Open Forum Infectious Diseases

Objectives: Electronic Health Records (EHRs) impose a significant time burden on physicians, often requiring work to be completed outside of scheduled hours. While this burden is well-documented, how it evolves throughout emergency medicine (EM) residency remains poorly understood. This study aimed to quantify EHR usage patterns, analyze the composition of after-shift work, and characterize the development of EHR efficiency across EM training. Methods: We conducted a retrospective cohort study of EM residents (postgraduate year [PGY] 1-4) using 5.5 years of EHR audit log data (2020-2025) at a single academic institution. We analyzed EHR time per new patient encounter, stratified by postgraduate year, and categorized activities into domains such as documentation, chart review, and orders. EHR work was measured both during and after scheduled shifts. Results: The analysis included 144 unique residents and 167,010 new patient encounters across 15,386 shifts. Encounter-attributed EHR time per encounter decreased by 52% from PGY-1 to PGY-4 (median 19.9 to 9.6 minutes, p<0.001), despite an 86% increase in patient volume per shift (median 7 to 13 encounters). This efficiency gain was driven primarily by a 69% reduction in documentation time (9.3 to 2.9 minutes), accompanied by shorter notes. After-shift work (EHR activity after the 9-hour clinical shift) was present in 89.9-94.4% of encounters. At the shift level, combined after-shift EHR time (encounter-attributed plus tracking board) was a median of 64.2 minutes per shift for PGY-1 and 104.2 minutes for PGY-4. Shift-level tracking board activity dominated the after-shift burden and increased with training (median 40.2 to 79.0 minutes per shift from PGY-1 to PGY-4). Conclusions: EM residents achieve substantial gains in on-shift EHR efficiency, with the largest reductions observed in documentation time, accompanied by shorter notes and faster input speed. However, a persistent after-hours workload, dominated by administrative and patient flow tasks, suggests that (at least at this single institution) system-level factors--not just individual skill--may contribute to this pattern. Monitoring these objective EHR metrics may help programs identify struggling learners and evaluate the impact of interventions aimed at improving resident well-being and workflow efficiency.

Background Post-acute sequelae are well described following COVID-19 but may also occur after other respiratory infections and Aedes-borne infections. Evidence remains fragmented due to heterogeneity in study design, populations, and exposure, outcome, and follow-up definitions. Methods We synthesized and compared post-acute sequelae across influenza, RSV-ARI, dengue fever, chikungunya, Zika, and yellow fever. We searched five databases from inception to 25-08-2025 for articles quantifying risk, incidence, or rates of post-acute sequelae following these diseases. Eligible non-randomized observational studies assessed post-acute neurological, psychiatric, gastrointestinal, cardiovascular, respiratory, renal, musculoskeletal, autoimmune, or endocrine outcomes after confirmed infection. Risk of bias was assessed using ROBINS-E. Random-effects meta-analyses with restricted maximum likelihood estimation were conducted when comparable effect estimates were available (PROSPERO #CRD420251124994). Findings 51 studies were included, predominantly from high-income regions. Most were retrospective cohorts using ICD-coded diagnoses; prospective studies used laboratory-confirmed infections. Data sources, comparator groups, exposure definitions, outcome ascertainment, and follow-up periods varied substantially. Meta-analyses were feasible for RSV, influenza, and dengue fever. All RSV-ARI studies were pediatric and assessed infections during infancy, which were associated with higher pooled odds of physician-diagnosed asthma (OR:2.93 [95%CI: 2.12-4.06]). Influenza studies used COVID-19-positive comparators; pooled estimates showed lower risk for neurological (HR:0.82 [0.76-0.89]) and composite outcomes (RR:0.88 [0.82-0.95]), with other organ systems non-significant. Dengue fever studies spanned all ages and showed increased risks of anxiety (HR:1.34 [1.01-1.78]), dementia (HR:1.61 [1.10-2.35]), autoimmune (RR:1.39 [1.17-1.67]), cardiovascular (HR:1.51 [1.27-1.80]), psychiatric (HR:1.17 [1.07-1.28]), and any sequelae (HR:1.19 [1.13-1.25]) versus those without prior infection. Interpretations Post-acute sequelae contribute to overall disease burden following RSV-ARI and dengue fever. The evidence remains limited by heterogeneity in study design, exposure and outcome definitions, comparator selection, and follow-up duration. Greater standardization in study design and reporting is needed to improve comparability and strengthen causal inference.

Introduction: Early exposure to otolaryngology (ENT) procedural skills in undergraduate medical education is limited by patient safety concerns, restricted clinical opportunities, and the cost of commercial simulators. As a result, essential ENT skills are often underrepresented in structured, hands-on curricula for medical students. Methods: We developed a low-cost, multistation ENT simulation curriculum consisting of five reproducible task trainers: ear examination and otologic procedures, mirror laryngoscopy, rigid and flexible endoscopic navigation, introductory mastoid drilling, and emergency cricothyrotomy. The curriculum was delivered as a 2-hour, faculty-led workshop during a third-year medical student otolaryngology rotation. Learners rotated through stations in small groups. Pre- and post-workshop surveys assessed self-reported anatomical familiarity, procedural confidence, and educational value using a 5-point Likert scale, with additional qualitative feedback collected. Results: All participants completed pre- and post-workshop evaluations. Learners demonstrated increased confidence across all assessed anatomical and procedural domains, including otoscopy, endoscopy, mirror laryngoscopy, mastoid drilling orientation, and cricothyroid membrane identification. Educational value ratings were high across all stations, with mean scores ranging from 4.33 to 5.00. Qualitative feedback emphasized the realism, accessibility, and benefit of hands-on practice in a low-stakes learning environment. Conclusion: This low-cost, multistation ENT simulation curriculum provides a feasible and reproducible approach for introducing foundational otolaryngology skills to medical students. The structured format and affordable models support early procedural exposure and may enhance learner preparedness prior to supervised clinical encounters, particularly in settings with limited simulation resources.

Background: The 2026 FIFA World Cup may bring over one million visitors to North America from around the globe to participate in mass gathering events. The nature of the event and recent news have raised concerns for some that the tournament could lead to infectious disease outbreaks or fuel existing epidemics. Objective: To systematically assess the infectious disease threat posed to the United States by the tournament. Design: A multi-institutional team evaluated pathogen-specific risk across three dimensions: importation, outbreak potential, and impact to identify a priority pathogen list. A systematic screening protocol ensured common criteria and that pathogen information was collected when necessary to inform inclusion. Results: Increased risk from the World Cup is near zero for 63 of 77 evaluated pathogens. Pathogens were predominantly excluded as threats due to low excess importation risk and low outbreak potential if introduced. The remaining priority pathogens fall into five categories: (a) mosquito borne pathogens with the potential for sustained transmission in some host cities, (b) seasonal respiratory viruses, (c) chronic infections with high prevalence outside the United States, (d) pathogens present in the United States with likely increased transmission at World Cup activities, and (e) high-consequence infectious threats. Limitations: Data availability is variable across diseases. Impact calculations may not reflect actual costs to host cities. Disease incidence in World Cup travelers may differ from national incidence rates. Conclusion: While infectious disease outbreaks at the 2026 FIFA World Cup are possible, in an already highly connected world where large gatherings are frequent, the elevated risk from the tournament is not as extreme as it first may seem.

Introduction: Viral load (VL) monitoring is the gold standard for antiretroviral therapy (ART) monitoring. Still, due to limited funds and infrastructure, many people living with HIV (PLHIV) in low- and middle-income countries do not receive timely VL testing. We evaluated the clinical performance and end-user acceptability of a prototype interferon gamma-induced protein 10 (IP-10) point-of-care (POC) test as a rule-out triage tool to identify individuals unlikely to have unsuppressed VL in PLHIV in Mozambique. Methods: A mixed-methods study was conducted between November 2023 and November 2024 at two primary healthcare facilities in Maputo Province. We enrolled 1,057 PLHIV on ART from stable and specialized risk clinics. Clinical performance of the IP-10 POC test (index test) was compared against plasma HIV VL (reference test; unsuppressed defined as >1000 copies/mL). Socio-demographic and clinical predictors of false-positive results were identified using multivariable logistic regression. Immediate acceptability was assessed through exit interviews on a subset of 43 PLHIV. Results: Among participants (71.7% female; median age 41.4 years), 12.0% had unsuppressed VL. The IP-10 POC test demonstrated high sensitivity (90.6%) and moderate specificity (35.6%). Specificity was higher in clinics treating stable patients (44.5% 95%CI: 39.7-49.3) compared to specialized risk clinics (26.5% 95%CI: 21.1-28.9). The proportion of false-positive results was also higher in patients attending specialized risk clinics. Independent predictors of false positivity included enrolment in a one-stop TB/HIV clinic (aOR=2.99 95%CI: 1.09-8.15), cotrimoxazole use (aOR=2.16, 95% CI: 1.13-4.13), and obesity (aOR=3.47 95%CI: 1.74-6.93). Acceptability was high: 70% of participants appreciated the test simplicity and rapid results, and 95.3% expressed interest in future testing. Most patients preferred finger-prick collection over venous draws. Conclusions: The IP-10 POC test is a highly sensitive triage tool, demonstrating superior performance among stable PLHIV enrolled in differentiated service delivery models like six-month multi-month dispensing. While factors associated with co-infections can reduce specificity, the test's high acceptability and potential to reduce confirmatory VL test demand suggests it could serve as a viable triage strategy for optimizing resources particularly in stable care pathways with a lower prevalence of inflammatory comorbidities. This could enable health systems to reallocate intensive monitoring toward higher-risk populations.

Objective: To characterize pregnancy outcomes and menstrual irregularities in Mexican women with systemic lupus erythematosus (SLE) and identify clinical factors associated with adverse pregnancy outcomes and early-onset menopause. Methods: We conducted a cross-sectional study of women with SLE enrolled in the Mexican Lupus Registry (LupusRGMX) between May 2021 and September 2024. Clinical and reproductive data were collected using standardized questionnaires. Menopause was defined as the absence of menstruation for [&ge;]12 consecutive months, and early menopause as onset before age 40. Univariable and multivariable logistic regression analyses were used to identify factors associated with pregnancy complications and early menopause. Results: A total of 210 women were included. Median age was 38 years (IQR 29-46) and median disease duration was 4 years (IQR 1-10). Among women with a history of pregnancy (47%), full-term delivery predominated (61%), while pregnancy loss occurred in 26% and preterm delivery in 13%. Pregnancy complications were reported in 9.6%, most commonly preeclampsia (6.7%). Younger maternal age was independently associated with pregnancy complications (OR 0.89, 95% CI 0.83-0.95) and adverse outcomes (OR 0.95, 95% CI 0.92-0.98). Higher disease activity was associated with complications in univariable analysis. Most pregnancies (68.3%) occurred before diagnosis. Early menopause was observed in 6.2% and independently associated with longer disease duration and older age. Conclusion: Younger maternal age was independently associated with adverse pregnancy outcomes, whereas disease activity showed an association in univariable analysis. Most pregnancies occurred prior to SLE diagnosis. Early menopause was associated with longer disease duration, suggesting impact of cumulative disease burden on ovarian function.

ObjectiveLeukemic and hematopoietic cell transplant patients have one of the highest incidences of C. difficile infection (CDI). While CDI patients are considered the primary source of transmission, asymptomatic colonized patients (AC) can progress to CDI or contribute to in-unit transmission. We aim to quantify the roles of CDI and AC patients in C. difficile importation and transmission within oncological units. DesignProspective cohort study SettingTwo leukemia and HCT transplant units in a large tertiary care hospital in the US MethodsWe developed a stochastic, individual-based network model to simulate C. difficile acquisition and transmission. Data from cultures and nucleic acid amplification testing (NAAT) obtained at admission and weekly, and toxin enzyme immunoassay (EIA) tests used for CDI diagnosis were used to calibrate the model. Healthcare worker room assignments informed the network structure. Key parameters were estimated via particle filtering. ResultsThe model reproduced observed weekly test counts and transmission pairs. AC patients were the primary source of new colonizations: 51% were due to importation (of those, 88% were admitted as AC), and 49% were due to transmission (AC was the source in 92% of transmissions). Sensitivity analysis showed that these findings were most influenced by the colonization rate and rates of environmental contamination and cleaning. ConclusionsThese findings reinforce the role of AC, particularly via admission importation, in sustaining C. difficile transmission in high-risk hospital settings. Infection control focused on CDI effectively reduced onward transmission, as indicated by CDIs low contribution to new colonizations.

Abstract Background: Pediatric respiratory infections are a leading cause of morbidity and mortality globally, representing a major health challenge in children. Research Gap: Despite extensive studies on epidemiology, clinical management, and specific pathogens, no bibliometric analysis has systematically evaluated the most influential research in this field. Objectives: This study aimed to evaluate the characteristics of the top 50 most-cited articles on pediatric respiratory infections and to identify emerging research trends. Methods: The Web of Science database was searched without publication year restrictions. Independent reviewers screened studies based on predefined inclusion and exclusion criteria. Data were extracted using a standardized form, including study details. Results: The 50 most-cited articles ranged from 34 to 384 citations and showed a right-skewed distribution with a sharp drop after the top ten. Publication years ranged from 1978 to 2021, with over half published in the 2010s. Articles appeared in 31 journals, with Pediatrics contributing five. Leading countries were the United States (18%), China (12%), and Canada (10%), with research largely concentrated in high-income regions and limited multicenter collaboration. Cohort studies dominated (66%), while randomized trials (12%) and reviews/meta-analyses (16%) were less common. Research clustered around three themes: clinical outcomes (e.g., pneumonia, bronchiolitis); viral etiology/diagnostics (e.g., RSV, SARS-CoV-2); and antimicrobial stewardship. Conclusion: Over the past decades, pediatric respiratory infection research has developed but remains unbalanced, relying heavily on observational evidence from high-income countries, with limited randomized trials, systematic reviews, multicenter collaborations, and LMIC-led studies. These findings provide insights that may direct researchers to identify potential focal points and guide future research in the field.

M.D.-Ph.D. programs in the United States have traditionally followed a "2-n-2" curricular model, with the graduate phase occurring between the pre-clerkship and clerkship portions of medical training. While well established, this format can limit trainee autonomy in shaping their physician-scientist training trajectories. In response, some programs have introduced a "3-n-1" model, allowing students to complete clerkships before beginning Ph.D. training. Our institution implemented multiple flexible curricula in 2017. Understanding why trainees choose one pathway is important as programs consider implementing more adaptable training structures. To investigate these factors, we surveyed M.D.-Ph.D. students at our institution, which offers multiple flexible curricular alternatives, about contributions to their curricular decisions. Responses supported that trainees weigh considerations across medical education, scientific development, and integrated physician-scientist training domains. Although the traditional pathway was a popular option, most students pursued one of the flexible pathways. Our findings suggest that introducing flexibility in the timing of undergraduate medical education and graduate training can support diverse educational, logistical, and personal priorities while maintaining the rigor of physician-scientist training. Offering multiple pathways empowers trainees to design trajectories that best fit their needs. Continued longitudinal studies are needed to assess the long-term impacts of flexible curricula on physician-scientist career outcomes.

Background Erythema nodosum leprosum (ENL) is a severe inflammatory complication of leprosy that often requires prolonged corticosteroid therapy which is associated with adverse effects. Methotrexate is an affordable immunomodulatory agent with limited evidence for its use in ENL treatment. We evaluated whether weekly oral methotrexate in additional to prednisolone reduces the need for additional prednisolone in adults with severe ENL. Methods and Findings We performed an international, multicentre, double-blind, randomised, placebo-controlled trial conducted at five leprosy referral centres in Ethiopia, India, Indonesia, and Nepal. Adults aged 18-60 years with severe ENL were randomised to receive oral methotrexate and prednisolone, or matching placebo and prednisolone. All participants received an identical prednisolone regime over 20 weeks and were followed for 60 weeks. The primary outcome was time to first ENL flare requiring additional prednisolone, assessed over 24 and 48 weeks. Between January 2023 and June 2024, 231 individuals were screened and 137 were randomised (68 methotrexate and prednisolone; 69 placebo and prednisolone). By 24 weeks, 85/137 (62.0%) participants experienced an ENL flare requiring additional prednisolone; the adjusted hazard ratio (HR) for methotrexate versus placebo was 0.98 (95% CI 0.62-1.54). By 48 weeks, 102/137 (74.5%) experienced an ENL flare; adjusted HR 0.95 (95% CI 0.62-1.43). Secondary outcomes were similar: methotrexate did not reduce ENL severity at first flare, flare frequency, or severity of subsequent flares. Health-related quality of life improved substantially in both groups with no evidence of a differential treatment effect. Methotrexate was generally well tolerated. The trial was registered at ClinicalTrials.gov (NCT03775460). Conclusions Oral methotrexate added to prednisolone did not reduce the requirement for additional prednisolone or delay ENL flares compared to placebo and prednisolone, and our study does not support the use of methotrexate for severe ENL.

Background: People living with HIV (PLHIV) in sub-Saharan Africa exhibit high rates of pneumococcal carriage compared to HIV-uninfected adults, despite antiretroviral therapy. We established a novel controlled human infection model of experimental pneumococcal carriage in people living with HIV to understand carriage dynamics in this at-risk population. Methods: Seventy-five virally suppressed and clinically stable PLHIV and 75 HIV-uninfected controls were inoculated with escalating doses of pneumococcus serotype 6B. Carriage acquisition and density were determined by microbiological culture of nasal wash samples collected before and up to 14 days after inoculation. Adverse events were identified by active and passive surveillance. Participant-reported acceptability was established using a Likert scale. Findings: No serious adverse events occurred. Mild adverse events were similar between groups (19% [14/75] in PLHIV, 13% [10/75] in HIV-uninfected; p=0.505). More than 90% of participants reported acceptability with all study procedures. Experimental carriage occurred in 21% (16/75) of PLHIV compared with 36% (27/75) of HIV-uninfected participants (adjusted odds ratio 0.39 [95% CI 0.16-0.91]). Among PLHIV without detectable cotrimoxazole, 28% (8/29) acquired experimental carriage. Carriage clearance rates were lower in PLHIV (hazard ratio 0.44 [95% CI 0.14-1.42]). Interpretation: In carefully selected PLHIV with effective viral suppression and clinical stability experimental pneumococcal carriage acquisition did not exceed that in HIV-uninfected adults, even after accounting for antibiotic use, natural pneumococcal co-colonisation, and sociodemographic differences. These findings suggest that high carriage prevalence in PLHIV in sub-Saharan Africa may be driven more by prolonged carriage duration than increased susceptibility to acquisition. This model provides a platform to investigate mechanisms underlying carriage susceptibility and impaired clearance in PLHIV and to evaluate interventions aimed at reducing the carriage burden in sub-Saharan Africa. Funding: Wellcome Trust

Background: Intrauterine contraceptives (IUCs) are effective, but effects on genital inflammation among women living with HIV (WLHIV) by antiretroviral therapy (ART) use are unclear. We evaluated the longitudinal effects of copper IUC (C IUC) and the levonorgestrel intrauterine system (LNG IUS) on cervicovaginal cytokine profiles in a secondary analysis of a randomized trial (NCT01721798, 2013 to 2016). Methods: Cervicovaginal secretions were collected from 100 WLHIV (non ART users; ART users) randomized 1:1 to C IUC or LNG IUS. Twenty eight cytokines were measured prior to insertion and 3 and 6 months post insertion. Cytokine concentrations at each follow up visit were compared with baseline, using participant fixed effects models stratified by ART status. Results: At enrolment, non ART users had higher average concentrations of most cytokines (21/28) than women using ART. Among non-ART users, IUC use was not associated with cytokine increases; only MCP1 increased significantly at 3 months among C IUC users (log10 geometric mean ratio 0.77, 95%CI 0.38 to 1.17), while none increased with LNG IUS use. Among ART users, C IUC insertion resulted in broad and sustained cytokine increases at both 3 (16/28) and 6 months (15/28). At month 3, the largest increases in log10 geometric mean were observed for IL6 (1.04, 0.72 to 1.36), RANTES (0.97, 0.54 to 1.40), MCP1 (0.71, 0.46 to 0.96), MIP1; (0.66, 0.37 to 0.94), and GCSF (0.63, 0.36 to 0.89), which was maintained until month 6. Cytokine changes following LNG IUS insertion were minimal (IL5, month 3). Conclusions: Among ART users, C IUC is associated with increases in cervicovaginal cytokines, across functional classes. This supports LNG IUS as a less inflammatory option for WLHIV to minimize genital immune activation.

Background Pediatric immunizations for Respiratory Syncytial Virus (RSV), including monoclonal antibodies for infants and vaccines for pregnant people, have become broadly available and can prevent severe RSV outcomes in infants. However, quantifying the impact of RSV immunization in prevention of severe pediatric illness at the population-level is limited by lack of RSV case surveillance data. The Massachusetts Department of Public Health (DPH) conducted a modeling analysis using routine public health surveillance data to estimate the state-level impact of new RSV immunization products on Emergency Department (ED) visits and hospitalizations in Massachusetts for highest risk pediatric groups. Methods A scenario projection tool, called R.Scenario.Vax, was utilized to simulate RSV-associated ED hospital encounters by age group in the context of newly available immunizations. ED visit and hospitalization data from the National Syndromic Surveillance Program (NSSP) during the time period 10/08/2017--10/19/2024 were analyzed, scaled to account for changes in RSV testing practices over time and missing encounter volume in historic data, and utilized to inform model fit of a "typical" RSV season. RSV immunization data from the Massachusetts Immunization Information System (MIIS) for the 2023--2024 and 2024--2025 RSV seasons informed high and moderate pediatric RSV immunization coverage scenarios and their impact was compared to a counterfactual reference scenario of no new immunizations. Median projections were quantitatively and qualitatively compared to observed 2024--2025 season data. Percent reduction in hospital encounters and encounters averted per 10,000 population were calculated for each scenario as compared to the reference. Results Projections for the youngest at-risk age groups showed significantly lower RSV-associated ED visits and hospitalizations during the 2024--2025 season for both high and moderate immunization coverage scenarios. Median projections for infants under 6 months old in the highest coverage scenario, wherein nearly all infants were immunized, showed 72.6% lower ED visits and 73.4% lower hospitalizations when compared to the reference scenario, equating to 262 ED visits and 85 hospitalizations averted per 10,000 population. Conclusions Our results support the use of modeling methods for public health insights and suggest that RSV immunizations for infant populations result in significantly lower RSV-related ED encounters in Massachusetts.

Background: Without tuberculosis preventive therapy (TPT), approximately 5% of individuals infected with M. tuberculosis progress to active tuberculosis (TB) disease. Recent studies have identified body mass index (BMI) < 25 kg/m2 as a predictor of TB progression, but additional markers are needed to better identify persons at increased risk. Methods: Close contacts of patients with culture-confirmed pulmonary TB were enrolled in the Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil cohort from 2015 to 2019 and followed for up to 24 months. Analyses were restricted to interferon-{gamma} release assay (IGRA)-positive contacts who did not receive TPT or received <30 days of isoniazid. Prediction models to identify close contacts at increased TB risk were constructed using two complementary approaches: incremental models used BMI as the base predictor and evaluated whether baseline whole-blood transcriptomic signatures, human genetic polymorphism risk scores derived from low-pass whole-genome sequencing, and BMI-related plasma biomarkers improved model discrimination. Agnostic models did not impose BMI in the model and used penalized regression for predictor selection. Results: Among 285 close contacts, 15 (5%) progressed to TB. The model with BMI as unique predictor had a C-index of 0.66 (95% confidence interval [CI] 0.55; 0.77). Adding Rajan5 or Duffy9 transcriptomic signature scores to BMI improved discrimination compared with BMI alone, with C-indices of 0.78 (95% CI 0.62; 0.99) and 0.75 (95% CI 0.61; 0.89), respectively, but did not further improve discrimination after accounting for adiponectin. Adding adiponectin to BMI increased the C-index to 0.80 (95% CI 0.68; 0.91), while adiponectin alone captured most of the discriminatory performance in agnostic models (C-index, 0.80, 95% CI 0.69; 0.91). Genetic risk scores, leptin, and the adiponectin:leptin ratio did not improve model discrimination compared with the BMI-only model. In exploratory post hoc analyses, higher adiponectin was associated with increased risk of progression to TB, with each two-fold increase associated with a higher hazard of TB (HR 2.91, 95% CI 1.73; 4.91, p < 0.001). Conclusions: Baseline adiponectin strongly predicted progression to TB among close contacts and captured most of the discriminatory information contained in epidemiological and transcriptomic variables. Its consistent selection across modelling approaches supports adiponectin as a promising biomarker for TB risk stratification.

Background: Advanced HIV disease (AHD) remains a major contributor to HIV-related morbidity and mortality despite widespread antiretroviral therapy (ART) access in sub-Saharan Africa. Although treatment-related adverse drug reactions (ADRs) may compromise treatment outcomes, evidence on the relationship between AHD and ADR occurrence remains limited. This study aimed to determine the prevalence and identify factors associated with AHD, characterize treatment-related ADR and assess the association between AHD and ADR occurrence among people living with HIV receiving ART in Dar es Salaam, Tanzania. Methods: We conducted a multicenter cross-sectional study among 1,513 people living with HIV receiving ART at selected HIV care and treatment clinics in Dar es Salaam, TanzaniaFor this adolescent/adult cohort, AHD was operationally defined as WHO clinical stage III/IV disease and/or baseline CD4 count <200 cells/mm3. Treatment-related ADRs were defined as participant-reported and/or clinically documented ART-related adverse events identified during routine HIV care, including both current and retrospectively reported events. Modified Poisson regression with robust standard errors was used to estimate crude and adjusted risk ratios (RRs) with 95% confidence intervals (CIs). Results: Among 1,508 participants with sufficient information for classification, 961 (63.7%) had AHD. Factors independently associated with AHD included age [&ge;]50 years (aRR 1.10, 95% CI 1.01-1.20), underweight nutritional status (aRR 1.17, 95% CI 1.00-1.35), and concomitant medication use (aRR 1.19, 95% CI 1.03-1.37), while DTG-based ART was associated with lower AHD prevalence (aRR 0.78, 95% CI 0.68-0.90). Overall, 569 participants (38.0%) reported at least one ADR. Composite AHD was not independently associated with ADR occurrence (aRR 0.95, 95% CI 0.82-1.11), but baseline CD4 <200 cells/mm3 was associated with increased ADR risk (aRR 1.20, 95% CI 1.02-1.41). Comorbidity (aRR 1.66, 95% CI 1.42-1.93) was the strongest correlate of ADR occurrence. Conclusion: AHD remains highly prevalent among people living with HIV receiving ART in Tanzania. While composite AHD was not independently associated with ADR occurrence, severe immunosuppression, comorbidity burden, and concomitant medication exposure were associated with increased ADR risk. These findings suggest that immunologic severity and broader clinical complexity may be more informative predictors of ART-related toxicity than composite syndromic AHD classification alone. Strengthened early diagnosis, differentiated advanced HIV care, integrated pharmacovigilance strategies, and routine medication risk assessment are needed.

Background Human challenge trials provide a unique opportunity to quantify pathogen infectivity in terms of the probability of infection given an inoculated dose. However, between-pathogen comparisons are often distorted by individual heterogeneity in host susceptibility and by differences in background immunity across trial populations. We examined how dose-dependent infection risks differ across common respiratory viruses when such heterogeneity is explicitly incorporated. Methods We conducted a systematic review of human challenge trials for four respiratory viruses: respiratory syncytial virus (RSV), influenza virus, rhinovirus, and adenovirus. Using the extracted data, we fitted dose-response models under different distributional assumptions, allowing both continuous susceptibility variation and discrete immune fractions. We compared alternative heterogeneity models and evaluated pathogen-specific dose-response patterns using original and scaled dose metrics. Results All four viruses showed substantial heterogeneity in host susceptibility, and models assuming homogeneous susceptibility were unsupported. RSV and influenza were best described by models with a distinct immune or effectively non-susceptible subgroup, and the estimated immune proportions were approximately 40% and 25%, respectively. In contrast, rhinovirus and adenovirus were better explained by continuously distributed susceptibility, with little evidence of a fully immune subgroup. On a scaled dose axis, rhinovirus and adenovirus showed steeper increases in infection risk with dose than RSV and influenza. Conclusions The structure of susceptibility heterogeneity differs across common respiratory viruses, which in turn shapes dose-dependent infection risks. Incorporating this heterogeneity is essential for valid cross-pathogen comparison and for interpreting human challenge data in epidemiologic and public health contexts.

Background: The isolation of many HIV broadly neutralizing antibodies (bnAbs) from people living with HIV (PLWH) and rigorous characterization of their ontogeny has promoted the goal of reverse engineering their natural development as a strategy for achieving an effective preventive HIV vaccine. We previously described the developmental process of CH103, a CD4-binding site (CD4bs)-specific monoclonal antibody, and the associated evolution of HIV Envelopes (Envs) within the person (CH505) from whom it was isolated. A series of monomeric gp120 protein subunit immunogens representing the transmitted founder (TF) and Envs that evolved during infection and optimally reacted with lineage members at each step of the CH103 clone maturation path were evaluated in this placebo controlled randomized vaccine trial to test for the first time in humans the concept of whether sequential immunization with gp120 monomeric proteins can recapitulate the development of CD4bs B-cell clonal lineages, including CH103. Methods: HIV Vaccine Trials Network 115 (HVTN 115) was a randomized placebo-controlled vaccine trial at US clinical research sites. We tested the safety and immunogenicity of CH505TF gp120 + GLA-SE (Part A), and then the ability of sequential CH505 gp120 proteins (corresponding to CH505s weeks 53 and 78 Envs) + GLA-SE immunizations to induce CD4bs-specific neutralizing antibodies (Part B). We assessed binding and neutralizing antibody responses, antibody dependent cellular cytotoxicity, antibody dependent cellular phagocytosis, T-cell responses and B-cell phenotyping. Results: We enrolled 42 participants between October 2017 and May 2018 for Part A, and 65 participants from December 2020 to October 2022 for Part B. Immunization with the CH505 gp120 proteins adjuvanted with GLA-SE was well tolerated and induced CD4bs-specific B cells and Env-specific plasma antibodies. The plasma neutralizing antibody response was limited to primarily tier 1 autologous and heterologous HIV-1 strains. Blood-derived B-cell repertoire analyses identified CD4bs antibodies that preferentially bound to open-occluded trimeric Envs that exist in an intermediate state between prefusion-closed to CD4-bound open confirmations, consistent with tier 1 HIV neutralizing activity. Conclusions: Together, these results suggest that the low-affinity CH505TF gp120 monomer elicited CD4bs antibodies in the sera and B-cell repertoires of humans. However, our findings also indicate that gp120 monomers are insufficient to induce detectable bnAb precursors to epitopes on native Env trimers. Nonetheless, our data provide a benchmark for comparison with ongoing clinical trials testing high-affinity CH505 Env trimers for induction of CD4bs bnAb precursors.

Using a commercially available H5 serology assay, we identified a 7.4% (n=5/68) anti-H5 seroreactivity rate among hunters in Northern Canada. All participants reported close contact with wild birds.

Background: Diarrheal illness in children leads to 3.5 million care visits and 200,000 hospitalizations annually in the US. Viruses are responsible for most pediatric diarrheal cases, yet limited guidance on distinguishing viral from bacterial etiologies complicates clinical decision-making, especially regarding empiric antibiotic use. Methods: We used clinical and qualitative molecular etiologic data from the Implementation of Molecular Diagnostics for Pediatric Acute Gastroenteritis (IMPACT) study to develop prediction models for viral etiology of diarrhea. We used conditional random forests to identify informative clinical and environmental predictors and evaluated model performance using logistic regression and random forests within a 5-fold cross-validation framework. We conducted external validation using the Alberta Provincial Pediatric Enteric Infection Team (APPETITE) dataset. Results: Variables predictive of viral etiology included younger age, non-bloody diarrhea, winter season, and presence of vomiting. External validation showed that an AUC of 0.82 can be achieved with a parsimonious 5-variable model, yielding a sensitivity of 0.92 and specificity of 0.55 Conclusion: Our results suggest that in North American healthcare settings, clinical prediction models can inform decision-making by identifying children with a high probability of viral diarrhea, improving diagnostic clarity, and reducing unnecessary testing and treatment.

Background: Shigella is a leading cause of childhood diarrhea in low- and middle-income countries and is increasingly resistant to first-line antibiotics. We conducted a surveillance study to determine the incidence, genomic characteristics, and AMR profiles of Shigella infections in children under five with moderate to severe diarrhea (MSD) in Lusaka, Zambia. Methods: Between 15 September 2020 and 30 November 2021, a prospective cohort study of 1,400 children under five was enrolled during a community census in a peri-urban setting and passively followed for 9.5 months for MSD. During enrollment, socio-demographic data were collected using electronic questionnaires, while clinical data were collected through the DHIS platform. The main outcome, Shigella in diarrheal stool in under 5 children, was detected using culture and Loop-mediated Isothermal Amplification (LAMP) targeting the ipaH gene. Cox proportional hazards models were used to assess the incidence and risk factors of Shigella (ipaH) infections. Whole-genome sequencing (WGS) was used to characterize the genomic diversity and antimicrobial resistance genes, complemented by phenotypic antibiotic susceptibility testing. Results: There were 230 first episodes of Shigella over a follow-up time of 9,581.7 child-months, yielding an incidence of 24.0 (95% CI 21.1-27.3) cases per 1,000 child-months, with the highest incidence among 2 to 3-year-olds. The key risk factors identified were the water source (p=0.025) and age group (p=0.014). Genotypic characterization revealed 10 S. flexneri, 9 S. sonnei, and 3 S. boydii. The S. sonnei isolates formed two clusters, differing in virulence factors and plasmid profiles, indicating two possible circulating strains. Shigella isolates exhibited phenotypic and genotypic multidrug resistance, including against trimethoprim, aminoglycosides, and beta-lactams. Plasmid-mediated quinolone resistance (qnrS1) was identified in four S. flexneri isolates, with these genes located on the IncFIB(K) plasmid, highlighting the potential for horizontal transmission and spread of quinolone resistance in this region. No phenotypic and genotypic resistance to macrolides, the first-line treatment for Shigella in Zambia, was observed. Interpretation: We report a high burden of Shigella with multidrug resistance, including resistance to fluoroquinolones. These findings highlight the increasing resistance of Shigella to first-line antibiotics and underscore the importance of developing safe and effective vaccines, improving WASH conditions, and ongoing AMR surveillance. Funding: The EDCTP2 program, supported by the European Union, the Faculty for the Future Foundation (FFTF), the Netherlands Organization for Health Research and Development (ZonMw), and Health-Holland AMR-Global, Gloria, and Track-AMR.