The Lancet Regional Health - Western Pacific

BackgroundCOVID-19 non-pharmaceutical interventions (NPIs) disrupted transmission of many infectious diseases worldwide. While disruption patterns are well-documented, systematic analysis of post-pandemic recovery trajectories across diverse pathogens remains limited. We examined disruption and recovery of 47 nationally notifiable diseases in Australia from 2015 to 2025. MethodsWe analysed NNDSS surveillance data for 47 diseases across six transmission modes, quantifying disruption using observed-to-expected (O/E) ratios against 2015-2019 baselines. We applied difference-in-differences (DiD) to estimate causal NPI effects, Kaplan-Meier survival analysis for time-to-recovery, and bootstrap 95% confidence intervals for cumulative immunity debt. ResultsDuring 2020-2021, 28 diseases decreased (median O/E 0.51), with border-sensitive and vaccine-preventable diseases most affected. DiD analysis estimated that border closures were associated with significantly greater suppression among import-dependent diseases (coefficient -0.50, 95% CI -0.90 to -0.10, p=0.016). By 2025, recovery was heterogeneous: 17 diseases exceeded baseline levels, 12 returned to expected levels, 15 remained below baseline (9 partially recovered, 6 in sustained suppression), and 3 had insufficient data for trajectory classification. Five diseases showed suppression-then-overshoot trajectories suggestive of immunity debt, though bootstrap 95% confidence intervals confirmed statistically significant cumulative excess for only one (rotavirus); for influenza, high baseline variability precluded statistical confirmation despite a large absolute overshoot. ConclusionsPost-pandemic disease recovery in Australia is heterogeneous and incomplete. Fifteen of 47 diseases have not returned to baseline levels by 2025, while 17 exhibit overshoot. These findings argue for differentiated surveillance of still-suppressed diseases and targeted catch-up vaccination in pandemic birth cohorts. Article summaryWe analysed disruption and recovery of 47 nationally notifiable diseases in Australia from 2015 to 2025, finding that 15 diseases remain below pre-pandemic levels three years after NPI relaxation. Border closures caused disproportionate suppression of import-dependent diseases, and recovery trajectories varied by disease characteristics, with immunity debt statistically confirmed for only one of five candidate diseases.

Understanding the burden of pertussis and pertussis-related mortality is important in enabling better understanding of population vulnerability and supporting vaccination programme planning. However, changes in laboratory practice can have important implications for public health surveillance. This study considers the impact of increasing use of multiplex panel testing for respiratory pathogens on ascertainment of pertussis-related deaths, drawing on multiple surveillance data sources from England. Information was sourced from Office of National Statistics cause of death records, public health case management records, laboratory results collated nationally, and death notifications received via General Practices. Figures covered the period 2023/24, coinciding with a large, national outbreak in England, and were compared with data from 2012 - the last major outbreak in England. Of 34 deaths identified among individuals aged >12 months in 2023/24, 11 ultimately met pre-defined criteria to be classified as pertussis-related deaths; none of the 5 possible cases identified in 2012 did so. A total of 25 of the 34 (74%) tested positive for pertussis via multiplex panel testing, of which 18 (72%) were ultimately excluded as pertussis-related deaths. Findings highlight significant challenges in attribution of pertussis-related mortality in an era of widespread multiplex panel testing.

IntroductionSporadic colorectal cancer (CRC) remains a significant driver of worldwide morbidity and mortality. Environmental factors associated with CRC are increasingly well-described and now include generalized colonic dysbiosis and individual enteric bacteria. Clostridioides difficile is one such species, with recent mouse model work suggesting prolonged exposure to C. difficile toxin B is conducive to colonic tumorigenesis. However, there is a dearth of real-world human evidence linking C. difficile infection and CRC. MethodsHerein, we analyzed a multicenter, longitudinal, Electronic Health Record (EHR)-based dataset to test the association between C. difficile test positivity and the risk for incident CRC utilizing unadjusted and multivariable (controlled for clinical conditions independently associated with CRC development) Cox proportional hazard modeling to compare C. difficile exposed and non-exposed cohorts ResultsWe found that individuals who tested recurrently positive for C. difficile had a significantly increased risk for incident CRC (aHR 2.05 [95% CI 1.27-3.29]) compared with those who tested positive only once (aHR 0.70 [0.45-1.10]) or never. Furthermore, we found potential trends that the effect of C. difficile test positivity on the risk for incident CRC was stronger amongst females compared with males. ImportanceThese findings help translate emerging mouse model work on C. difficile-influenced colorectal tumorigenesis and lay groundwork for more substantial human investigations into this connection. These findings also may begin to help guide the personalized deployment of novel fecal microbiota-based therapies designed to interrupt the life cycle of C. difficile within the gut of human hosts and, potentially, prevent long-term health sequelae of chronic C. difficile infection.

The gut microbiome composition varies across human populations, but its characteristics and determinants in a multi-ethnic setting remain incompletely understood. Singapore, a multicultural city-state, provides a context in which culturally diverse groups share a broadly similar built environment. Using the Health for Life in Singapore (HELIOS) cohort, we profiled the gut microbiome of ethnic Chinese, Indian, and Malay participants (n=861) who resided in the country. Despite substantial overlap in the overall microbial compositions, each group displayed distinct microbial signatures that paralleled culturally rooted dietary habits. Specifically, ethnic Indian participants showed enrichment of multiple Bifidobacterium species associated with greater intake of traditional grain-based staples such as idli and thosai; ethnic Malay participants exhibited higher abundance of Ruminococcaceae associated with coconut-and rice-based dishes; and ethnic Chinese participants had greater levels of Bacteroides associated with seafood- and meat-rich diets. These ethnicity-diet-microbiome relationships were further corroborated by additional data from two independent Malaysian cohorts (n=544), a cohort from the United States (n=210), and an in vitro microbial culture model showing selective Bifidobacterium expansion by a fermented rice-based batter. Analysis of fecal microbiome-based risk scores revealed ethnic gradients in colorectal neoplasia scores that mirrored population-level cancer incidence patterns. Together, these findings characterize gut microbiome variations across major Asian ethnicities residing in a shared urban environment, providing a reference for precision health strategies relevant to over two billion ethnically relevant people in the Asia-Pacific region and beyond.

Introduction Heat waves are increasingly frequent and linked to higher mortality risks in Hong Kong. However, estimates of total excess mortality associated with heat waves remain unavailable. This study quantifies excess deaths associated with heat waves in Hong Kong from 2014 to 2023. Methods Daily age- and sex-specific mortality rates and population data were obtained from the Hong Kong Life Tables and Census and Statistics Department. Temperature data came from the Hong Kong Observatory, and relative risks were derived from local research. A Monte Carlo simulation was used to estimate heat-attributable deaths under different heat wave definitions, calculating total excess deaths and annualized death rates per 100,000 population. Results Between 2014 and 2023, heat exposure resulted in an estimated 1,455 (95% CI: 1,098-1,812) to 3,238 (95% CI: 3,234-3,242) excess deaths. In 2023, annualized excess death rates ranged from 2.95 (95% CI: 2.41-3.50) to 5.09 (95% CI: 5.07-5.12) per 100,000 people. Males and individuals aged 65 or older were disproportionately affected. Conclusion Over the 10-year study period, 1,455 to 3,238 excess deaths in Hong Kong were attributed to extreme heat. Heat waves now rank among the top ten causes of death in Hong Kong, with mortality rates comparable to diabetes. These findings underscore the need for urgent public health interventions to mitigate the impact of extreme heat.

This study evaluated awareness and preference for Human Papillomavirus (HPV) self-collection for cervical screening among Aboriginal and Torres Strait Islander screen-eligible participants. A whole-of-population online survey was conducted between December 2023 and April 2024, with responses from 555 Aboriginal and Torres Strait Islander women and people with a cervix. Around 80% of survey participants had heard of self-collection, with healthcare providers the most mentioned source of this knowledge. Never-screened participants were less likely to have heard of self-collection and more likely to report traditional (n=18, 23%) and social media (n=12, 15%) as sources of knowledge of self-collection compared to their healthcare provider (n=13, 16%). Most never-screened participants said self-collection would make them more likely to have a cervical screening test (n=59, 75%). Overall, 275 participants indicated a clear preference for self-collection (50%). Screening history was significantly associated with a preference for self-collection, with Aboriginal and Torres Strait Islander women and people with a cervix who did not screen regularly (adjusted odds ratio [adjOR]=1.9, 95% confidence interval [95%CI]=1.2-3.0, p<0.01), who had never screened (adjOR=3.5, 95%CI=1.8-6.9, p<0.001), or who lived in regional or remote areas (ajdOR=1.6, 95%CI=1.0-2.5, p=0.03) significantly more likely to prefer self-collection. Age, educational attainment and sexuality did not influence preference in the model. These findings indicate a clear preference for self-collection among under- and never-screened Aboriginal and Torres Strait Islander women and people with a cervix. Despite this, never-screened participants were less likely to have heard of this option. There is an opportunity to reach clients who have never screened or are overdue for cervical screening by raising awareness of self-collection. Other than remoteness, sociodemographic characteristics were not associated with a preference for self-collection, reinforcing the need to offer all eligible clients the choice of collection methods.

BackgroundColorectal carcinoma (CRC) remains a significant cause of cancer morbidity and mortality worldwide. Right- and left-sided tumours differ in clinical, morphological, and molecular features. Microsatellite instability-high (MSI-H) tumours, often right-sided, are associated with distinct histopathological characteristics and prognostic implications. In Sri Lanka, molecular MSI testing is currently unavailable, highlighting the need for alternative predictive approaches. ObjectivesGeneral Objective: To describe the clinical and histopathological characteristics of right- and left-sided colorectal cancers in a Sri Lankan cohort and evaluate their usefulness in predicting MSI-H tumours. Specific ObjectivesTo compare clinicopathological features between right- and left-sided colorectal cancers. To predict MSI-H tumours based on clinicopathological features, including assessment of the MsPath score and histological parameters. To determine interobserver agreement for MsPath score application in selecting cases for MSI assessment. MethodsA retrospective analytical study was conducted on 156 colorectal carcinoma resections diagnosed between 2019 and 2021 at the National Hospital of Sri Lanka. Histopathological evaluation included tumour differentiation, mucinous and medullary features, tumour-infiltrating lymphocytes (TILs), and Crohn-like reaction. MsPath scores were calculated based on age, tumour site, and histological parameters. Immunohistochemistry (IHC) for PMS2 and MSH6 was performed on 46 selected cases to assess mismatch repair (MMR) status. ResultsOf 156 cases, 41 (26%) were right-sided and 115 (74%) left-sided. The majority were moderately differentiated adenocarcinomas (89%). Histological features suggestive of MSI-H including TILs (29%) and Crohn-like lymphoid reaction (23%) were more frequent in right-sided tumours. MsPath scores ranged from 0.0 to 5.9, with 50% of cases scoring below 1. Among the 46 cases evaluated by IHC, MMR deficiency was observed predominantly in higher MsPath score categories, and a significant association was found between MsPath score category and MMR status ({chi}{superscript 2} = 13.76, df = 2, p = 0.001). Interobserver agreement for MsPath scoring was substantial (Kappa = xx, indicating reproducibility). ConclusionRight-sided colorectal carcinomas in this Sri Lankan cohort more frequently exhibited histological features suggestive of MSI-H, including mucinous differentiation, TILs, and Crohn-like lymphoid reaction. MsPath scoring correlated with MMR deficiency in the IHC-tested subset, but its predictive value is limited without immunohistochemical confirmation. IHC using a two-antibody panel (PMS2 and MSH6) proved to be a feasible, cost-effective, and reliable method for MSI screening in resource-limited settings. This study is the first comprehensive evaluation of right-versus left-sided colorectal carcinomas and MsPath utility in Sri Lanka, underscoring the need for expanded IHC capacity, larger cohorts, and integration of molecular testing for MSI validation.

Dengue virus (DENV), comprising four distinct serotypes (DENV-1 to DENV-4), poses a major public health challenge in tropical regions. Infection with one serotype confers long-term immunity to that serotype alone, while subsequent heterologous infections are associated with increased risk of severe disease, necessitating vaccines that induce durable, balanced immunity across all serotypes. However, achieving such balance immunity remains a central challenge for dengue vaccine development. Using passive surveillance data from Kamphaeng Phet, Thailand (2004-2022), we characterized long-term serotype circulation and contributions to clinical dengue burden in a hyperendemic setting. We observed sustained co-circulation of all four serotypes over nearly two decades, with periodic shifts in dominant serotype. Among 6,840 PCR-confirmed dengue cases, the majority of which were hospitalized, DENV-1 through DENV-4 accounted for 32.8%, 25.9%, 24.8%, and 16.5% of detected dengue cases, respectively. Compared with DENV-1, clinically-apparent DENV-2 and DENV-4 infections were more likely to represent secondary infections (odds ratio 4.94 and 5.24, respectively) and occurred at older ages, underscoring the context-dependent clinical expression of different serotypes. Together, these findings demonstrate that all four dengue serotypes contribute meaningfully to clinical disease burden in Thailand and caution against de-emphasizing individual serotypes based on transient epidemiologic patterns. These results reinforce the importance of tetravalent vaccine strategies alongside continued evaluation of vaccine performance in evolving epidemiologic settings. Author SummaryDengue is a mosquito-borne disease that infects millions of people every year. The virus consists of four serotypes. Infection with one serotype does not provide full protection against the others, and a second infection with a different serotype can increase the likelihood of severe illness. For this reason, understanding which serotypes are circulating is important for designing and evaluating effective vaccines. Our analysis of nearly two decades of surveillance data from Kamphaeng Phet, Thailand demonstrates that all four serotypes were consistently present over time, each contributing a substantial number of cases. The serotypes showed distinct age- and immunity-dependent epidemiologic patterns. No single serotype could be considered unimportant. These findings highlight the complex nature of DENV transmission in Thailand and emphasize the need for vaccines that provide protection against all four serotypes. Continuous monitoring of circulating serotypes is essential to guide vaccine development and to ensure their effectiveness in real-world settings.

BackgroundThis study of Malawian children with rheumatic heart disease (RHD) sought to detect demographic, clinical, and echocardiographic risk factors for mortality. MethodsPediatric patients with RHD were recruited from March to October, 2018 from clinic rosters and inpatient consults in Lilongwe and Blantyre, Malawi. An echocardiogram was performed upon study enrollment. Cox regression analyses were performed to assess for factors associated with mortality over nearly 2 years of follow-up. ResultsOf 118 patients, nearly two-thirds were female (64.4%) and median age was 12 (IQR 10-14). Just under half (47.0%) lived >40km from a tertiary care center. There was a high prevalence of severe mitral regurgitation (65.3%), and pericardial effusion was present in 18.6%. Nearly a quarter (23.7%) died during follow-up. In univariable Cox regression, living >40km from tertiary care, living in a remote area, moderate or severe malnutrition, taking a beta blocker, severe mitral stenosis, any severe valve disease, severe left atrial enlargement, and presence of a pericardial effusion were statistically significant risk factors for mortality (p<0.05). In the adjusted model, living >40km from tertiary care (HR 2.66, CI 1.06-6.07, p=0.037), malnutrition (mild HR 3.92, CI 1.03-14.91, p=0.045); moderate HR 7.41, CI 1.92-28.54, p=0.004; severe HR 4.91, CI 1.44-16.71, p=0.011), beta blocker use (HR 4.62, CI 1.63-13.10, p=0.004), and presence of a pericardial effusion (HR 6.96, CI 3.00-16.13, p<0.001) remained independent risk factors for mortality. ConclusionsThis study of Malawian children emphasizes the dire prognosis of RHD in under-resourced settings and provides potential area of focus for targeted intervention.

Influenza forecasting in (sub-)tropical regions remains understudied due to year-round, irregular transmission patterns. Further, the variation in seasonality and transmission characteristic of influenza in post-COVID-19 pandemic could be attributed to various drivers to quantify for better understanding. To address this issue, this study introduced an ensemble forecasting approach that incorporates varied dataset lengths to forecast influenza activity in Hong Kong, integrating multi-stream surveillance data, including absolute humidity, temperature, ozone, and school closures/holidays. We applied temporal cross-validation to evaluate forecasting performance for short- and long term separately across different training-sets and model variants, ultimately constructing ensemble forecasts weighted by individual model performance. The optimal ensemble model could forecast the 2019/20 winter influenza season onwards and evaluate the impact of COVID-19 public health and social measures (PHSMs). We further extended the framework to forecast influenza in post-pandemic period since March 2023, accounting for the impact of cessation of PHSMs and COVID-19-induced cross-protection/competition in population susceptibility. Forecasts showed two peaks in 2019/20 season, which could account for 95.2% (95% prediction interval (PI): 89.1%, 98.3%) reduction in attack rate for COVID-19 PHSMs. The post-pandemic forecasts indicated changes in influenza transmission dynamics and seasonality, highlighting the need to consider factors such as population immunity and co-circulation with COVID-19 in future influenza forecasts. This study emphasizes the importance of incorporating diverse factors for better influenza forecasts in (sub-)tropical regions. The proposed framework offers a scalable tool for forecasting other respiratory virus transmissions, supporting healthcare agencies in managing future infection burdens and enhancing preparedness. Author summaryReliable and proactive forecasts of influenza activity and timing of epidemic outcomes enable public health officials to plan targeted responses. However, unlike temperate locations, the irregular seasonality of influenza in tropical/subtropical locations leads to highly variable forecasting patterns when models use varying lengths of historical data, reducing the robustness of forecasts. By leveraging multi-stream surveillance data in Hong Kong, we developed a mechanistic model-based ensemble forecasting framework that integrate potential combinations of data and models for short-, medium-, and long-term forecasts of influenza outcomes. Beyond methodological advancement, this framework has broader implications in assessing the impact of COVID-19-related interventions on influenza dynamics during pandemic and evaluating potential co-circulation risk of respiratory viruses including influenza and COVID-19 in post-pandemic era.

Accurate quantification of individual exposure to air pollutants remains a major challenge in environmental health, as fixed-site monitoring fails to account for mobility, indoor environments, and physiological variability. We deployed TracMyAir, a smartphone-based digital health platform designed to generate time-resolved, personalized exposure and inhaled dose estimates for PM2.5 and ozone under real-world conditions. In an exploratory study of 18 adults contributing more than 1,500 participant-hours, the platform integrated smartphone geolocation, regulatory (AirNow) and community-based (PurpleAir) air quality data, building infiltration modeling, microenvironment classification, and wearable-derived physical activity metrics to compute eight tiers of hourly exposure estimates, culminating in individualized inhaled dose. Hourly dose estimates derived from smartphone-and smartwatch-based step counts were concordant (Spearman correlation p=0.97-0.98), while heart rate-based estimates yielded greater variability and higher mean values (p=0.82-0.92). Exposure explained 51-73% of variance in inhaled dose of PM2.5 and 68-84% of ozone, suggesting that physiological-based modeling approaches improve hyperlocal estimates of personal pollutant burden. Substantial inter-and intra-individual variability reflect dynamic microenvironmental transitions and activity patterns. Modeled doses based on regulatory and community sensor networks were strongly correlated (R=0.84), with community sensors located closer to participants on average, supporting the feasibility of integrating dense, low-cost monitoring networks. No consistent association was observed between outdoor pollutant levels and neighborhood socioeconomic status in this cohort. These findings demonstrate the feasibility of a scalable, smartphone-centered digital health approach for hyperlocal exposure and inhaled dose modeling. By leveraging ubiquitous consumer devices and existing air quality networks, TracMyAir enables personalized environmental exposure assessment with potential applications in epidemiology, population health, and precision environmental medicine.

BackgroundDengue fever is a major neglected tropical disease with a rapidly rising global burden, and localized outbreaks are increasingly reported in southern subtropical China. Fujian Province, a coastal subtropical region with favorable ecological conditions for Aedes albopictus breeding and frequent cross-border exchanges with dengue-endemic areas, has had continuous local dengue cases for over a decade, raising concerns about the establishment of a stable natural endemic focus. Sustained local dengue transmission is defined by four core criteria, but no systematic assessment of these criteria has been conducted for Fujian using long-term multi-dimensional surveillance data. We aimed to evaluate whether a natural endemic focus for sustained local dengue transmission has been established in Fujian Province from 2014 to 2024 using four core evidence dimensions. MethodsWe extracted data on imported and locally acquired dengue cases in Fujian from 2014 to 2024 from Chinas National Notifiable Disease Reporting System (NNDRS). Serological surveillance for dengue IgG antibodies and virological surveillance for dengue virus in Aedes albopictus were conducted at seven sentinel sites. The study period was stratified into three phases based on the impact of COVID-19 non-pharmacological interventions: pre-pandemic (2014-2019), pandemic(2020-2022), and post-pandemic(2023-2024). Descriptive epidemiological analysis and data visualization were performed using R software (version 4.4.1), with t-tests for continuous variables and {chi}{superscript 2} tests for categorical variables. ResultsA total of 3,606 dengue cases were reported in Fujian during the study period, including 1,229 imported and 2,377 locally acquired cases. Key findings were as follows: (1) Temporal distribution: Local dengue transmission was completely interrupted during the 2020-2022 COVID-19 pandemic (0 local cases, only 26 imported cases), and resumed at a low level in 2023-2024 (160 local cases). (2) Serology: The overall population dengue IgG antibody positivity rate was 4.2% (66/15,736), with no statistically significant difference between pre-epidemic (3.8%, 30/7,835) and post-epidemic seasons (4.5%, 36/7,901; P=0.48), and no year with a positivity rate exceeding 10%. (3) Vector surveillance: Only one dengue virus-positive sample was detected among 385,000 Aedes albopictus mosquitoes collected during routine surveillance (Taijiang District, Fuzhou, October 2017), with no viral nucleic acid detected in all other samples. (4) Age distribution: The mean age of locally acquired cases (46.1{+/-}19.8 years) was significantly higher than that of imported cases (35.8{+/-}11.2 years, P<0.001), and local cases were concentrated in the middle-aged group (40-60 years) with no child-dominant pattern observed. ConclusionsFujian Province has not established a stable natural endemic focus for sustained local dengue transmission, and imported cases are the primary driver of local outbreaks in the region. Strengthened surveillance and early management of imported cases, integrated vector control targeting Aedes albopictus, and targeted public health education are critical and essential strategies to prevent the establishment of a dengue natural endemic focus in Fujian and other subtropical coastal regions with similar epidemiological characteristics. Author SummaryDengue fever is a rapidly spreading neglected tropical disease worldwide, and southern China faces persistent threats of local transmission due to favorable ecological conditions for mosquito breeding and frequent cross-border travel. Fujian Province, a subtropical coastal region in southeastern China, has reported annual local dengue cases for over a decade, raising public health concerns about the potential establishment of a stable natural endemic focus--where the virus circulates sustainably without relying on imported cases. To address this critical question, we conducted a comprehensive 11-year assessment (2014-2024) of dengue transmission in Fujian using four key evidence dimensions defined for identifying dengue endemic foci: the continuity of local cases independent of imported sources, population antibody levels, dengue virus detection in local mosquitoes (Aedes albopictus), and the age distribution of infected patients. We also leveraged the COVID-19 pandemic(2020-2022) as a unique natural experiment, during which strict travel restrictions drastically reduced imported dengue cases, to test whether local transmission could persist on its own. Our findings showed that local dengue transmission in Fujian completely stopped during the COVID-19 pandemic and only resumed when cross-border travel and imported cases recovered, confirming local transmission is entirely dependent on imported virus sources. Additionally, the local population had a very low dengue antibody positivity rate (4.2%), dengue virus was detected in only one mosquito sample over 11 years of surveillance, and local cases were concentrated in middle-aged adults (not children--the typical group affected in endemic areas). Together, these results confirm that Fujian Province has not established a stable natural endemic focus for dengue fever. While no endemic focus exists yet, Fujian remains at high risk of imported-driven local outbreaks due to its climate and cross-border exchanges. Our study highlights three critical strategies to prevent the future establishment of a dengue endemic focus in Fujian and other similar subtropical coastal regions: strengthening surveillance and early response for imported dengue cases, implementing targeted mosquito control measures during peak transmission seasons, and conducting public health education to raise awareness of dengue prevention. These evidence-based interventions are key to blocking the formation of sustained local dengue transmission and protecting regional population health.

BackgroundSerotype 3 (S3) has remained a major cause of invasive pneumococcal disease (IPD) despite its inclusion in 13-valent pneumococcal conjugate vaccine (PCV). In October 2023, a 15-valent PCV (PCV15) including S3 was introduced into the Catalan universal childhood immunization program. MethodsWe conducted a retrospective pre-post surveillance study to compare pediatric IPD incidence in Catalonia during a pre-PCV15 period (October 1, 2022-September 30, 2023) and two post-PCV15 periods (October 1, 2023-September 30, 2024, and October 1, 2024-September 30, 2025). All IPD episodes in children <18 years attended in 34 hospitals were included. IPD was defined as detection of S. pneumoniae in a sterile site by culture or PCR. Results323 IPD episodes were identified in 319 children (mean age, 4.5 years). Overall IPD incidence declined from 13.0 to 9.4 episodes per 100,000 children in the first post-PCV15 period compared with the pre-PCV15 period (28% reduction; p=0.02), but returned to baseline in the second post-PCV15 period. S3-IPD incidence decreased significantly from 4.1 to 1.6 episodes per 100,000 (60% reduction; p=0.001) in the first post-PCV15 period and remained lower in the second period: 2.3 episodes per 100,000 (42% reduction compared with baseline; p=0.04). In contrast, IPD incidence caused by PCV7 serotypes increased from 0.3 in the pre-PCV15 and first post-PCV15 period to 2.7 episodes per 100,000 in the second post-PCV15 period (690% increase; p<0.001). ConclusionPCV15 introduction was associated with a sustained reduction in S3-IPD over two years. However, a marked increase in PCV7 serotypes offset overall gains in IPD incidence. SUMMARYPCV15 introduction in Catalonia achieved sustained reduction in serotype 3 invasive pneumococcal disease over two years, but a marked increase in PCV7 serotypes offset the overall disease reduction in the second post-vaccination year.

BackgroundAustralia is experiencing its worst syphilis epidemic in decades, driven by two distinct outbreaks -- a heterosexual epidemic disproportionately affecting Aboriginal and Torres Strait Islander communities in northern Australia, and a predominantly MSM-associated epidemic in urban centres. We examined the spatial dynamics of this dual epidemic, including geographic clustering, service accessibility associations, and COVID-19 impacts. MethodsWe analysed publicly available aggregate surveillance data (2013-2024). Spatial autocorrelation (Global/Local Morans I, Getis-Ord Gi*), spatial regression (OLS, spatial lag, spatial error), and geographically weighted regression (GWR) were applied to 74-75 Victorian local government areas (LGAs). Congenital syphilis vulnerability was mapped at SA3 level using composite proxy scoring. COVID-19 impact was assessed using interrupted time series (ITS) analysis. ResultsNational notifications rose 3.5-fold from 1,719 (2013) to 6,036 (2022). Strong spatial clustering was identified (Morans I=0.560, p<0.001), with 11 high-high clusters in inner Melbourne. The spatial lag model identified distance to sexual health clinic (coefficient: -0.225, p=0.050) and Indigenous population proportion (coefficient: 0.210, p=0.045) as significant predictors. Eleven SA3 areas were classified as high vulnerability for congenital syphilis, predominantly in remote northern Australia. Monthly NSW ITS found a non-significant 6% reduction in notifications during COVID restrictions (IRR=0.94, p=0.123). Comparing the COVID period (2020-2021) with pre-COVID means, remote area notifications increased 91% and female notifications increased 108% compared with 45% for males, reflecting the steep underlying epidemic trajectory. ConclusionsAustralias syphilis epidemic exhibits distinct spatial patterns shaped by service accessibility and sociodemographic factors. The concentration of high-vulnerability areas in remote northern Australia highlights the need for targeted service expansion, point-of-care testing, and culturally appropriate outreach. The acceleration of heterosexual transmission signals increasing congenital syphilis risk requiring urgent antenatal screening strengthening.

Structured AbstractO_ST_ABSIntroductionC_ST_ABSCervical cancer screening is difficult to initiate and sustain during war due to disrupted health services, population displacement and limited clinical capacity. Evidence on whether human papillomavirus (HPV)-based screening using self-sampling can function as a screening pathway during armed conflict is unknown. This study evaluated the feasibility, acceptability and operational performance of HPV self-sampling for cervical cancer screening in a war-affected region of Ukraine. MethodsWomen aged 30-60 years living in Zaporizhzhia Oblast, Ukraine, were offered HPV testing using self-collected cervicovaginal samples distributed through outpatient clinics, community outreach activities and refugee centres. Samples were analysed locally using PCR-based HPV assays with external laboratory quality assurance. Women positive for HPV16/18 were referred directly for colposcopic evaluation. Primary outcomes included screening uptake, kit return rate, HPV positivity and follow-up completion among HPV16/18-positive women. Secondary outcomes included turnaround times, HPV positivity by age and sampling setting, and participant feedback. ResultsBetween April and December 2025, 593 women were offered HPV self-sampling; only four (0.67%) declined participation. Of 589 distributed kits, 572 samples were returned and analysed (attendance rate 96.46%, 572/596), with non-return occurring only in refugee centres. Overall, 52/572 women (9.1%) tested positive for targeted HPV types, including 22 (3.8%) positive for HPV16/18 and 30 (5.2%) positive for HPV31/33/35/45/52/58. All women testing positive for HPV16/18 were contacted and referred for specialist follow-up; among those completing follow-up, all were assessed within two months. Median turnaround time from self-sampling to results was 6.3 days. All recorded participant feedback was positive. ConclusionHPV self-sampling-based cervical cancer screening can be initiated and maintained during active war with high uptake, timely laboratory processing and effective referral of women at highest risk. Simplified, low-contact screening pathways may support cervical cancer prevention under wartime conditions. Trial registrationClinicalTrials.gov identifier: NCT07275333. What is already known on this topicO_LIHPV-based screening is the most effective method for cervical cancer prevention and is recommended globally. C_LIO_LIHPV self-sampling increases participation and acceptability in stable healthcare settings. C_LIO_LIWhether cervical cancer screening can be implemented during an active armed conflict is unknown. C_LI What this study addsO_LIDemonstrates that HPV self-sampling-based screening can be initiated and sustained during active war. C_LIO_LIShows high uptake, timely laboratory processing and effective referral of HPV16/18-positive women under severe operational constraints. C_LIO_LIIdentifies distribution models that minimise sample loss in highly mobile and displaced populations. C_LI How this study might affect research, practice or policyO_LISupports inclusion of HPV self-sampling in cervical cancer prevention strategies for conflict-affected settings. C_LIO_LIInforms programme design choices, favouring simplified, single-visit screening pathways when population mobility is high. C_LIO_LIProvides implementation evidence relevant for countries rebuilding screening programmes during or after military conflicts. C_LI

BackgroundTwo RSV immunisations products: a maternal vaccine, Abrysvo, and a long-acting monoclonal antibody, nirsevimab, both designed to prevent RSV illness in infants, have recently become available. Modelling evidence is required to inform how to optimally use these products in immunisation programs to reduce the burden of RSV in young children. MethodsWe extend a dynamic transmission model calibrated to RSV-hospitalisation data of children aged < 5 years in temperate Western Australia (WA) to simulate a range of potential RSV immunisation programs. Using our model, we estimate the impact of both single-product and hybrid RSV immunisation programs. The analysis considers timing of administration, coverage levels and targeting of high-risk groups. Impact on RSV burden is analysed in the context of the WA setting and the possible significant cost differences between the two products. ResultsAll programs analysed were effective in reducing RSV burden. Programs using nirsevimab for newborn infants at similar coverage levels to the Abrysvo programs, averted more RSV-hospitalisations annually. Seasonal programs that focused on protection during high RSV activity and programs targeting high-risk infants were the most efficient in reducing RSV burden. When dose cost is considered alongside program impact on RSV burden, we find evidence to support further economic analysis of hybrid programs as they could mitigate the cost differential between the two products while remaining highly effective in reducing RSV burden. ConclusionsOur study is the first to comprehensively analyse hybrid RSV immunisation programs that use Abrysvo and nirsevimab. RSV immunisation programs can substantially reduce the burden of RSV in young children. Our modelling analysis provides evidence on immunisation type, timing, coverage, high-risk groups and dosage cost that will support decision makers and can be used in economic evaluations.

BackgroundMultiplex bead assays (MBAs) provide quantitative measurements of many analytes from small sample volumes, reducing cost and processing time compared with traditional immunoassays. These advantages have made MBAs valuable for studying diverse diseases, particularly in low-resource settings. However, most analytical approaches focus on individual diseases, while integrated surveillance platforms would benefit from methods that jointly analyse the full range of pathogens included in multiplex assays. MethodsWe applied factor analysis combined with a Dirichlet process mixture model to identify sub-populations based on MBA responses and assess whether these groups show spatial patterns or share socioeconomic characteristics and disease exposures. Data were drawn from four districts in northern Sabah, Malaysia, and included antibody responses for several neglected tropical diseases (NTDs): strongyloidiasis, lymphatic filariasis, giardiasis, toxoplasmosis, trachoma, and yaws. ResultsThe model identified four distinct sub-populations. Three of these were spatially distributed and included people with similar socioeconomic profiles. These shared characteristics may help explain the antibody patterns observed within each group, offering a comprehensive characterization of each sub-population. ConclusionThis methodology replicable to other MBA datasets and can provide new insights into the interplay of various exposures at the population level. It also has potential to strengthen integrated surveillance systems by informing more targeted sampling strategies.

BackgroundCervical cancer, generally induced by human papillomavirus (HPV) infection remains one of the most prevalent and deadly female cancers in sub-Saharan Africa (SSA). In Cameroon, the impact of prevention strategies is limited by systemic challenges, and insufficient evidence base to guide effective interventions. This study aimed to synthesize available evidence on the prevalence and key determinants of HPV infection among Cameroonian women. MethodsA comprehensive search was conducted across PubMed, Scopus, Web of Science, Embase, Cochrane electronic databases and local online publishers. Quality assessment of included studies was performed using the Joanna Briggs Institute (JBI) critical appraisal tool. The random effect model was used to pooled the estimates. Heterogeneity was evaluated using the I2 statistics. Statistical significance was set at p <0.05 and all analyses were conducted using R Statistics version 4.5.2. The protocol was registered on PROSPERO (CRD420261279093). ResultsThirty-six studies (20,033 participants) were included. The pooled prevalence of HPV infection 36.10 (95% CI: 27.28-45.97) with high heterogeneity (I2 = 98.4%). Higher estimates were observed among female sex workers 62.10% (95% CI: 58.08-66.00%, 1 study, n = 599) and women with pre-cancerous genital lesions 85.53% (95% CI: 61.72-95.59%, 4 studies, n = 673). Significant determinants of HPV infection included age below 40 (OR = 1.31; 95% CI: 1.14-1.49; 7 reports), unmarried status (OR = 1.43; 95% CI: 1.24-1.64; 15 reports), having five or more sexual partners (OR = 1.26; 95% CI: 1.05-1.51; 2 reports), parity below four (OR = 1.29; 95% CI: 1.09-1.52; 2 reports), HIV infection (OR = 1.92; 95% CI: 1.24-2.98; 6 reports), CD4 count below 500 cells/mm3 (OR = 2.00; 95% CI: 1.02-3.95; 2 reports), and viral load below 1000 copies/mL (OR = 2.12; 95% CI: 1.27-3.53; 2 reports). ConclusionsOur study demonstrates a high and persistent burden of HPV infection in Cameroon, with a greater impact on younger women and women living with HIV. These findings highlight an urgent public health need to strengthen and expand prevention strategies to effectively reduce and eliminate cervical cancer incidence in the country.

Individuals with occupational exposure to swine may have disproportionate risk for zoonosis with swine influenza A virus (IAV). To evaluate human antibody responses, sera or plasma from swine veterinarians, swine farm employees, and the general population were tested by hemagglutination inhibition (HI) assays against representative swine and human seasonal influenza vaccine strains. HI data were analyzed by antigenic cartography to assess strain relationships, and reproduction number modeling to evaluate pandemic potential using age-stratified immunity profiles. Occupationally exposed groups had lower human seasonal vaccine uptake (45.5% vs 70%) and significantly lower odds of seropositivity to several H1 and H3 from swine compared to general population cohorts. One swine strain exhibited significant antigenic drift (3.62 AU) from its nearest vaccine strain. Multiple strains required lower R thresholds for pandemic spread (1.09-1.35) than recorded pandemic strains (1.46-1.80). This demonstrates that population immunity gaps heighten zoonotic risk to circulating swine H1 and H3 strains.

BackgroundOlder age is widely considered a risk factor for post-acute sequelae of SARS-CoV-2 infection (PASC), typically attributed to immunosenescence and inflammaging. However, whether this association reflects intrinsic biological ageing or accumulated comorbidity burden remains unclear, with implications for clinical risk stratification. MethodsWe conducted a retrospective cohort study using the Precision PASC Research Cohort (P2RC) from Mass General Brigham, comprising 133,792 COVID-19 patients from 12 hospitals and 20 community health centres in Massachusetts (March 2020-May 2024). PASC was ascertained using a validated computational phenotyping algorithm. We used generalised estimating equations with cluster-robust variance to model PASC risk, causal mediation analysis to decompose age effects through comorbidity burden and acute severity, and specification curve analysis across 768 analytical specifications to assess robustness. FindingsAfter adjustment for comorbidity burden, each decade of age was associated with 6% lower odds of PASC (OR 0.94; 95% CI 0.93-0.95). Causal mediation analysis revealed that comorbidities accounted for 145% of the total age effect, indicating inconsistent mediation wherein ages direct protective effect was masked by its indirect harm through chronic disease accumulation. This protection was age-dependent: adults younger than 65 years retained robust resilience independent of comorbidities (ADE:-0.0042, p<0.001), whereas adults 65 years and older showed complete loss of this protection (ADE: +0.0020, p=0.14). InterpretationLong COVID susceptibility is driven by physiological reserve rather than chronological age until approximately age 65, beyond which age-related protective mechanisms become exhausted. Risk stratification should prioritise comorbidity burden over birth year in younger adults. FundingNational Institute of Allergy and Infectious Diseases (NIAID).