BACKGROUNDUp-to-date estimates of chronic hepatitis B virus (HBV) prevalence in both general and key populations are challenging to obtain because of underdiagnosis, heterogeneous surveillance systems and underrepresentation of key populations.AIMWe aimed to test the Workbook Method to estimate chronic HBV prevalence in 2022 across the EU/EEA, by country and among men who have sex with men (MSM), people who inject drugs (PWID) and migrants.METHODSWe used the Robert Koch Institute's version of the Joint United Nations Programme on HIV/AIDS (UNAIDS) Workbook Method to generate HBV prevalence estimates for each EU/EEA country and for MSM, PWID and migrants within each country. We combined data on population size and HBV prevalence for each population group gathered from scientific sources and reviewed by the European Centre for Disease Prevention and Control's hepatitis national contact points.RESULTSOverall, 0.7% (lower bound-upper bound: 0.5-0.9%) of the EU/EEA population (3,226,000 (2,397,000-4,149,000) individuals) were estimated to be living with HBV in 2022. National HBV prevalence ranged from 0.1% (0.1-1.0%) to 3.1% (2.8-3.3%). Prevalence estimates varied from 0.8% (0.5-1.0%) to 10.5% (9.3-11.9%) for migrants, < 0.1% to 8.7% (lower and upper bounds not available) for PWID and from < 0.1% (< 0.1- < 0.1%) to 10.5% (10.2-10.8%) for MSM.DISCUSSIONDespite limitations, including the inability to address overlapping populations, these estimates confirm substantial chronic HBV prevalence in the EU/EEA, with considerable variation between countries and population groups. This relatively straightforward method offers an alternative means of generating HBV prevalence estimates.

BACKGROUNDMany countries use school-based vaccination for adolescent vaccination; it has been shown to reduce inequities in uptake compared with other delivery routes. In England, coverage for human papillomavirus (HPV), meningococcal groups A, C, W and Y (MenACWY) and tetanus, diphtheria and inactivated polio virus (Td/IPV) vaccine programmes exceeded 80% before the COVID-19 pandemic. However, recent data show declining uptake.AIMThis study examined the relationship between socio-economic deprivation and coverage over time.METHODSWe conducted an ecological analysis of first-dose coverage for HPV (females and males), MenACWY and TdIPV in adolescents across 150 local authorities in England from 2017 to 2024. Coverage data were linked to 2025 Index of Multiple Deprivation (IMD) scores. Associations between IMD quintile, academic year and vaccination coverage were estimated using beta regression models.RESULTSBetween 2020 and 2024, lower coverage was consistently associated with higher deprivation, and differences in coverage between the most and least deprived IMD quintiles more than doubled. In 2024 these differences were 17.7%, 18.2%, 16∙8% and 16.9% for HPV (females), HPV (males), MenACWY and Td/IPV, respectively. The consistency of these findings suggests the effect of deprivation on coverage is not vaccine-specific.CONCLUSIONWe demonstrated a consistent and strengthening association between coverage and deprivation across multiple adolescent school-based vaccination programmes in England over time. Contributory factors may be numerous, and further research is needed to understand which factors are driving trends for different populations. Addressing these inequalities will require sustained targeted interventions to improve awareness of and access to vaccination.

Ongoing monitoring of hepatitis C virus (HCV) and HIV incidence among people who inject drugs (PWID) is important for epidemic control and assessing progress towards disease elimination. We estimated trends in HIV and HCV infection incidence in a community-based cohort of PWID in Montreal, Canada. Data from March 2011 to March 2025 were drawn from the HEPCO study of PWID aged ≥ 18 years and living in Montreal. Participants with at least two visits were included in analyses. We used a random point approach to estimate the date of each infection event, imputing each date 1000 times, and Rubin's rules to pool incidence rates and 95% CIs across imputations. A total of 743 participants contributed to HCV analyses, with 152 infection events and incidence of 6.47 per 100 person-years (p-y) (95% CI 6.46-6.49). Incidence peaked in 2013 and declined to 2019 before increasing again post-pandemic. There were 61 primary HCV infection events (incidence: 6.15 per 100 p-y; 95% CI 4.79-7.90) and 91 reinfection events (incidence: 6.71 per 100 p-y; 95% CI 6.69-6.73). A total of 836 participants contributed to HIV analysis, with only eight infections over 3089.89 p-y (incidence: 0.26 per 100 p-y; 95% CI 0.13-0.52). Declining HCV incidence among PWID in Montreal may have reversed, but limited data collection during the years 2020-2021 complicates interpretation. HIV incidence was persistently low. HCV incidence remains above World Health Organization elimination targets, highlighting the need for sustained investment in prevention and linkage to care for PWID.

Pre-exposure prophylaxis (PrEP) is a powerful HIV infection prevention tool. We aimed to determine how PrEP users evaluated its impact on different aspects of their sex life. We elaborated and disseminated an online questionnaire on social media and through billboards in consultation waiting rooms of sexually transmitted infection clinics or hospital infectious diseases units. The questionnaire featured nine questions from the New Sexual Satisfaction Scale and seven further questions to explore participants' experience. Participants were also asked to evaluate their sex life under PrEP on a 0-100 scale and the negative/positive impact of PrEP on their sex life on a - 100 to + 100 scale. Lastly, participants were asked the extent to which PrEP modified their self-esteem and whether different parts of the PrEP program were important. The study included 459 persons currently on PrEP: 95.4% were males and 92.4% were men having sex with men. Median age was 39 years. Most initiated PrEP in 2020 or afterwards. Most participants reported a positive impact of PrEP, particularly regarding "my 'letting go' during sex," "my emotional opening up during sex," "my mood after sexual activity," and "the quality of my orgasms." A total of 81.7% agreed that "Overall, my sex life has improved under PrEP". Participants evaluated the quality of their sex life as 80 (IQR 70-90) and the impact of PrEP as 80 (IQR 50-95). A total of 51.1% Considered that PrEP had improved their self-esteem. In conclusion, PrEP users report it improved their sex life. This should be mentioned when proposing PrEP.

Sexually transmitted infections (STIs) constitute a significant public health concern, with an increasing incidence in recent years. The management of these infections among the adolescent population represents a current challenge and should be based in comprehensive educational interventions (such as access to comprehensive sexuality education from early childhood and specialized training in sexual health for health care professionals), preventive strategies (including access to vaccination, implementation of pre- and post-exposure prophylaxis programs, and organized STI screening initiatives), and ensuring free, confidential access to public health care services for adolescents. This approach facilitates timely and appropriate diagnosis and treatment, thereby preventing complications and reducing the stigma associated with these infections. This document describes the main advances in the management of sexually transmitted infections in the adolescent population, with an analysis of the specific characteristics of this vulnerable group.

The genetic diversity of Human Papillomavirus (HPV) poses challenges for molecular detection and genotyping, particularly in regions with distinctive circulating variants such as South America. This study aimed to quantitatively characterize HPV genomic variability using Shannon entropy (H) and to establish a reproducible framework for systematic variability assessment. Positional entropy was calculated across complete and partial HPV genomic sequences and aggregated by gene to compare intra- and intergenotypic conservation patterns using publicly available South American sequences. Intragenotypic analyses showed that most genomic positions were highly conserved (H ≈ 0), consistent with functional constraints. In contrast, intergenotypic comparisons revealed a dual pattern of variability: early genes E5, E6, and E7 displayed higher divergence, whereas capsid genes L1 and L2 were comparatively conserved. These patterns align with known functional and evolutionary constraints across HPV genes. Rather than proposing diagnostic implementations, these results provide a quantitative basis for the preliminary prioritization of conserved and variable genomic regions. Entropy profiling provides a quantitative framework for characterizing genomic variability and may support the identification of conserved and variable regions for future investigation and genomic surveillance efforts, although experimental validation is required to determine diagnostic performance. Overall, this work presents a reproducible and data-driven approach for assessing HPV genomic variability and contributes to the understanding of regional viral diversity in South America.

Frontline healthcare workers providing HIV services to children, adolescents and their families in Africa face significant stressors and well-being related challenges. These in turn may also impact their ability to provide high-quality, compassionate care. Despite healthcare providers' central role in the delivery of care and support for others, there is limited research exploring their well-being and self-care. This study examined the well-being and self-care-related challenges and needs among healthcare workers providing HIV services to children, adolescents and their caregivers in Africa. A qualitative study design was employed, including participatory priority-setting and focus group discussions with 801 providers across 24 sites in 12 high HIV-prevalence African countries. Data were thematically analysed and Orem's Theory of Self-Care and the Self-Care Matrix were employed to guide the interpretation and organization of findings. The study identified four major themes. First, participants described burnout and personal struggles as well-being related challenges. Second, they described the belief that addressing these challenges was important for their own well-being, as well as the well-being of their patients. Third, awareness of healthcare worker well-being, alongside effective communication are important contributors to a healthier workforce. Lastly, several interventions were suggested, including fostering teamwork, providing education, and offering psychosocial support within the workplace. Findings emphasize the critical need for tailored interventions that can inform future practices and strategies for healthcare worker well-being. Ultimately, these interventions are crucial for better supporting healthcare providers, enhancing their well-being, and addressing the ongoing challenges in HIV care to children and adolescents in Africa.

This supplement presents scientific reports from industry-sponsored IDWeek 2025 symposia, highlighting selected advances in infectious diseases and HIV care through clinical case scenarios. One article explores therapeutic approaches to metabolic complications in people with HIV, emphasizing treatment strategies and the clinical reasoning that supports individualized management of excess adiposity. The second examines the clinical integration of metagenomic next-generation sequencing for diagnosing central nervous system infections, outlining both its opportunities and limitations within current diagnostic pathways.