Introduction Sexual behaviour data are essential for monitoring sexual behavioural trends and designing effective sexual health interventions. In Singapore and other Southeast Asian countries, where research has largely focused on key populations, this study aimed to characterise sexual behaviour patterns in the general adult population and their associations with socio-demographics, engagement with sex workers and sexually transmitted infection (STI) positivity.Methods We conducted a nationwide cross-sectional survey (September 2023 to July 2024) using voluntary response sampling among adults aged ≥21 years, collecting data on socio-demographics and sexual behaviours in the past year, 6 months and 3 months. Partner numbers and sexual activity frequency were modelled using a Lomax distribution across partnered activities (mutual masturbation, oral, vaginal sex and anal sex), and associations with socio-demographics, sex worker engagement and self-reported STI positivity were evaluated using logistic regression.Results Among the 2297 eligible participants, 51.5% were male (1183) and 95.6% were aged 21–60 years (2195). Individuals reporting same-sex partners were more likely to have five or more same-sex partners in the past year. The model-estimated prevalence of engaging with sex workers among individuals aged 21–60 years in Singapore was 4.7% (95% CI 3.7 to 6.2) for females and 18.1% (95% CI 16.1 to 20.4) for males, with higher odds among those with at least five partners in the past year (eg, vaginal sex AOR=7.40, 95% CI 4.03 to 13.58). Self-reported STI positivity was associated with having at least five partners in the past year (eg, vaginal sex AOR=5.03, 95% CI 1.44 to 17.61) and ever engaging with sex workers (eg, vaginal sex AOR=3.16, 95% CI 1.67 to 5.99), but not with barrier protection frequency.Conclusions Patterns varied by sex, sexual orientation and risk behaviours, underscoring the need for context-specific behavioural data to inform STI modelling and public health interventions.

Initial investigation into the emerging mpox outbreak caused by novel monkeypox virus (MPXV) clade Ib in the eastern Democratic Republic of the Congo has identified signs of sustained human-to-human transmission and epidemiological links to sexual contacts involving female sex workers (FSWs), which have not been observed in previous clade Ia outbreaks. Using mathematical models incorporating age-dependent contact patterns, we quantified the role of frequent sexual interactions as opposed to community contacts in clade Ib's dynamics and found that this additional mode of transmission could explain its increased outbreak potential compared with clade Ia. As with the globally circulating clade IIb, which is transmitted predominantly among men who have sex with men, our findings reinforce the importance of protecting key population groups-specifically FSWs for clade Ib-in controlling ongoing mpox outbreaks.

BACKGROUND:Although tuberculosis (TB) treatment success rates are high globally, growing evidence indicates that many TB survivors experience persistent respiratory symptoms, impaired quality of life and reduced well-being after treatment completion. Delayed TB diagnosis may exacerbate these long-term consequences by prolonging untreated disease and lung injury. However, longitudinal evidence linking diagnosis delay to longer-term outcomes remains limited. This study examines the association between TB diagnosis delay and respiratory health, quality of life and mental health among TB survivors in Cambodia. METHODS:A prospective cohort study of adults with newly diagnosed TB was conducted with a baseline in 2022 and 1 year and 2 year follow-ups. TB diagnosis delay was defined as the time from symptom onset to diagnosis and categorised as short or long using the median (64 days). Outcome variables included respiratory health, quality of life and depressive symptoms, assessed with the St George's Respiratory Questionnaire for Chronic Obstructive Pulmonary Disease (SGRQ-C), WHO Quality of Life-Brief (WHOQOL-BREF) and Centre for Epidemiologic Studies Depression Scale, 10-item version (CES-D-10), respectively. Linear mixed-effects models, adjusted for potential confounders, were applied. RESULTS:Among 712 participants at baseline, the long-delay group had worse respiratory health before treatment completion and over 2 years, with higher SGRQ-C total (β=4.37, 95% CI 1.10 to 7.64), symptom (β=5.83, 95% CI 2.34 to 9.31) and activity scores (β=6.95, 95% CI 2.67 to 11.23) than the short-delay group. Long delay was also associated with poorer psychological (β=-3.17, 95% CI -5.31 to -1.03) and environmental domains (β=-1.74, 95% CI -3.07 to -0.4) of the quality of life but not with its physical and social domains or depressive symptoms. The differences between the groups remained relatively stable over time. CONCLUSIONS:TB diagnosis delay may influence recovery beyond treatment success, highlighting the importance of early case detection and integrated post-treatment support in high-burden settings.

Public health and social measures (PHSMs) are key interventions during pandemics. This study quantifies temporal changes in daily interpersonal contacts associated with PHSM implementation and their potential impact on disease transmission across different phases of the COVID-19 pandemic in Hong Kong from 2021 to 2023. We recruited 7,053 individuals from the general population and 3,462 participants from selected high-contact groups between September 2021 and December 2023. The study period spanned the infection-naïve phase before 2022 through the city’s fifth wave of COVID-19 (January–April 2022) driven by the Omicron BA.2 variant. Reported cumulative incidence was < 0.2

Background: The first human papillomavirus (HPV) vaccines were licensed in 2006. Global vaccine access and coverage have improved tremendously since then, but gaps between countries remain. To track progress over two decades of HPV vaccine rollout globally, this study aims to estimate how the magnitude and distribution of lifetime health impacts among vaccinated females have evolved from 2006 to 2024 at the global, regional, and national levels. Methods: We parameterised a previously validated static HPV vaccination model (the Papillomavirus Rapid Interface for Modelling and Economics, PRIME) with data on country-level HPV vaccine introductions, female HPV vaccination coverage, cervical cancer burden and demography to assess the lifetime vaccine-attributable reduction in cervical cancer cases, deaths, and disability-adjusted life years (DALYs) during 2006 - 2024. We explored the extent to which vaccines reached the countries with the highest disease burden at global and regional levels using concentration curves and concentration indices. Findings: Over 109 million girls were vaccinated with the HPV vaccine from 2006 to 2024. This is estimated to have already prevented 38,557 cervical cancer cases, 8,786 deaths, and 481,920 DALYs. Over the lifetime of the vaccinated cohorts, it is projected to prevent 5·92 million cases, 4·14 million deaths, and 87·76 DALYs. Initially, vaccines mainly reached countries with low disease burden, but these inequities have narrowed as more high-burden countries have included HPV vaccination in their national immunisation programme. Interpretation: The historical HPV vaccination programme over the past two decades has contributed to substantial health benefits. Inequities in vaccine coverage have narrowed but still remain. Sustained momentum is needed to broaden national HPV vaccination implementation and to ensure equitable access wherever needed.

Designing a fit-for-purpose global health architecture requires regional coordination and global alignment.

Background:The ongoing 2023-2024 mpox outbreak in several African countries, driven by the novel Clade Ib strain, has resulted in imported cases being reported in Sweden, Thailand and India. The potential high transmissibility of this new strain and shifts in transmission modes may make territories in Asia, which were minimally affected by previous mpox waves, susceptible to community-wide transmission following importation. While this highlights the importance of early preparedness, current knowledge of the virus's transmission dynamics remains too limited to effectively inform policymaking and resource planning. Methods:A compartmental model was constructed to characterise potential mpox transmission dynamics. Importation-triggered outbreaks were simulated in 37 Asian cities under scenarios with one, three and five initial local infections. The impacts of various non-pharmaceutical interventions (NPIs), including isolation and quarantine, were projected and compared. Findings:Our simulations revealed substantial disparities in outbreak sizes among the 37 Asian cities with large-scale outbreaks expected in territories with a high proportion of sexually active individuals at risk or low immunity from smallpox vaccination. Total case counts in 1 year following initial local infections would increase linearly with initial infection size. In the scenario with three initial local infections, up to 340 cases per million residents were expected without interventions. Isolation for diagnosed cases was projected to lower the outbreak size by 43.8% (IQR: 42.7-44.5%), 67.8% (IQR: 66.5-68.9%), 80.8% (IQR: 79.5-82.0%) and 88.0% (IQR: 86.8-89.1%) when it reduced interpersonal contacts by 25%, 50%, 75% and 100%, respectively. Quarantining close contacts would contribute to a further decrease in cases of up to 22 percentage points over 1 year. Interpretation:A potential mpox outbreak in an Asian setting could be alleviated through strong surveillance and a timely response from stakeholders. NPIs are recommended for outbreak management due to their demonstrated effectiveness and practicability.

The new variant of the monkeypox virus (MPXV) clade Ib has recently spread to other African countries outside the Democratic Republic of the Congo (DRC), prompting the World Health Organisation to declare the outbreak as a public health emergency of international concern (PHEIC). This comes just two years after the initial PHEIC that was issued for the clade IIb outbreaks. Compared to the clade IIb outbreaks, clade Ib shows a demographic shift, including higher case fatality rates for younger individuals, indicating a possibility of additional transmission pathways through heterosexual and household contacts. Given that many countries in the Western Pacific (WPR) and the Southeast Asian region (SEAR) hold a disproportionate burden of endemic infectious diseases and have difficulties engaging key at-risk populations, an outbreak of the potentially more virulent clade Ib virus could have devastating impacts on the health care systems. Thus, strategy planning against the potential emergence of clade Ib MPXV in the regions is required, including surveillance systems for detection, modelling studies to perform risk assessments, implementation of non-pharmaceutical interventions, and vaccination, and regional collaboration to ensure equitable distribution of vaccinations.

INTRODUCTION:In Cambodia, of all people living with HIV, 89% knew their status, 89% were receiving antiretroviral therapy (ART) and 87% had their viral load suppressed in 2023. In 2017, the national HIV programme introduced the multi-month dispensing (MMD) model to reduce visits to ART clinics, thereby reducing the burden on people living with HIV and health facilities. A quasi-experimental study introduced the community ART delivery (CAD) model, where community action workers (CAWs) delivered pre-packaged antiretrovirals to their peers in the community. This study examined the cost-effectiveness of the CAD compared to the MMD model. METHODS:This study was conducted between 2021 and 2023 and involved 2040 stable people living with HIV in the CAD arm and 2049 in the MMD arm. Baseline and endline surveys included self-reported ART adherence, quality of life, and medical and non-medical expenses. Intention-to-treat analyses (ITTs) were conducted based on participants' original treatment assignment, with multiple imputations performed for participants lost to follow-up at the endline. Incremental cost-effectiveness ratios (ICERs) on ART adherence and quality of life were generated using health system and societal perspectives. Cost-effectiveness thresholds (CETs) were one-time gross domestic product (GDP) per capita and opportunity cost. RESULTS:Both arms observed a decline in ART adherence and good physical health, with a decline in CAD less than in the MMD (p-value < 0.001). Similarly, a reduced proportion of participants reported good mental health across both arms; however, the difference was statistically insignificant. The ICERs for good physical health at the health system and societal levels were below the one-time GDP per capita (Incremental Net Benefit = 77.49-83.03) but exceeded the opportunity cost CET. The ICERs for ART adherence at the health system and societal levels were above both CETs. CONCLUSIONS:The results showed that the CAD model was cost-effective in reducing the decline in the physical health of people living with HIV during the COVID-19 pandemic in Cambodia when a less stringent threshold was used. Further investigations are required to ascertain the cost-effectiveness of the CAD model by factoring in the productivity gains within the health system. CLINICAL TRIAL NUMBER:NCT04766710.

Cambodia achieved the UNAIDS 90-90-90 targets in 2017; however, clinic congestion, stigma, and mental health disparities continue to challenge sustained HIV care. This quasi-experimental study evaluated a community-based antiretroviral therapy delivery model compared with multi-month dispensing among people living with HIV across 20 clinics (N = 4,089) from 2021 to 2023. Baseline and endline surveys and clinical data assessed treatment adherence, viral suppression, retention in care, stigma, depressive symptoms, and quality of life. Both approaches achieved high retention in care (>97%) and viral suppression rates (>99%). The community-based model showed significantly improved adherence, reduced depressive symptoms, and higher physical health-related quality of life. Modest reductions in experienced stigma were observed, but effects on internalised and anticipated stigma were inconclusive. These findings indicate that community-based antiretroviral therapy delivery effectively sustains adherence and improves health outcomes, supporting its integration into Cambodia's HIV care system alongside interventions targeting stigma reduction.

Background Countries are recommended to immunise adolescent girls routinely with one or two doses of human papillomavirus (HPV) vaccines to eliminate cervical cancer as a public health problem. With most existing vaccine doses absorbed by countries (mostly high-income) with existing HPV vaccination programmes, limited supply has been left for new country introductions until 2022; many of those, low- and middle-income countries with higher mortality. Several vaccination strategies were considered by the Strategic Advisory Group of Experts on Immunization to allow more countries to introduce vaccination despite constrained supplies. Methods We examined the impact of nine strategies for allocating limited vaccine doses to 100 pre-introduction countries from 2020 to 2030. Two algorithms were used to optimise the total number of cancer deaths that can be averted worldwide by a limited number of doses (knapsack and decreasing order of country-specific mortality rates), and an unoptimised algorithm (decreasing order of Human Development Index) were used. Findings Routinely vaccinating 14-year-old girls with either one or two doses and switching to a routine 9-year-old programme when supply is no longer constrained could prevent the most cervical cancer deaths, regardless of allocation algorithm. The unoptimised allocation averts fewer deaths because it allocates first to higher-income countries, usually with lower cervical cancer mortality. Interpretation To optimise the deaths averted through vaccination when supply is limited, it is important to prioritise high-burden countries and vaccinating older girls first. Funding WHO, Bill & Melinda Gates Foundation.

Background The COVID-19 pandemic both relied and placed significant burdens on the experts involved from research and public health sectors. The sustained high pressure of a pandemic on responders, such as healthcare workers, can lead to lasting psychological impacts including acute stress disorder, post-traumatic stress disorder, burnout, and moral injury, which can impact individual wellbeing and productivity. Methods As members of the infectious disease modelling community, we convened a reflective workshop to understand the professional and personal impacts of response work on our community and to propose recommendations for future epidemic responses. The attendees represented a range of career stages, institutions, and disciplines. This piece was collectively produced by those present at the session based on our collective experiences. Results Key issues we identified at the workshop were lack of institutional support, insecure contracts, unequal credit and recognition, and mental health impacts. Our recommendations include rewarding impactful work, fostering academia-public health collaboration, decreasing dependence on key individuals by developing teams, increasing transparency in decision-making, and implementing sustainable work practices. Conclusions Despite limitations in representation, this workshop provided valuable insights into the UK COVID-19 modelling experience and guidance for future public health crises. Recognising and addressing the issues highlighted is crucial, in our view, for ensuring the effectiveness of epidemic response work in the future.

Background While human papillomavirus (HPV) vaccines have been available since 2006, the coverage has varied among countries. Our aim is to analyse the equity impact of HPV vaccination on the lifetime projections of cervical cancer burden among vaccinated cohorts of 2010–22 in 84 countries. Methods We used WHO and UNICEF estimates of national immunisation coverage for HPV vaccination in 84 countries during 2010–22. We used PRIME (Papillomavirus Rapid Interface for Modelling and Economics) to estimate the lifetime health impact of HPV vaccination on cervical cancer burden in terms of deaths, cases, and disability-adjusted life years (DALYs) averted by vaccination in their respective countries. We generated concentration indices and curves to assess the equity impact of HPV vaccination across 84 countries. Findings The health impact of HPV vaccination varied across the 84 countries and ranged from Switzerland to Tanzania at 2 to 34 deaths, 4 to 47 cases, and 40 to 735 DALYs averted per 1000 vaccinated adolescent girls over the lifetime of the vaccinated cohorts of 2010–22. The concentration index for the distribution of average coverage during 2010–22 among the 84 countries ranked by vaccine impact was 0.33 (95% CI: 0.27–0.40) and highlights the wide inequities in HPV vaccination coverage. Interpretation Our findings suggested that countries with a relatively higher cervical cancer burden and thereby a relatively higher need for HPV vaccination had relatively lower coverage during 2010–22. Further, there were significant inequities in HPV vaccination coverage within the Americas, Europe, and Western Pacific regions, and in high- and low-income countries with a pro-advantaged and regressive distribution favouring countries with lower vaccine impact. Funding Gavi, the Vaccine Alliance; Bill & Melinda Gates Foundation.

Background While human papillomavirus (HPV) vaccines have been available since 2006, the coverage has varied among countries. Our aim is to analyse the equity impact of HPV vaccination on the lifetime projections of cervical cancer burden among vaccinated cohorts of 2010-22 - 22 in 84 countries. Methods We used WHO and UNICEF estimates of national immunisation coverage for HPV vaccination in 84 countries during 2010-22. - 22. We used PRIME (Papillomavirus Rapid Interface for Modelling and Economics) to estimate the lifetime health impact of HPV vaccination on cervical cancer burden in terms of deaths, cases, and disability-adjusted life years (DALYs) averted by vaccination in their respective countries. We generated concentration indices and curves to assess the equity impact of HPV vaccination across 84 countries. Findings The health impact of HPV vaccination varied across the 84 countries and ranged from Switzerland to Tanzania at 2 to 34 deaths, 4 to 47 cases, and 40 to 735 DALYs averted per 1000 vaccinated adolescent girls over the lifetime of the vaccinated cohorts of 2010-22. - 22. The concentration index for the distribution of average coverage during 2010-22 - 22 among the 84 countries ranked by vaccine impact was 0.33 (95% CI: 0.27-0.40) - 0.40) and highlights the wide inequities in HPV vaccination coverage. Interpretation Our fi ndings suggested that countries with a relatively higher cervical cancer burden and thereby a relatively higher need for HPV vaccination had relatively lower coverage during 2010-22. - 22. Further, there were significant fi cant inequities in HPV vaccination coverage within the Americas, Europe, and Western Pacific fi c regions, and in high- and low-income countries with a pro-advantaged and regressive distribution favouring countries with lower vaccine impact. Funding Gavi, the Vaccine Alliance; Bill & Melinda Gates Foundation. Copyright (c) 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Background:The COVID-19 pandemic both relied and placed significant burdens on the experts involved from research and public health sectors. The sustained high pressure of a pandemic on responders, such as healthcare workers, can lead to lasting psychological impacts including acute stress disorder, post-traumatic stress disorder, burnout, and moral injury, which can impact individual wellbeing and productivity. Methods:As members of the infectious disease modelling community, we convened a reflective workshop to understand the professional and personal impacts of response work on our community and to propose recommendations for future epidemic responses. The attendees represented a range of career stages, institutions, and disciplines. This piece was collectively produced by those present at the session based on our collective experiences. Results:Key issues we identified at the workshop were lack of institutional support, insecure contracts, unequal credit and recognition, and mental health impacts. Our recommendations include rewarding impactful work, fostering academia-public health collaboration, decreasing dependence on key individuals by developing teams, increasing transparency in decision-making, and implementing sustainable work practices. Conclusions:Despite limitations in representation, this workshop provided valuable insights into the UK COVID-19 modelling experience and guidance for future public health crises. Recognising and addressing the issues highlighted is crucial, in our view, for ensuring the effectiveness of epidemic response work in the future.

Prophylactic drugs against dengue are currently under development. In this study, we explored how such prophylactic approaches might affect dengue cases in four communes of Nha Trang City, Vietnam. A community level dengue transmission survey indicated high levels of previous exposure to dengue (89.7%; 95% CI: 87.2,92.0). We fitted a spatially explicit model to an observed outbreak and simulated likely effectiveness of Case-Area Targeted Interventions (CATI) and One-Time Mass Distribution (OTMD) of drug and vector control strategies. Increasing radius and effectiveness and decreasing delay of CATI was most effective, with drugs being more effective in averting dengue cases than vector control. Using an OTMD approach early in the outbreak required the least number of treatments to avert a case, suggesting that OTMD strategies should be considered as pre-emptive rather than reactive strategies. These findings show that pre-emptive interventions can substantially reduce the burden of dengue outbreaks in endemic settings.

Globally, gender-neutral Human Papillomavirus (HPV) vaccination programmes are gaining traction. Although cervical cancer remains the most prevalent, other HPV-related cancers are increasingly recognised as important, especially among men who have sex with men. We assessed if including adolescent boys in Singapore's school-based HPV vaccination programme is cost-effective from the healthcare perspective. We adapted a World Health Organization-supported model, Papillomavirus Rapid Interface for Modelling and Economics, and modelled the cost and quality-adjusted life years (QALY) associated with vaccinating 13-year-olds with the HPV vaccine. Cancer incidence and mortality rates were obtained from local sources and adjusted based on the expected direct and indirect vaccine protection for various population subgroups at an 80 % vaccine coverage. Moving to a gender-neutral vaccination programme with a bivalent or nonavalent vaccine could avert 30 (95 % uncertainty interval [UI]: 20-44) and 34 (95 % UI: 24-49) HPV-related cancers per birth cohort, respectively. At a 3 % discount rate, a gender-neutral vaccination programme is not cost-effective. However, with a 1.5 % discount rate, which puts more value on long-term health gains from vaccination, moving to a gender-neutral vaccination programme with the bivalent vaccine is likely cost-effective, with an incremental cost-effectiveness ratio of SGD$19 007 (95 % UI: 10 164-30 633) per QALY gained. The findings suggest the need to engage experts to examine, in detail, the cost-effectiveness of gender-neutral vaccination programmes in Singapore. Issues of drug licensing, feasibility, gender equity, global vaccine supplies, and the global trend towards disease elimination/eradication should also be considered. This model provides a simplified method for resource-strapped countries to gain a preliminary estimate of the cost-effectiveness of a gender-neutral HPV vaccination programme before investing resources for further research.

AbstractBackgroundUnderstanding context-specific determinants of antiretroviral therapy (ART) adherence is crucial for developing tailored interventions for improving health outcomes and achieving the UNAIDS’ third 95% target. This cross-sectional study explores factors associated with ART adherence among stable people living with HIV on ART in Cambodia.MethodsWe used baseline survey data from a quasi-experimental study conducted in 2021. The participants were recruited from 20 ART clinics in nine provinces for face-to-face interviews. A structured questionnaire collected information on sociodemographic characteristics, ART adherence, perceived ART self-efficacy, mental health, quality of life, stigma, and discrimination. We conducted bivariate and multiple logistic regression analyses to identify factors associated with ART adherence.ResultsOut of the 4101 participants, 86.5% reported adhering to ART in the past two months. The adjusted odds of ART adherence were significantly higher among participants in older age groups than those aged 15–29, participants with elevated cholesterol than those without it, participants who exhibited strong self-efficacy in health responsibility to maintain life than those with poor self-efficacy in health responsibility, participants who scored < 3 on the stigma and discrimination scale than those who scored ≥ 3, participants who scored ≥ 42 on the mental component of the quality-of-life scale than those who scored < 42. The adjusted odds of ART adherence were significantly lower in participants who earned > 301 USD per month than those who earned ≤ 100 USD per month.ConclusionThe ART adherence rate among stable people living with HIV in this study was comparable to that of the general people living with HIV in Cambodia. The results suggest the need for innovative interventions to further reduce stigma and discrimination and strategies to improve the self-efficacy and mental health of people living with HIV to improve ART adherence.