Daily Respiratory Research Analysis
Three impactful studies span prevention, diagnostics, and critical care. An individual-based model in Nature Medicine suggests RSV prefusion F vaccines could avert 35–64% of older-adult and 5–50% of infant hospitalizations in 13 high-income countries, with impact hinging on uptake. A Science Advances report presents an ultrasensitive microfluidic device that captures intact SARS-CoV-2 (LOD ~3 copies/mL) from complex biofluids, enabling longitudinal viral monitoring. An EClinicalMedicine network
Summary
Three impactful studies span prevention, diagnostics, and critical care. An individual-based model in Nature Medicine suggests RSV prefusion F vaccines could avert 35–64% of older-adult and 5–50% of infant hospitalizations in 13 high-income countries, with impact hinging on uptake. A Science Advances report presents an ultrasensitive microfluidic device that captures intact SARS-CoV-2 (LOD ~3 copies/mL) from complex biofluids, enabling longitudinal viral monitoring. An EClinicalMedicine network meta-analysis in obese, extubated ICU patients shows NIV (alone or with HFNC) reduces reintubation and mortality versus HFNC/COT.
Research Themes
- RSV vaccination impact modeling for population health
- Ultrasensitive intact-virus detection from complex biofluids
- Post-extubation respiratory support strategy in obesity
Selected Articles
1. Impact of RSVpreF vaccination on reducing the burden of respiratory syncytial virus in infants and older adults.
An individual-based model across 13 high-income countries projects that RSV prefusion F vaccines could prevent 35–64% of older-adult hospitalizations and 5–50% of infant hospitalizations, with mortality reductions mirroring hospitalization declines. The analysis assumes no effect on infection/transmission and underscores that impact is highly contingent on vaccine uptake.
Impact: Timely, policy-relevant modeling quantifies the potential population impact of newly rolled-out RSV vaccines, guiding prioritization of maternal and older-adult immunization programs.
Clinical Implications: Health systems should prioritize strategies to maximize uptake (e.g., co-administration, outreach) among older adults and pregnant women, as real-world benefit hinges on coverage. Economic planning should account for substantial hospitalization cost savings.
Key Findings
- Older-adult RSV vaccination prevented an estimated 35–64% of hospitalizations across 13 high-income countries.
- Maternal RSV vaccination averted 5–50% of infant hospitalizations.
- Mortality reductions mirrored hospitalization reductions; overall impact was highly dependent on uptake assumptions.
- Model assumed no prevention of infection/transmission, focusing on disease mitigation.
Methodological Strengths
- Individual-based modeling across multiple countries incorporating country-specific uptake rates
- Scenario exploration with explicit assumptions (no infection/transmission prevention)
Limitations
- Assumes no effect on infection/transmission; real-world indirect effects may be underestimated
- Uses influenza vaccine uptake as a proxy for RSV vaccine uptake; generalizability limited to high-income settings
Future Directions: Incorporate uncertainty in transmission-blocking effects and dynamic uptake scenarios, extend to low- and middle-income countries, and integrate cost-effectiveness and equity metrics.
Respiratory syncytial virus (RSV) causes a substantial health burden among infants and older adults. Prefusion F protein-based vaccines have shown high efficacy against RSV disease in clinical trials, offering promise for mitigating this burden through maternal and older adult immunization. Employing an individual-based model, we evaluated the impact of RSV vaccination on hospitalizations and deaths in 13 high-income countries, assuming that the vaccine does not prevent infection or transmission. Using country-specific vaccine uptake rates for seasonal influenza, we found that vaccination of older adults would prevent hospitalizations by a median of 35-64% across the countries studied here. Vaccination of pregnant women could avert infant hospitalizations by 5-50%. Reductions in RSV-related mortality mirrored those estimated for hospitalizations. While substantial hospitalization costs could be averted, the impact of vaccination depends critically on uptake rates. Enhancing uptake and accessibility is crucial for maximizing the real-world impact of vaccination on reducing RSV burden among vulnerable populations.
2. Ultrasensitive detection of intact SARS-CoV-2 particles in complex biofluids using microfluidic affinity capture.
An engineered-ACE2 microfluidic device captures intact SARS-CoV-2 from plasma, saliva, and stool with an LOD of ~3 copies/mL and detected virus in 72% of plasma samples across 103 patients. The platform supports longitudinal tracking and is adaptable to other viruses via alternative entry molecules.
Impact: Provides a broadly adaptable, ultrasensitive intact-virion detection platform overcoming limitations of nucleic acid assays, enabling precise viremia monitoring and potentially informing infectiousness and treatment response.
Clinical Implications: Could augment clinical decision-making by detecting low-level viremia and monitoring antiviral response, and may stratify patients by persistent plasma virions; future adaptation to other pathogens may broaden viral load management.
Key Findings
- Engineered ACE2 affinity microdevice detects intact SARS-CoV-2 at ~3 copies/mL in complex biofluids.
- Clinical validation across 103 plasma, 36 saliva, and 29 stool samples; 72% positivity in plasma.
- Supports longitudinal plasma monitoring for active infection.
- Platform is adaptable to other viruses by swapping entry molecule ligands.
Methodological Strengths
- Combined engineered receptor affinity, microfluidic herringbone mixing, and nanoparticle coatings to boost capture efficiency
- Clinical validation on multiple biofluids with longitudinal assessment
Limitations
- Single-pathogen focus; generalizability to other viruses requires re-engineering and validation
- Positivity less than 100% in plasma; clinical thresholds for decision-making need definition
Future Directions: Define clinical cutoffs for infectious risk, correlate with culture-based infectivity and outcomes, and extend to multiplex capture for co-infections.
Measuring virus in biofluids is complicated by confounding biomolecules coisolated with viral nucleic acids. To address this, we developed an affinity-based microfluidic device for specific capture of intact severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our approach used an engineered angiotensin-converting enzyme 2 to capture intact virus from plasma and other complex biofluids. Our device leverages a staggered herringbone pattern, nanoparticle surface coating, and processing conditions to achieve detection of as few as 3 viral copies per milliliter. We further validated our microfluidic assay on 103 plasma, 36 saliva, and 29 stool samples collected from unique patients with COVID-19, showing SARS-CoV-2 detection in 72% of plasma samples. Longitudinal monitoring in the plasma revealed our device's capacity for ultrasensitive detection of active viral infections over time. Our technology can be adapted to target other viruses using relevant cell entry molecules for affinity capture. This versatility underscores the potential for widespread application in viral load monitoring and disease management.
3. Noninvasive respiratory support following extubation in critically ill adults with obesity: a systematic review and network meta-analysis.
Across 7 RCTs (n=1,933), NIV alone or combined with HFNC reduced day-7 reintubation versus COT and reduced 28-day mortality versus HFNC in obese, extubated ICU patients. NNT to prevent one death was ~15, supporting NIV as preferred post-extubation support in this population.
Impact: Synthesizes randomized evidence to resolve a clinically relevant controversy in a high-risk population (obesity), offering actionable guidance for post-extubation respiratory support.
Clinical Implications: For obese ICU patients after extubation, initiate NIV (with or without HFNC) rather than HFNC or COT to lower reintubation and mortality; implement protocols and monitoring to optimize NIV tolerance and efficacy.
Key Findings
- NIV + HFNC reduced day-7 reintubation versus COT (RR 0.36; NNT ~10).
- NIV alone reduced day-7 reintubation versus COT (RR 0.45; NNT ~11).
- Versus HFNC, both NIV and NIV + HFNC reduced 28-day mortality (NNT ~15).
- HFNC alone did not significantly reduce reintubation versus COT.
Methodological Strengths
- Network meta-analysis of RCTs with direct and indirect comparisons
- Risk of bias assessed with RoB 2.0; PROSPERO registration
Limitations
- Heterogeneity in NIV protocols and patient severity may influence effect sizes
- Limited to obese population; generalizability to non-obese patients requires caution
Future Directions: Head-to-head trials of NIV versus NIV+HFNC to define incremental benefit, and implementation studies optimizing adherence and comfort in obese patients.
BACKGROUND: Patients with obesity are at high-risk of extubation failure. Discrepancies were found in the results of recent randomized controlled trials (RCTs) regarding the roles of noninvasive ventilation (NIV), high flow nasal cannula (HFNC) and conventional oxygen therapy (COT) to prevent extubation failure in critically ill patients with obesity. METHODS: In this systematic review and network meta-analysis, we searched MEDLINE, Cochrane Center Register of Controlled Trials and Web of Science from 1 January 1998 to 1 July 2024 for RCTs evaluating noninvasive respiratory support therapies (NIV, HFNC, COT, NIV + HFNC) after extubation in critically ill adults with obesity. Primary outcome was reintubation at day 7. Secondary outcome was 28-day mortality. We generated pooled risk ratios (RR) and numbers needed to treat (NNT). We rated risk of bias using the Cochrane risk-of-bias 2.0 tool. The study was registered with PROSPERO (CRD 42022308995). FINDINGS: In seven RCTs including 1933 patients, NIV + HFNC (RR 0.36 [95% confidence interval (CI) 0.16-0.82], NNT = 10 [95% CI 7-33]) and NIV (RR 0.45 [95% CI 0.23-0.88], NNT = 11 [95% CI 8-50]) but not HFNC (RR 0.79 [95% CI 0.40-1.59]) reduced reintubation at day 7, compared to COT. Compared to HFNC, NIV + HFNC (RR 0.46 [95% CI 0.23-0.90], NNT = 14 [95% CI 10-77]) but not NIV (RR 0.57 [95% CI 0.32-1.02]) reduced reintubation at day 7. Compared to HFNC, both NIV (RR 0.31 [95% CI 0.13-0.74], NNT = 15 [95% CI 12-40]) and NIV + HFNC (RR 0.30 [95% CI 0.10-0.89], NNT = 15 [95% CI 11-90]) reduced 28-day mortality. INTERPRETATION: The results suggest that compared to COT and HFNC, NIV alone or with HFNC reduces reintubation in critically ill patients with obesity after extubation. Compared to HFNC, NIV alone or with HFNC reduces mortality. The number needed to treat with NIV or NIV + HFNC to avoid one death was 15. These findings support the application of NIV to mitigate extubation failure in critically ill adults with obesity. FUNDING: None.