The exact pathogenesis of Long COVID remains unclear. Microvascular and endothelial dysfunction, established contributors to SARS-CoV-2-related conditions, appear to play a role in pediatric Long COVID.

At the Children's University Hospital of LMU Munich, we conducted a comparative cohort study including pediatric Long COVID patients. Microcirculation was assessed using sublingual sidestream dark field (SDF) imaging, analyzing the microvascular flow index (MFI), the total vessel density (TVD), and the proportion of perfused vessels (PPV). Endothelial function and arterial stiffness were evaluated using peripheral arterial tonometry (EndoPAT), measuring reactive hyperemia index (RHI) and augmentation index (AIx@75).

We analyzed 37 pediatric Long COVID patients (13.5 ± 2.6 years; 22 females) with persisting symptoms (> 4 weeks) and 46 healthy controls (12.4 ± 4.8 years; 21 females). Patients exhibited significant microcirculatory alterations, with reduced MFI (2.59 [IQR, 2.38-2.75] vs. 2.83 [IQR, 2.69-2.96]; p = .003), TVD (16.12 [IQR, 15.24-17.86] mm/mm2 vs. 19.38 [IQR, 17.58-20.57] mm/mm2; p < .001), and PPV (13.58 [IQR, 12.72-14.89]% vs. 17.67 [IQR, 16.60-19.32]%; p < .001). Microcirculatory changes varied with clinical phenotype and were most pronounced in patients presenting with dyspnea.We analyzed 37 pediatric Long COVID patients (13.5 ± 2.6 years; 22 females) with persisting symptoms (> 4 weeks) and 46 healthy controls (12.4 ± 4.8 years; 21 females). Patients exhibited significant microcirculatory alterations, with reduced MFI (2.59 [IQR, 2.38-2.75] vs. 2.83 [IQR, 2.69-2.96]; p = .003), TVD (16.12 [IQR, 15.24-17.86] mm/mm2 vs. 19.38 [IQR, 17.58-20.57] mm/mm2; p < .001), and PPV (13.58 [IQR, 12.72-14.89]% vs. 17.67 [IQR, 16.60-19.32]%; p < .001). Microcirculatory changes varied with clinical phenotype and were most pronounced in patients presenting with dyspnea.

We demonstrate measurable vascular alterations in pediatric Long COVID, including microvessel reduction and increased arterial stiffness. Our findings support a role of vascular changes in Long COVID and highlight the importance of integrating cardiovascular monitoring and follow-up into the management of affected children.

• Microvascular and endothelial dysfunction appear to play a role in SARS-CoV-2-related diseases. • Adults with Long COVID show persistent capillary rarefaction and endothelial impairment supporting a vascular mechanism underlying ongoing symptoms.

• Pediatric Long COVID is likewise associated with significant microvascular damage and furthermore with increased arterial stiffness. • Children with dyspnea exhibit a distinct vascular phenotype characterized by marked capillary loss, indicating a potential microvascular origin of persistent respiratory symptoms.

This longitudinal study investigated the differential composition of the nasopharyngeal microbiome in patients presenting different COVID-19 infectious phenotypes and its evolution during convalescence, with a focus on post-acute sequelae of SARS-CoV-2 (PASC) and its potential microbiome-related mechanisms. Microbiota composition was assessed for a cohort of healthy participants (n = 25), influenza patients (n = 24), and patients with moderate (n = 50) and severe (n = 57) COVID-19. Samples were collected at two time points: during the acute infection phase and at approximately 3-month follow-up. From collected nasopharyngeal swab samples, metagenomics using shotgun sequencing was performed and the microbiota composition was analyzed. Alpha and beta diversity analyses revealed no significant differences in overall community diversity between patient groups across visits. However, differential abundance testing identified specific species, such as Dolosigranulum pigrum and various Corynebacterium species, whose profiles correlated with PASC development. Furthermore, the analysis of microbial co-associations identifies commensal species, including D. pigrum and Corynebacterium species, which are less abundant in patients who develop PASC, consistent with a potential protective role suggested by experimental studies but not proven by our observational data. Antibiotic use was associated with lower levels of key protective taxa, which may increase susceptibility to PASC in case of superinfection. These findings highlight the potential importance of the nasopharyngeal microbiome in acute COVID-19 disease outcomes and suggest that preserving or restoring a balanced respiratory microbiome could mitigate the risk of COVID-19 persistent symptoms and PASC development. Our results may set the stage for future clinical interventions involving probiotics or microbial-derived metabolites to promote respiratory health post-COVID-19.IMPORTANCEThis study highlights the importance of bacteria naturally found in the upper respiratory tract, particularly the nasopharynx (the nasopharyngeal microbiome), in shaping how severely COVID-19 affects patients and whether they experience persistent symptoms, also called long-COVID or post-acute sequelae of SARS-CoV-2 (PASC). By examining microbiome samples from healthy people, influenza patients, and individuals with COVID-19 during acute and convalescent phases, we found that certain commensal bacteria, namely, Dolosigranulum pigrum and Corynebacterium species, were less abundant in individuals who developed long-COVID and more abundant in those who fully recovered. We also observed that antibiotic treatment was associated with lower abundances of these commensal taxa, in turn coinciding with a higher frequency of PASC. These findings suggest that the composition of the nasopharyngeal microbiome is associated with recovery trajectories after COVID-19 and motivate future research into treatments aimed toward the microbiome to improve respiratory health following infection.CLINICAL TRIALSThis study is registered with ClinicalTrials.gov as NCT05557539.

Early in the COVID-19 pandemic, there was a lack of consensus regarding maternity care infection mitigation practices, including maternal-infant separation when COVID-19 was suspected or confirmed, partner presence and breastfeeding.

To gain insight into the perceived maternity care and birth experiences of women during and following the COVID-19 pandemic in two neighbouring WHO European-Region countries.

Qualitative content analysis was conducted using the text responses to open-ended questions in an online survey regarding hospital-based maternity care experiences of 157 women who gave birth between 2020-2023 in Cyprus and Israel.

Three common themes of women's experiences and perceptions in both countries were identified: COVID-19 shaped maternity care context; professional atmosphere of the birth experience; and professionalism of breastfeeding support. Women feared infection, faced restricted partner presence, were separated from their infants, experienced unprofessional communication and received limited breastfeeding support.

The findings highlight that challenges were amplified during the pandemic, underscoring the urgency for healthcare providers and policymakers to address these concerns. Findings can inform improvement of post-pandemic maternity care to enhance birth experiences and guide emergency preparedness, protecting the needs and rights of birthing women, including permitting a companion of choice, reducing maternal-infant separation and providing early breastfeeding support.

Clinical Trials NCT04847336.

Yeasts belonging to the Candida genus typically reside on the mucosal surface and within the respiratory and gastrointestinal tract as commensals. Under conditions of host vulnerability, they can act as opportunistic pathogens, leading to various forms of candidiasis, including candidemia. Such infections can be particularly problematic when caused by isolates that exhibit resistance to antifungal drugs, which are becoming more prevalent in many regions. One hundred and seven samples of Candida spp. were isolated from patients with candidemia in the hospital San Matteo in Pavia (Italy) over a period of 6 years, from 2015 to the first COVID wave in spring 2020. In order to understand the epidemiology of Candida infections in this hospital setting, the isolates were whole-genome sequenced, confirming that most belonged to C. parapsilosis and C. albicans. Comparative genomics revealed that isolates of C. albicans were genomically diverse, indicative of repeated introductions in the hospital from the community. C. parapsilosis isolates on the other hand belonged to two groups of highly similar isolates, representing strains capable of long-term persistence in the hospital. All isolates of the main persistent group were resistant to fluconazoleresulting from the Y132F substitution in ERG11 and the N455D substitution in UPC2, while presenting variable levels of resistance to voriconazole and itraconazole. Interestingly, with the exception of the single isolate susceptible to both voriconazole and itraconazole, all the 61 isolates presented one unreported missense mutation in MRR1 (S1907C).

COVID-19 resulting from SARS-CoV-2 infection has presented significant challenges to global health over the past several years. Animal models are essential for studying the pathogenic mechanisms of SARS-CoV-2 and facilitating the development of therapeutic strategies. Transgenic hACE2 mouse models are widely used to explore the mechanisms responsible for severe and lethal COVID-19. However, current lethal transgenic mouse models are reported to die primarily from central nervous system infection, whereas in human patients, respiratory system infection is the primary cause of death. Moreover, earlier mouse models require the use of high-containment biosafety laboratories, which significantly limits SARS-CoV-2 studies and restricts broader experimental applications. Here, we established mouse models with systemic or lung-specific expression of the SARS-CoV-2 nucleocapsid (N) protein based on the K18-hACE2 KI mice. Both strains of mice are susceptible to SARS-CoV-2 ΔN/GFP-HBiT replicon delivery particles (RDPs), allowing efficient viral replication without producing infectious virions. Notably, lung-specific N-expressing mice exhibit only pulmonary infection, with lethality and pathological features closer to the clinical presentations of COVID-19. This RDP-infected mouse model enables the evaluation of anti-SARS-CoV-2 drugs, with infection phenotypes closely resembling those of wild-type SARS-CoV-2. Overall, this model offers a safer, increasingly convenient, and more universally applicable tool for SARS-CoV-2 research and antiviral therapy development.

The detection of bioaerosols has become increasingly important, particularly following the COVID-19 pandemic, which highlighted the significant threat posed by airborne pathogens to human health and mobility in public transportation. However, the real-time detection of ambient aerosols remains a pressing challenge. To address this issue, we aimed to evaluate a novel measuring setup, to the best of our knowledge, for monitoring the environment through aerosol fluorescence. Fluorescence is collected by integrating spheres with dedicated detectors for selected wavelength bands to improve signal collection and, consequently, the detection limit. To determine the optimal configuration, we utilized a dedicated simulation framework to evaluate the spatial positioning of the detectors. Through the simulation, we analyzed the core aspects of such setups and their dependencies, allowing us to compare different implementation variants and propose a candidate for the experimental realization of a real-time monitor capable of classifying bioaerosols.

Trauma is a leading cause of mortality in the pediatric population. Approximately 50% of pediatric trauma deaths occur within the first 24 hours, with 30% considered preventable or potentially preventable. A significant percentage of these deaths are due to hemorrhage, secondary to the hyperfibrinolytic phenotype of trauma-induced coagulopathy (TIC). The progression to hemorrhagic shock due to trauma in pediatrics is associated with high mortality (36%-50%), which is higher than that reported in adults. Damage control resuscitation (DCR), aimed at controlling TIC through its strategies, has been shown to improve outcomes in the adult population with severe trauma, and has evidence-based clinical practice guidelines available for the management of coagulopathy in trauma patients. In pediatrics, the strategies used in DCR have not yet been fully validated due to the lack of high-quality evidence to support them; however, in the last 10 years, research in this area has increased substantially. The objective of this review is to update the current evidence regarding the relevance of DCR in the pediatric population with severe trauma, focusing mainly on initial medical management, to establish best management practices guidelines for this condition. This first part analyzes the existing evidence regarding crystalloid restriction, permissive hypotension, and hemostatic resuscitation with balanced blood products in the pediatric population with severe trauma.

Introduction. Childhood overweight and obesity are known risk factors linked to the development of masked hypertension (MH). These factors may have a greater impact on ambulatory blood pressure (BP) than on office BP and be associated with early target organ damage. Objective. To evaluate the presence of markers of MH in an overweight and obese pediatric population. Population and methods. An analytical, observational, cross-sectional study was performed. Overweight and obese children aged 5 to 16 years who consulted at two tertiary hospitals in the Autonomous City of Buenos Aires were included. Office blood pressure and ambulatory blood pressure monitoring (ABPM) were recorded. Clinical and anthropometric parameters were evaluated, as were the metabolic profile, renal function, and albuminuria. Results. A total of 409 children were included, with a median age of 11.3 years; 236 (57.7%) were male. There were 301 (73.6%) normotensive children, 27 (6%) with true hypertension, 42 (10.2%) with white coat hypertension, and 39 (9.5%) with MH. Univariate and multivariate regression models, adjusted for age and sex, showed an association between ambulatory hypertension and office systolic BP (OR 1.1, p <0.001) and albuminuria (OR 3.37, p = 0.03). The presence of albuminuria was the only predictor of MH in obese individuals (OR 3.6, p <0.01). Conclusion. A significant prevalence of MH was identified in overweight and obese pediatric populations. An association was observed between hypertension, including MH, and the presence of albuminuria in overweight and obese pediatric patients.

Background Supracardiac atherosclerosis is a major cause of stroke. Although vessel wall MRI (vwMRI) can assess plaques, current techniques lack full head-neck-aortic arch coverage and efficiency. Purpose To develop and evaluate a head-neck-aortic vwMRI protocol for supracardiac atherosclerosis, compare its performance with that of supra-aortic CT angiography (CTA), and determine its feasibility in helping identify causes of embolic stroke of undetermined source (ESUS). Materials and Methods We developed a noncontrast head-neck-aortic vwMRI protocol integrated with neural network-based acceleration and multichannel coils, enabling a scan time of approximately 15 minutes. Then, participants with acute ischemic stroke or transient ischemic attack were recruited from October 2024 to March 2025. They received routine supra-aortic CTA and this new vwMRI protocol. Plaque vulnerabilities, vascular stenosis, and stroke etiologies were compared between the modalities. The accuracy of vwMRI for detecting calcification was evaluated using CTA as the reference standard, and the McNemar test was used to compare the findings between CTA and vwMRI. Results Among 108 participants who underwent imaging with both modalities (mean age, 56 years ± 14 [SD]; 89 male participants), the plaque detection rate was higher with vwMRI than CTA (88 of 108 participants [81.5%] vs 75 of 108 participants [69.4%]; P = .002). Moreover, vwMRI helped achieve 91% (98 of 108 participants) accuracy for calcification detection. vwMRI helped identify intraplaque hemorrhage in 27.8% (30 of 108) of participants and demonstrated an ulceration rate comparable with that of CTA (28 of 108 participants [25.9%] vs 25 of 108 participants [23.1%]; P = .51). CTA helped identify 49 participants with vascular stenosis, whereas vwMRI helped identify 47 participants with causes including atherosclerosis (n = 41), thrombus (n = 3), and dissection (n = 3). For 38 participants initially classified with ESUS via CTA, vwMRI enabled reclassification of 16, reducing the percentage of participants with ESUS from 35.2% (38 of 108 participants) to 20.4% (22 of 108 participants) (P < .001). Conclusion This head-neck-aortic vwMRI protocol was feasible and demonstrated a higher plaque detection rate than supra-aortic CTA. © RSNA, 2026 Supplemental material is available for this article. See also the editorial by von Kummer in this issue.

The goal of the TREAT study is to estimate the prevalence of true resistant hypertension in a Belgian setting of patients with apparent treatment resistant hypertension (aTRH) and to evaluate which determining factor of pseudo-resistant hypertension contributes the most to this prevalence. TREAT is a single-visit, multicentric, non-interventional, cross-sectional survey. Inclusion criteria included: patients over 18 years receiving 3 or more antihypertensive molecules and referred to specialized hospital centers for aTRH. A total of 201 eligible patients were included. Only 56.7% of the patients were treated with the guideline recommended triple combination therapy (i.e. renin-angiotensin-aldosterone system inhibitor, calcium channel blocker and thiazide (-like) diuretic), and only 23.4% were treated with the maximal recommended dose. WCH was present in 8.7% of the 115 patients with available ambulatory blood pressure recordings. Therapeutic adherence was self-reported as good by 80% of patients, while 20% reported poor or moderate adherence. In this cohort, the prevalence (95% CI) of true resistant hypertension was estimated at 21.9% (14.7%-30.6%). Among patients referred to specialized centers for aTRH, about 3 out of 4 presented with pseudo-resistant hypertension. The occurrence of WCH and poor adherence appeared rather limited in our study, but half of the participants were polymedicated with non-recommended combinations of antihypertensive molecules. Inadequate dosing was observed in the majority of patients and a third was not using a single pill combination. Hence, pseudo-resistant hypertension seems to be mainly associated with the underuse of triple combination therapy and, most likely, with suboptimal dosing.