Objective: To analyze the incidence and genetic characteristics of Sapovirus infection in pediatric diarrhea cases aged ≤5 years in Guangdong Province. Methods: Epidemiological data and stool samples were collected from hospitalized children aged ≤5 years with diarrhea in Guangdong between January 2022 and December 2024. Sapovirus RNA detection from stool samples was conducted by using real-time RT-PCR, and partial VP1 region was amplified and sequenced. Phylogenetic tree analysis was conducted to characterize the genotype of each sequence. Whole-genome sequencing of samples with predominant GⅠ.1 genotype were conducted to analyze its mutation features. Results: In 2 080 pediatric diarrhea cases aged ≤5 years, the positive rate of Sapovirus was 2.45% (51/2 080). The positive rate in boys and girls were 2.20% (28/1 271) and 2.84% (23/809) respectively. The positive rate was highest in age group 13-24 months (4.40%, 22/500), and the detection peak occurred during October-December. Partial VP1 gene sequences were obtained from 31 out of 51 cases, with the GⅠ.1 genotype being predominant (80.65%, 25/31). Phylogenetic analysis indicated close evolutionary relationships among GⅠ.1 strains. Whole-genome sequencing found some amino acid substitutions at multiple conserved sites in GⅠ.1 genotype, and its mutation characteristics were highly consistent with those of the strains circulating in recent years. Conclusions: From 2022 to 2024, Sapovirus infection caused diarrhea occasionally in children aged ≤5 years in Guangdong. Sapovirus GⅠ.1 was the predominant pathogen, and the strains had close evolutionary relationship. It is necessary to further strengthen local surveillance and molecular epidemiological characterization of Sapovirus to provide evidence for epidemic trend analysis and early warning of potential outbreaks.

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection in young children, yet subtype-specific and age-stratified epidemiological patterns remain incompletely characterised in tropical settings. To address this gap, we aimed to assess the age distribution and seasonal patterns of RSV infections in a large hospitalized paediatric population. We analysed surveillance data from 27,440 children tested for RSV. Age-specific positivity and subtype distributions were estimated. Seasonal dynamics were assessed using generalised linear mixed models to estimate annual amplitude, peak timing, and epidemic duration. Multivariable logistic regression examined independent associations of age, sex, and season with RSV infection. Our results showed that RSV infection was highly concentrated in early life, and positive rates peaked at 27.7% (95% CI: 25.4-30.2) among infants aged 2-3 months and declined with age. The mean age at infection was 2.0 years (2.2 for RSV-A; 1.7 for RSV-B). RSV-B predominated in early infancy, whereas RSV-A became dominant from 1 year onward (p < 0.001). Transmission was strongly seasonal, with 76.8% of infections occurring during the rainy season. In conclusion, the RSV burden was concentrated in infancy, with distinct subtype-specific age patterns and pronounced rainy-season seasonality, informing the timing and targeting of RSV preventive strategies.

Respiratory syncytial virus (RSV) is a leading cause of pediatric respiratory infections. This systematic review and meta-analysis aims to estimate the in-hospital positivity among children in Europe post-COVID-19 and prior to the implementation of the recent RSV prophylactic strategies. A systematic search was conducted across three databases: PubMed, Scopus and Web of Science from 01/01/2021-31/12/2025. Studies enrolling children aged 0-18 years who were hospitalized with respiratory infection and detected positive for RSV were eligible for inclusion. A random-effect model was applied and heterogeneity was assessed using I[2] statistics. Thirty-eight studies met the inclusion criteria, encompasing 66,065 children. The overall pooled RSV in-hospital positivity was 48% (95%CI: 41%-56%). Positivity estimates per year were: 53% (95%CI:49%-56%) for 2021-2022, 49% (95%CI:36%-62%) for 2022-2023, and 62% (95%CI:51%-73%) for 2023-2024 (p = 0.308). RSV positivity in studies with infants (<12-months-old) was 69% vs 30% in studies including older children (0-18 years). Among RSV-positive patients, co-infections were detected in 17%, respiratory support was required in 62% and ICU/NICU admission in 11%. RSV-B predominated over RSV-A during the study period. A substantial burden of RSV-related hospitalizations was detected, especially in infants < 12-months-old; however, the overall pooled positivity estimate should be interpreted with caution. These findings provide an important pre-immunization baseline for evaluating the impact of maternal RSV vaccination and monoclonal antibodies and support the need for continued RSV surveillance across Europe.

The discovery of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway as a key regulator of immune function and inflammation led to the development of JAK inhibitors (JAK-i), several of which are now approved for autoimmune and chronic inflammatory conditions. Recently, JAK-i have been repurposed for infectious diseases, most notably with baricitinib, a United States Food and Drug Administration (FDA)-approved JAK1/2 inhibitor for individuals hospitalized for COVID-19, demonstrating a survival benefit by dampening cytokine-mediated hyperinflammation. This has generated increased interest in leveraging JAK-i for treating people with viral infections associated with chronic immune activation, inflammation or viral persistence. This review summarizes JAK/STAT signaling in viral infections characterized by latency or chronic sequelae. We explore how modulation of this pathway may alter immune responses, impact viral control, and mitigate the consequences of chronic inflammation. We also critically examine the therapeutic potential and limitations of JAK-i in these contexts. Finally, we outline key gaps in the field and propose future directions for research into JAK/STAT targeted immunomodulation in chronic viral infections.

Vietnam bears a substantial burden of methicillin-resistant Staphylococcus aureus (MRSA), yet neonatal data on epidemiology, antimicrobial resistance, treatment, and prevention remain limited and fragmented across regions and healthcare settings.

Pseudomonas aeruginosa (P. aeruginosa) is widely distributed in the environment. As an opportunistic pathogen, it commonly causes infections in immunocompromised individuals, including respiratory tract infections and burn wound infections. P. aeruginosa possesses multiple antibiotic resistance mechanisms, including efflux pumps, resistance genes, and population dynamics. Phage therapy is a potential approach for addressing drug-resistant P. aeruginosa infections; however, clinical experience and standardized guidelines for its application in severe pneumonia remain limited. A 14-month-old infant was hospitalized for pneumonia. Four days later, he developed acute pneumonia and was sent to the ICU for 38 days of antibiotic therapy; nonetheless, P. aeruginosa remained detectable in the patient's respiratory secretions. During the clinical course, phage zjk6 was detected from a longitudinal P. aeruginosa isolate in the absence of phage therapy. This finding documents the coexistence of a naturally detected phage and MDR P. aeruginosa during prolonged pneumonia, but does not establish that the phage mediated bacterial clearance or clinical recovery. We performed whole-genome sequencing on P. aeruginosa isolates from patients to ascertain if they were infected by the same infection and assessed their antibiotic resistance using drug sensitivity testing. We isolated phages using the drip technique and double-layer plate method, examined their appearance by transmission electron microscopy, and assessed their biological properties through one-step growth curve analysis and lysis spectrum detection. Genome sequencing and comparative genomic analyses were performed to characterize phage zjk6 and representative bacterial isolates and to evaluate phage-host genomic relatedness. P. aeruginosa was isolated repeatedly during 49 days of treatment. Comparative genomic analysis of representative longitudinal isolates revealed multiple strain backgrounds, including distinct ST508 and ST266 lineages and a closely related ST836 lineage. Phage zjk6 was isolated from the fifth clinical isolate, which served as the propagation/reference host. This phage possesses an elongated tail and a limited lysis spectrum, which is capable of gradually lysing the fifth isolated P. aeruginosa strain. Genomic analysis showed that zjk6 formed plaques and displayed slow lytic behavior under the tested conditions, while also carrying lysogeny-associated regulatory modules, indicating temperate potential rather than a strictly lytic lifestyle. A naturally detected slow lytic Pseudomonas phage may coexist with MDR P. aeruginosa during prolonged infection. These findings support further study of phage-bacterium interactions in clinical infections, while the therapeutic significance of zjk6 requires additional validation.

Airborne transmission is an important route for the spread of respiratory viruses. To assess the potential for airborne shedding of influenza A virus (IAV) and respiratory syncytial virus (RSV), this study compared the presence of viral RNA in air samples collected near hospitalized patients. Patients with IAV or RSV infection and a nasopharyngeal swab cycle threshold value of 28 or lower were included. Air sampling was performed using a vacuum cleaner equipped with a detachable soluble air filter attached to the hose inlet. For each patient, one sample was collected 50 cm dorsally and one 50 cm ventrally relative to the patient's face, each for 2 min. Filters were dissolved and analyzed for viral RNA by RT-qPCR. In total, 59 patients were included: 39 with IAV infection and 21 with RSV infection, including one patient co-infected with both viruses. Air samples were more frequently positive in RSV-infected patients than in IAV-infected patients (12/21 [57%] vs. 6/39 [15%], p = 0.0012). In multivariable analysis, RSV-infections remained associated with higher rates of air sample positivity after adjustment for nasopharyngeal viral load. These findings suggest different aerosol shedding between RSV and IAV, although differences in infectious potential remain to be determined.

Children recovering from complicated severe acute malnutrition (SAM) have a high risk of infectious mortality and morbidity, which could reflect impaired anti-microbial defence. We used blood samples from a cross-sectional cohort of children under 5 years' old admitted to hospital with SAM in Zambia and Zimbabwe (cases, n = 125) and adequately nourished non-hospitalised children from the same communities (controls, n = 73) to characterise anti-bacterial innate immune cell function. We did not find evidence that inpatient immune function differed between cases who experienced subsequent adverse clinical outcomes (death, readmission, SAM at 48 weeks) versus those who did not. However, pro-inflammatory cytokine (IL-6, IL-8 and TNF) responses to E. coli lipopolysaccharide and heat-killed Salmonella typhimurium were positively associated with subsequent gains in mid-upper arm circumference, an indicator of nutritional recovery. We then characterised how innate immune cell function changed during post-discharge rehabilitation in a longitudinal sub-cohort of cases who provided repeat blood samples at discharge, 12, 24 and/or 48 weeks post-discharge (n = 83). Relative to inpatient immune function, bacterial binding capacity declined whilst anti-bacterial pro-inflammatory cytokine secretion increased in the cases over the post-discharge follow-up period with both normalising towards control ranges. These changes were also evident in cases who had recovered to a healthy nutritional status (weight-for-height Z score ≥ -2). Collectively, our data suggest that restoration of anti-bacterial innate immune cell function following complicated SAM lags behind nutritional recovery. Thus, children who are no longer wasted may continue to have deficient anti-bacterial innate immunity months after hospital admission for SAM.