Bronchiolitis, Respiratory Syncytial Virus Infection, Viral Lower Respiratory Tract Infection (LRTI)
Conditions
Keywords
RSV, gut microbiome, 16S rRNA, Gut-lung axis, Vietnam, infants, Biomarkers, Bronchiolitis, Lower respiratory tract infection
Brief summary
Respiratory syncytial virus (RSV) is a leading cause of severe lower respiratory tract infection in young children, and a substantial proportion of severe cases occur in previously healthy infants. The gut-lung axis suggests that gut microbiome composition may modulate respiratory immune responses. This prospective observational study in Vietnam will compare gut microbiome profiles and systemic immune cytokine responses between infants with severe RSV infection and those with mild RSV infection, aiming to identify microbiome-immune signatures associated with disease severity.
Detailed description
This is a single-center, prospective observational study conducted at Vietnam National Children's Hospital in Hanoi over 48 months. Approximately 250 infants aged 1-24 months with RT-PCR-confirmed RSV lower respiratory tract infection will be enrolled and classified into severe vs mild groups based on need for advanced respiratory support (HFNC/CPAP/invasive ventilation) and/or PICU admission versus no/low-flow oxygen requirement. Stool samples collected within the first 24 hours of admission will undergo 16S rRNA sequencing (V3-V4 region) to characterize gut microbiome diversity and taxa abundance. Blood samples collected within the first 24 hours will be used to quantify key cytokines (e.g., TNF-α, IL-6, IL-8, IL-1β, IFN-γ, IL-10, IL-17A, IL-22) using ELISA; immune cell subsets may be assessed by flow cytometry. Clinical severity will be assessed using standardized pediatric scores (PRISM III, PELOD, pSOFA) and treatment outcomes will be recorded. The study will evaluate associations among microbiome features, immune response markers, and RSV severity to propose candidate integrated biomarkers for early risk stratification.
Interventions
None listed
Sponsors
Phuc Huu Phan
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
1 Months to 24 Months
Healthy volunteers
No
Inclusion criteria
Age 1 to 24 months RT-PCR positive for RSV from respiratory specimen Symptoms consistent with acute lower respiratory tract infection Parent/legal guardian provides informed consent
Exclusion criteria
Prematurity \<32 weeks gestation or birthweight \<1500 g Chronic conditions (e.g., congenital heart disease, chronic lung disease, chronic liver/kidney disease) Primary or acquired immunodeficiency Severe malnutrition (weight-for-age Z-score \< -3 SD) Antibiotic use within 2 weeks before admission Probiotic use within 4 weeks before admission Co-infection with other pathogens (viral/bacterial) Stool sample not obtained within 24 hours of admission
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Association between gut microbiome diversity/composition and RSV severity | Within 24 hours of hospital admission | Differences in gut microbiome diversity and taxonomic composition assessed by 16S rRNA sequencing (alpha diversity, beta diversity, and differential taxa abundance) between severe and mild RSV groups |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Systemic cytokine response in severe versus mild RSV infection | Within 24 hours of hospital admission | Serum concentrations of inflammatory and regulatory cytokines (TNF-α, IL-6, IL-8, IL-1β, IFN-γ, IL-10, IL-17A, IL-22) measured by ELISA All cytokines will be measured using the same assay platform and reported in the same unit of concentration. Unit of measurement is pg/ml |
| Clinical severity scores in RSV infection measured by Pediatric Sequential Organ Failure Assessment (pSOFA) Score | within 24 h of hospitalization | Clinical severity scores in RSV infection measured by Organ dysfunction severity assessed using the Pediatric Sequential Organ Failure Assessment (pSOFA) score (range: 0-24), with higher scores indicating more severe organ dysfunction |
| Integrated microbiome-immune signature predicting severe RSV | Baseline (first 24h) predicting severity classification during index hospitalization | Multivariable model performance (AUC/ROC; or adjusted odds ratios for selected taxa + cytokines) |
| ICU resource utilization | Up to day 28 | ICU-free days: calculated as 28 minus ICU length of stay for patients discharged alive before Day 28; assigned 0 for patients who die before Day 28 or remain in ICU on/after Day 28. Ventilator-free days: calculated as 28 minus days of invasive mechanical ventilation for patients alive and ventilated \<28 days; assigned 0 for patients who die before Day 28 or remain ventilated on/after Day 28. Vasopressor-free days: calculated as 28 minus days receiving vasoactive agents for patients alive and requiring vasoactives \<28 days; assigned 0 for patients who die before Day 28 or remain on vasoactives on/after Day 28. Discontinuation requires ≥12 hours without vasoactive support |
Countries
Vietnam
Contacts
CONTACTPhuc H Phan, M.D.
Outcome results
None listed