 12-monthly viral load monitoring reduced the 5-year risk of immunological failure from 1.6 to 1.0% and the mean time spent on failing ART from 6.6 to 3.6 months; 1% of children with CD4⁺ compared with 12% with viral load monitoring switched to second-line ART. Differences became larger when assuming higher rates of virological failure. When assuming higher virological failure rates with CD4⁺ than with viral load monitoring, up to 4.2% of children with CD4⁺ compared with 1.5% with viral load monitoring experienced immunological failure; the mean time spent on failing ART was 27.3 months with CD4⁺ monitoring and 6.0 months with viral load monitoring. Conclusion: Viral load monitoring did not affect 5-year mortality, but reduced time on failing ART, improved immunological response and increased switching to second-line ART.