Daily Respiratory Research Analysis
Three impactful studies advanced respiratory health today: a macaque study showed that an intramuscular prime plus mucosal adenoviral boost vaccine regimen provided complete protection against lethal H5N1 challenge, a nationwide Dutch cohort quantified strong but incomplete COVID-19 vaccine protection in patients with hematologic malignancies, and a large real-world analysis found COPD survivors of sepsis have markedly higher viral infection risks that are mitigated by vaccination.
Summary
Three impactful studies advanced respiratory health today: a macaque study showed that an intramuscular prime plus mucosal adenoviral boost vaccine regimen provided complete protection against lethal H5N1 challenge, a nationwide Dutch cohort quantified strong but incomplete COVID-19 vaccine protection in patients with hematologic malignancies, and a large real-world analysis found COPD survivors of sepsis have markedly higher viral infection risks that are mitigated by vaccination.
Research Themes
- Pandemic-preparedness vaccines with mucosal boosting
- Vaccine effectiveness in immunocompromised populations
- Post-sepsis vulnerability and vaccination in COPD
Selected Articles
1. An intramuscular prime and mucosal boost vaccine regimen protects against lethal clade 2.3.4.4b H5N1 challenge in cynomolgus macaques.
In cynomolgus macaques, an intramuscular prime followed by a mucosal (intratracheal RhAd52) boost generated robust mucosal immunity and provided complete survival against lethal H5N1 clade 2.3.4.4b challenge. Vaccinated animals rapidly suppressed viral replication to undetectable titers in both upper and lower airways.
Impact: This establishes a promising, translatable vaccine strategy combining systemic priming with mucosal boosting to achieve sterilizing-like protection against a pandemic-threat H5N1 strain in a stringent NHP model.
Clinical Implications: Supports advancing intramuscular prime plus mucosal adenoviral boosting regimens into clinical trials for H5N1 preparedness and potentially for other respiratory pathogens where mucosal immunity is critical.
Key Findings
- 100% (17/17) survival in vaccinated macaques versus 17% (1/6) in shams after lethal H5N1 challenge
- Vaccination suppressed upper and lower airway viral titers to undetectable levels by days 4–14
- Mucosal RhAd52-HA boosting elicited strong mucosal antibody and T cell responses and large log10 viral load reductions
Methodological Strengths
- Stringent lethal nonhuman primate challenge model
- Head-to-head assessment of prime routes and mucosal boosting with immunologic readouts
Limitations
- Preclinical animal study; human immunogenicity and durability remain to be tested
- Abstract truncation limits full visibility into magnitude of log reductions and correlates
Future Directions: Phase 1/2 trials to assess safety, mucosal immunogenicity, and breadth against drifted H5N1 strains; optimization of dosing and routes for scalable deployment.
The H5N1 clade 2.3.4.4b avian influenza virus outbreak in poultry and dairy cattle is a potential pandemic threat for humans. A safe and effective H5N1 influenza vaccine will be needed if the virus acquires the capacity for efficient human-to-human transmission and may also be useful as a veterinary vaccine. In this study, we demonstrate robust vaccine protection in a lethal model of H5N1 clade 2.3.4.4b influenza infection in cynomolgus macaques. We vaccinated 24 cynomolgus macaques with mRNA or rhesus adenovirus serotype 52 (RhAd52) vaccines expressing the hemagglutinin (HA) from H5N1 clade 2.3.4.4b by the intramuscular or intratracheal route and challenged them with the H5N1 human isolate hu-TX37-H5N1. Of sham control animals, 83% (five of six) developed severe rapidly progressive consolidative pneumonia and were euthanized by days 5 to 7 after challenge. In contrast, 100% (17 of 17) of vaccinated macaques survived and controlled virus replication to undetectable titers in both the upper and lower respiratory tracts by days 4 to 14 after challenge. Mucosal boosting with the RhAd52 HA vaccine generated robust mucosal antibody and T cell responses and afforded 6.3 and 5.1 log
2. COVID-19 Vaccine Effectiveness in Patients with Hematologic Malignancies: a Nationwide Cohort Study.
In a nationwide cohort of 4.65 million SARS-CoV-2-positive adults, patients with hematologic malignancies had the highest risk of severe COVID-19; vaccination reduced severe outcomes by up to 74%, with effectiveness varying by variant period, vaccination number, and time since vaccination. Recent diagnosis, chronic disease, and active therapies (e.g., CD38/CD20 antibodies) were key risk modifiers.
Impact: Provides granular, population-scale effectiveness data in a highly vulnerable group and identifies modifiable and non-modifiable risk determinants to tailor prevention.
Clinical Implications: Supports prioritizing booster strategies and adjunctive prophylaxis (e.g., monoclonal antibodies when available) for hematologic malignancy patients, especially early post-diagnosis and during B-cell–depleting or proteasome inhibitor therapies.
Key Findings
- Vaccine effectiveness against severe COVID-19 in hematologic malignancies reached up to 74% (95% CI 60–83%)
- Highest severe disease risk in recently diagnosed and chronic hematologic malignancies
- Tumor-directed therapies (CD38/CD20 antibodies, proteasome and kinase inhibitors) tended to increase severe outcome risk
Methodological Strengths
- Nationwide, population-based cohort including all test-positive adults
- Robust subgroup analyses across variant periods and treatment classes
Limitations
- Observational design susceptible to residual confounding (e.g., health-seeking behavior)
- Vaccine products, dosing intervals, and variant-specific exposure heterogeneity
Future Directions: Evaluate hybrid strategies (updated boosters plus long-acting antibodies) and optimize vaccination timing relative to immunosuppressive cancer therapies.
BACKGROUND: In patients with hematologic malignancies, COVID-19 vaccine effectiveness is unknown and determinants of severe COVID-19 lack granularity. METHODS: To identify determinants of SARS-CoV-2 infection outcome we conducted a population-based, nationwide cohort study, including all adult Dutch residents who tested positive for SARS-CoV-2 between June 1, 2020, and March 31, 2022. Individuals were classified as having a (history of) hematologic malignancy, solid malignancy, or no malignancies. Primary outcome was severe COVID-19, defined as COVID-19-related hospitalization or death following first SARS-CoV-2 infection. RESULTS: Among 4 649 341 included individuals, those with hematologic malignancies were at highest risk of severe COVID-19. Vaccine effectiveness against severe COVID-19 in patients with hematologic malignancies was up to 74% (95% confidence interval, 60 to 83%), depending on the SARS-CoV-2 variant period, the number of received vaccinations, and the time interval since vaccination. Risk of severe COVID-19 was highest for patients with recently diagnosed hematologic malignancies and declined over time, except for patients with chronic hematologic malignancies. Risk of severe COVID-19 tended to be higher in patients on tumor-specific treatment such as CD38 and CD20 antibodies, proteasome inhibitors, and protein kinase inhibitors. CONCLUSIONS: COVID-19 vaccination lowered the risk of severe COVID-19 in SARS-CoV-2-infected patients with hematologic malignancies, although these patients remained at elevated risk compared to others. Determinants of severe COVID-19 included type of malignancy, time interval between malignancy diagnosis and SARS-CoV-2 infection, and treatment. These data can guide healthcare professionals in designing additional prevention and therapeutic strategies against respiratory virus infections for patients with hematologic malignancies.
3. Higher risk of viral infections in chronic obstructive pulmonary disease patients recovering from sepsis compared to non-sepsis patients: a propensity score-matched observational study.
In >190,000 matched COPD patients, prior sepsis conferred 2–3-fold higher 1-year risks of RSV and influenza (and elevated HSV/VZV/CMV) versus COPD without sepsis. Vaccination against RSV, influenza, and VZV significantly reduced these risks, underscoring actionable prevention in a high-risk COPD subgroup.
Impact: Identifies a clinically meaningful, previously underrecognized vulnerability window after sepsis in COPD and demonstrates vaccine-modifiable risk with large-scale, matched evidence.
Clinical Implications: Implement proactive RSV and influenza vaccination (and zoster vaccination) in COPD survivors of sepsis and enhance surveillance during the first post-sepsis year.
Key Findings
- Sepsis in COPD increased 1-year RSV infection risk (HR 3.297, 95% CI 3.158–3.443) and influenza (HR 3.197, 95% CI 3.071–3.328)
- Elevated risks also observed for HSV (HR 1.936), VZV (HR 3.050), and CMV (HR 2.101)
- Vaccines reduced risk: RSV prefusion F (HR 0.676), influenza (HR 0.709), VZV gE (HR 0.724)
Methodological Strengths
- Very large federated EHR dataset with 1:1 propensity score matching
- Consistent sensitivity analyses across sepsis severities
Limitations
- Retrospective database study; potential coding and vaccination misclassification
- Unmeasured confounding (e.g., frailty, health access) may persist despite PSM
Future Directions: Prospective validation, exploration of optimal vaccine timing post-sepsis, and assessment of additional prophylactic strategies in COPD survivors.
BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) who survive sepsis remain immunocompromised and are at increased risk of subsequent viral infections, including influenza and respiratory syncytial virus (RSV). OBJECTIVE: This study aimed to address the 1-year risk of viral infections after sepsis in patients with COPD through the use of a federated database, TriNetX. DESIGN: A propensity score-matched (PSM) retrospective cohort study. METHODS: We used data of 903,683 COPD patients and identified 113,589 who experienced sepsis. The risk of distinct viral infections, including herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), RSV and influenza, within 1 year post-sepsis was analyzed, with the employment of PSM to minimize confounding. The effect of vaccination was also assessed to determine its protective efficacy. RESULTS: A total of 98,883 COPD patients with sepsis and 1:1 matched COPD without sepsis were eligible for analyses. COPD patients with sepsis had consistently higher risk for viral infections within 1 year after the sepsis compared with COPD patients without sepsis. The hazard ratios (HRs) were as follows: HSV 1.936 (95% CI: 1.775-2.112), VZV 3.050 (2.489-3.737), CMV 2.101 (1.832-2.410), RSV 3.297 (3.158-3.443), and Influenza 3.197 (3.071-3.328). Sensitivity analysis demonstrated the consistently elevated risks across sepsis with varying severities. We further explored the protective effect of vaccinations among patients with COPD and found the significant protective effect of VZV glycoprotein E (HR 0.724, 95% CI: 0.595-0.882), RSV prefusion F protein-based vaccine (HR 0.676, 95% CI: 0.563-0.812) and influenza vaccine (HR 0.709, 95% CI: 0.649-0.776). CONCLUSION: COPD patients recovering from sepsis remain at increased risk of viral infections, highlighting the importance of targeted preventive strategies, including vaccination.