Swiss Medical Weekly

To deal with the COVID-19 pandemic, Denmark implemented an aggressive program aimed at controlling the pandemic which included both testing and contact tracing programs. The large amount of data collected in Denmark on the pandemic and its integrated nature made it possible to investigate the effectiveness of the testing and contact tracing effort. The results of that investigation and a discussion of the effectiveness and limitations of the different control efforts are reported herein, as are lessons learned concerning possible improvements for the future. The analysis is limited to the period from the start of the COVID-19 pandemic in Denmark (late Feb. 2020) into May 2021, at which time the impact of vaccination intervention was already playing a role with ~25% of the Danish population at least partially vaccinated. From the available data sets we estimate the national Infection Detection Efficiency (IDE) starting around July 1, 2020, the time at which the national infection detection program started to be implemented in a more robust form. The results rely on daily COVID-19 hospital admissions, PCR test results, and anti-body prevalence values for the Danish population. We find that for the long-term average, the combined Danish national testing and contact tracing program identified on average about 55 to 60% of the infected individuals during the period from Sept. 1, 2020, into early May 2021. However, higher infection detection efficiencies were achieved in localized areas for short time intervals. Our investigations further indicate that the Danish testing and contact tracing program, which was among the most ambitious in the world, could have had a better balance between voluntary probing on the one hand and focused contact tracing and targeted testing on the other hand. As typically implemented, it proved to be largely ineffective in controlling the pandemic. However, in at least one case when it was implemented in an enhanced and focused mode, it was able to bring a large local outbreak that dominated the country's cases under control. We have compiled a list of lessons learned regarding the use of contact tracing procedures to control potential future pandemics before vaccinations become available.

BackgroundCOVID-19 pandemic modified trends of infant bronchiolitis, leading cause of emergency room (ER) attendance in infants in high income countries, primarily due to Respiratory Syncytial Virus. Understanding recent pandemic-related epidemiological shifts could inform affordable prevention efforts to improve sustainability and coverage of prophylactic treatments beyond maternal vaccines and infant monoclonal antibodies. MethodsWe estimated incidence rates (IR) of bronchiolitis ER presentations in 0-6month olds in 2012-2023 in a region-wide cohort of almost 1 million births using administrative health data from Lombardy, Italy. To assess potential contributors, we investigated direct and indirect COVID-19-related factors, including disease severity, shape of the epidemic peak, parental health seeking behaviour and vaccine coverage. We estimated COVID-19 maternal vaccination associations using mothers-infants data linkages and multivariable-adjusted logistic regression. FindingsCompared to pre-pandemic levels, IRs doubled in 2021-2023 (from 2 to [≥] 4/100 person-time). The surge could not be explained by changes in infant age at ER visit, clinical severity or in the shape of the epidemic peak. Adjusted models showed little support for a role of infant routine or maternal COVID-19 vaccination on bronchiolitis episodes (respectively hazard ratio 1.09, 95%CI: 0.98-1.22 and odds ratio 0.91, 95%CI: 0.76-1.09). InterpretationThe post-pandemic increase in infant bronchiolitis is likely driven by multiple epidemiological changes rather than a single factor. As maternal RSV vaccination and infant RSV monoclonal antibodies are introduced and scale up, identifying these mechanisms will be critical to maximise their public health impact, inform complementary prevention strategies, and improve preparedness for future RSV epidemics.

Background: A large increase in mortality from severe acute respiratory infections (SARI) in Brazil in 2025 was mainly driven by influenza A and respiratory syncytial virus (RSV) among children and the aged, but 2026 data remain largely unpublished. Methods: Secondary data on SARI by age group (<2, 2-4, 5-14, 15-49, 50-64, 65+ years) and virus (Influenza A/B, RSV, SARS-CoV-2, adenovirus, rhinovirus, bocavirus, and metapneumovirus) were retrieved for 35 weeks of 2026. Weekly variations in infection rate (IR) and mortality rate (MR) were described by virus and age group. Case fatality ratio (CFR) and vaccine-preventable deaths from influenza, RSV, and SARS-CoV-2 were analysed by age group. Missing virus classification was estimated by multinomial regression. Poisson-based 95% confidence intervals (CI) were calculated for MR. Results: Influenza A infections quintupled during February and March, with a mortality peak in April, mainly due to H2N3. RSV and rhinovirus caused more deaths than influenza viruses, especially among young children (<2) and the aged (65+). The former were most frequently infected by RSV and the latter by rhinovirus. For those 50 years or older, influenza B reached a CFR of about 20%, compared with 5-15% for influenza A, metapneumovirus, rhinovirus, and other non-subtyped viruses. The highest vaccine-preventable MRs per 100,000 were 17.23 for the oldest and 8.62 for the youngest. Under ideal conditions, 6418 lives could have been saved, about half among children and adolescents <15 years old. Conclusions: Vaccine-preventable SARI in Brazil exerted a high toll in fall and winter 2026, mainly due to influenza A, RSV, and rhinovirus. Better vaccine coverage may significantly reduce this toll.

Importance: Nirsevimab, a monoclonal antibody against RSV, was implemented in France in September 2023. Recently, rare resistance-associated substitutions were described in RSV but the effectiveness according to lineages remains unclear. Objective: We aimed to estimate the effectiveness of nirsevimab against hospitalization for RSV bronchiolitis according to RSV lineages. Design: We conducted a multicenter test-negative case-control study from October 15, 2023 to March 15, 2025. Setting: This study was based on data from three national multicentric prospective studies. The 12 participating centers were secondary or tertiary hospital with a pediatric department located in France. Participants: We included all children younger than 12 months who were hospitalized for RSV bronchiolitis in one of the participating centers in France during the two first RSV epidemic seasons following the implementation of nirsevimab (from October 15, 2023 to February 29, 2024, and from October 10, 2024 to March 15, 2025). Main outcomes and measures: The main outcome of the study was the RSV test result of bronchiolitis cases. RSV whole-genome sequencing was performed using a tiled amplicon approach covering the complete viral genome, as previously described in the POLYRES studies. We estimated the effectiveness of nirsevimab by a multivariable logistic regression model adjusted for potential confounders. We estimated the adjusted risk of immunization failure for each lineage by calculating relative odds ratio to a reference lineage. A range of sensitivity analyses were conducted. Results: We included 3019 infants with bronchiolitis among which 2273 had a positive RSV test (case patients) and 746 had a negative RSV test (control patients). Overall, 373/2273 (16.4%) case patients were immunized by nirsevimab versus 423/746 (56.7%) control patients. The adjusted effectiveness of nirsevimab against hospitalization for bronchiolitis was 88.4% (95% CI, 84.5-91.4) with RSV-B and 79.4% (95% CI, 73.7-83.8) with RSV-A. The risk of immunization failure was 3.2-fold (95% CI 1.8-5.7) higher for lineages derived from A.D.3 than for lineages derived from B.D.4.1. Conclusion and relevance: In this multicentric case-control study, we observed that nirsevimab effectiveness was variable across RSV lineages, with a lower effectiveness against A.D.3 lineages compare to others. Further surveillance is needed to confirm these findings and assess their implication on RSV lineages epidemiology as nirsevimab use expands.

PurposeTo examine the association between BMI-for-age z-score (BAZ) and BMI status with refractive error prevalence, incidence, subtypes, and quantitative refraction in Vietnamese schoolchildren. MethodsWe retrospectively analyzed body mass index and refractive error data from annual school health checks in three Vietnamese cities, 2022 to 2024. The main analysis set was restricted to children age 6 and older (49,415 examinations, 31,522 children). Refractive error subtypes and quantitative refraction came from a Hanoi autorefractor sub-cohort (13,059 examinations). We used sex-stratified Poisson models with generalized estimating equations, adjusted for age, city, and year, plus linear mixed models for quantitative outcomes. ResultsAny refractive error followed a U shaped curve across BAZ in both sexes, significant in girls (prevalence ratio 1.01 per 1-SD BAZ, p = 0.027) but not boys (p = 0.099). Obesity was associated with higher any refractive error prevalence in girls (adjusted prevalence ratio 1.05, p = 0.017). Astigmatism was associated with BAZ in both sexes (p < 0.001), anisometropia in boys only (p < 0.001), with no association for myopia or hyperopia. Spherical equivalent shifted slightly toward hyperopia, not myopia, with higher BAZ. A supplementary check over 1 to 2 years found no evidence that prior BAZ predicted new refractive error onset (prevalence ratio 1.02, p > 0.6 in both sexes), and the nonlinear pattern did not reappear. ConclusionsAdiposity relates cross-sectionally to refractive error in a nonlinear, sex specific way concentrated in astigmatism and anisometropia rather than myopia, though this did not hold up short term.

Automated surveillance systems can prove to be extremely useful in detecting outbreaks of respiratory diseases that need further epidemiological investigation. In order for the system to be effective, careful attention has to be paid to the baseline used, absence of the observations, and the use of proper statistical methods. As a solution, the paper describes EpiAlert, a weekly surveillance system based on CDC FluView ILINet. The system is able to transform the number of ILI visits and the total number of visits into a ILI prevalence for the region, create the first reference from the three previous years using a +/- 2-week interval, transform the rate value, and apply two different detectors - CUSUM and EWMA. CUSUM is set at k=0.5 and h=5, whereas EWMA uses {lambda}=0.2 and H=2.7 values. Among the 55 districts, the system gives 45,138 pieces of information about the disease by transforming 44,297 pieces of data into alerts. It is found that there are 2,820 alerts in total (out of which 2,711 alerts used CUSUM, 402 used EWMA, and 293 used both detectors). Additionally, the experiments show that the sensitivity of the device depends greatly on the detector. The latest statistics can be tracked in the report for week 37 of 2026 that recently concluded in West.

Background HPV-vaccination prevents HPV-related cancers, but uptake remains suboptimal. In the Netherlands, a catch-up campaign invited 18-27-year-olds for an additional cost-free opportunity to initiate or complete their HPV-vaccination in 2023-2024, which led to 24% of this invited population getting vaccinated. As young adults increasingly seek health information online, understanding online questions, concerns and misinformation in response to the campaign may help improve future vaccination efforts. Supplemental to overall evaluation of the vaccination campaign, we piloted online social listening processes to generate an insight report for Public Health Service (PHS) Amsterdam. Objective This study piloted online social listening processes at the PHS Amsterdam to identify actionable insights into questions, concerns and misinformation surrounding the HPV-vaccination catch-up campaign among young adults. Methods Upon inventory of potential platforms and data sources, a retrospective online social listening analysis was conducted across the platforms Instagram, Facebook, and X, collecting data from PHS, the National Public Health Institute for Public Health and the Environment (RIVM), the Dutch public broadcasting foundation (NOS), and LINDA.meiden sources from January 1, 2023, to June 1, 2024. Publicly available posts, comments, and engagement concerning HPV-vaccination were manually collected, and inductively coded. Themes were assessed for risk, based on expected potential harm and observed reach, and used to develop recommendations. Results A total of 821 posts and 5157 comments were collected and analysed. Ten recurring themes were identified across varying levels of risk. Two themes were classified as high risk: an information gap regarding the effectiveness of HPV-vaccination and concerns about the transparency on HPV-vaccine side effects. Three themes were classified as medium risk: questioning HPV-vaccine effectiveness under certain circumstances, reduced general vaccine trust following COVID-19, and accessibility issues related to vaccination locations and service times. Two themes were classified as neutral risk: questions regarding eligibility criteria for the campaign and calls for broader HIPV-prevention measures. Finally, three low risk themes concerned questions regarding HPV-vaccine brand specifics, campaign choices, and questions about scheduling or rescheduling HPV-appointments. Comments also referred to subsequent information sources, including reliable sources (public health institutes), false narratives and misinformation. Recommendations focused on addressing questions and information gaps (i.e. improving HPV risk perception and providing more detailed HPV-vaccine information), improving communication about HPV-vaccination, and reducing practical barriers to vaccination. Conclusions Manual social listening across selected online sources provided actionable insights into the public discourse during the HPV-vaccination catch-up campaign. Results mostly reflected questions, concerns and information gaps. Although some themes were critical of HPV-vaccination, false narratives and misinformation did not dominate the discourse. Recommendations aim to reduce practical barriers and address information needs. This pilot showed that online social listening can be effectively implemented even with limited resources.

Background: Underweight, overweight, and linear growth during and after cancer treatment can impact treatment efficacy and survival in childhood cancer patients, and long-term health in childhood cancer survivors (CCS). However, scientific evidence on the weight status and growth of CCS is limited. Previous studies have been small, focused on specific cancer types, or lacked objectively measured longitudinal data. The availability of standardized, semantically interoperable routine data from oncology clinics offers an unprecedented opportunity to investigate nutritional status across all childhood cancer types, treatment regimens, and critical time windows. Objectives: We will investigate underweight, overweight, and growth trajectories from birth to adulthood in childhood cancer patients and survivors. We will identify predictors associated with distinct growth and weight trajectories and assess the consistency of findings across European countries. Methods: The Growth study will collect routinely recorded sociodemographic, clinical, and anthropometric data from paediatric and adolescent cancer patients (aged <20 years) from Switzerland, Portugal and Slovenia, We will include patients diagnosed between 2004-2026, by linking data from the Swiss Childhood Cancer Registry (ChCR), the Swiss Childhood Cancer Survivor Study (SCCSS), the Swiss Federal Statistical Office (FSO), and oncology clinics in Switzerland. Deterministic linkage of data sources (ChCR, SCCSS, oncology clinics, and FSO) will be performed using social security numbers. We will calculate age- and sex-specific z-scores for weight, height, and BMI based on country-specific and World Health Organization growth references. Latent trajectory modelling will be applied to identify distinct growth and weight trajectories and to detect subgroups at increased risk of growth impairment. We will use logistic regression models to identify predictors of impaired growth. Results: The project was funded in 2025; first study results are expected to be published by autumn 2027. We will obtain routinely collected data from approximately 12,250 childhood cancer patients and survivors - 7,800 from Switzerland, 3,350 from Portugal, and 1,100 from Slovenia. Conclusions: The Growth study will provide insights into the nutritional status of childhood cancer patients and survivors and improve understanding of growth patterns in this population. Identifying high risk groups and tumour or treatment related factors will inform targeted surveillance strategies and early nutritional interventions.

Objective: Overweight and obesity in childhood and adolescence are major risk factors for health problems across the lifespan. This manuscript reports the current prevalence of overweight and obesity among children and adolescents aged 4-17years living in Germany and compares them with previous population-based results. Methods: A representative, cross-sectional sample of 4-17-year-olds was drawn following a multistage sampling process. Analyses are based on weight and height of 3,978 individuals measured in the field by trained test instructors between 2023-2025. Overweight and obesity classification was defined using age- and sex-specific body-mass-index percentiles. To allow for comparability of prevalence estimates derived from previous assessment waves and other panel studies dating back to 2005, an alignment factor was derived using an inverse probability of participation weighting approach. Together with sampling weights, the alignment factor was applied to obtain current, representative prevalence estimates of overweight and obesity. Results: The aligned, weighted prevalence of overweight and obesity was 16.1% (95%CI[14.5-17.9%]), whereas prevalence of obesity was 6.7% (95%CI [5.5-8.1%]). Age- and sex-specific prevalence rates are reported and compared to previous waves. Conclusions: The current prevalence of overweight and obesity in children and adolescents aged 4-17 years living in Germany remains stable over the past two decades.

The 2026 Andes virus (ANDV) outbreak aboard the MV Hondius cruise ship resulted in 11 confirmed cases and 3 deaths and raised questions regarding the origin of infection, with much media focus resting on a landfill in Tierra del Fuego. We evaluated competing exposure hypotheses by assembling open data on reservoir host occurrences, rodent serosurveys, and historical ANDV outbreaks along with the index case's self-documented, publicly-posted citizen-science digital record of their movements. Historical outbreaks associated with human-to-human transmission were concentrated within a restricted region spanning southern Chile and adjacent western Argentina, coinciding with the distribution of the principal reservoir host, Oligoryzomys longicaudatus, and areas identified as elevated risk by multiple ecological and genetic models. The index case was documented within this transmission focus shortly before the putative exposure period. Together, our open data approach was able to rapidly locate initial exposure within the established ANDV transmission focus and develop scenarios to prioritise further epidemiological investigation.

Background: Disaster medicine has been a formal curricular recommendation in German health professions education since 2006, and comparable recommendations exist internationally. Evidence on implementation is confined almost entirely to human medicine, rests on faculty self-reports or small student samples, and measures delivery rather than retention. Whether curricular exposure is associated with willingness to serve has not been adequately examined in interprofessional samples. Objective: We aimed to characterize disaster medicine education across 7 health professions in Germany, distinguishing delivery from retention, to identify profession-specific gaps and training priorities, and to examine how educational and experiential factors relate to willingness to serve. Methods: We conducted an anonymous nationwide online cross-sectional survey of students and trainees across 7 health professions in Germany between July 9 and August 25, 2026, recruited through institutional distribution lists. The interprofessionally developed instrument comprised 48 items. We assessed delivery and retention of 12 disaster medicine topics (4-point scale), self-rated confidence in 22 clinical and nursing skills (6-point scale), desired content, formats, motivators and barriers, and formal and spontaneous willingness. For all rating scales, higher values denote the more favorable level. We derived a delivery-retention gap and a want-deficit index, examined the dimensional structure of the competence battery, tested for differential item functioning by prior civil protection engagement, and modeled willingness with a cumulative link model. Results: Of 8133 respondents (completion rate 87.5%), 33.1% had never been taught disaster medicine and 25.0% only in passing; 22.1% had comprehensive teaching including practical exercises. Across the 12 topics, the proportion able to retrieve content confidently never exceeded 23.9%; the delivery-retention gap reached 47.3 percentage points. More than half (54.6%) had never taken part in a practical exercise. Competence formed more than 1 dimension: 18 acute-technical items loaded 0.54-0.86 on the first factor, 4 relational and nursing items 0.14-0.28. Prior civil protection engagement was associated with higher confidence on every acute-technical item (Cliff delta 0.26-0.55) and lower confidence on all 4 relational items (-0.22 to -0.09). Willingness was high and homogeneous across groups (78.7% formal, 84.1% spontaneous), whereas competence varied by about 2 scale points. Adjusted, active civil protection engagement (odds ratio 2.49, 95% CI 2.12-2.94) and practical exercise experience (odds ratio 1.78, 95% CI 1.54-2.05) were the strongest predictors; curricular exposure contributed weakly (odds ratio 1.06 per SD, 95% CI 0.99-1.14). Conclusions: Two decades after the curricular recommendation, disaster medicine is largely absent from health professions education in Germany, and what is delivered is not retained. Willingness is nevertheless high and largely decoupled from competence, so qualification and recruitment require separate instruments. Curricula should be prioritized by the coincidence of demand and deficit rather than by coverage, built for retention, and should treat relational and nursing competence as a distinct learning objective.

Background Exposure-history data collected during epidemics or pandemics within digital contact-tracing applications hold immense potential for rapid, scalable epidemiological inference. The sensitivity of these data makes privacy-preserving designs essential to secure public trust and app uptake. However, during the COVID-19 pandemic, such approaches were not yet available at the scale or maturity required for deployment. We present a Bayesian decentralised framework to infer transmission dynamics from exposure-history data while protecting user privacy. Methods Our approach is based on iterative communication between user devices and a central server, computing log-likelihood gradients on device from exposure-history data and centrally updating parameter values using only aggregated gradients. Applying this framework to synthetic exposure-history data from a hypothetical respiratory pathogen epidemic simulated on dynamic contact networks, we assessed its ability to estimate the underlying transmission parameters, perform infector attribution, and reconstruct serial-interval (SI) distributions. We systematically explored how inference was affected by incomplete exposure-history data arising from partial app adoption, case under-ascertainment, and incomplete exposure logging, and by transmission scenarios. Findings Our decentralised framework accurately recovered transmission parameters, closely matching estimates derived from centralised data with no systematic bias in posterior means. Parameter recovery remained robust when hazards from unobserved exposures were known as a daily average across the population. Although incomplete exposure-history data and specific transmission scenarios introduced compensatory parameter biases, the inferred host infectiousness profile retained sufficient accuracy, and the weekly SI distributions reconstructed from infector attributions closely resembled the ground-truth distributions. Interpretation Our findings highlight that, beyond its primary role as a control measure, digital contact tracing could help characterise transmission dynamics almost in real time and inform public health interventions while preserving user privacy. Funding Oxford Martin School Programme on Digital Pandemic Preparedness; National Institute for Health and Care Research (NIHR) Health Protection Research Unit in Emerging and Zoonotic Infections.

Background Psychiatric diagnoses and psychotropic medication use among children, adolescents, and young adults have increased in high-income countries, with concerns about geographic variation. We described national trends and geographic variation in Denmark from 2010 to 2025 and developed an interactive online tool to explore these patterns. Methods We conducted a nationwide, descriptive, repeated cross-sectional register-based study of all Danish residents aged 0-24 years in 2010-2025 (n=2,930,744), using the Danish National Patient Registry and the Danish National Prescription Registry. We estimated annual incidence, prevalence, and, for selected diagnoses, lifetime prevalence, by age and sex, and age- and sex-standardised rates across regions, health councils, and municipalities. We assessed geographic variation using deviations from national means, coefficients of variation, Gini coefficients, and funnel plots. Findings Psychiatric diagnoses and psychotropic medication use increased from 2010 to 2025. The annual prevalence of attention-deficit hyperactivity disorder (ADHD) increased from 0.41 to 2.3 per 100 individuals, autism spectrum disorders from 0.20 to 1.2, and melatonin use from 0.14 to 3.0. ADHD and autism spectrum disorders were more prevalent among boys and anxiety disorders among girls. Sertraline use was also more prevalent among girls. Geographic variation was observed across diagnoses and psychotropic medications at regional, health council, and municipal levels. For example, lifetime prevalence of autism ranged from 1.3 to 5.9 per 100 across municipalities, and in 2025 regional coefficients of variation ranged from 0.11 (sertraline) to 0.41 (atomoxetine). Results can be explored in the interactive online tool (https://bupstat.sdu.dk/?lang=en). Interpretation Psychiatric diagnoses and psychotropic medication use increased among Danish children, adolescents, and young adults, with marked geographic variation. Descriptive data cannot establish the causes of this variation, but the findings identify areas for further review and support continued monitoring. Funding Best for Us project (www.bedstforos.dk), funded by the Novo Nordisk Foundation (NNF24SA0093635) and the Obel Family Foundation (69348).

Introduction: The TREOCAPA (Prophylactic TREatment Of the duCtus Arteriosus in Preterm infants by Acetaminophen) trial was a pan-European, multi-centre, phase II/III trial investigating the impact of prophylactic paracetamol (also known as acetaminophen) given during the first 5 days of life for children born before 29 weeks' gestational age (GA) on survival to 36 weeks' post-menstrual age without severe neonatal morbidities. However, due to time restrictions, long-term follow-up was not planned as part of the initial trial despite recommendations for neonatal trials to include endpoints measuring efficacy after discharge from the neonatal unit and on-going debate about the long-term effects of paracetamol in the neonatal period. This protocol describes a study to follow-up participants in the TREOCAPA trial at 2 years corrected age initiated after the trial's onset. Methods and analysis: The TREOCAPA Long Term (TREOCAPA-LT) study population consists of all children included in the TREOCAPA phase III trial in centres in countries participating in the follow-up study who are aged between 23.5 and 27.5 months corrected age during the study period. Families are contacted by the clinical teams and a parent or guardian is invited to complete an internet-based (online) questionnaire. The primary outcome is cognition, as measured by the non-verbal Cognitive Scale standard score from the Parent Report of Children's Abilities-Revised (PARCA-R) questionnaire. Secondary outcomes are moderate to severe neurodevelopment, health service use and costs. Data will be analysed according to the study groups to which children were randomised in the original TREOCAPA RCT. Ethics and Dissemination: The TREOCAPA-LT protocol was first approved by ethics' committees in France (the study's sponsor) and subsequently by all participating countries. Results from TREOCAPA-LT will be published in open access journals in accordance with the funder's regulations. Registration: https://clinicaltrials.gov/study/NCT06064825

Background Short-term weather conditions can trigger paediatric hospital admissions, but evidence remains limited on the health relevance of intraday temperature variability, humidity, and precipitation, and generally on which subgroups are most susceptible. Methods We conducted a nationwide case time-series study of Swedish children and adolescents aged 6-18 years using linked register data. Associations between daily mean temperature, intraday temperature variability, relative humidity, and precipitation and inpatient hospitalisations were estimated with Poisson regression (individual fixed effects) combined with distributed lag non-linear models over lags 0-21 days. Outcomes included all-cause hospitalisation and cause-specific admissions. Effect modification was examined by sex, age group, socioeconomic indicators, region, and calendar periods. Findings Among 4,638,247 children and adolescents in the cohort, 1,070,702 (23.1%) experienced at least one inpatient hospitalisation, contributing 1,736,169 hospitalisation events. All-cause hospitalisation increased with higher mean temperature, with risk highest at hot extremes. Intraday temperature variability showed a U-shaped association, with higher rates at both lowest and highest exposure levels. Relative humidity showed no association with hospitalisation risk. Higher precipitation was associated with increased hospitalisation risk, but estimates at high rainfall levels were imprecise. Stratified analyses indicated modest differences by sex and socioeconomic indicators, but clearer heterogeneity by age and region, with the highest risks among younger children and in East Sweden; associations varied across calendar periods and were imprecise for most cause-specific outcomes. Sensitivity analyses mostly showed that the main curve shapes were robust. Interpretation Short-term exposure to hot temperatures, both low and high intraday temperature variability, and higher levels of precipitation were associated with an increased risk of all-cause hospitalisation among children in Sweden, with clearer variation by age group and region than by sex or socioeconomic position. These findings support targeting paediatric climate-health preparedness and early-warning systems toward younger children and higher-risk regions such as eastern Sweden and extending such systems beyond mean temperature to include intraday temperature variability, a distinct, currently overlooked driver of risk that heat-focused systems are not designed to capture. Fundings This research was funded by Formas the Swedish Research Council for Sustainable Development (grant no. 2023-01774 and 2022-01845) and the Swedish Research Council (2025-02804 and 2022-06599).

Background: Gender-affirming medical care (GAMC) for children and adolescents in Australia has become increasingly politicized, despite care being provided in accordance with latest evidence-based international guidelines. Critics of GAMC claim that current assessment and deliberation processes are insufficient, and that too many young people are accessing medical interventions, no longer identifying as trans, and expressing treatment regret. These claims have led to widespread bans on the provision of paediatric GAMC, despite growing evidence regarding harms caused by such bans. Aim: This study sought to describe the care journeys of the young people attending Australia's largest paediatric gender service, with a focus on reporting the rates at which young people commenced medical interventions, re-identified with their birth-assigned sex, and expressed regret about their treatment. Methods: The Royal Children's Hospital Gender Service (RCHGS) is a statewide service that provides individualised multidisciplinary care to trans and gender diverse young people in Victoria, Australia. An initial extended triage appointment explores the needs and goals of the young person and their family. Some proceed to receive individualised multidisciplinary care (MDC) at RCHGS which can include psychosocial assessment and management, family support, and medical interventions including pubertal suppression (PS) and gender-affirming hormonal therapy (GAHT). We undertook a retrospective file audit of all patients who had attended at least one RCHGS appointment and been discharged between 1/1/2017-31/12/2024. For each person, key data were extracted from their electronic medical record and recorded in REDCap. Results: 1,391 patients were discharged over the 8-year study period and many different care trajectories were observed. 814 (58.5%) did not access ongoing MDC. Of the remaining 577, 353 (25.4% of total cohort) started a medical intervention ((PS: n=64/1391 (4.6%); estradiol: n=97/1391 (7.0%); testosterone: n=244/1391 (17.5%)). For those who started these medical interventions, the median duration and number of sessions from first appointment until commencement of medications was 530 (IQR: 371-693) days and 9 (IQR: 7-13) sessions. 346 of these patients (98.0%) had data on gender identity at discharge and subsequent care pathways. 7 (2.0%) re-identified with their birth-registered sex and stopped treatment: 4 did so after commencing PS (4/61=6.6% of those starting PS), 2 did so after commencing testosterone, and 1 did so after commencing estradiol (3/341=0.9% of those starting GAHT). Just one of these patients, who had been on estradiol for 1 month, expressed treatment regret given concerns about initial breast budding and future fertility. Conclusion: This study highlights varied trajectories of those referred to paediatric gender services, directly challenges claims used to justify restrictions on paediatric GAMC and underscores the importance of a person-centred approach to care.

Youth are increasingly engaging with generative AI beyond its use as a productivity tool, with a growing share turning to AI for social interaction and emotional support. This leads to unknown risks for their well-being and development. Online community discussions reveal that youth already perceive risks that caregivers have not recognized.

Background and objective. The WHO growth reference judges a child's height against the population at one age, without using the child's own earlier growth. This study built and validated a quantile regression based conditional growth reference predicting a child's future height for age distribution from early growth status. Methods. Using deidentified longitudinal annual school children health check data from three major cities in Vietnam, this study linked a baseline height and BMI for age Z score near age 6 to outcome visits near age 12 or 15 in 4,857 children. A linear quantile regression and a pooled quantile generalized additive model, fit by sex, were compared against a linear benchmark and a naive persistence model on a held out test set, using pinball loss, interval coverage, and width against the WHO 90% band. This study also tested adding growth phenotype and checked generalization across the three cities. Results. The pooled model outperformed the discrete quantile regression in every group. Every individualized 90% interval was narrower than the WHO band, by 34.6 to 54.5%. Growth phenotype improved accuracy in most groups. The model generalized well to a held out Hanoi or Haiphong but poorly to a held out Ho Chi Minh City, where coverage fell to between 0.35 and 0.52, though the all-city model stayed well calibrated for Ho Chi Minh City itself. Conclusion. Conditional quantile modeling gives individualized growth predictions markedly narrower than a fixed population reference and gains further from growth phenotype, but needs local validation before use at an unrepresented site.

Background. Public-health use of influenza surveillance - situational awareness, planning for clinical surge, and issuing advisories or warnings - needs more than an accurate point estimate of next week's count. What matters operationally is whether a rise is caught early, whether the direction of change is right, and whether an alert threshold is about to be crossed, all with honest uncertainty. For such use a forecast must also respect reporting delay, later data revision, and the calibration of its prediction intervals. Using Japan's sentinel surveillance, we evaluated short-term probabilistic forecasts that respect the data release history, and we measured what adding other surveillance series contributes, focusing on the properties that matter for public-health decisions. Methods. The target was the number of influenza reports per sentinel site in each of the 47 prefectures. For each forecast we predicted, as quantiles, the value 1-4 weeks after the most recent observed week. We compared three models: a ridge regression trained jointly across prefectures; a gradient-boosting quantile regression (GBQR) that learns from many surveillance series; and their equal-weight combination on the log scale. Six seasons were used to develop the models. The 2025/26 season was held out as a temporal evaluation period after the specification was fixed; because its epidemic profile had already been seen, it is not a fully independent prospective test. We scored forecasts with the weighted interval score (WIS) and checked prediction-interval coverage. For the Japanese target series we used the value first published for each week; some auxiliary series were taken as retrieved and therefore include later revisions. Results. In 2025/26, the combination's WIS relative to a persistence forecast was 0.841, 0.811, 0.794 and 0.818 at horizons of 1-4 observed weeks - that is, 16-21% lower than persistence. Coverage of the 80% prediction interval was 79.7%, 77.1%, 74.5% and 75.1%, and of the 95% interval 94.3%, 93.4%, 92.6% and 91.8%. Adding auxiliary series improved the GBQR over the development period. However, on the original scale the combination's edge over ridge regression was not statistically clear, and in some low-level rising phases the combination did worse than ridge. Conclusions. Over the period studied, models that share information across regions scored better than a persistence forecast. For public-health use, however, the operative questions are the real lead time once reporting delay is accounted for, whether rises from low levels and threshold exceedances are caught in time, and whether the upper prediction intervals are wide enough; on these, the present evidence is not yet sufficient. The 2025 change to the sentinel system also means that pre-change advisory and warning thresholds cannot be read mechanically. A prospective evaluation with strictly controlled data availability is needed before such forecasts are used to support advisories or planning.

Objectives: To evaluate the epidemiological evolution of unique pneumococcal serotypes covered by either PCV20 or PCV21, common serotypes by both vaccines and non-vaccine serotypes in adults. Methods: We characterized all national IPD clinical isolates from January 2009 to June 2026. Results: The highest burden of IPD was caused by serotypes shared between PCV20 and PCV21 with serotypes 3 and 8 the most prevalent in adults of all ages. During the pre-pandemic period, IPD caused by unique-PCV20 serotypes declined probably due to herd protection by paediatric vaccination with PCVs. In contrast, unique-PCV21 serotypes increased in incidence accounting for more cases than unique-PCV20 serotypes. However, after the COVID-19 pandemic, a different pattern was observed with unique-PCV20 serotypes increasing in incidence due a marked rise in IPD caused by serotypes 4 and 14 that has progressively reduced the gap in disease coverage. In adults aged 18-64 years, the fraction of disease that could be prevented with PCV20/PCV21 changed from 5% in favour of PCV21 (years 2022/2023) to 15% in favour of PCV20 (year 2026) whereas in adults [&ge;]65 years the vaccine contribution declined from 20% in favour of PCV21 (year 2022) to 8% in 2026. Conclusions: IPD trends in adults have changed after the COVID-19 pandemic, especially in recent years. Our study emphasizes the rapid re-emergence of infections caused by traditional PCV7 serotypes especially serotypes 4 and 14 and reinforce the idea that the use of broader PCVs must be accompanied by an increase in the uptake rates in adults of all ages.