Infectious Diseases and Therapy

Nasopharyngeal (NP) swabs remain the dominant gold standard for respiratory infection diagnostics. While there has been increased use of alternative sample types since the COVID-19 pandemic, guidance on their use for detecting respiratory viruses is not yet definitive, especially for children. In this systematic review and meta-analysis, we aimed to compare the diagnostic accuracy and tolerability of multiple respiratory specimen types for detecting respiratory viruses in pediatric populations. Searches were conducted on July 17, 2025 in MEDLINE, Embase, Web of Science, and Scopus, with screening and data extraction performed in Covidence. English-language primary research articles published since 2000 comparing respiratory virus detection rates in children, using nucleic acid amplification tests between paired respiratory specimens, were included. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies criteria. We calculated pooled sensitivities and specificities of index specimens: nasopharyngeal aspirates (NPA), mid-turbinate swabs (MT), anterior nasal swabs (ANS), oropharyngeal swabs (OP), and bronchoalveolar lavage fluid (BAL), as compared to the reference, NP swabs, using random-effects modeling, firstly without discrimination by virus. Index specimens were then grouped by sample collection site as nasal, oral, and lower respiratory tract (LRT) specimens for virus-specific analyses. Overall performance and statistical validity were evaluated by hierarchical summary receiver operating characteristic (HSROC) analysis. Data regarding sampling tolerability was also assessed. We screened 2,448 studies and identified 36 publications (total N participants = 10,687) that reported diagnostic test accuracy using paired index-reference data in children. Of these, 18 (total N participants = 4,310) used NP specimens as the reference and were included in the diagnostic test accuracy analysis. Virus-agnostic pooled sensitivity estimates indicated that MT (0.92%) performed most similarly to NP, though sensitivities of ANS (0.79%) and OP (0.70%) were also moderately high for detection of any respiratory virus. BAL sensitivity was the lowest (0.37%). All sample types demonstrated high specificity (0.98%-0.99%). Group estimates and HSROC statistics found that nasal specimens, when grouped, had the highest sensitivity and accuracy for all examined viruses, including for influenza (92%) and RSV (90%). By comparison, oral and LRT specimens performed less well, with more variability, though both showed moderately high sensitivities for RSV (78%, 76%, respectively) and influenza (82%, 80%, respectively), and LRT samples showed high sensitivity for HMPV (82%). Analysis of sample tolerability found that NP swabs consistently ranked as the least comfortable and least preferred, while nasal swabs and saliva both performed well. Datasets for LRT and oral specimens were sparser than for nasal, and this contributed to greater variability, underscoring the need for further diagnostic accuracy studies on alternatives to NP sampling. These data support the viability of nasal and oral alternatives to NP swabs and affirm their application in pediatric care, particularly in outpatient settings. Such alternatives could greatly improve sampling tolerability and increase global access, including in resource-limited settings, to accurate diagnostic methods for respiratory infections.

Background: Digital antimicrobial stewardship (AMS) interventions, such as clinical decision support systems, audit and feedback platforms, and electronic prescribing tools, have been increasingly adopted to improve antibiotic use. However, the effectiveness of these interventions across healthcare settings remains uncertain, and the certainty of the evidence has not been comprehensively evaluated. The objective of this study was to provide a comprehensive understanding of the role of digital interventions in optimizing antimicrobial use and improving clinical outcomes within a broad spectrum of healthcare settings. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials evaluating digital AMS interventions that followed PRISMA 2020 guidelines and registered in PROSPERO CRD420251178854 and funded by the Wellcome Trust CAMO Net programme. Searches were performed across major databases. Primary outcomes included the appropriateness of antibiotic prescriptions and the antibiotic prescription rate. Secondary outcomes included 30 day mortality, 30 day hospital readmission, and length of hospital stay (LOS). Random effects models were used to pool effect sizes. Risk of bias was assessed RoB 2, and certainty of evidence was rated using GRADE. A Summary of Findings table was prepared to present effect estimates, sample sizes, and evidence certainty. Results: Eleven RCTs met the inclusion criteria, and nine were included in the quantitative synthesis. Digital AMS interventions did not show a significant effect on appropriateness of antibiotic prescribing (RR 0.99, 95%CI 0.93 to 1.05; very low certainty). There was no reduction in antibiotic prescription (RR 0.98, 95%CI 0.88 to 1.09), with substantial statistical heterogeneity and very low certainty. Across clinical outcomes, digital AMS showed no effect on 30 day mortality (RR 0.91, 95%CI 0.77 to 1.09; very low certainty) or 30 day readmission (RR 0.95, 95%CI 0.79 to 1.14; very low certainty). For LOS, results were inconsistent across studies, and the pooled effect showed no clinically meaningful change (MD 0.17 days, 95%CI 0.01 to 0.35; very low certainty). Most trials had some concerns of bias due to deviations from intended interventions. Conclusion: Meta-analyses of digital AMS RCTs showed a lack of evidence with a high level of certainty on antibiotic prescribing or clinical outcomes due to high heterogeneity in interventions and study designs, as well as RCTs' limitations (no adoption/fidelity metrics).

Use of fungal mycelia, which has antiviral properties, constitutes a novel strategy for addressing existing and newly emerging viral diseases. We evaluated safety and feasibility of fungal mycelia (Fomitopsis officinalis and Trametes versicolor, FoTv) for treatment of COVID-19 and assessed its antiviral effects and potential to reduce symptoms. In a randomized, double-blind, placebo-controlled, dual site (UCSD/UCLA medical centers) clinical trial we examined non-hospitalized patients who contracted mild-to-moderate COVID-19 [≤] 96 hours, and experienced symptom onset [≤] nine days, before enrollment. FoTv was safe, well-tolerated, and feasible for COVID-19 treatment. Minor differences in biochemical markers were observed between groups (26 FoTv, 24 Placebo). FoTv significantly reduced the number and severity of symptoms, particularly sore throat/cough, and in vitro SARS-CoV-2 (pseudovirus) cellular infection. In conclusion, FoTv was safe and reduced COVID-19 symptoms and cellular viral infection. Future studies should investigate therapeutic benefits of fungal mycelia for SARS-CoV-2 and other viruses. Clinicaltrials.gov registration:NCT04667247.

Introduction: Synthetic oligopeptides provide a rapid and cost-efficient approach to developing antibodies and diagnostics for emerging viral variants. Methods: This study computationally and experimentally characterized a synthetic peptide analog of the SARS-CoV-2 spike subdomain 2 major disulfide loop (SD2MDL), designated S621 (CPVAIHADQLTPTWRVYSTC). Binding affinity was computationally estimated using the Heuristic Affinity Prediction Tool for Immune Complexes (HAPTIC), while experimental validation was performed using enzyme-linked immunosorbent assay (ELISA) with rabbit-derived antipeptide antibodies. Clinical diagnostic accuracy testing was done using plasma samples from RT-PCR-confirmed COVID-19 patients and pre-COVID-19 controls. Results: S621 demonstrated nanomolar binding affinity (Kdapp = 1.14 nM) and high avidity (3.67 nM), closely matching HAPTIC predictions (3.54 nM). Diagnostic evaluation yielded a sensitivity of 89.92% and specificity of 27.79%, corresponding to an overall accuracy of 71.79%. Discussion: These findings demonstrate that a single synthetic peptide derived from a conserved spike subdomain can function as a high-affinity surrogate for full-length antigens, supporting its potential application in rapid peptide-based immunodiagnostics.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious condition associated with pediatric SARS-CoV-2 infection. While COVID-19 vaccines prevent infection and reduce severity, less conclusive evidence exists regarding their role in preventing MIS-C during breakthrough infections. This systematic review assessed the impact of SARS-CoV-2 vaccination on MIS-C risk during breakthrough infection. Cross-sectional studies, surveillance studies, and cohort studies were included. Of the 944 studies identified, 6 were included. A significant protective effect was seen in patients who received two doses of SARS-CoV-2 vaccination after exclusion of a biased sample (d= 0.71 [95% CI 0.07 to 1.35; p=0.03]). A trend towards a protective effect was seen after one dose of vaccination, but this effect was not statistically significant. Current literature supports a protective effect of two doses of SARS-CoV-2 vaccination against development of MIS-C in breakthrough COVID-19. The evidence supports clinician advocacy for continued vaccination of children against SARS-CoV-2.

Background Despite the significant impact of longstanding paediatric pneumococcal conjugate vaccine (PCV) use in the United Kingdom (UK), pneumococcal disease burden remains substantial and is primarily driven by nonPCV13 serotypes. Higher valent vaccines such as the 20 valent PCV (PCV20) may provide additional public health and economic benefits, yet their value in the contemporary UK setting has not been fully assessed using recent data. Methods We updated an age structured dynamic transmission model using post COVID 19 UK epidemiology (2001 to 2023) to compare pediatric PCV20 with PCV13 and PCV15. Over a 10 year horizon, we assessed cost effectiveness and number needed to vaccinate (NNV), capturing invasive and non invasive disease cases, deaths, costs, quality adjusted life years, and incremental cost effectiveness ratios. PCV20 was evaluated under 1+1 and 2+1 schedules; PCV13 and PCV15 were assessed under 1+1. Scenario analyses examined key uncertainties. Results PCV20 was estimated to avert more cases and deaths than PCV13 or PCV15, driven by broader serotype coverage and indirect effects. Both PCV20 schedules were dominant or cost saving versus lower valent comparators, with lower NNVs. PCV20s higher vaccination costs were offset by reductions in downstream healthcare expenditures. Conclusion Paediatric PCV20 implementation in the UK could deliver substantial health gains while improving economic efficiency, supporting timely adoption.

Background: Community-acquired pneumonia (CAP) remains a major global health burden disproportionately affecting older adults and people with comorbidities, with Streptococcus pneumoniae as one of the leading bacterial causes in Europe. The Hungarian Occurrence and Burden of PnEumonia (Hungarian-HOPE) study examined the incidence, hospitalization rates, and mortality of CAP between 2016 and 2020 in Hungary. Methods: The National Health Insurance Fund database was used to identify adult CAP patients (all-cause) based on ICD-10 codes J10-18. Outcomes included CAP incidence, 0-15-day hospitalization, and 0-30-day mortality after hospitalization, stratified by age, sex, and comorbidities (chronic obstructive pulmonary disease [COPD], asthma, cardiovascular disease [CVD], and type 1 and 2 diabetes [T1DM, T2DM]). Risk maps visualized relative risk gradients across population strata. Results: During the pre-pandemic period (2016-2019), over 100,000 CAP cases and more than 50,000 hospitalizations were recorded annually. In 2020, recorded cases fell to approximately 98,000, while hospitalizations increased to 66,200. Hospitalization rates increased from 25.1% in 2016 to 29.1% in 2019, then increased to 43.1% in 2020. The 30-day mortality among hospitalized patients rose from 22.7% in 2016 to 23.6% in 2019. Incidence, hospitalization, and mortality all increased with age. Relative to healthy males aged 30-39 years, CAP risk escalated steeply in the [≥]80 years cohort (incidence 5-15-fold; hospitalization >3-fold; mortality 11-24-fold) and was further amplified by COPD, CVD, or T2DM, with a lesser effect for T1DM. Conclusions: The results highlight the substantial age- and comorbidity-driven CAP burden in Hungary and support prioritization of preventive strategies including pneumococcal vaccination for older adults and high-risk groups.

Background and Aims SARS-CoV-2 infection is associated with an increased risk of cardiovascular, cerebrovascular and venous thromboembolism events. We aimed to assess the impact of COVID-19 vaccination prior to SARS-CoV-2 infection on the risk of these events post-infection. Methods Embase and MEDLINE were searched from January 2021 to 11 September 2025, supplemented by citation searching. Observational studies were included if they reported risks of cardiovascular, cerebrovascular, or venous thromboembolic events after SARS-CoV-2 infection between different vaccination groups (e.g. unvaccinated, vaccinated, or booster vaccinated), or reported risk of events after SARS-CoV-2 infection compared with no infection, stratified by vaccination status. Random-effects meta-analyses were conducted to estimate pooled hazard ratios (HRs) comparing vaccinated and unvaccinated individuals across prespecified outcomes. Results Twenty-three studies were included in the systematic review; most reported an association between vaccination and a reduced risk of post-infection vascular events. Ten studies were included across meta-analyses comparing vaccinated and unvaccinated individuals. Pre-infection vaccination was associated with significantly reduced risks of composite cardiovascular/cerebrovascular events (HR 0.60, 95% confidence intervals [CI] 0.51-0.69), stroke (HR 0.75, 95% CI 0.64-0.88), acute coronary syndrome (HR 0.70, 95% CI 0.52-0.95), arrhythmias (HR 0.82, 95% CI 0.69-0.98), and venous thromboembolism (HR 0.51, 95% CI 0.36-0.73). No statistically significant reduction was observed for heart failure (HR 0.72 [95% CI 0.47-1.10]). Conclusions Pre-infection COVID-19 vaccination is associated with lower risks of cardiovascular, cerebrovascular and venous thromboembolism events following SARS-CoV-2 infection in the pre- and post-Omicron eras, supporting its role within broader prevention strategies

Rationale: Efficacious dose selection for anti-tuberculosis drugs has traditionally relied on achieving plasma exposures above the minimum inhibitory concentration, but this approach has not consistently aligned with clinical outcomes. Objectives: We sought to identify early pharmacokinetic-pharmacodynamic targets most predictive of clinical efficacious dose. Methods: We conducted a back-translational, pharmacokinetic-pharmacodynamic simulation-based analysis of 15 anti-tuberculosis drugs. Using pharmacokinetic data from multiple biological matrices and a range of pharmacodynamic metrics, we established candidate exposure-response targets for attainment. We systematically evaluated the predictive accuracy of each target pair against established clinical doses to formulate a decision-making framework linking key drug properties to the most predictive targets. Measurements and Main Results: Depending on the target used, projected clinical doses varied widely - both within and across compounds - highlighting the importance of target selection for dose projection and go/no-go decisions. In general, targeting cellular lesion-level drug exposures relative to in vivo preclinical potency provided an effective approach for early dose selection. However, for highly penetrating drugs, targeting site-of-action therapeutic exposures in the caseum was more predictive of clinical dose. Based on these findings, we developed a preliminary dose prediction tool that enables drug developers to estimate clinically relevant dose ranges of compounds using in vitro and early in vivo data. Conclusions: This work establishes and validates a simple, evidence-based framework to standardize early translational decision-making on dose selection of anti-tuberculosis candidates in development.

Ganciclovir (GCV), and its orally available pro-drug valganciclovir (VGCV), are preferred therapies for treating congenital cytomegalovirus (cCMV), however, their use carries a significant risk of neutropenia for the child. This risk limits dosing and effectiveness of VGCV, particularly in the treatment of infants with cCMV infection, who are at increased risk for sensorineural hearing loss (SNHL). We hypothesized that an improved understanding of the pharmacokinetics (PK) and pharmacodynamics (PD) of VGCV in cCMV-infected infants at risk for SNHL would inform strategies for optimizing safe and effective VGCV dosing. Participants were enrolled in one of two clinical studies interrogating the PK, safety, and efficacy of VGCV treatment in cCMV-infected infants at risk for SNHL. GCV exhibited a short median half-life of 2.02 h and the median (range) area under the 24 h concentration-time curve (AUC24) was 60.8 (26.8, 99.4) g*h/mL. An AUC24 > 70 g*h/mL was associated with an elevated risk of neutropenia (Fisher's Exact p = 0.029). No associations between GCV PK and hearing outcomes were observed. Taken together, these results indicate vast inter-individual variability in GCV PK that is associated with dose-related toxicity, supporting the need for individualized dosing in the cCMV-infected population.

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.

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.

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.

Objectives In Quebec, Canada, vaccination against human papillomavirus (HPV) has been publicly-funded since January 2016 for gay, bisexual, and other men who have sex with men (GBM) aged [≤]26 years. The study aimed to analyze data collected in Greater Montreal (Engage study) to evaluate the HPV vaccination program for GBM in Quebec. Study Design Engage is a cohort of sexually active GBM aged [≥]16 recruited via respondent-driven-sampling (RDS) in Canada. Participants completed a questionnaire and tested for sexually transmitted infections. Methods RDS-II weights were applied to adjust for recruitment. Subgroups were compared using standardized mean differences. Odds ratios of HPV vaccination and prevalence ratios of anal HPV infection adjusted for potential confounders were estimated using robust regression models. Results Of 1179 participants, 309 were eligible for free HPV vaccination. Vaccine coverage among eligible GBM was 42%. Among those who disclosed same-sex sexual activity and discussed HPV vaccination with their healthcare provider, coverage reached 82%. Anal HPV prevalence among eligible GBM was 26.5% for [≥]1 HPV-6/11/16/18 genotypes without significant difference between vaccinated and unvaccinated individuals. Among unvaccinated GBM aged [≤]26 who were aware of the vaccine, 60% intended to get vaccinated within the next year. Conclusions One to two years after GBM aged [≤]26 were included in the Quebec HPV vaccination program, 42% of eligible GBM in Greater Montreal had been vaccinated. Anal HPV prevalence was high among GBM. Vaccinees were more likely to self-report a prior STI diagnosis. Offering vaccination to all preadolescents in schools appears essential to maximize vaccination benefits.

Shigella is a major cause of childhood diarrhea in sub-Saharan Africa. Current World Health Organization (WHO) guidelines recommend empiric antibiotics only for dysentery, yet non-dysenteric presentations account for 40-89% of Shigellainfections. We quantified the performance of existing guidelines to identify Shigella infection and evaluated enhanced syndromic criteria for improved management of Shigella cases. We leveraged data from the Enteric for Global Health (EFGH) Kenyan site, which enrolled children aged 6-35 months with medically attended diarrhea, collected rectal swabs at enrolment, and tested these for Shigella using both the culture and TaqMan-array cards (TAC). Shigella positivity was defined as either a culture-confirmed Shigella or a TAC-attributable result (CT <29.5). We compared categorical variables using the {chi}{superscript 2} test or Fishers exact as appropriate while continuous variables were compared between groups using the Wilcoxon rank-sum test. A logistic regression model was fitted to identify a parsimonious set of predictors. Out of the enrolled 1400 MAD cases, of whom 175 (12.5%) were Shigella positive, of which 134 (76.5%) being non-dysenteric. Among all enrolled children, 148 (10.6%) were dysenteric and 1,252 (89.4%) were non-dysenteric. Of the non-dysenteric cases, 57/1,252 (4.6%) and 129/1,251 (10.3%) of children were Shigella attributable by culture and TAC, respectively. Compared to Shigella negative cases, positive cases were older (Median age in months [Q1-Q3]: 20 [14-24] vs 13 [8-19], p<0.001), had higher stool frequency (5 [3-6] vs 4 [3-5], p<0.049) and were more likely to be dysenteric (42 [24%] vs 106 [8.7%], p<0.001). Contrarily, Shigella positive cases were less likely to present with vomiting (66 [37.7%] vs 587 [47.9%], p=0.014) and difficulty in breathing (0 (0%) vs 27 [2.2%], p<0.040). Dysentery alone had minimal predictive power to identify Shigella (area under the ROC curve (AUC) [95% CI]: 0.58 [0.54-0.61]), while Dysentery and Age binary (<17 months) (0.70 [0.66-0.74]), and Dysentery, Vomiting, Difficult breathing, and Age binary (0.72 [0.68-0.76]) had acceptable predictive performance. Our data shows that current guidelines miss up to 76.5% of Shigella-positive cases which are non-dysenteric. This suggests that dysentery alone has limited predictive power, but incorporating additional symptoms increases discriminatory ability by up to 14%, with age alone improving it by 12%. These findings support the need to re-evaluate the current syndromic based guidelines to better detect Shigellosis and strengthen antibiotic stewardship.

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 Erythema nodosum leprosum (ENL) is a severe inflammatory complication of lepromatous leprosy characterised by recurrent inflammatory episodes often requiring prolonged immunosuppression. The severity of ENL can be quantified using the validated and reliable ENLIST ENL Severity Scale (EESS). The longitudinal course of ENL and how it is captured using standardised severity measures has not been well described. We prospectively evaluated the changes in ENL severity over time using the EESS in a randomised clinical trial. Methods We conducted a post-hoc analysis of participants enrolled in the Methotrexate and Prednisolone Study in ENL, an international multicentre randomised controlled trial conducted in Ethiopia, India, Indonesia, and Nepal. Adults with severe ENL (EESS score [&ge;]9) were followed for 60 weeks with repeated EESS assessments. Longitudinal trajectories were analysed using mixed-effects regression models. Item-level analyses characterised the clinical phenotype captured by the scale. Associations between EESS score, prednisolone exposure, and dermatology-specific health-related quality of life measured using the Dermatology Life Quality Index (DLQI) were examined. Findings A total of 135 participants contributed 1,958 EESS assessments. Mean EESS declined rapidly during the first four weeks of treatment (-2.10 points/week; 95% CI -2.36 to -1.84; p<0.001), increased modestly during reduction in corticosteroid dose (weeks 4-20), and gradually declined thereafter. Severe ENL (EESS score [&ge;]9) occurred in 20.6% of visits and was characterised primarily by pain and cutaneous inflammatory manifestations. Participants who required additional prednisolone had persistently higher EESS scores and showed limited improvement compared with those who did not receive additional prednisolone. Longitudinal EESS scores were strongly correlated with the DLQI score (Spearmans {rho}=0.75; p<0.001). Conclusion The EESS captures clinically meaningful changes in ENL severity, aligns with treatment decisions, and reflects patient-reported severity over time. These findings support the use of the EESS as a robust tool for monitoring ENL severity in both clinical research and routine care.

Introduction: A prominent symptom of post-acute sequelae of SARS-CoV-2 infection (i.e., Long COVID) is exercise intolerance with or without post-exertional malaise (PEM). PEM is characterized by the worsening of both symptoms and function following even minor physical or mental exertion, with symptoms typically worsening 12 to 48 hours after activity and lasting for days or even weeks. Individualized, supervised cardiopulmonary rehabilitation is considered a safe and effective intervention for many cardiac and pulmonary conditions, and has been effective in gradually improving function in previously hospitalized and nonhospitalized patients with severe COVID-19. While traditional cardiopulmonary rehabilitation approaches appear helpful in some situations, the exercise intolerance symptoms experienced by many individuals with Long COVID may require a different approach, especially when attempts to increase physical activity result in PEM. No clear consensus exists on the optimal treatment of PEM, and no major studies have evaluated the efficacy in individuals with Long COVID of either carefully supervised, individualized cardiopulmonary rehabilitation programs for exercise intolerance without significant PEM or activity pacing interventions designed to treat or prevent PEM. Methods and Analysis: The Researching COVID to Enhance Recovery Clinical Trials (RECOVER-CT) initiative funded by the National Institutes of Health (NIH) included a prospective, multicenter, randomized controlled platform trial (RECOVER-ENERGIZE) designed to assess two interventions in patients with Long COVID and exercise intolerance: (1) cardiopulmonary rehabilitation for patients without significant PEM and (2) structured activity pacing to prevent or reduce PEM in participants who experience the symptom. The intervention duration will be 12 weeks. The primary endpoints for the trial include the Endurance Shuttle Walk Test as a measure of endurance capacity for the cardiopulmonary rehabilitation intervention and a modified version of the DePaul Symptom Questionnaire - Post-Exertional Malaise for the pacing intervention. Assessments will be completed at baseline, middle of intervention, end of intervention, and 12 weeks after completion of the intervention, and include physical performance measures and patient-reported surveys. Ethics and Dissemination: The RECOVER-ENERGIZE trial protocol has been approved by an institutional review board (Advarra), and written informed consent will be obtained from all participants prior to enrollment. The trial is registered on ClinicalTrials.gov (NCT06404047). Formally assessing PEM and developing a structured activity pacing intervention delivered by local pacing coaches are novel features of this trial. Results will be disseminated through peer-reviewed publications, presentations at scientific conferences, and communication with participants, patient advocacy organizations, and the broader Long COVID community. De-identified participant data will be made available through the NIH RECOVER data repository in accordance with NIH data-sharing policies. If successful, this protocol will provide accessible tools that clinicians can use to address exercise intolerance and PEM in patients with Long COVID.

Background. Infectious mononucleosis (IM) with hepatitis is associated with suppression of high-density lipoprotein cholesterol (HDL-C), but the magnitude, specificity, recovery kinetics, and long-term cardiovascular implications of this finding have not been systematically characterised. Methods. Using the TriNetX Global Collaborative Network (<190 million patients, 178 healthcare organisations), we conducted a retrospective real-world evidence study in 1,944 adults with IM and hepatitis. We compared HDL-C distributions at presentation across 14 propensity-score-matched (PSM) comparator cohorts spanning other infectious, metabolic, and immune-mediated conditions. Gaussian mixture modelling characterised the HDL distribution. Longitudinal HDL trajectory was assessed across six post-index time windows, with the number of patients contributing a measurement ranging from 318 (16-30 days) to 2,849 (1-3 years) per window. Long-term major adverse cardiovascular events (MACE) were analysed in PSM cohorts of IM patients with very low HDL ([&le;]20 mg/dL, n = 979 per arm after PSM) versus those without low HDL, over up to 20 years of follow-up, with COVID-19 (n = 83,888 per arm) and pharyngitis (n = 10,618 per arm) as comparators. Results. At presentation, mean HDL in IM hepatitis was 36.7 +/- 22.6 mg/dL (median 33 mg/dL), ~14-17 mg/dL lower compared to pre-illness values. Nearly one quarter (23.9%) had HDL [&le;]20 mg/dL and 43.9% had HDL [&le;]30 mg/dL. HDL suppression was equivalent to CMV hepatitis but substantially greater than pharyngitis and IM without hepatitis, supporting a hepatitis-driven mechanism. Gaussian mixture modelling identified a discrete suppressed subpopulation (mean 16 mg/dL, 41% of patients) absent in non-hepatitis controls. Recovery was rapid in most patients (mean HDL 50.0 mg/dL by 16-30 days) but prolonged among the severely suppressed ([&le;]20 mg/dL), who required 3-6 months to approach baseline. In PSM MACE analyses, IM patients with very low acute HDL had significantly higher long-term event rates for all outcomes (HR 1.92-2.47 versus IM without low HDL), a pattern mirrored in the COVID-19 cohort (HR 2.04-2.70) and, with attenuated effect size, in pharyngitis (HR 1.43-1.69). Conclusions. Very low HDL-C is a prevalent, hepatitis-driven finding in IM affecting approximately one quarter of patients. It identifies a subgroup at elevated long-term cardiovascular risk comparable to that observed after COVID-19. These findings warrant prospective evaluation of cardiovascular follow-up strategies for affected patients.

Effective filtration and concentration of stool specimens is an essential pre-analytical step for reducing fecal debris and improving organism recovery using microscopy-based ova and parasite (O&P) examination. This study evaluated three commercially available fecal sedimentation-based filtration/concentration systems, ParaPak SpinCon (Meridian Bioscience), Mini Parasep SF (Apacor), and the newly-available ParadeviceReingenuity), for qualitative parasite detection and workflow logistics using conventional and artificial intelligence (AI)-assisted microscopy. Forty clinical stool specimens (20 parasite-positive and 20 parasite-negative) were processed with the 3 devices, and the resultant 120 wet mount and 120 trichrome stained smear preparations were examined using conventional microscopy. Trichrome-stained slides were also scanned at 40x magnification using a Hamamatsu NanoZoomerS360 flatbed digital slide scanner and images were analyzed using the Techcyte Fusion Human Fecal Trichrome AI algorithm. Positive and indeterminate digital findings were confirmed by conventional glass slide microscopy. Slides and digital images were reviewed in a blinded manner. Concordance was assessed among the 360 initial evaluations (microscopy and AI-assisted), and discrepant parasitology results were resolved through re-review and specimen reprocessing as needed. Final qualitative agreement across slide/image evaluations using all three concentration systems was 100%. Minor discrepancies in protozoan and white/red blood cell detection/identification were noted in 5 and 7 cases, respectively, and likely reflected sampling and observer variability. While the three concentration systems produced equivalent qualitative results, the Paradevice and Mini Parasep SF offered the most streamlined workflows. These findings support the Paradevice and Mini Parasep SF as efficient, analytically equivalent systems that are compatible with traditional and AI-assisted O&P workflows.