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The Lancet Regional Health - Americas

○ Elsevier BV

Preprints posted in the last 90 days, ranked by how well they match The Lancet Regional Health - Americas's content profile, based on 22 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

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Beyond Healthcare Utilization: A Whole-Child, Multi-Sector Approach to Pediatric Risk Stratification

Zolotor, A. F.; Gertner, A.; Chung, R. J.; Hatley, J.; Swanson, C.; Flower, K. B.; Steiner, M. J.; Bainbridge, J. M.; Lamb, C.; Wertman, E.; Cholera, R.

2026-09-09 health systems and quality improvement 10.64898/2026.09.08.26361653 medRxiv
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Objectives: The North Carolina Integrated Care for Kids (NC InCK) pediatric demonstration model created a whole-child risk stratification approach to identify children for enhanced care management. Unlike traditional approaches that rely primarily on healthcare data, NC InCK integrates health, education, social, and juvenile justice data. We described the NC InCK risk stratification approach and compared its output to Medicaid managed care organization (MCO)-assigned risk levels, with the hypothesis that these approaches would identify distinct populations. Methods: This was a cross-sectional study including NC Medicaid participants aged 0-20 years residing in a five-county region in central NC in October 2022. The NC InCK risk stratification algorithm was used to assign participants to Service Integration Levels (SILs) 1, 2, or 3, reflecting increasing anticipated need for integrated cross-sector support. Descriptive analyses compared participant baseline characteristics by NC InCK and Medicaid MCO risk level. Results: Of 99,564 children, 90,151 (90.5%) were assigned to SIL 1, 5,482 (5.5%) to SIL 2, and 3,931 (4%) to SIL 3. About 24% and 20% of children assigned to SILs 2 or 3 by NC InCK were identified as low risk by their Medicaid MCO. Conclusions: The NC InCK risk stratification approach assigns children to SILs 2 and 3 using health, education, social, and juvenile justice data. These populations differ from those identified by Medicaid MCO risk stratification, suggesting that inclusion of non-clinical variables adds unique value. This approach is a step forward in demonstrating the feasibility of methods that proactively identify populations for preventive support by including upstream risk factors.

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Spatial clustering of undervaccination amplifies local measles transmission but limits geographic spread: South Carolina, 2025-2026

Pandey, A.; Bleichrodt, A. M.; Serman, E. A.; Tanim, S. H.; Bento, A. I.; Rennert, L.

2026-09-26 epidemiology 10.64898/2026.09.21.26363346 medRxiv
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The 2025 measles outbreak in South Carolina, the largest in the United States in over two decades, produced 997 confirmed cases, predominantly among school-aged children in an under-vaccinated community in Spartanburg County. To support the South Carolina Department of Public Health (DPH) measles response, we developed a stochastic agent-based model to forecast outbreak trajectory and evaluate intervention strategies in real time, integrating transmission across three spatial scales and grounded in geocoded households, school enrollment records, and census-derived demographic data. The model predicted a median of 1,020 total infections (90% prediction interval: 840-1,273). Counterfactual simulations without active contact tracing and quarantine projected a median of 2,432 infections (90% prediction interval: 1,867-3,185), approximately 138% more than the model-predicted baseline (1,020 cases). Model fidelity required a highly localized between-school contact structure; broader contact assumptions substantially overpredicted both case counts and geographic spread. Simulated regional introductions confirmed that outbreaks arose only near connected clusters of undervaccination, while well-vaccinated areas remained contained. Model versions deployed prospectively at weeks 9, 17, and 34 of the response informed resource allocation decisions and provided operational evidence for the effectiveness of contact tracing and quarantine strategies. Critically, the model reproduced geographic spread, number of affected schools, and breakthrough infection counts not used in fitting, validating its structural fidelity and establishing a replicable framework for jurisdictions maintaining school-enrollment and vaccination records.

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The 2026 public charge rule and long-term health impacts among NYC immigrants: a simulation study

Nadhamuni, K.; Curcio, E.; Solomon, S.; Lim, S.; Van Wye, G.; Parakh, M.

2026-07-27 health policy 10.64898/2026.07.23.26358686 medRxiv
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Importance: The 2026 public charge rule could discourage immigrants from accessing health coverage programs, creating a chilling effect that potentially leads to negative health outcomes; However, its long-term health impact is poorly understood. Objective: To model potential impacts of the 2026 public charge rule on primary care and premature mortality among immigrants in New York City (NYC). Design, Setting, and Participants: The simulation used a deterministic compartmental model with Ordinary Differential Equations (ODEs) using 2023 NYC Vital statistics data and American Community Survey, and estimates obtained from 2 previous studies about effects of healthcare access on primary care and Medicaid expansion on premature mortality. Main Outcomes and Measures: Rates of primary care outcomes (access, doctor's visits) in 5 years, and premature mortality in 5 and 20 years, projected by the model under conservative, moderate, and aggressive scenarios of avoidance/disenrollment due to the public charge rule, known as the 'chilling effect'. Effects of the avoidance/disenrollment on primary care outcomes and premature mortality were obtained from 2 previous studies. Projected rates of the outcomes under each scenario were compared with counterfactuals to estimate the health impacts of the chilling effect. Results: Implementation of the public charge rule was projected to decrease the primary care access rate by 4.1% (conservative) to 9.9% (aggressive) over 5 years, relative to the counterfactual scenario without the rule. The rate of doctors' visits was projected to decrease over 5 years by 5.1% (conservative) to 12.2% (aggressive). Premature mortality was projected to increase by 4.4% (conservative) to 10.6% (aggressive) in 5 years and 7.4% (conservative) to 17.4% (aggressive) in 20 years. Legal noncitizens and Black immigrant New Yorkers were predicted to experience higher burdens of premature mortality attributed to the chilling effect, compared with other immigrant groups and racial/ethnic groups, respectively. Conclusions and Relevance: This study demonstrates adverse health consequences of federal public charge rule changes among immigrants in NYC. The model projected a decrease in primary care visits and increase in premature mortality across various scenarios. These findings suggest urgent reconsideration of a regulatory change that disproportionately increases risk of premature mortality among immigrants in NYC.

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Cold spots of postacute rehabilitation therapy delivery among Original Medicare beneficiaries across the United States: Statistical spatial clustering analysis

Jesus, T. S.; Frazier, M.; Monteiro, P. C.; Pinho, C. S.; Delaney, G. K.; Heinemann, A. W.; Deutsch, A.

2026-07-31 health systems and quality improvement 10.64898/2026.07.29.26359230 medRxiv
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This study aims to map significant cold spots of postacute rehabilitation therapy delivery rates for Original Medicare beneficiaries in the U.S. and determine the prevalence of those cold spots in rural areas. Statistical spatial clustering of postacute therapy delivery rates was conducted in ArcGIS Pro using hot and cold spot analyses (Getis-Ord Gi*). County-level therapy delivery volume was defined as the total minutes of physical, occupational, and speech therapy provided by skilled nursing facilities (SNFs), home health agencies (HHAs), and inpatient rehabilitation facilities (IRFs). Therapy delivery rates were then computed as minutes per Original Medicare beneficiary at the county level and adjusted using a county-level Hierarchical Condition Category risk score. Spatial clustering identified cold spots (statistically significant clusters of low rates) and hot spots (clusters of high rates). We also computed the proportion of cold spots in rural counties and the relative percentage difference compared to the national rural county baseline, using two rural classification systems. Identified coldspots varied by provider type. For SNFs, they were notably identified in the Mountain and West North Central US divisions. For HHAs, cold spots appeared across more U.S. Census Divisions, including areas (e.g., Kentucky, Indiana, southern Illinois) where SNFs showed hot spots. Cold spots were more prevalent in rural--and especially in small rural--counties across all provider types. In rural counties, cold spot rates were 42.8% to 71.5% higher than the rural county baseline. In small rural counties, differences were larger, at 69.1% to 95.5% higher. Concluding, cold spots of postacute therapy delivery varied across the continental U.S. by provider type but were more prevalent in rural and especially in rural counties with smaller population size -- across provider types. Identifying these cold-spot locations may support geographically targeted policy responses and the development of alternative service?delivery models in underserved areas.

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The Burden of Long COVID: Re-Infection, Symptoms, and Barriers to Care in the Arizona CoVHORT Study

Pogreba-Brown, K.; McFadden, C.; Heslin, K. M.; Carr, D. L.; Falk, L. P.; Catalfamo, C.; Ernst, K.; Farland, L. V.; Cordova-Marks, F.; Sun, X.; Barraza, L.; Austhof, E.

2026-08-21 epidemiology 10.64898/2026.08.18.26360693 medRxiv
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Long COVID (LC) impacts quality of life, daily functioning, and healthcare utilization. Understanding the onset and duration of symptoms, characteristics of those at higher risk, and the barriers and facilitators for healthcare access and therapeutics are key to addressing this growing disease burden. In 2024 the Arizona CoVHORT, an ongoing 6-year longitudinal study, distributed a cross-sectional LC survey to gain additional in-depth information. Of 1,543 participants, 700 reported LC symptoms lasting 2-49 months. Following their first infection, LC+ participants had a 21% higher risk for a second infection and were 3.2 times more likely to report LC symptoms after that second infection compared to LC- participants. Significant factors associated with LC included female sex (OR=2.3), Hispanic ethnicity (OR=1.5), BMI>34.5 (OR= 1.7) and >2 infections (OR=3.2), while vaccination prior to first infection decreased the odds of reporting LC by 51% (R=0.49). Qualitative analyses detailed significant barriers to care and encounters with providers who lacked knowledge to test for or treat LC symptoms. With an estimated 400 million people impacted globally by LC, it is critical to gain in-depth information from patients to improve both access and quality of care, improve messaging, and target mitigation strategies to decrease the burden over time.

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Continued genomic surveillance of Vibrio cholerae O1 isolates from cholera cases in Europe, 2023-2024

Njamkepo, E.; Dupke, S.; Tauhid, T.; Stephan, R.; van der Putten, B.; Nyholm, O.; Herrera-Leon, S.; Drew, R. J.; Cormican, M.; Greig, D. R.; Tsafarova, B.; Sacheli, R.; Clarke, C.; Ivanov, I. N.; Jenkins, C.; Lanzl, M.; Froding, I.; Scholz, H.; Rouard, C.; Weill, F.-X.

2026-09-24 genomics 10.64898/2026.09.18.752729 medRxiv
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Background: Following the global resurgence of cholera in 2022, 51 cholera cases were reported by European countries. We previously characterised 49 Vibrio cholerae O1 isolates from these cases using whole genome sequencing. In 2023 and 2024, 59 additional cholera cases were reported by 11 European countries. Aim: We aimed to confirm that V. cholerae O1 isolates associated with cholera cases reported in Europe in 2023-2024 belonged to the epidemic seventh pandemic El Tor (7PET) lineage rather than to non-epidemic V. cholerae O1 lineages, and to characterise their virulence, antimicrobial resistance (AMR) determinants and phylogenetic relationships. Methods: Fifty V. cholerae O1 isolates were available for whole genome sequencing, of which 49 yielded genomes of sufficient quality for analysis. Genomes were analysed together with more than 1,500 publicly available 7PET genomes to place the European isolates into a global phylogenetic context. Results: All 49 genomes belonged to the 7PET lineage and Wave 3. Four sub-lineages were identified: BD1.2 (2/49), AFR12 (6/49), AFR13 (8/49) and Pre-AFR15 (33/49). The predominance of Pre-AFR15 confirms its continued contribution to the ongoing global cholera resurgence. In contrast to our 2022 survey, eight highly drug-resistant AFR13 isolates were detected, documenting the international spread of this highly drug-resistant clone resistant to multiple first-line antimicrobial agents. Conclusion: Whole genome sequencing should be routinely used by reference laboratories to distinguish epidemic 7PET from non-epidemic V. cholerae O1 lineages and to monitor the emergence and international spread of AMR clones. Continued collaborative genomic surveillance of travel-associated cholera cases can provide early insights into the emergence, international spread and antimicrobial resistance of 7PET sub-lineages.

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From Tumor Board Presence to Documented Review: A Coverage Cascade for Multidisciplinary Cancer Care in India

Bodetti, V.; Nihalani, N.; Nivsarkar, R.; Patkar, A.

2026-10-05 health systems and quality improvement 10.64898/2026.10.01.26364522 medRxiv
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Background: Multidisciplinary tumor boards (MTBs) are a standard part of cancer care, yet India has no national measure of how many cancer patients are discussed at one. A national survey of hospitals in the National Cancer Registry Programme (NCRP), published in 2026, gives the first structured look at board presence and functioning. Objective: To describe how far hospital-level tumor board presence translates into all-case review, documentation and follow-up, and to define the data needed to measure patient-level coverage. Methods: Secondary analysis of published aggregate data: the ICMR-NCDIR survey of 229 hospitals in the NCRP hospital-based cancer registry (HBCR) network (October 2024), the HBCR 2021 report, national incidence estimates (ICMR-NCDIR 2022; GLOBOCAN 2024) and two published single-center MTB audits. We calculated proportions with Wilson 95% confidence intervals, non-response bounds across all 229 hospitals, and logical bounds for joint conditions. No individual-level data were used. Results: A total of 229 hospitals were invited and 172 responded (75.1%). Among the respondents, 137 (79.7%; 59.8% to 84.7% across all hospitals) reported a functional tumor board. Only 65 respondents (37.8%; 28.4% to 53.3%) reported boards that review all cases, 71 (41.3%) had a follow-up system, 50 (29.1%) used any electronic documentation and 7 (4.1%) always took part in cross-hospital reviews. The share of hospitals with both all-case review and a follow-up system could lie anywhere from 0% to 37.8% of respondents. Boards were reported more often in private (86.6%) than in public hospitals (72.5%). Two single-center audits reported about 800 case discussions (573 new patients) and 1,260 case discussions (about 917 patients) a year, but neither reported new registrations at the same hospital, so coverage could not be calculated. Conclusions: Tumor board presence is common in India, but evidence of all-case review, documentation and follow-up is much thinner, and the share of patients reviewed nationally is unknown. We propose six indicators that hospital-based registries could report to measure coverage directly.

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Spatial Accessibility and Health-System Concentration of Reachable Hospital Capacity in New Jersey

Zheng, Y.

2026-09-07 health systems and quality improvement 10.64898/2026.09.02.26362067 medRxiv
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Background: Spatial accessibility measures estimate how much hospital capacity a community can reach but do not show how that capacity is distributed across health systems. A community may have several reachable hospitals but still depend on one or a few systems. Methods: We used the enhanced two-step floating catchment area method to estimate staffed-bed spatial accessibility for New Jersey census tracts. We included short-term acute care hospitals in New Jersey and neighboring states within a 30-minute drive of at least one New Jersey tract. For each tract, we grouped hospital-level accessibility contributions by health system and calculated a Herfindahl-Hirschman Index (HHI). Spearman correlations examined associations of E2SFCA and HHI with tract-level sociodemographic characteristics. Results: Of 163 reachable hospitals, 94 were outside New Jersey and supplied 62.7% of reachable staffed beds. Across 2,172 tracts, the mean E2SFCA score was 1.98 beds per 1,000 distance-weighted residents; among 2,161 tracts with positive scores, the median HHI was 0.31. Using cutoffs of E2SFCA <2.0 and HHI [&ge;]0.18, 934 tracts met both criteria, while an E2SFCA-only rule missed 655 tracts with higher accessibility but high concentration. E2SFCA and HHI correlations had opposite signs for seven of eight sociodemographic characteristics. Conclusions: E2SFCA and HHI classified New Jersey tracts differently under the illustrative cutoffs. Contribution-based HHI identifies tracts in which a closure, service relocation, or capacity reduction involving a major contributing system could affect a large share of modeled accessible capacity. Keywords: Spatial accessibility; hospitals; E2SFCA; health systems; Herfindahl-Hirschman Index

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Effect of health-system continuous quality improvement on long-term retention in HIV care among pregnant and breastfeeding women in the Democratic Republic of Congo: A cluster-randomized trial

Yotebieng, M.; Ravelomanana, N. L.; Kawende, B.; Tabala, M.; Malongo, F.; Lumande, F.; Zotova, N.; Babakazo, P.

2026-09-25 health systems and quality improvement 10.64898/2026.09.24.26363877 medRxiv
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Background. Despite relatively high coverage of interventions to prevent vertical transmission, HIV incidence among children born to women living with HIV (WLH) remains above elimination targets, partly because of substantial disengagement from antiretroviral therapy (ART) during the postpartum period. We evaluated the effectiveness of a data-driven continuous quality improvement (CQI) intervention in improving retention in care, virological suppression, and prevention of vertical transmission among pregnant and breastfeeding WLH receiving ART in maternal and child health (MCH) clinics. Methods and findings. This pragmatic cluster-randomized trial was conducted in 105 MCH clinics--three high-volume clinics in each of the 35 health zones (HZs) of Kinshasa Province, Democratic Republic of the Congo. During the pre-randomization phase (November 2016-December 2017), routine data collection using prevention of mother-to-child transmission registers was strengthened in all participating clinics. In January 2018, HZs were randomized 1:1 to implement CQI or continue the standard of care. In intervention HZs, quality improvement (QI) teams were established at the HZ and clinic levels. Indicators selected collaboratively with QI teams were calculated from routine program data and shared quarterly. Through July 2019, QI teams met quarterly to identify service-delivery challenges and develop strategies to improve outcomes, with an emphasis on retention. Thereafter, responsibility for producing indicators was transferred to QI teams, and meetings continued virtually through WhatsApp. Pregnant and breastfeeding WLH and their infants receiving care at participating clinics between November 2016 and July 2019 were enrolled and followed for at least 24 months. Primary outcomes were loss to follow-up (LTFU), viral suppression (<1,000 copies/mL), and a positive HIV test among live-born infants. Overall, 2,376 women were enrolled, including 1,217 (51.2%) before randomization. The analysis of CQI effectiveness included 1,900 participants who remained in care at randomization or enrolled thereafter: 1,103 (58.1%) in control HZs and 797 (41.9%) in intervention HZs. At 6, 12, and 24 months, LTFU was lower in the intervention group than in the control group: 18.6% versus 21.6% (adjusted risk difference [aRD], -5.2 percentage points; 95% CI, -9.6 to -0.8), 29.2% versus 31.0% (aRD, -3.9; 95% CI, -10.2 to 2.4), and 50.1% versus 55.5% (aRD, -7.1; 95% CI, -15.2 to 1.0), respectively. Estimated effects were larger in PEPFAR-supported and urban clinics, although interaction tests were not statistically significant. Viral-load results were available for 38.2%, 50.4%, and 73.5% of eligible participants at 6, 12, and 24 months, respectively. Neither viral-load-result availability nor viral suppression differed between groups. Infant HIV-test results were available for 8.1%, 32.7%, 34.2%, and 28.5% of eligible infants at 6 weeks and 6, 12, and 24 months, respectively. Conclusions. CQI implementation produced a modest improvement in retention, with the clearest evidence at 6 months and favorable but imprecise estimates through 24 months. Limited availability of maternal viral-load and infant HIV-test results precluded definitive conclusions about virological suppression and vertical transmission. Local quality-improvement interventions may strengthen processes within frontline teams control but cannot alone overcome failures across an interconnected care system. Future studies should align interventions operational reach with all health-system levels responsible for the intended outcomes.

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Mortality and vaccine-preventable deaths from severe acute respiratory infections in Brazil in 2026

Kupek, E.

2026-10-05 epidemiology 10.64898/2026.10.03.26364639 medRxiv
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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.

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Comparison of Influenza Vaccine Effectiveness Estimates Using Test-Negative Prospective Enrollment and Electronic Health Record Data, United States, 2024--2025

Price, A. M.; McLean, C.; Cleary, S.; Leis, A. M.; Vaughn, I. A.; House, S.; Ellsworth, S.; Moehling Geffel, K.; Taylor, L. H.; Gaglani, M.; Murthy, K.; Saade, E. A.; Ladikos, C.; Murugan, V.; Kramer, J. L.; Williamson, B. D.; Kiniry, E.; Walter, E. B.; Bontrager, N. A.; Ellington, S.; Flannery, B. M.; Chung, J.; US Flu VE Network Investigators,

2026-07-27 epidemiology 10.64898/2026.07.23.26358258 medRxiv
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Background: Influenza vaccine effectiveness (VE) is assessed annually through prospective enrollment of patients presenting with acute respiratory symptoms in a test-negative study design. Influenza VE has also been estimated from electronic health record (EHR) databases by linking medical diagnoses, laboratory test results, and patient influenza vaccination. There are limited data on agreement between influenza VE estimates from prospective enrollment versus EHR databases. Methods: The US Influenza Vaccine Effectiveness Network prospectively enrolled outpatients meeting clinical screening criteria and collected respiratory specimens to determine influenza virus infection. Seven study sites also identified EHR databases that included diagnostic codes for outpatient encounters associated with medically attended acute respiratory illness (MAARI), clinical respiratory virus testing, and influenza vaccination status. Effectiveness of influenza vaccination against laboratory-confirmed influenza was estimated from both data sources using logistic regression models including patient age, study site, and month of illness as 100(%) x (1 - adjusted odds ratio), comparing influenza vaccination among laboratory-confirmed influenza-positive patients versus laboratory-confirmed influenza-negative patients. Results: From October 2024--April 2025, 2,016 (30%) of 6,793 prospectively enrolled patients and 75,885 (24%) of 282,444 EHR MAARI encounters had laboratory-confirmed influenza virus infection. Effectiveness of vaccination against laboratory-confirmed influenza was 36% (95% confidence interval [CI]: 26-44) among prospectively enrolled patients and 38% (95% CI: 36-39) among EHR MAARI encounters. Comparing influenza VE estimates from the two data sources, confidence intervals overlapped for all age groups except for adults aged [&ge;]65 years: -3% (95% CI: -53-30) among prospective enrollment versus 35% (95% CI: 32-39) VE from EHR MAARI encounters. Conclusion: Overall, influenza VE estimates from retrospective EHR data were similar to VE estimates using the test-negative design with prospective enrollment. The age group-specific differences in estimated VE observed in US adults aged [&ge;]65 years compared with younger age groups merit further investigation.

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COVID-19 vaccination and survival of cancer patients in Northwestern Russia: a historical registry-based cohort study

Dyachenko, A. A.; Bogdanov, M. A.; Bogdanov, D. V.; Meldo, A. A.; Chernina, V. Y.; Gombolevskiy, V. A.; Grjibovski, A. M.; Valkov, M. Y.

2026-10-13 oncology 10.64898/2026.10.12.26365129 medRxiv
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Background: Cancer patients face a significantly elevated risk of severe COVID-19 outcomes. Although vaccination is a cornerstone of prevention, data on vaccination coverage and association with survival among Russian cancer patients remain scarce. We assessed COVID-19 vaccination coverage and its association with overall survival in a population-based cohort of cancer patients in Northwest Russia. Methods: This retrospective registry-based cohort study integrated data from the Population-Based Cancer Registry (PBCR) of the Arkhangelsk Region and the Nenets Autonomous Okrug, regional vaccination records, and an artificial intelligence (AI)-based analysis of chest computed tomography (CT) scans. The cohort consisted of 1,144 cancer patients who underwent CT between August 2020 and April 2021. Vaccination status was ascertained via data linkage. Overall survival (OS) was compared between vaccinated and unvaccinated patients using Kaplan-Meier analysis and multivariable Cox proportional hazards regression, adjusted for demographic, clinical, and AI-derived CT biomarkers. To mitigate immortal time bias, the primary analysis used a landmark approach restricted to patients alive on March1, 2021 (N=1,136). A sensitivity analysis used a November1, 2021 landmark (N=894). Vaccination status was defined as receipt of at least one dose before the landmark date. Results: Only 6.6% (n=76) of patients received at least one dose of a COVID-19 vaccine (Sputnik V or Sputnik Light). Vaccinated patients were more likely to have earlier-stage cancer and were less likely to be receiving active treatment. In the primary landmark analysis, vaccination was associated with a significantly higher 3-year OS (80.3% vs. 45.7%, p<0.001). In multivariable analysis, vaccination was independently associated with a 60% lower hazard of all-cause mortality (adjusted HR 0.40, 95% CI 0.25-0.64). AI-detected COVID-19 pneumonia on baseline CT was also an independent predictor of poorer survival (adjusted HR 1.32, 95% CI 1.09-1.59). In the sensitivity analysis (November1, 2021 landmark), the adjusted HR for vaccination was 0.56 (95% CI 0.34-0.92), showing a consistent but attenuated association. Conclusion: This study reveals critically low COVID-19 vaccination coverage among cancer patients in Northwest Russia. Nevertheless, vaccination was strongly associated with a substantial survival benefit, underscoring its importance as a potentially lifesaving intervention for this vulnerable population.

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Innovations, recipients, and contexts in the implementation of pediatric neurocritical care programs: a multisite qualitative study refining i-PARIHS

Vogel, M. T.; Wallisch, J. S.; De Souza, B. J.; Chaudhari, P.; Hassan, A.; Jampani, A.; Steffen, K. M.; Pineda, J. A.

2026-10-14 health systems and quality improvement 10.64898/2026.10.13.26365431 medRxiv
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Background Pediatric neurocritical care (PNCC) has emerged as a distinct field, and many hospitals have moved to establishing dedicated PNCC programs. How practice change is implemented within these programs is not well understood. This study had two objectives. First, we sought to understand the barriers and facilitators of practice change in PNCC from the perspectives of the multiprofessional clinicians who deliver it. Second, we sought to characterize how well the integrated Promoting Action on Research Implementation in Health Services (i-PARIHS) implementation determinant framework captures them. Methods We conducted semi-structured interviews with a purposive sample of clinicians involved in PNCC at three U.S. academic medical centers. The interview guide was developed using i-PARIHS to organize barriers and facilitators of practice change across the innovation, recipients, context, and facilitation constructs. We applied framework analysis, combining deductive i-PARIHS, study-specific, and inductively derived categories. Two coders independently indexed the transcripts and reconciled them to consensus, with first-author adjudication. Preliminary site-level findings were validated with participants. Results We interviewed 33 clinicians: 24 physicians, 7 nurses, and 2 advanced practice providers. Most determinants of practice change mapped to existing i-PARIHS constructs, but three were not adequately captured by the framework as currently specified. The most consequential was an interprofessional authority gradient that determined whose preferences prevailed when intensive care, neurology, and neurosurgery disagreed. The other two were clinician autonomy, which served as the lens through which the acceptability of a change was judged, and the affective state clinicians bring to practice change. Receptivity depended more on recipients' values, prior experience, and capacity to absorb change into a demanding workflow. Facilitation was variable, frequently under-resourced, and dependent on credibility across professional groups. We translated these findings into three propositions linked to implementation strategies and outcomes. Conclusions Participants attributed practice change in PNCC more to the recipients of change, the multiprofessional context, and the availability of facilitation than to the strength of evidence for a given practice. i-PARIHS captured most barriers and facilitators well but may be adapted in this setting. Credible, resourced, authority-sensitive facilitation may improve the prospects for sustained practice change as institutions develop PNCC programs.

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Impact of mass oral cholera vaccination in an endemic area of the Democratic Republic of the Congo: a surveillance-based counterfactual modeling analysis

Perez-Saez, J.; Malembaka, E. B.; Bouman, J. A.; Bugeme, P. M.; Hutchins, C.; Jackson, J.; Tshiwedi-Tsilabia, E.; Hulse, J. D.; Saidi, J. M.; Rumedeka, B. B.; Itongwa, M.; Cumming, O.; German, E.; Kulondwa, J.-C.; Dighe, A. B.; Clutter, C.; Lessler, J. T.; Leung, D. T.; Gallandat, K.; Lee, E. C.; Okitayemba, P. W.; Mukadi-Bamuleka, D.; Knee, J.; Azman, A. S.

2026-09-20 epidemiology 10.64898/2026.09.17.26363298 medRxiv
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Abstract Background Oral cholera vaccines (OCVs) are a key component of cholera control recommended in cholera-endemic areas. Yet evidence of their population-level impact is limited, especially in Africa where most cholera deaths occur. Here, we estimate the impact of mass administration of OCVs in the cholera-endemic city of Uvira, Democratic Republic of the Congo. Methods We conducted enhanced cholera surveillance at the two official cholera treatment facilities in Uvira between Jan 2017 and Dec 2023, centered around a mass vaccination campaign that achieved 66% coverage with at least one dose of Euvichol Plus vaccine in 2020. We combined systematic rapid diagnostic case testing with repeated, representative population surveys capturing healthcare-seeking behavior, vaccination, population mobility, and antibody profiles to estimate seroincidence. We developed a Bayesian framework that integrates these data into an ensemble of mechanistic cholera transmission models that account for time-varying transmissibility, realistic immunity dynamics and loss of vaccination coverage to population turnover. OCV impact was assessed through ensemble counterfactual modeling of alternative vaccination scenarios. Findings We estimate that the 2020 mass vaccination averted 56% (95% Credible Interval: 34-81) of infections and deaths over the subsequent three years. This corresponds to 2,350 (median, 95% CrI: 890-8,960) averted facility-attended cases, and 44 (median, 95% CrI: 16-150) averted facility and community deaths. Vaccination of the entire eligible population of Uvira would have averted 64% (median, 95% CrI: 43-87) of cases and deaths, with a negative but limited influence of vaccine coverage loss because of population turnover (71% median, 95% CrI: 52-90 at half the population turnover). Interpretation Although mass vaccination averted a significant fraction of cholera cases that would have otherwise occurred in this endemic setting, imperfect coverage, population turnover, and high transmission rates contributed in offsetting the larger potential benefits of OCV. Successful cholera control in Uvira hinges on multisectorial approaches including provision of safe water and sanitation. Setting and communicating realistic expectations for mass vaccination programs in highly endemic areas is critical for maintaining confidence in the current generation of OCVs. Funding Gavi (M&E 9166 09 20 A16) and the Wellcome Trust (221688/Z/20/Z).

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Rethinking seasonal COVID-19 vaccination in the endemic era: summer timing, eligibility, and frequency in the United States

Bubar, K. M.; Park, H. J.; Bents, S. J.; Tan, S. T.; Singer, B. J.; Kelly, J. D.; Leon, T. M.; Watt, J.; Schechter, R.; Lo, N. C.

2026-09-25 public and global health 10.64898/2026.09.23.26363810 medRxiv
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Importance: With a recent shift towards summer seasonal predominance of COVID-19 across much of the US, debate continues over optimal COVID-19 vaccination strategies regarding timing (including summer vaccination), eligibility, and dosing frequency. We evaluated the population-level impact of alternative vaccine strategies to inform US and state vaccine policy. Objective: To compare reductions in COVID-19 hospitalizations under different vaccination timing, eligibility, and dosing frequency. Design: Decision analytical model using a stochastic individual-based model of SARS-CoV-2 transmission, calibrated to US COVID-19 hospitalization incidence from May 2024-April 2025. Setting: Simulated US national population, with additional scenarios representing state-level seasonal patterns. Participants: Simulated population of 5 million individuals with US age structure, stratified by risk group (immunocompetent, high risk with comorbid conditions, or immunocompromised). Exposures: Vaccination timing, universal or age- and risk-based eligibility, and dosing frequency, including a hybrid strategy of universal annual vaccination with a second dose for adults [&ge;]65 years and immunocompromised adults (US vaccine policy during the study period). Main Outcomes and Measures: COVID-19 hospitalization risk per 100,000 persons by age-risk group, measured among vaccinated individuals and in the total population. Results: If summer COVID-19 vaccination timing is feasible, annual universal vaccination in July minimized risk (441 [95% UI: 423-463] COVID-19 hospitalizations per 100,000 persons among adults [&ge;]65 years) compared to a counterfactual scenario with no additional vaccination given during the study period (578 [553-601]). If timing does not change, hybrid vaccination minimized risk, followed by semiannual risk-based vaccination (460 [440-487] and 477 [454-499] hospitalizations per 100,000 in adults [&ge;]65 years, respectively). The advantage of summer timing diminished if vaccine coverage decreased by 5-10 absolute percentage points (25-50% relative decrease). The magnitude of benefit from summer-timed vaccination and semiannual doses in the highest-risk groups varied regionally. Conclusions and Relevance: Although annual COVID-19 vaccination has historically been timed for winter transmission, summer vaccination may avert more hospitalizations if coverage is maintained, especially in states with predominantly summer transmission including Western and Southern states. The comparative impact of vaccination strategies, especially the benefit of a semiannual dose in the highest-risk groups, may vary regionally. COVID-19 vaccination timing and eligibility may warrant reconsideration.

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Patterns of Influenza Vaccine Uptake by Age Group and Product Type in Michigan, 2017-2021

Zhou, Z.; Malosh, R.; Sudan, S.; Wagner, A.; Eisenberg, M. C.; Monto, A.; Martin, E. T.

2026-10-21 epidemiology 10.64898/2026.10.19.26365920 medRxiv
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Background Influenza vaccines have seen many changes over recent years in terms of both policy recommendations and product types. Immune responses and vaccine effectiveness vary by vaccine strain composition and product type. This study aimed to explore this variation on a regional level through examining spatial and temporal autocorrelations of vaccine uptake of different product types within Michigan from 2017 to 2021. Methods Influenza vaccine administration data from the 2017/18 to 2021/22 seasons were obtained from the Michigan Care Improvement Registry. Population size estimates for 2017 and 2019 were obtained from the Michigan Department of Health and Human Services. Age-standardized and age-stratified vaccination rates were computed. Disparate county-level vaccine uptake clusters were constructed using spatial autocorrelation indicators and spatiotemporal clusters were identified using scan statistics. Linear mixed effect models were used to study the impact of social vulnerability and urbanicity level on seasonal influenza vaccination rate. Results Vaccination incidence rates for adjuvanted, recombinant, and nasal sprays vaccines and for any vaccines increased significantly through the study period. County-level spatiotemporal clusters of type-specific uptake rates were identified. Most notably, we identified an emerging cluster with high uptake of adjuvanted vaccine radiating from Ottawa County, located in suburban Grand Rapids, and the disappearance of high uptake cluster for high-dose vaccine uptake in the area. Vaccination rates by any product type were found to vary seasonally and showed weak negative association with more rural regions. The overall vaccination rates appear to be lower among counties with higher social vulnerability in certain urbanicity levels, but social vulnerability and urbanicity were not significantly associated with overall vaccination rate during the study period. Conclusions Vaccine type-specific uptake was spatially and temporally diverse in Michigan between 2017 and 2022. Mid and Northern Michigan had consistently relatively lower vaccination rate compared to other regions in Michigan.

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The impact of neighborhood socioeconomic deprivation on metastatic pancreatic cancer treatment and survival: An incidence-based, causally-structured observational study

Raghu, A.; Shah, S.; Pattnaik, A.; Permuth, J. B.; Park, M. A.; Dhahri, H.; Huang, H. C.; Fleming, J. B.; Anaya, D. A.; Powers, B. D.

2026-08-10 oncology 10.64898/2026.08.06.26359821 medRxiv
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Purpose: Metastatic pancreatic ductal adenocarcinoma (PDAC) portends a poor prognosis. Prior studies have assessed the association of socioeconomic deprivation (SED) in PDAC often with large geographic areas. This study employed a causal framework to characterize neighborhood SED on treatment receipt and survival in metastatic PDAC. Methods: Using the incidence-based Florida Cancer Data System, metastatic PDAC patients diagnosed from 2007-2015 were identified. The Area Deprivation Index, a composite measure of SED that ranks neighborhoods from 1-100 (higher scores = higher deprivation), was used to assess receipt of systemic therapy and overall survival (OS). Exposures and covariates were assessed using descriptive statistics and a causal inference framework. Results: Overall, 9,574 patients met inclusion criteria. 46.6% of patients received systemic therapy, ranging 39.4% to 54% in the highest and lowest SED quartiles, respectively. After adjustment, the lowest quartile had increased odds of systemic therapy relative to the highest (OR 1.93; 95% CI 1.70-2.18). Median OS was 3.8 months for the lowest quartile and 2.4 months for the highest (p = 0.01). Patients in the highest quartile had an estimated 32% higher hazard of death than the lowest (HR 1.32, 95% bootstrap CI 1.20-1.40). Conclusion: In an incidence-based statewide cohort, most patients did not receive treatment for metastatic PDAC and median OS was poor-2.9 months. Using a causal inference framework, higher SED led to lower rates of systemic therapy receipt and worse overall survival in metastatic PDAC. Future research should focus on the mechanisms that shape these findings.

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Entrepreneurial Methods for Healthcare Redesign: A Pre-Post Cohort Study in Glioblastoma Care

Howran, J.; Sharma, A.; Andrews, K.; Pople McCord, D.; Salim, S. K.; Janka, D.; Ynoe Moraes, F.; Goldie, K.; Babiolakis, C.; Alkins, R.; Taslimi, S.; Pasarikovski, C.; Ebinu, J.; Cook, D. J.; Levy, R.; Purzner, J.; Purzner, T.

2026-07-29 surgery 10.64898/2026.07.28.26358976 medRxiv
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Objective: To evaluate whether entrepreneurial methodologies applied to system-wide healthcare redesign were associated with improved survival, care timeliness, and rural-urban equity among patients with glioblastoma. Design: Non-randomized pre-post cohort study Setting: Tertiary neuro-oncology centre in Ontario, Canada Participants: Adults aged >18 years with histologically confirmed glioblastoma who underwent surgical resection between January 1, 2018, and February 28, 2025 Interventions: Implementation of the Integrative Brain Tumor Program (IBTP), a system-wide care intervention grounded in user-defined priorities and developed using a design thinking approach (empathize, define, ideate, prototype, test) integrated with operational frameworks adapted from early-stage innovation. System change was treated as a deliberate, deployable intervention that could be designed, launched, iteratively refined, and evaluated. Coordinated changes were embedded across healthcare services within existing infrastructure and resource constraints through a single centralized nurse navigator who standardized referrals, patient education, and real-time care coordination. Main Outcomes and Measures: Primary outcomes were one-year overall survival and time to postoperative MRI completion and radiotherapy initiation. Secondary outcomes assessed rural-urban equity in these measures. Associations were evaluated using Cox proportional hazards and Fine-Gray competing-risk models adjusted for age, sex, rurality, MGMT promoter methylation status, and calendar time. Results: Among 297 patients (244 pre-implementation, 53 post-implementation), baseline demographic and tumor characteristics were similar across cohorts. One-year overall survival was higher in the post-implementation cohort (60.4% vs 42.2%), corresponding to an adjusted hazard ratio of 0.61 (95% CI, 0.38-0.99). Postoperative MRI completion within 48 hours increased from 45.9% to 66.0% (adjusted cause-specific hazard ratio, 1.50; 95% CI, 1.05-2.14) with similar improvements observed at 7 days. Time to radiotherapy initiation did not differ between cohorts. Survival and MRI timeliness did not differ by rural or urban residence in either period, though rural radiotherapy delays were attenuated postimplementation. Conclusions: Systematic application of entrepreneurial methods to health system redesign was associated with clinically meaningful improvements in glioblastoma survival and care timeliness using minimal resources (single nurse navigator). These findings suggest that treating system change as an intervention grounded in user-defined priorities and oriented toward integrated systems rather than sequential process optimization can support sustainable transformation of complex, coordination-dependent care pathways and warrants evaluation in other disease settings.

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Implementing ESAMyN: Ecuador's National Standard for Mother- and Baby-Friendly Health Facilities

Tello, B.; Ruilova-Maldonado, M.; Olmedo-Valarezo, A. J.

2026-07-31 health systems and quality improvement 10.64898/2026.07.28.26359056 medRxiv
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Background Ecuador's Mother- and Baby-Friendly Health Facilities Standard (ESAMyN, Establecimientos de Salud Amigos de la Madre y el Nino) is an integrated national quality improvement strategy that combines evidence-based recommendations for antenatal, childbirth, postpartum, newborn and breastfeeding care within a single implementation and certification framework. However, little is known about the factors influencing its implementation in routine health services. This study explored the organizational, contextual and behavioural factors that facilitated or hindered ESAMyN implementation across public health facilities. Methods We conducted a secondary qualitative analysis of 36 semi-structured interviews originally collected during a programme systematization in 11 public health facilities across five Ecuadorian provinces. Participants included health authorities, managers, ESAMyN focal points, quality coordinators, healthcare professionals and women receiving maternity services. Interview transcripts were analysed inductively using thematic analysis. Results Implementation was perceived as an organizational transformation rather than the adoption of a new clinical guideline. Strong leadership, multidisciplinary teamwork, continuous training and institutional commitment facilitated implementation and promoted the adoption of respectful, family-centred and evidence-based maternity care practices. However, staff turnover, workload, infrastructure limitations, shortages of equipment and funding, and reliance on local adaptation challenged implementation and contributed to variability across facilities. Participants emphasized that sustaining ESAMyN required institutionalization beyond certification through continuous monitoring, refresher training, supportive supervision and stable organizational support. Conclusions Integrated national quality standards can strengthen maternal and newborn care through sustained leadership, adequate resources and continuous quality improvement, providing practical lessons for implementing WHO recommendations in routine health services.

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Reducing friction, enabling response: a realist evaluation of a mobile outreach model for marginalized populations

Cristancho, S.; Eby, D.; Dobbyn, F.; McNab, K.

2026-08-02 health systems and quality improvement 10.64898/2026.07.30.26358580 medRxiv
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Background: Mobile outreach initiatives have emerged to address persistent barriers to care for people experiencing homelessness, substance use, and mental illness. Although these models show promise, less is known about how and under what conditions they enable engagement and coordinated care. This study explains how, why, and under what circumstances a mobile, cross sector outreach model enables access to care for marginalized populations. Methods: We conducted a realist evaluation of Supportive Outreach Services (S.O.S.), a mobile, cross sector outreach program in Grey County, Ontario. Data included 31 semi structured interviews with outreach providers, partner organizations, system leaders, and clients, supplemented by document review and stakeholder feedback. Using retroductive reasoning and constant comparison, we developed and refined context mechanism outcome configurations to construct an explanatory program theory. Results: Five interconnected realist explanations account for how the model enables access to care. Trust built through repeated, non judgmental encounters supports engagement; proximity reduces barriers to participation; accessible support enables timely help seeking; cross sector relationships enable adaptive coordination; and visible results build legitimacy that sustains participation and resources. Together, these explanations provide a linked explanatory account of how mobile outreach reduces friction between marginalized populations and fragmented services while identifying the structural conditions that constrain its effectiveness. Conclusions: The effectiveness of mobile outreach depends less on the services delivered than on its capacity to reduce friction, sustain relationships, and adapt care across organizational boundaries. The resulting program theory offers transferable explanations for designing coordinated community based services while highlighting the structural conditions required for durable change.