Active — Not RecruitingPhase 1

Pilot Influenza Challenge Study

United States12 participantsStarted 2025-05-20

Plain-language summary

This is a research study to understand what happens when a person is infected with influenza ("flu") and how the body controls the infection. Healthy participants (challenge) will be infected with a strain of flu (H3N2), and followed to see what symptoms occur and when they occur. Blood will be drawn and nasopharyngeal (NP) swabs will be collected before participants are infected to understand if having antibodies can protect participants from flu infection or lead to a milder flu illness. Blood will also be drawn and NP swabs collected after participants are infected to understand how and when the body's immune response to flu occurs. Participants will also breathe through a device for virus collection every other day. Participants will be screened during one or more visits and will stay in the inpatient challenge unit for at least 10 days, maybe longer. Participants will complete a FLU PRO Diary Card daily. Blood will be drawn before the challenge and on Days 2, 4, and 8 while in the inpatient unit. NP samples will be taken every day to check for viruses and on certain days, immune responses such as antibodies. If on Day 8 (7 days after the challenge) the participant still has flu virus, medicine will be offered to treat the flu and the participant will be asked to stay in the challenge unit until NP swabs are negative for 2 consecutive days. Once the participant is discharged from the challenge unit, they will be asked to return to the clinic for 3 more visits. At the end of the study will be a final phone call.

Who can participate

Age range18 Years – 45 Years

SexALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

✓. Provide written informed consent prior to initiation of any study procedure.
✓. Are able to understand and comply with planned study procedures and be available for all study visits.
✓. Agree to remain an inpatient for at least seven days after challenge, AND until they have no virus shedding,1 determined by qualitative RT-PCR for a minimum of two consecutive days post-challenge 1For a minimum of seven days post-challenge (Study Day 8).
✓. Healthy2 males and non-pregnant, non-breastfeeding females3 aged ≥18 and ≤45 years of age, inclusive, at enrollment.

Exclusion criteria

✕. Female subject who has a positive pregnancy test on screening or admission, is breastfeeding or planning to become pregnant from 30 days prior to challenge through the end of the study.
✕. Presence of self-reported or medically documented significant medical or psychiatric condition(s)15 15Significant medical or psychiatric conditions include but are not limited to:
✕. Respiratory disease (e.g., chronic obstructive pulmonary disease \[COPD\], asthma) requiring daily medications15 currently or any treatment of respiratory disease exacerbations (e.g., asthma exacerbation) in the last 5 years 16Asthma medications: inhaled, oral, or intravenous (IV) corticosteroids, leukotriene modifiers, long and short acting beta agonists, theophylline, ipratropium, biologics.

What they're measuring

Frequency of Adverse Events (AEs) and Serious Adverse Events (SAE) during inpatient challenge

Timeframe: Post-challenge Day 1 through Day 8

Frequency of AE and SAE post-inpatient discharge

Timeframe: Thoughout the duration of the study (approximately three months post challenge)

FLU-PRO symptomatic scoring of clinical symptoms twice daily

Timeframe: Day 2 through at least Day 8 after challenge

H3N2-specific polymerase chain reaction (PCR) on nasopharyngeal (NP) samples daily

Timeframe: Day 2 through at least Day 8 post-challenge

H3N2 viral loads as assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Timeframe: Days 2, 4, 6, and 8 post challenge

H3N2 viral clonotypic complexity by Next-Gen sequencing of NP and exhaled breath samples.

Timeframe: Days 2, 4, 6, and 8 post challenge

Studies of biologically relevant mutations in the H3N2 viral genome post-challenge discovered by Next-Gen sequencing of NP and exhaled breath samples

Timeframe: Days 2, 4, 6, and 8 post challenge

Trial details

NCT IDNCT07063849

SponsorDaniel Hoft, MD, PhD

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-06-30

View on ClinicalTrials.gov More Influenza trials

Plain-language summary

Who can participate

Age range18 Years – 45 Years

SexALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

✓. Provide written informed consent prior to initiation of any study procedure.
✓. Are able to understand and comply with planned study procedures and be available for all study visits.
✓. Agree to remain an inpatient for at least seven days after challenge, AND until they have no virus shedding,1 determined by qualitative RT-PCR for a minimum of two consecutive days post-challenge 1For a minimum of seven days post-challenge (Study Day 8).
✓. Healthy2 males and non-pregnant, non-breastfeeding females3 aged ≥18 and ≤45 years of age, inclusive, at enrollment.

Exclusion criteria

✕. Female subject who has a positive pregnancy test on screening or admission, is breastfeeding or planning to become pregnant from 30 days prior to challenge through the end of the study.
✕. Presence of self-reported or medically documented significant medical or psychiatric condition(s)15 15Significant medical or psychiatric conditions include but are not limited to:
✕. Respiratory disease (e.g., chronic obstructive pulmonary disease \[COPD\], asthma) requiring daily medications15 currently or any treatment of respiratory disease exacerbations (e.g., asthma exacerbation) in the last 5 years 16Asthma medications: inhaled, oral, or intravenous (IV) corticosteroids, leukotriene modifiers, long and short acting beta agonists, theophylline, ipratropium, biologics.

What they're measuring

Frequency of Adverse Events (AEs) and Serious Adverse Events (SAE) during inpatient challenge

Timeframe: Post-challenge Day 1 through Day 8

Frequency of AE and SAE post-inpatient discharge

Timeframe: Thoughout the duration of the study (approximately three months post challenge)

FLU-PRO symptomatic scoring of clinical symptoms twice daily

Timeframe: Day 2 through at least Day 8 after challenge

H3N2-specific polymerase chain reaction (PCR) on nasopharyngeal (NP) samples daily

Timeframe: Day 2 through at least Day 8 post-challenge

H3N2 viral loads as assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Timeframe: Days 2, 4, 6, and 8 post challenge

H3N2 viral clonotypic complexity by Next-Gen sequencing of NP and exhaled breath samples.

Timeframe: Days 2, 4, 6, and 8 post challenge

Studies of biologically relevant mutations in the H3N2 viral genome post-challenge discovered by Next-Gen sequencing of NP and exhaled breath samples

Timeframe: Days 2, 4, 6, and 8 post challenge