Herpes zoster (HZ) and its complication, postherpetic neuralgia (PHN), disproportionately affect older adults and impose a considerable disease and economic burden. Although the Korea Disease Control and Prevention Agency recommends vaccination for adults aged ≥50 years, uptake remains limited. This study assessed the epidemiologic and economic impact of expanding vaccine coverage through inclusion of the live-attenuated zoster vaccine (ZVL) and the recombinant zoster vaccine (RZV) in the National Immunization Program (NIP). Using the incidence data from the Health Insurance Review and Assessment Service Open Statistics, along with vaccine effectiveness, coverage rates, and treatment cost estimates adjusted to 2025 values, we projected cases averted and associated cost savings. At the current 10% coverage, ZVL and RZV were estimated to prevent 36269 and 56681 HZ cases and 15988 and 20712 PHN cases, yielding societal cost savings of USD 78.47 million and USD 107.14 million, respectively. Expanding NIP coverage to 70% amplified benefits approximately sevenfold, yielding cost savings of USD 549.34 million (ZVL) and USD 749.98 million (RZV). These results demonstrate the substantial value of zoster vaccination and underscore the need for policy measures to improve vaccine coverage among older adults in South Korea.

The COVID-19 pandemic has highlighted limitations in case-based surveillance due to inconsistent testing and reporting. Wastewater-based epidemiology (WBE) has emerged as a complementary surveillance approach for tracking SARS-CoV-2 transmission, capturing both symptomatic and asymptomatic infections. The aim of this study was to evaluate the effectiveness of WBE in estimating the effective reproduction number ($ {R}_t $) of SARS-CoV-2 in Georgia, USA. We used a Generalized Linear Mixed Model (GLMM) to analyse viral concentration data from multiple wastewater treatment plants (WWTPs) collected between 1 June 2022 and 15 December 2022. After controlling for flow rates and site-level heterogeneity, model residuals were transformed into a non-negative incidence-like series used to estimate wastewater-based $ {R}_t $. Wastewater-based $ {R}_t $was compared with case-based $ {R}_t $estimates using Spearman correlation. The two $ {R}_t $ estimates showed concordant temporal patterns across most sites, with stronger correlations in areas with higher case counts (Spearman correlations ranging from 0.39 to 0.84, $ p<0.001 $). Wastewater-based $ {R}_t $ tracked increases and decreases in transmission over similar time scales as case-based estimates, while exhibiting reduced sensitivity to short-term changes in clinical testing and reporting behaviour. These findings suggest that WBE can support estimation of transmission trends and complement traditional case-based surveillance for public health monitoring.

Cholera remains a major public health concern in conflict-affected Tigray, Ethiopia, where disrupted water, sanitation, and hygiene (WaSH) services and displacement have increased transmission risk. This study analysed outbreak dynamics, attack rates (AR), and predictors of cholera to inform interventions aligned with Ethiopia’s Cholera Elimination Plan (2022–2028). A retrospective analysis was conducted on 802 suspected and confirmed cholera cases reported from 25 July to 4 October 2024 across 25 districts in Central and Northwestern Tigray. Data from the Tigray Health Research Institute line list were analysed using descriptive statistics, Chi-square tests, and Generalized Estimating Equation (GEE) models. Attack rates were highest in Asgede (357.25/100000) and Endabaguna (88.12/100000). Significant associations were observed with age, sex, occupation, water source, travel history, vaccination, latrine access, and contact history. GEE analysis showed strong intra-cluster correlation (α = 0.949). Higher odds of cholera were associated with males, adults aged 16–45 years, and use of unsafe water sources, while vaccination and latrine availability reduced risk. Strengthening WaSH services, vaccination coverage, surveillance, and targeted risk communication is essential to reduce cholera transmission in Tigray.

A fieldworker got more involved in research than intended when he contracted a Giardia duodenalis infection shortly after collecting faecal samples from wild Norwegian reindeer. Almost 50% of the reindeer samples showed heavy infections with G. duodenalis assemblage AI. Molecular comparison with the fieldworker’s infection revealed identical sequences at the loci successfully amplified. Although causality is inherently difficult to establish in wildlife-associated infections, the worker’s long history without previous infection, his intense exposure during sampling, absence of alternative known risk factors, and onset of symptoms consistent with exposure indicate that the reindeer samples were the most plausible source. These findings suggest a rare case of well-supported wildlife-associated Giardia transmission.

Evidence on the association between chronic hepatitis B virus (HBV) infection and stroke is limited, inconsistent, and confined predominantly to endemic regions in Asia. This study investigated the association between chronic HBV infection and stroke using data from the largest healthcare provider in Israel. All individuals aged 20 and older who were tested for hepatitis B surface antigen (HBsAg) between 2005 and 2023 were identified. Newly diagnosed HBV patients (HBsAg-positive) were propensity scorematched to non-HBV subjects (HBsAg-negative) in a 1:4 ratio and followed for stroke occurrence through 2024. The study included 20 544 HBV patients and 82 176 matched controls. Overall stroke was diagnosed in 472 HBV patients and 1 717 controls (incidence rates: 2.13 vs. 1.94 per 1 000 person-years). Hazard ratios were 1.09 (95% CI, 0.98–1.22) for overall stroke, 1.01 (0.89–1.14) for ischemic stroke, and 1.82 (1.35–2.45) for intracerebral hemorrhage (ICH). Ischemic stroke risk was specifically increased in younger individuals and females (p-for-interaction = 0.006 and 0.079, respectively). Results remained consistent when excluding patients with prior stroke. Exploratory analysis suggested hepatitis D coinfection is associated with increased ICH risk. In conclusion, chronic HBV infection was associated with significantly increased ICH risk, with subgroup-specific increases in ischemic stroke risk.

Non-pharmaceutical interventions (NPIs) imposed during the COVID-19 pandemic were known to create an immunity debt. This study aimed to quantify the immunity debt for respiratory syncytial virus (RSV), adenovirus, group A Streptococcus (GAS), and influenza in Japan between 2014 and 2024. We conducted a retrospective observational study using national surveillance data and electronic health records in 23 clinics. We conducted an interrupted time series analysis using a quasi-Poisson regression model to estimate the counterfactual incidence that would have occurred in the absence of NPIs. The number of RSV cases declined by 84% in the 2020–2021 season and increased by 39% in the 2021–2022 season, primarily due to an increase in cases among 2-year-old children (94%). Adenovirus, GAS, and influenza were suppressed during the 2020–2022 season by 58–99%. Adenovirus cases increased by 195% in 2023, with a 458% increase among children aged 5–9 years. GAS increased by 36% in 2024, with a 96% increase among 10- to 14-year-olds. Influenza increased by 158% in 2023, with a 299% increase among 10- to 14-year-olds. Surveillance data and 23 clinics’ data showed similar trends. The study suggests that the intensity and timing of the immunity debt differed by pathogen.

In 2024, an outbreak of Salmonella typhimurium affected two regions in Portugal. To identify the vehicle, we conducted a case–case study using a ‘same disease, different time period’ design. We compared S. typhimurium cases linked by whole-genome sequencing (WGS) (cluster cases) with salmonellosis cases notified in 2023 (historical cases) and calculated odds ratios (OR) for food exposures in surveillance data using logistic regression. We performed WGS on 58 isolates from the outbreak period (11/03/2024–2118/06/2024), and all belonged to a single cgMLST cluster (HierCC HC5_410,410). Compared with the 552 historical cases, cluster cases more frequently reported fresh cheese consumption (OR 18; 95% CI: 8.5–38). We visited the implicated cheese production site, identified food safety non-conformities, and enforced hygiene measures. Environmental and product specimens collected at the visit tested negative for Salmonella spp. Taken together, the most plausible vehicle in this outbreak was fresh cheese. The case–case design enabled a rapid, low-cost analysis to support targeted investigation using surveillance data. Using WGS cluster cases as the case definition, rather than all S. typhimurium cases during the outbreak period, yielded a higher OR in the case–case study, increasing confidence in the findings. We recommend this combined approach as part of the toolkit for foodborne outbreak investigations in Portugal in similar contexts.

Fluctuations in disease severity occurred throughout the COVID-19 pandemic in England due to emerging variants and changing population immunity. Deaths caused by COVID-19 reduced from 2022; however, a smaller reduction was observed in deaths following a COVID-19 test. This study examines whether mortality risk within 28 days of a positive SARS-CoV-2 test remained elevated during a period of reduced disease severity. National-level routinely collected health data containing SARS-CoV-2 test results, vaccination, hospital, and death records were linked to create a population-level cohort. Individuals testing positive and negative were matched on demographic and disease characteristics. Mortality risk was compared using univariable and multivariable conditional logistic regression models for the overall time-period (March 2020–April 2022) and the focus time-period (January–April 2022). Individuals testing positive in the overall time-period had a 228% increased risk of death than those testing negative. In the focused time-period, test positive individuals had 63% higher odds of death, accounting for vaccination and previous hospitalisation. The increased risk of death associated with testing positive was greater among unvaccinated individuals (238%) than vaccinated individuals (155%). Mortality risk following COVID-19 remained elevated at the end of the pandemic, especially among unvaccinated individuals, supporting continued COVID-19 booster vaccination campaigns.

The global health landscape has entered a period of profound change. Official development assistance for health has sharply declined, while new U.S. policies threaten long-standing public health norms and undermine evidence-based guidance. Vaccine hesitancy, political interference in medical recommendations, and climate policy reversals illustrate a troubling erosion of scientific authority. These developments coincide with growing polarization, revealing that ‘following the science’ is neither straightforward nor free from uncertainty. The COVID-19 pandemic exposed how public health decisions were often made under evolving evidence, with limited transparency about risks, trade-offs, and unintended consequences. Subsequent international initiatives, such as the WHO’s global agenda on Public Health and Social Measures, now seek to build a more balanced evidence base. Rebuilding public trust demands openness about uncertainty, acknowledgement of past missteps, and transparent communication of policy rationales. Structured after-action reviews and community engagement are essential to demonstrate accountability and learning. Ultimately, restoring confidence in science and public health will require humility, consistency, and cross-partisan collaboration to show that science is adaptive, responsive, and committed to improvement.

Human metapneumovirus (HMPV), which belongs to the a family, has shown the emergence of the A2b2 clade as the dominant global genotype. Whether this represents true evolutionary selection or surveillance artefacts remains unclear. We analysed 315 complete HMPV genome sequences (1994–2024) from the Nextstrain database using sampling-corrected statistical approaches, including temporal homogeneity testing, rarefaction analysis, and entropy-based dynamics to examine non-random patterns in A2b2 emergence. Temporal homogeneity testing revealed strong directional evolution towards A2b2 dominance (Z = −46.62, p < 0.001), confirming non-random patterns rather than surveillance artefacts. The clade showed strong persistence (206 self-transitions) with limited backward transitions. After controlling for sampling bias, A2b2 represented 68.3% (95% CI: 58.2–78.4) of isolates in 2023–2024. A2b2 demonstrated significantly higher temporal entropy (2.1) than other clades (A1: 1.2, A2a: 1.5, A2b1: 2.0), indicating more complex dynamics. Geographic rarefaction revealed significant regional structuring, with Africa showing the highest diversity (3.00, 95% CI: 1.00–3.05) despite lower sampling. HMPV A2b2’s global expansion represents genuine directional evolution with potential selective advantages, similar to patterns in respiratory syncytial virus. These findings underscore the need for enhanced genomic surveillance and integration of HMPV monitoring into respiratory virus surveillance frameworks to track emerging variants and assess public health implications.

This study aimed to investigate a four-month Ralstonia pickettii outbreak by characterizing clinical and environmental isolates while also demonstrating the infection control measures taken to identify and eliminate the sources. R. pickettii was isolated from patients’ blood cultures, and an epidemiological investigation was initiated to determine the source of the outbreak. Clonal relatedness among clinical and environmental samples was assessed using pulsed-field gel electrophoresis. In total, R. pickettii was isolated from 14 patient blood cultures and 3 bottles of sterile distilled water. Between April 14 and May 15, six patients had positive port cultures, including four with positive peripheral cultures. The contaminated water was identified as the outbreak source, and its use was discontinued on May 15. Nevertheless, two additional cases occurred in June. Port catheter colonization with R. pickettii was considered to be linked to contaminated water used during chemotherapy preparation. A recall of port catheter patients who received chemotherapy in April–May identified six more cases. Pulsed-field gel electrophoresis revealed two pulsotypes among water isolates, and most clinical isolates were clonally related to clone 1. This investigation highlighted the role of contaminated sterile distilled water and colonized medical devices as potential sources of R. pickettii outbreaks.

Malaria remains one of the critical public health threats, particularly in endemic sub-Saharan countries like Malawi. Although malaria prevalence has declined over the years, the disease continues to pose a notable public health burden, contributing to high levels of morbidity and mortality. This study mapped malaria risk in Nsanje District, southern Malawi. Environmental variables (temperature, rainfall, elevation, slope, and proximity to rivers) were used to model malaria hazard, while socio-economic factors (proximity to health facilities and roads, and population density) defined vulnerability. Land use and land cover derived from Sentinel-2 using the random trees classifier in ArcGIS Pro were used to delineate elements at risk. The analytical hierarchy process and weighted overlay analysis were applied to generate hazard, vulnerability, and risk maps. Additionally, sensitivity analysis was conducted to determine the most influential factors. Results show that temperature and rainfall contributed more within the model to malaria hazard, with 20.4% and 35.1% of the area classified as high- and very high-hazard zones, respectively. Vulnerability was mainly affected by proximity to health facilities and population density, while 43.1% of the district was categorized as high risk and 40.5% as moderate risk. Overall, malaria hazard contributed most to the total risk, followed by vulnerability. The findings of this study are essential for understanding the complex dynamics of malaria transmission, which are influenced by a combination of environmental, climatic, and socio-economic factors. The study recommends enhancing healthcare accessibility and developing early warning systems, including malaria risk maps, to support targeted prevention and control efforts. Future studies should integrate long-term climate projections and real-time, high-frequency environmental and epidemiological data to enhance malaria risk modelling.

National foodborne outbreaks of gastrointestinal disease often require rapid case–control investigations to identify the source. Online market panels offer a potential alternative to traditional control recruitment. We compared market panel controls to traditional controls in case–control recruitment during a 2024 UK outbreak of STEC O145. Two case–control studies were conducted for two different control groups (a) Salmonella cases as case–controls and (b) online market panel members. Timeliness, cost, and resources were compared, and a logistic regression compared findings in a control–control analysis. In total, 43 cases of STEC O145, 63 Salmonella case–controls, and 93 panel controls were recruited. Neither control group reached the recruitment target for the younger adult age group. Salmonella case–controls had a ninefold greater staff time to recruit and cost five times more than panel controls (£25.82 vs. £4.99 per control), partially due to interviewer-administered questionnaires compared with self-completion by panel controls. Both analytical approaches identified the same outbreak source, with no significant differences in exposures between the control groups. The cost and resource savings associated with panel controls justify their use as a standard procedure in outbreak investigations. We recommend exploring engagement with age groups that are difficult to recruit and assessing alternative strategies to reach them.

People experiencing homelessness (PEH) are at increased risk of tuberculosis (TB) infection and progression to TB disease. Data on TB infection prevalence among hospitalised PEH in low-incidence countries remain limited. This study aimed to estimate TB infection prevalence and describe associated demographic and clinical characteristics among PEH admitted to an urban tertiary hospital in Dublin, Ireland. A prevalence study was conducted between November 2023 and March 2025 using an opt-out screening model. Hospitalised PEH were offered interferon gamma release assay (IGRA) testing on admission. Demographic and clinical data were collected, and positive IGRA results were assessed clinically and radiographically to exclude active TB disease. Estimated lifetime risk of progression to TB disease was calculated using a validated risk-modelling algorithm.Among 118 PEH screened, 13 (11%) were IGRA-positive and 3 (2.5%) had indeterminate results. The cohort was predominantly male (77%) with a mean age of 46 years. Non–Irish-born individuals had higher IGRA positivity than Irish-born participants (23.8% vs 8.3%, p = .054). Substance and alcohol use disorders were common, over half had previous incarceration, and one-third were sleeping rough at admission. Among IGRA-positive individuals, the mean estimated lifetime risk of progression to TB disease was 6.96% (SD 3.3). These findings support strengthened, integrated TB prevention strategies for PEH.

Time-varying effective reproductive numbers of infectious diseases are commonly estimated using renewal equation models. In the widely applied R package EpiEstim and various related tools, this approach is combined with a Poisson distributional assumption. This has been criticized on various occasions, mostly on grounds of general model realism or a desire to estimate dispersion parameters. Here, we argue that an important issue arising from the Poisson assumption is that inference about the effective reproductive number becomes overconfident in the presence of overdispersion. The extent to which standard errors are underestimated follows from theory on generalized linear models in a straightforward manner. We therefore recommend to replace the Poisson assumption by quasi-Poisson or negative binomial extensions, and contrast their respective properties. We illustrate our arguments in detailed simulation studies and three case studies on Ebola, pandemic influenza, and COVID-19.

Epidemiological estimates for the incidence of skin and soft-tissue infections (SSTIs) in England are limited. We aimed at evaluating the incidence of SSTIs and associated complications through a retrospective, observational 11-year study (2010–2020). We retrieved data on SSTI and associated complications from Clinical Practice Research Datalink, Hospital Episode Statistics, and the Office for National Statistics for England. More than four million SSTI episodes were identified, which corresponded to an overall incidence of 33.1 per 1000 person-years of observation (PYO). The incidence per 1000 PYO was highest in patients with a previous history of SSTI (109.8), ≥65 years (70.1), and those with comorbidities (69.0). The incidence of abscesses/cellulitis/other SSTIs (25.7) was the most frequent, followed by chronic ulcers (4.7) and surgical site infections (2.8). Of the 0.4 million SSTI hospitalizations, ~62.8% were due to abscesses/cellulitis/other SSTIs. Recurrences in the 12 months after the first SSTI were found in 19.5% of cases. Mortality due to SSTI and related complications varied between 0.4% and 0.5% across years, mostly in hospitalized settings. These results show that SSTIs are responsible for a substantial burden of disease in England and will help clinicians in better understanding the epidemiology of SSTI.

Late HIV diagnosis increases morbidity and mortality. In this retrospective cohort study on the national HIV register, we analysed risk factors for late HIV diagnosis among newly registered people living with HIV (PLWH) between 2008 and 2023, using the updated definition. Of 2683 PLWH registered, 1813 (67.6%) were newly diagnosed with CD4+ T-cell count available ≤90 days for 1572 (86.7%). Eighty-seven of the 609 (14.3%) individuals with CD4+ T-cell count <350/μL had recent infections and were reclassified as non-late. Of the newly diagnosed, 50.3% were diagnosed late. Multivariable analysis identified higher age as an independent risk factor for late diagnosis (adjusted OR 1.42 per ten years, 95% CI 1.30–1.56). Of the Finnish-born, females had lower odds than males (aOR 0.59, 95% CI 0.39–0.88). Asian-born (aOR 6.83, 95% CI 3.49–13.35) and African-born females (aOR 3.26, 95% CI 1.58–6.73) had significantly higher odds than Finnish-born females. In urban municipalities, men who have sex with men had lower odds than individuals with heterosexual transmission (aOR 0.55, 95% CI 0.40–0.76). Higher age was the most important factor for increasing the proportion of late diagnoses. We recommend enhanced testing and risk awareness for older adults and migrants from high-prevalence countries.