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Travel Medicine and Infectious Disease

Elsevier BV

Preprints posted in the last 90 days, ranked by how well they match Travel Medicine and Infectious Disease's content profile, based on 14 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

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HPAI H5N1 risk in Australia: a model for the prediction of poultry outbreaks

Zhang, P.; Lim, S.; Quigley, A.; MacIntyre, C. R.

2026-07-28 bioinformatics 10.64898/2026.07.27.740638 medRxiv
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The panzootic highly pathogenic avian influenza (HPAI) H5N1 virus has now been detected on the Australian mainland, with incursions from the sub-Antarctic region posing an increasing threat to domestic wildlife and poultry populations. Our study aimed to predict the risk of HPAI H5N1 poultry outbreaks across Australia at the local government area (LGA) level using a range of influential risk factors. We first used a Maximum Entropy (MaxEnt) model to estimate the environmental suitability for HPAI H5N1 occurrence across Australia. The resulting suitability layer was then integrated with five additional predictor layers, including abundance data for two Southern Ocean wild birds, one of which has introduced HPAI H5N1 into Australia; abundance data for 28 native Australian wild birds; native bird flyways across Australia; Australian chicken density; and poultry farm density. The six layers were aggregated and averaged to generate an HPAI H5N1 risk map for poultry outbreaks across Australian LGAs. Although most incursions have occurred in Western Australia (WA) and South Australia (SA), we identified New South Wales (NSW) and Victoria (VIC) as having the highest predicted risk of HPAI H5N1 poultry outbreaks. Additional high-risk areas were identified in WA, SA, and Tasmania (TAS). In contrast, the Northern Territory (NT) and large parts of Queensland (QLD), WA, and SA were predicted to be at low risk. These findings provide a spatially explicit framework to support targeted surveillance, preparedness, and biosecurity measures aimed at mitigating the impact of future HPAI H5N1 outbreaks in Australian poultry.

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Travel health needs in people visiting friends and relatives: a retrospective analysis of the UK National Travel Health Advice Line, 2019-2025

Elkheir, N.; Kanagarajah, S.; Patel, D.

2026-07-20 public and global health 10.64898/2026.07.17.26358325 medRxiv
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Background: Travellers visiting friends and relatives (VFRs) experience a disproportionate burden of travel-associated infectious diseases, yet little is known about the complexity of pre-travel consultations required to support their care. We compared enquiries relating to VFR travellers and tourists received by the UK National Travel Health Network and Centre (NaTHNaC) specialist Advice Line to identify differences in traveller characteristics, destinations and clinical complexity. Methods: We conducted a retrospective observational study of enquiries to the NaTHNaC Advice Line between 1 January 2019 and 31 December 2025. Enquiries relating to VFR travellers and tourists were compared using descriptive statistics and appropriate statistical tests. Traveller demographics, travel characteristics, destinations and enquiry management were analysed. Results: Of 16,367 enquiries relating to specific travellers, 3,090 (18.9%) concerned VFR travellers and 7,237 (44.2%) concerned tourists. Compared with tourists, VFR travellers were younger (median age 24 vs 52 years, P<0.001), more likely to undertake long-stay (8.4% vs 1.8%, P<0.001) and last-minute travel (5.0% vs 1.1%, P<0.001), and more frequently travelled to the WHO African Region (56.6% vs 29.2%, P<0.001) and Eastern Mediterranean Region (12.7% vs 2.8%, P<0.001). Pregnancy was substantially more common among VFR travellers (11.6% vs 4.3%, P<0.001). Enquiries concerning VFR travellers were more likely to require a call-back (16.1% vs 13.8%, P=0.012) and escalation to a specialist doctor (13.1% vs 10.5%, P<0.001), indicating greater consultation complexity. General practice generated a higher proportion of VFR-related enquiries than tourist enquiries (69.5% vs 63.9%, P<0.001). Conclusions: VFR travellers generate disproportionately complex pre-travel consultations characterised by higher rates of specialist escalation, distinct travel patterns and travel to destinations associated with the greatest burden of imported infectious diseases. These findings highlight the importance of specialist travel medicine support for healthcare professionals managing VFR travellers and reinforce the need for equitable access to timely, high-quality pre-travel healthcare for this high-risk population.

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Cost analysis of overseas versus domestic vaccination of US-bound refugees

Joo, H.; Maskery, B.; Klosovsky, A.; Marquez, M.; Taher, S.; Dalal, W.; Weinberg, M.; Mitchell, T.

2026-06-18 health economics 10.64898/2026.06.09.26355167 medRxiv
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Context: To ensure healthy resettlement and protect US health security, the Vaccination Program for US-bound Refugees (VPR) offers some recommended vaccines to refugees overseas before resettlement to the United States. The selected vaccines and number of doses vary by country of departure. VPR was found to be cost-saving in 2018 but had since expanded to more sites. Objective: Assess VPR's current costs and impact on post-arrival domestic vaccination needs and costs. Setting and Participants: A model-based analysis of the Federal government costs for VPR and post-arrival (US) vaccination of resettled refugees separated across five regions: Africa, Asia, the Middle East and North Africa/Republic of Turkiye and Middle East, Europe, and the Americas using fiscal year 2024 data. Design: We quantified and compared full vaccination costs for refugees under two scenarios: (1) 'No VPR' and (2) 'VPR'. Refugees would receive no vaccines overseas and be fully vaccinated after US arrival under 'No VPR'. Under 'VPR', refugees receive one or two doses of selected vaccines overseas before completing vaccination schedules after arrival. Main Outcomes: Costs were reported in 2023 US dollars for 'VPR' and 'No VPR' scenarios and further subdivided by grouping countries/sites depending on whether the International Organization for Migration (IOM) provides vaccination services for refugees (IOM sites) versus non-IOM providers (non-IOM sites). Results: 'VPR' resulted in average net cost savings of $147 per person or $14.7 million per 100,000-refugee cohort compared to providing all vaccines after US arrival ('No VPR'). 'VPR' was cost-saving across most regions, except for IOM sites in Europe, where a net cost of $44 per person was observed. Net cost savings per person were highest for IOM sites in Africa ($333). Conclusions: VPR remains a cost-saving strategy, while protecting US-bound refugees' health and US health security by preventing disease outbreaks during resettlement.

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Estimating the Cost of Typhoid Conjugate Vaccine Delivery in Ghana and the Democratic Republic of the Congo

Mensah, K. A.; Lumbala, R.; Hwang, Y.; Morgan, W.; Phoba, M.-F.; Agyapong, F. O.; Owusu, M.; Mbuyamba, J.; Owusu-Ansah, M.; Thwe, T. T.; Siribie, M.; Kumbukama, J.-P.; Khuwa, P. C.; Jeon, H.; Tadesse, B. T.; Twumasi-Ankrah, S.; Marks, F.; Lunguya, O.; Owusu-Dabo, E.; Lee, J.-S.

2026-08-14 health economics 10.64898/2026.08.12.26360337 medRxiv
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Typhoid fever remains a significant burden in low- and middle-income countries (LMICs). The World Health Organization recommends incorporating typhoid conjugate vaccines (TCVs) into the routine immunization programs of typhoid-endemic countries. Although TCV has been shown to be safe, well tolerated, and effective, evidence on its delivery costs in African settings remains limited. This study provides economic evidence on the cost of implementing TCV catch-up campaigns. This retrospective provider-perspective costing study evaluated TCV catch-up vaccination campaigns conducted in the Asante-Akim North District of Ghana and the Kisantu Health Zone of the Democratic Republic of the Congo (DRC). The campaigns targeted children aged 9 months to 15 years. An incremental costing approach was used, and a Microsoft Excel-based tool was developed to estimate costs. The total number of vaccinated individuals was 54,814; 10,052 in Ghana and 44,762 in the DRC. The financial cost per fully immunized person (FIP), including vaccine and vaccination supply costs, was estimated at US$ 5.78 in Ghana and US$ 5.47 in the DRC. The corresponding economic costs were estimated at US$ 6.09 in Ghana and US$ 5.89 in the DRC. Vaccine procurement and vaccination supplies represented the largest cost component, accounting for US$ 2.76 per FIP in Ghana and US$ 2.39 per FIP in the DRC, followed by service delivery and service delivery support activities. This study provides empirical estimates of the financial and economic costs of TCV catch-up campaigns in Ghana and the DRC. These findings provide country-specific evidence to inform planning, budgeting, economic evaluation, and policy decisions regarding future TCV introduction in typhoid-endemic settings.

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Economic burden associated with ESBL-producing Escherichia coli infections in Laos: econometric modeling using evidence from a prospective cost-of-illness study

Choi, W.; Santisouk, P.; Yum, Y.; Lee, J.; Song, S.; Souvanhnavong, P.; Salodchanar, K.; Khathtiyavong, N.; Thi Ha, N.; Phanthavong, S.; Manivanh, L.; Phetsouvanh, R.; Detleuxay, K.; Dittaphong, V.; Lee, J.-S.

2026-08-10 health economics 10.64898/2026.08.05.26358101 medRxiv
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Introduction: Antimicrobial resistance poses a major global health threat, yet evidence on its economic impact in low- and middle-income countries remains limited. This study estimated the economic burden of infections caused by ESBL-producing Escherichia coli (E. coli), a key resistant pathogen, in Laos. Methods: A prospective cost-of-illness study was conducted among patients with laboratory-confirmed infections in Setthathirath hospital in Vientiane, Laos, collecting cost data through repeated interviews and medical records. Descriptive analyses and econometric modeling approaches, including inverse probability weighting (IPW) and instrumental variable (IV) analyses, were used to estimate out-of-pocket expenditures, public expenditures, total cost of illness, and length of stay, accounting for potential confounding. Results: ESBL-producing E. coli was consistently associated with higher economic burden across all analyses. The unadjusted per-patient cost was US$ 689.0 for ESBL-producing E. coli, compared with US$ 489.4 for non-ESBL-producing E. coli and US$ 537.6 for non-E. coli. The association remained statistically significant for out-of-pocket cost after IPW-adjustment (US$156.2; 95% CI, 14.3 to 298.1; P = 0.03), while other outcomes were not statistically significant. Instrumental variable analyses showed consistent directional effects but with wide confidence intervals and no statistically significant differences. Conclusions: Findings suggest that ESBL-producing E. coli may be associated with increased economic burden in Laos; however, this association was not consistently statistically robust across analytical approaches. These findings suggest a potential economic impact of ESBL infection, although uncertainty remains regarding the magnitude of the effect. Strengthening antimicrobial stewardship, infection prevention and control, and improved diagnostic capacity remain essential to mitigate the potential AMR burden.

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Costs and Benefits of Malaria Elimination in Kenya by Means of IVM Implementation

Movilla Blanco, S.

2026-06-22 health economics 10.64898/2026.06.19.26355954 medRxiv
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Introduction: Integrated Vector Management (IVM) (Beier et al., 2008) is considered to be one of the most cost-effective tools to reduce malaria transmission. This rational decision-making tool supports the design of an intelligent and optimal management of resources meant for malaria prevention and vector control. Some of the most widespread components of IVM include the distribution of bed nets, spraying operations and environmental management to reduce mosquito density. IVM was launched in Kenya in 2001, and during the last two decades the country has advocated for the use of this tool to combat malaria. IVM, however, requires a customized choice of interventions in order to achieve the optimal use of resources for vector control in the area of interest. Methods: In this article, we present a malaria simulation model that helps us assess the potential impact of different future IVM strategies to achieve optimal malaria reduction results in Kenya. The model used for this analysis is inspired by the Malaria Management Model (MMM) (Pedercini, Movilla Blanco, & Kopainsky, 2011), which has been developed by means of the System Dynamics methodology. The version of the model presented in this paper is adapted for Kenya, and the study includes the assessment of the cost and main socio-economic benefits from eliminating malaria in the country. The model also integrates the main impacts of malaria transmission into the socio-economic development, evaluating the effect of malaria on GDP production, literacy rate and life expectancy, among others. Results: Our model includes data collected from 1980 until 2018, before the RTS,S/AS01 vaccine was piloted in Kenya, and the simulation results confirm that the IVM programs in Kenya would not achieve malaria elimination within this decade. In addition to a substantial increase in the malaria budget, a reallocation of such a budget across interventions would be necessary in order to reach a malaria-free country by 2030 (Kenya Malaria Strategic Plan). The results also confirm that, despite the need for further efforts, malaria reduction in Kenya has provided sufficient economic benefits to cover the costs of malaria control. Conclusions: The System Dynamics simulation model illustrates how a computer-aided scenario analysis tool can inform the design of malaria control policies and assist decision-makers. Simulation models create systematic mechanisms for analyzing alternative interventions and inform about the different tradeoffs.

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Incidence of bacterial sexually transmitted infections and associated factors in men who have sex with men: results from the ANRS 12 400/DepIST-H cohort

ADAMA, O. I. W.; Bercot, B.; Sadio, A. J.; Gbeasor-Komlanvi, F. A.; Tchankoni, M. K.; Konu, Y. R.; Salou, M.; Mensah, E.; Dagnra, A. C.; Ghosn, J.; Ferre, V. M.; Descamps, D.; Charpentier, C.; Ekouevi, D. K.; Bebear, C.

2026-07-30 epidemiology 10.64898/2026.07.28.26359109 medRxiv
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Background. The objective was through an analysis of longitudinal data from the DepIST-H cohort to estimate the incidence, describe the dynamics and factors associated with CT/NG infection in MSM in Togo. Methods. A total of 200 MSM in Lome, Togo, were included in the ANRS I MIE 12400/DepIST-H cohort, half living with HIV. After inclusion in the study, participants received follow-up clinical visits at 6 and 18 months, and laboratory tests were performed at baseline (M0) and at 12 and 24 months (M12 and M24). PCR tests for CT and NG were performed from pharyngeal, anal and urine samples collected using the Xpert(R) CT/GC kit (Sunnyvale, CA, USA). To identify the factors associated with anal bacterial STIs, offset term Poisson regression models were performed. Results. Among 200 MSM (median age 24 years), CT and NG incidence rates were high ({approx}22 cases per 100 person-years), particularly at the anal site. Multiple partners significantly increased anal NG incidence (aIRR 2.35). Anal NG incidence was significantly lower among participants with income-generating activity (aIRR 0.57). Trends suggested higher anal CT and NG incidence in the presence of pharyngeal infection, but associations were not statistically significant Conclusion. This study confirms that MSM remain highly exposed to STIs in Togo and highlights the need to strengthen prevention efforts within this population. Postexposure doxycycline prophylaxis and multisite pooled-sample screening represent promising avenues to strengthen prevention efforts within these populations.

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Cost-effectiveness of measles rapid diagnostic tests for replacing or expanding laboratory testing in Ethiopia

McAndrew, F.; Khant, K.; Delport, D.; Abeysuriya, R. G.; Alayu, M.; Fowkes, F. J. I. J.; Gavioli, R.; Kehali, K. Y.; Mekoro, M.; Moore, K. A.; Sheel, M.; Yirgu, B.; Oo, W. H.; Scott, N.

2026-06-17 health economics 10.64898/2026.06.15.26355722 medRxiv
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Background: In low- and middle-income countries, laboratory testing to rapidly detect measles outbreaks is limited by infrastructure availability and high costs. This study estimates the potential impact and cost-effectiveness of measles rapid diagnostic tests (RDTs) if implemented nationally in Ethiopia to either replace or expand current testing. Methods: An agent-based model to simulate measles outbreaks was calibrated to Ethiopian measles surveillance data. Modelled outbreak outcomes were aggregated over a 10-year period. Scenarios included using RDTs to (1) replace laboratory testing; (2) replace epidemiological linkage; and (3) increase case detection, in addition to replacing laboratory testing and epidemiological linkage. Testing and outbreak response costs (in 2025 US$) were obtained from Ethiopian Public Health Institute from a government perspective. Total costs and disability-adjusted life years (DALYs) for each scenario were compared to baseline. Results: All scenarios were cost saving compared to baseline. Replacing laboratory testing with RDTs saved US$4.2M (3.2M-4.9M) over 10-years, but due to very low testing rates the benefits of eliminating laboratory testing delays were offset by missed cases from the lower RDT sensitivity, leading to similar outbreak detection times and DALYs. Replacing epidemiological linkage with RDTs had similar DALYs but increased the cost savings to US$9.7M. Using RDTs to double case detection reduced outbreak detection time from 113 to 80 days, averted 17,000 DALYs, and saved US$4.3M. Conclusions: In Ethiopia, use of measles RDTs could be cost saving, and if used to expand testing could prevent measles infections through faster outbreak detection and response.

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Cost-Effectiveness of an Integrated Antenatal Care Testing Panel to Accelerate the Triple Elimination of Mother-to-Child Transmission of HIV, Syphilis, and Hepatitis B in Nigeria: Modeling Study

Dzimbiri, I. K.; Dusabeyezu, P.; Ahmed, A.; Ochwoto, M.; Kingsley, M.; Shepard, D. S.

2026-08-17 health economics 10.64898/2026.08.14.26360312 medRxiv
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Background. In 2025, the World Health Organization pre-qualified an integrated antenatal care (ANC) testing panel that tests for HIV (including p24 antigen and antibody), syphilis, and hepatitis B (HBV) with one finger prick. The panel would accelerate the triple elimination of vertically transmitted infections by shortening the HIV detection window and increasing testing rates. Nigeria is considering adoption but needs performance and cost projections. Methods. We constructed deterministic (with Microsoft Excel) and probabilistic (with Python) models, including parallel testing and treatment post-exposure prophylaxis algorithms for positive p24. We calibrated the models to Nigeria's 6.4 million women entering ANC annually using epidemiologic literature, product prices, and occasionally expert opinion. We compared costs (in 2025 US dollars) and outcomes between current and projected future (2027) practices. Results. The panel would avert 562 of the current 3,299 vertical infections per 100,000 women in ANC. Per woman in ANC, the panel would avert 0.0656 disability adjusted life years (DALYs) at a net cost of US$7.55. With low current testing rates. HBV testing averts the most DALYs (33%), followed by acute HIV (29%), chronic HIV (25%), and syphilis (14%). The incremental cost-effectiveness ratio (ICER) is $115 (95% confidence interval: $91-$143) per DALY averted--more favorable than Nigeria's conservative historical $137 average. The benefit-cost ratio is also favorable (1.19; 95% confidence interval: 0.93-1.51). Conclusions. The integrated ANC testing panel would be a valuable and cost-effective addition to ANC care. Piloting in Nigeria and similar sub-Saharan African countries would refine parameters for potential scale up.

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Early assessment of potential airline-mediated importation risk during the 2026 DRC-Uganda Bundibugyo virus disease outbreak

Kinoshita, R.; Suzuki, M.; Yoneoka, D.

2026-06-09 public and global health 10.64898/2026.06.01.26354569 medRxiv
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During the 2026 Bundibugyo virus disease outbreak in the Democratic Republic of the Congo and Uganda, we projected potential airline-mediated importation risk using contemporary airline network and an externally calibrated Ebola importation hazard. Effective-distance analyses identified major international hub countries, including Belgium, France, South Africa, Kenya, and the United Arab Emirates, as higher-probability gateways within 30 days. These early projections provide a reproducible framework for real-time international situational awareness, while emphasizing that importation risk does not imply local transmission risk.

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Predictive models for hospitalization and mortality in dengue using SINAN data: study protocol for development, temporal validation, and performance evaluation

Delpino, F. M. M.; Magalhaes, D.; Peres, I. T.; Gusberti, T.; de Lima, C. J.; Bozza, F. A.; Ranzani, O.; Bastos, L.

2026-08-04 infectious diseases 10.64898/2026.08.03.26359583 medRxiv
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Background: Dengue continues to place a heavy clinical and organizational burden on health care systems, particularly during epidemics, when the high volume of cases adds pressure on triage, decisions regarding hospitalization, and the monitoring of patients at higher risk of severe outcomes. Despite the growing body of literature on dengue prediction, many studies still exhibit heterogeneity in outcomes, insufficiently detailed analytical designs, and a lack of validation. Objective: To describe the protocol for a study on the development and validation of predictive models for the outcomes of hospitalization among reported cases and mortality among hospitalized patients. Methods: A retrospective study will be conducted using secondary data from the Brazilian Notifiable Diseases Information System (SINAN), covering the period from 2017 to 2025. We will build two independent models: one to predict hospitalization among reported dengue cases and another to predict mortality among patients hospitalized for dengue. The protocol will follow TRIPOD+AI guidelines and include prior definition of eligible predictors, restriction to variables available at the clinically appropriate time of decision-making, handling of missing data, comparison between regression and machine learning algorithms, internal and temporal validation, and assessment of discrimination, calibration, and clinical utility. Conclusion: The study aims to establish a transparent and reproducible analytical protocol to support the development of risk models that could be applied to clinical screening and surveillance for dengue.

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Metagenomic profiling of bacterial endosymbionts in wild mutant and permethrin-susceptible head lice shows an expanded microbiota in the resistant strain

Mohammadi, J.; Alipour, H.; Azizi, K.; Kalantari, M.; Moemenbellah-Fard, M. D.

2026-07-20 bioinformatics 10.64898/2026.07.14.738380 medRxiv
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BackgroundHuman head lice (Pediculus humanus capitis de Geer) are known to harbor diverse maternally inherited bacterial symbionts. These endosymbiotic bacteria may contribute to insecticide degradation, potentially helping lice withstand particular environmental pressures. Using next-generation sequencing (NGS), this study investigated the bacterial symbionts present in wild head-louse populations and characterized their phylogenetic relationships in mutant and permethrin-susceptible strains. MethodsHead lice specimens were collected from 10 locations across Fars Province, Iran. Following DNA extraction, the samples were analyzed using polymerase chain reaction (PCR), and the resulting amplicons were sequenced to detect mutations in specimens from each location. Lice were then classified according to the presence or absence of mutations and subjected to NGS to characterize the symbiotic bacterial communities in mutant and putatively permethrin-susceptible strains. ResultsMutant strains were detected at only three sampling stations. Bioinformatic analysis of the nucleic acid sequences revealed three exons and two introns, with an expected amplicon length of 582 bp. NGS analysis showed that Candidatus Riesia pediculicola (Arsenophonus), belonging to the phylum Proteobacteria, was the predominant bacterial genus. Actinobacteria and Firmicutes were the second- and third-most abundant phyla, respectively. Most of the remaining 25 bacterial taxa were associated with the mutant strain. Additionally, two previously unreported bacterial genera were deposited in GenBank. ConclusionsThe distinct distribution of Arsenophonus species between susceptible and mutant head-lice strains--along with the greater abundance of Escherichia, Shigella, Lawsonella, and Megamonas in mutant strains--highlights the need for advanced metagenomic analyses to determine how these endosymbionts may help their hosts withstand specific environmental disturbances.

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Tick-Induced Mammalian Meat Allergy in Australia: National Prevalence and Geographic Distribution from Laboratory Surveillance, 2014-2024

Smith, E.; Campbell, P.; Kennedy, C.; Baumgart, K.; Wallman, L.; Barker, S. C.; van Nunen, S.; Walker, A. A.; Gofton, A. W.

2026-07-15 epidemiology 10.64898/2026.07.13.26358004 medRxiv
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Objectives: To characterise the national epidemiology of tick-induced mammalian meat allergy (MMA) in Australia, including temporal trends in Gal specific IgE testing and case detection, geographic distribution, demographic risk factors, and longitudinal antibody dynamics. Design: Retrospective analysis of Gal sIgE ImmunoCAP test results from 1 January 2014 to 31 December 2024. Setting, Participants: Deidentified laboratory records from 14,075 individuals tested across Australia, with residential postcodes mapped to Statistical Areas Level 3 (SA3). A subset of 1,515 individuals with repeat testing contributed to longitudinal analyses. Main outcome measures: Test volumes, suspected MMA case counts, positivity rates, spatial clustering metrics, demographic risk ratios, and longitudinal Gal sIgE trajectories. Results: Overall, 35.7% (5,025) of individuals tested positive. Testing volume increased 331% over the study period, with case detection accelerating sharply from 2020. Decomposition analysis attributed 59-81% of case growth to expanded testing, with the remainder unexplained by surveillance expansion alone. Cases were concentrated along the eastern seaboard within the range of Ixodes holocyclus, with extreme spatial clustering: three SA3 regions accounted for over one-quarter of national cases. Females comprised the majority of positive cases, and MMA risk increased with age, peaking at 45-74 years. Among 1,515 individuals with serial testing, Gal sIgE levels antibodies declined predictably in 93% of people. Conclusions: This first national assessment of MMA in Australia reveals a substantial, geographically concentrated, and growing burden. The extreme spatial concentration of cases suggests that targeted public health interventions could efficiently address a large proportion of national disease burden. While testing expansion is the dominant driver of rising case numbers, it does not fully account for observed trends, and prospective studies are needed to disentangle surveillance effects from genuine disease emergence. Declining antibody levels support the utility of serial testing for clinical monitoring, though persistent sensitisation underscores the need for sustained risk mitigation and continued surveillance.

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Cost-Effectiveness Analysis of the mRNA-1345 RSV Vaccine for Older Adults in Italy

Dronova, M.; Moyon, C.; Pyrek, L.; Hicks, K.; Xiao, Z.; Rumi, F.; de Waure, C.; Scholz, S.; Ghaswalla, P.

2026-08-18 health economics 10.64898/2026.08.17.26360570 medRxiv
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Introduction Respiratory syncytial virus (RSV) is an important cause of respiratory disease in older adults and adults with chronic medical conditions, contributing substantially to the healthcare burden in Italy. The availability of effective RSV vaccines provides an opportunity to reduce RSV-related morbidity, mortality, and healthcare costs in populations at high risk of severe disease. This study evaluates the potential public health impact and cost-effectiveness of vaccination using mRNA-1345 administered as a single dose compared with no vaccination in Italian high-risk adults aged 60-74 years and all adults aged [&ge;]75 years. Methods A static decision-analytic model was developed to project clinical and economic outcomes over a 5-year time horizon. Economic outcomes were evaluated from the Italian National Health Service (Servizio Sanitario Nazionale, SSN) perspective. Model inputs were informed by the most recent Italian epidemiological, clinical, and economic evidence, supplemented by published international data when necessary. Deterministic, probabilistic, and scenario analyses were conducted to assess the impact of uncertainty in model inputs and assumptions on the study results. Results Vaccination with mRNA-1345 in high-risk adults aged 60-74 years and all adults aged [&ge;]75 years was projected to avert over 19,800 hospitalizations, 4,000 emergency department visits, 381,000 outpatient visits, 6,000 RSV-attributable deaths, and 212,000 antibiotic prescriptions compared with no vaccination over a 5-year period. The total incremental cost of {euro}1,143 million and the additional 47,477 QALYs gained resulted in an ICER of {euro}24,078, which was below the commonly referenced willingness to-pay range of {euro}33,000-40,000 per QALY gained. Sensitivity analyses confirmed robustness of the analysis results. Conclusions Vaccination with mRNA-1345 is a cost-effective strategy for the prevention of RSV in high-risk adults aged 60-74 years and all adults [&ge;]75 years in Italy and has the potential to provide substantial public health benefits.

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Cost-effectiveness and cost-utility of antenatal sexually transmitted infection screening to reduce preterm birth and low birthweight in South Africa

Smith, E.; Babalola, C. M.; Medina-Marino, A.; Mdingi, M. M.; Mukomana, F.; Low, N.; Obse, A.; Peters, R. P. H.; Cleary, S.; Sinanovic, E.

2026-08-10 health economics 10.64898/2026.08.08.26360003 medRxiv
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Background: Curable sexually transmitted infections (STIs) are associated with adverse birth outcomes, yet little cost-effectiveness evidence guides antenatal STI screening policy in high-burden settings. We conducted a cost-effectiveness and cost-utility analysis of the Philani Ndiphile trial in South Africa, comparing One-Time and Two-Time antenatal screening for C. trachomatis, N. gonorrhoeae, and T. vaginalis with standard syndromic management. Methods: A decision-analytic model from the provider perspective simulated costs and outcomes for pregnant women and infants. Costs included diagnostics, treatment, and neonatal hospitalisation for a primary composite outcome of preterm birth and/or low birthweight and its components (secondary trial outcomes). Modelled outcomes included incremental cost (US$) per composite (preterm birth and/or low birthweight) case, per component case and per disability-adjusted life year (DALY) averted. The analysis captured infant outcomes in the first year. Univariate and probabilistic sensitivity analyses were conducted to assess parameter uncertainty and robustness of results. Results: Screening for C. trachomatis, N. gonorrhoeae, and T. vaginalis twice during pregnancy was not cost-effective for preventing the primary composite outcome, nor for preventing low birthweight alone. However, two-time screening was cost-saving for preventing preterm birth alone, averting more DALYs and thereby yielding better health outcomes while reducing healthcare costs compared with syndromic management. One-time screening was not cost-effective for preventing any outcome. Conclusions: Repeat antenatal screening for C. trachomatis, N. gonorrhoeae, and T. vaginalis has the potential to prevent preterm births while reducing healthcare costs in high-burden settings. These findings support further research to confirm the clinical effectiveness of repeat screening and to evaluate longer-term health and economic impacts.

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Serological Markers Predict Plasmodium vivax Relapses in Returning Indonesian Soldier Cohorts

Noviyanti, R.; Setya Utami, R. A.; Smith, L.; Trianty, L.; Ekawati, L.; Sutanto, E.; Amalia, R.; Amelia, A. R.; Hafidzah, M. A.; Fadila, N.; Puspitasari, A. M.; Nisa, F. A.; Hidar, H.; Kariodimedjo, P.; Farinisia, A.; Hutahaean, G.; Christian, M.; Kesuma, T. A.; Subekti, D.; Soebianto, S.; Wulandari, F.; Nuraeni, N.; Budiman, W.; Ertanto, Y.; Widiarta, M. D.; Furkan, F.; Nekkab, N.; Mazhari, R.; White, M.; Robinson, L.; Longley, R.; Baird, J. K.; Mueller, I.

2026-06-10 infectious diseases 10.64898/2026.06.08.26355218 medRxiv
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Summary Background Persistent transmission from relapsing Plasmodium vivax infections threatens malaria elimination programs in the Asia-Pacific and Americas. Tools to identify people at risk of relapse are urgently required. We aimed to validate a panel of eight P. vivax serological biomarkers for predicting future relapses. Methods In this observational study, soldiers returning from malaria-endemic Papua to non-endemic East Java, Indonesia, were screened at enrolment using antibody measurement (Luminex) and trained random forest classification algorithms, then followed for 6 months. Active case detection was performed fortnightly by microscopy. Algorithms classified soldiers as recently infected (last nine months) and thus at risk of relapse, based on anti-vivax antibody measurements at enrolment. Findings Between December 2018 and July 2022, 592 soldiers were enrolled, with 553 completing follow-up; 119 experienced a P. vivax relapse. Of these, 102 were correctly classified as at risk of relapse at enrolment, corresponding to 86% sensitivity and 86% specificity, with an AUC of 0.92. Interpretation P. vivax serological biomarkers can identify people at risk of relapse with high sensitivity and specificity and could be used as a novel public health intervention, P. vivax serological testing and treatment (PvSeroTAT), to reduce relapse-driven transmission.

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Prevalence and Determinants of Scabies Infection among Male Inmates at Kiambu Main Prison, Kenya: A Mixed-Methods Cross-Sectional Study

Kulundu, E. M.; Onkoba, W. N.; Ngwawe, C. O.

2026-08-04 epidemiology 10.64898/2026.08.03.26359545 medRxiv
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Background Scabies remains a major neglected tropical disease in correctional facilities due to overcrowding and limited hygiene resources. However, evidence regarding the determinants of scabies infection among inmates in Kenyan prisons remains limited. This study assessed the prevalence and determinants of scabies infection among male inmates at Kiambu Main Prison, Kiambu County, Kenya. Methodology A mixed-methods analytical cross-sectional study was conducted among 188 male inmates recruited using a ward-stratified pragmatic sampling approach between May and June, 2026. Quantitative data were collected using questionnaires and clinical examinations based on the International Alliance for the Control of Scabies (IACS) diagnostic criteria. Qualitative data were obtained through focus group discussions and key informant interviews. Quantitative data were analysed using descriptive statistics, chi-square tests, and logistic regression, whereas qualitative data were analysed thematically. Results The prevalence of scabies was 54.8%, with a weighted prevalence of 54.0% (95% CI: 46.5-61.6%). Daily bathing (AOR = 0.07, 95% CI: 0.01-0.31), bathing 2-3 times per week (AOR = 0.09, 95% CI: 0.01-0.44), and daily clothes washing (AOR = 0.21, 95% CI: 0.06-0.65) were independently associated with lower odds of scabies infection. Remandees had higher odds of infection than convicted prisoners (AOR = 1.97, 95% CI: 1.00-3.91). Qualitative findings identified overcrowding, inadequate hygiene resources, limited health education, medication shortage, and delays in treatment as key contributors to scabies transmission. Conclusion Scabies remains highly prevalent among inmates at Kiambu Main Prison. Both individual hygiene practices and institutional conditions contribute to disease transmission. Strengthening prison health services through routine screening, structured health education, improved access to hygiene resources, and timely diagnosis and treatment may help reduce transmission. These findings provide evidence to inform prison health policies and targeted scabies control programmes in Kenya and other resource-limited correctional settings.

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Micro-Costing Analysis for Human Papillomavirus (HPV) Vaccination Services for Out-of-School (OOS) Girls in Indonesia: Evidence from a Pilot Study

Siregar, A.; Amelia, I.; Rahma, R.; Hotma, P.; Alyasa, F. M.; Sari, L. N. I.; Mumtazah, S.; Andini, R.; Widyastuti, N.; Hidayatullah, T.; Anartati, A.; Patel, S.; Anisiska, D.; Hastuti, E. B.; Yosephine, P.

2026-06-29 health economics 10.64898/2026.06.24.26356497 medRxiv
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Cervical cancer remains a major public health challenge in Indonesia, with Human Papillomavirus (HPV) infection responsible for nearly all cases. The government has integrated HPV vaccination into the national School Children Immunization Month (BIAS). However, out-of-school (OOS) girls remain difficult to reach because they are not covered by the school-based vaccination platform. Micro-costing approach was used to estimate both economic and financial costs of delivering HPV vaccination to OOS girls in Bekasi City, Bandar Lampung City, and Bangka District. This study aimed to estimate the cost of delivering a single-dose HPV vaccination program to OOS girls and to project the national-level cost of scaling up the program. Costs were categorized into outreach efforts, such as community mobilization and identification of girls, and delivery components including logistics, storage, and administration. A scale-up costing analysis was also conducted to estimate national-level costs. The results show that the cost per vaccinated OOS girl aged 11 ranged from US$ 22.77 to 38.55, while the financial cost range from US$ 12.70 to 29.50, varied by implementation context, with outreach activities, transportation, and vaccine delivery supplies identified as the main cost drivers. The estimated national annual economic and financial cost of scaling-up HPV vaccination for OOS girls are US$ 644,215.23 and US$ 483,138.35, respectively. Our national cost estimates show that reaching and vaccinating OOS girls accounts for less than 3% of the national immunization budget. Factors such as local context and implementation challenges should be recognized as they may directly influence the cost and hinder the program scale-up.

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From Epidemic to Endemic: Longitudinal Surveillance of Congenital Zika Syndrome in Brazil

Oliveira Ferreira, R.; Ma, H. L.; Pestana Garcez, P.; Zatz, M.

2026-07-10 epidemiology 10.64898/2026.07.07.26357442 medRxiv
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Zika virus (ZIKV) emerged in Brazil in 2015, causing an unprecedented epidemic of Congenital Zika Syndrome (CZS). A decade later, longitudinal analyses evaluating temporal trends and subnational heterogeneity in CZS burden remain limited. Using publicly available data from SINAN/DATASUS and the RESP-Microcephaly registry (SVS/Ministry of Health, updated July 2024), we conducted a descriptive ecological analysis of ZIKV infection and CZS in Brazil from 2015 to 2023. Of 331,309 notified Zika cases (2015-2023), 213,350 occurred in 2016, followed by an 91.75% decline in 2017 and sustained low-level endemic circulation thereafter. Among 3,751 confirmed microcephaly cases, 1,828 were confirmed with ZIKV etiology. The Northeast region accounted for 75.4% of confirmed cases despite representing approximately 27% of the national population. State-level analyses revealed distinct epidemiological patterns, including persistent microcephaly notifications of non-Zika etiology in Minas Gerais and continued detection of ZIKV-attributed CZS in Amazonas and Goias through 2023. These findings highlight pronounced geographic disparities in congenital Zika burden, reflect significant heterogeneity in diagnostic capacity, and underscore the need for sustained surveillance and systematic etiological investigation of congenital abnormalities in the post-epidemic era.

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Genomic epidemiology and emerging antimicrobial resistance profiles of Salmonella Paratyphi A in returning travellers to Australia

Connor, C. H.; Wick, R. R.; Taouk, M. L.; Barden, J.; Dougall, S.; McAllister, J.; Judd, L. M.; Mercoulia, K.; Howden, B. P.; Ingle, D. J.

2026-08-25 public and global health 10.64898/2026.08.20.26360952 medRxiv
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Enteric fever is endemic to many low- and middle-income countries (LMICs), particularly those in sub-Saharan Africa, South and South-East Asia. The causative agents are typhoidal serovars of Salmonella enterica, including Typhi (S. Typhi) and Paratyphi A (SPA). There are no vaccines currently licensed for SPA, leaving antimicrobials as the only therapeutic option. Multi-drug resistance (MDR) S. Typhi is increasingly prevalent, but to date has not been detected in SPA. In Australia, cases of SPA are notifiable. Here we report on the genomic epidemiology of 208 cases of SPA in returned travellers to Australia, and their close contacts, from 2018 to 2025. A total of 15 unique genotypes were detected, and these were correlated with geographical regions of reported travel. There was a low incidence of antimicrobial resistance with only a single isolate carrying acquired resistance genes. Mutations in quinolone resistance determining regions were common across the genotypes, detected in 95.7% of isolates. A single isolate in a traveller returning from India was resistant to several first line antibiotics including: ampicillin, amoxicillin plus clavulanic acid, ceftriaxone, azithromycin and ciprofloxacin. The isolate carried a plasmid encoding an extended spectrum beta-lactamase (blaCTX-M-231), two macrolide resistance genes (mphA and ermB) and a quinolone resistance gene (qnrS1). Elements of the pangenome were explored, with stable maintenance of small plasmids encoding hypothetical proteins detected in four genotypes. Copy number variation in genes encoding surface antigen biosynthesis genes were detected in six genotypes. These biosynthesis genes are targets for one of the two SPA vaccines in development, and the potential variation in surface antigens could have implications for vaccine efficacy. Linking epidemiological data with genomic studies of SPA provides an opportunity to improve understanding of the emergence, spread and risk of drug-resistant SPA infections, and to better inform empirical treatment guidelines in returned travellers.