Wood smoke and nasal immune response to the flu

The Effects of Woodsmoke Exposure on Nasal Immune Responses to Influenza Infection in Normal Human Volunteers

Phase 4 Interventional University of North Carolina, Chapel Hill · NCT06841913

This study will test if a short, two-hour wood smoke exposure changes nasal immune responses, symptom severity, and antibody production after a live nasal flu vaccine in healthy adults aged 18 to 49.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment112 (estimated)
Ages18 Years to 49 Years
SexAll
SponsorUniversity of North Carolina, Chapel Hill Academic / other
Locations1 site (Chapel Hill, North Carolina)
Trial IDNCT06841913 on ClinicalTrials.gov

What this trial studies

Healthy volunteers are randomized to a two-hour exposure to either wood smoke or filtered air, then receive either live attenuated influenza vaccine (LAIV) or placebo. Nasal samples, symptom reports, and blood are collected on days 1, 2, 3, 7, and 21 to measure viral quantity, mucosal secreted proteins, tissue-level gene expression, cell counts, and virus-specific antibodies. Targeted and untargeted analyses of the nasal secretome and gene expression are used alongside computational modeling to identify biomarker signatures associated with infection outcomes. The approach tests whether wood smoke alters mucosal antiviral defenses and increases LAIV-induced nasal symptoms.

Who should consider this trial

Good fit: Healthy, non-smoking adults aged 18–49 with normal lung function, no chronic illnesses, and no recent respiratory symptoms are the intended participants.

Not a fit: People with chronic diseases (such as diabetes, heart disease, asthma or COPD), current smokers, pregnant individuals, those outside the 18–49 age range, or those with egg allergy are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, results could inform public health guidance about wood smoke exposure during flu season and identify nasal immune markers for prevention or treatment strategies.

How similar studies have performed: Prior work using LAIV as a human viral challenge and studies linking air pollution to impaired respiratory immunity have shown effects on mucosal responses, but controlled human wood smoke exposure studies are comparatively limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Normal lung function,
* oxygen saturation of \>94%,
* normal blood pressure,
* no respiratory symptoms on history, no abnormalities on exam, normal pulmonary function testing,
* 18-49 Years of age.

Exclusion Criteria:

* A history of significant chronic illnesses (to include diabetes, autoimmune diseases, immunodeficiency state, known ischemic heart disease, chronic respiratory diseases such as chronic obstructive pulmonary disease or asthma, hypertension)
* Positive pregnancy test within 48 hours of the time of challenge
* Use of any inhaled substance (for medical or recreational purposes).
* Nonsmokers must have been abstinent from smoking for the prior 12 months, having not smoked more than 1 pack over the course of the previous year.
* History of allergy to eggs
* Acute, non-chronic, medical conditions, including (but not limited to) pneumonia or bronchitis requiring antibiotics, febrile illnesses, flu-like symptoms must be totally resolved symptomatically for 3 weeks
* Unspecified illnesses, which in the judgment of the investigator increase the risk associated with the experimental LAIV infection, will be a basis for exclusion.
* Expected exposure of subject to immunocompromised individuals (who can be infected by LAIV) for the 3 weeks following LAIV inoculation.
* Use of immunosuppressive drugs within the past 6 months.
* Previous Woodsmoke exposure \<3 weeks, which is considered to an appropriate washout period

Where this trial is running

Chapel Hill, North Carolina

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Smoke ExposureInfluenzaLAIVFlumistWood SmokeSmokeFire
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.