InfluenzaFluCHIMNCT06972810
Human Infection Study of H3N2 Influenza in Healthy Adults
A study testing A/Texas/71/2017, clade 3C3a H3N2 influenza virus in people with Influenza, run by University of Melbourne at 1 site in Australia.
Trial summary
This study will examine how the immune system responds to a flu virus (H3N2) during and after infection in health adults aged between 18 and 50 while in an inpatient facility. The study uses a specific flu virus called the H3N2 influenza challenge virus, that was produced specifically for use in clinical research in… Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Influenza
- What is being tested?
- A/Texas/71/2017, clade 3C3a H3N2 influenza virus
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 11 participants
- Where
- 1 siteAustralia
- Study dates
- 5 May 2025to 26 Nov 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- General good health, without significant medical conditions that would interfere with participant safety, as defined by medical history, physical examination, screening laboratory tests, and ECG at a screening evaluation.
- Susceptible to the challenge virus as determined by a baseline serum HAI and NAI antibody titer to the RG-A/Texas/71/2017 (H3N2; clade 3c3a) virus of 1:40 or less.
- Able to understand and comply with planned study procedures and available for the duration of the trial.
- Willing to participate in the study and adhere to all trial requirements, including providing written consent to remain at the trial site for at least seven days after administration of the challenge virus. This willingness must be demonstrated by signing the informed consent document.
- Willing to allow the investigators to discuss the participant's medical history with their General Practitioner or any relevant health professional.
- Willing to refrain from donating blood for the duration of the study period.
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- Willing to refrain from smoking and illicit drug use during the quarantine period.
- Women of childbearing potential (WOCBP)* are required to practice a highly effective form of contraception during the course of the study. Acceptable forms of contraception for female participants include:
- Established use of oral, injected or implanted hormonal methods of contraception (established for a minimum of 4 weeks prior to first inpatient quarantine).
- Placement of an intrauterine device (IUD) or intrauterine system (IUS).
- Male sterilization, if the vasectomized partner is the sole partner for the participant and appropriate post vasectomy documentation of sterilization success is available.
- Same sex intercourse only.
- True abstinence from heterosexual intercourse, when this is in line with the preferred and usual lifestyle of the participant (Periodic abstinence and withdrawal are not acceptable methods of contraception). Careful history and documentation regarding the reliability of this method must be recorded.
Who cannot join
- History of clinically significant or currently active neurological, cardiac, respiratory, hepatic, rheumatological, autoimmune, or renal disease. Specifically:
- History of chronic obstructive pulmonary disease, pulmonary hypertension, or chronic lung condition of any etiology;
- Current diagnosis of asthma or reactive airway disease (e.g., to viral infections) within the past 2 years;
- History of thromboembolic, cardiovascular or cerebrovascular disease;
- Current diabetes mellitus (Type I or Type II);
- Any history of malignancy except for non-recurrent basal cell carcinoma;
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- History or evidence of clinically significant autoimmune disease or known immunodeficiency of any cause (including HIV);
- History of a surgical splenectomy;
- History of severe psychiatric illness at any time (e.g., psychiatric illness that resulted in inpatient admission, psychosis, suicide attempt) or current significant active symptoms of anxiety and/or depression; i. Participants with history of anxiety-related symptoms of any severity within the last 2 years if the Generalized Anxiety Disorder-7 score is ≥5 ii. Participants with a history of depression of any severity within the last 2 years if the Patient Health Questionnaire-9 score is ≥4
- Bleeding disorder (e.g., factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following injections or venepuncture; OR
- Other conditions that, in the opinion of the Investigator, could interfere with a participant completing the study and necessary investigations.
- Any clinical laboratory test parameters ≥ 1.5x upper limit of normal (ULN) unless deemed by the investigator to have no clinical significance.
- Body Mass Index (BMI) of less than 18.5 or greater than 32.
- Behavioral or cognitive impairment that in the opinion of the investigator affects the ability of the participant to understand and cooperate with the study protocol.
- The use of alcohol or psychoactive drugs/controlled substances in the past 12 months that:
- Has had a functional impact on the participant's life;
- Has resulted in or been a medical condition that required treatment; OR
- Could constitute abuse or misuse
- Current use of illicit substance use, defined as a negative urine drug screen at screening and at admission (cannabis (THC), amphetamine, barbiturates, benzodiazepines, cocaine, ecstasy, methamphetamine, methadone, opiates, Phencyclidine (PCP)).
- History of anaphylaxis.
- Allergy to both Oseltamivir and Baloxavir.
- Known allergy to two or more classes of antibiotics (e.g., penicillins, cephalosporins, fluoroquinolones, or glycopeptides).
- Personal or family history a severe response to a viral infection including but not limited to:
- Guillain-Barré Syndrome;
- Clinically significant post-viral fatigue or other post-viral long-term sequalae.
- Previous hospitalization with influenza or related complications.
- Use of corticosteroids (including nasal sprays/inhaled preparations but excluding other topical preparations) or immunosuppressive drugs within 30 days prior to challenge.
- Receipt of a live vaccine within 4 weeks or other vaccine within 2 weeks prior to enrollment.
- Receipt of any investigational drug or vaccine within 3 months or 5.5 half-lives (whichever is greater).
- Receipt of blood or blood-derived products (including immunoglobulin) within 6 months prior to challenge.
- Smoking or vaping:
- Current smoker defined as anyone who has smoked a nicotine product (including any vaping) at anytime in the month prior to enrollment; OR
- Significant past history of smoking (defined as ≥ 20 year pack history and ceased smoking <10 years ago).
- Participants who share a household with someone at higher risk for influenza-related complications, including:
- Persons ≥65 years of age or <5 years of age;
- Persons with chronic pulmonary disease (e.g., asthma), chronic cardiovascular disease (e.g., cardiomyopathy, congestive heart failure, ischemic heart disease), metabolic disease (e.g., diabetes mellitus, renal dysfunction, haemoglobinopathies), immunosuppression, neurological and neurodevelopmental conditions,
- Children and teenagers who are receiving long-term aspirin therapy, OR
- Women who are pregnant or who are trying to become pregnant.
- Infection with human immunodeficiency virus-1 (HIV-1), hepatitis C virus (HCV), or hepatitis B (HBV)
- Clinically significant abnormalities on ECG (as determined by the study investigator).
- Concurrent enrollment (or planned at anytime over the course of this trial) in a study which uses an investigational product or collects participant's blood.
- Acute medical condition which is either undiagnosed/still being investigated at time of challenge, OR requiring new or adjustment of prescription medication use in the 30 days prior to challenge.
- Any neurologic abnormality impairing the gag reflex or contributing to aspiration.
- Significant abnormality altering the anatomy of the nose/nasopharynx or clinically significant nasal deviation or any other clinically significant nasal pathology.
- Recent history (180 days prior to challenge) of nasal/sinus surgery or epistaxis requiring a medical procedure to control it (e.g., cauterisation, packing, the use of topical vasoconstrictors).
- Current sinusitis.
- Venous access deemed inadequate for the phlebotomy demands of the study.
- Confirmed infection with influenza virus (on PCR) within the past 6 months prior to enrollment.
- Receipt of a seasonal influenza vaccine in the past 6 months prior to enrollment or planned receipt in the first 2 months of the study.
- Any condition or finding, to include medical and psychiatric conditions, that in the opinion of the Investigator, might interfere with the safety of the participant, affect the participant's ability to participate in the trial and/or interfere with the collection or interpretation of the study objectives.
- Participants who are excluded from the study because they have been discovered during screening procedures to be suffering from a previously undiagnosed condition thought to require further medical attention will, with their consent, be referred appropriately to their GP or a specialist.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Controlled Human Infection Study of a Recombinant H3N2 (A/Texas/71/2017, Clade 3C3a) Influenza Virus in Healthy Adults in Australia
This study will examine how the immune system responds to a flu virus (H3N2) during and after infection in health adults aged between 18 and 50 while in an inpatient facility.
The study uses a specific flu virus called the H3N2 influenza challenge virus, that was produced specifically for use in clinical research in controlled conditions. From a previous study, mild to moderate symptoms are expected.
This is the first time that a flu challenge study has been undertaken in Australia.
Read the detailed description
Influenza A and B viruses cause seasonal outbreaks that affect 2-10% of people in developed countries annually and contribute to up to 650,000 global deaths, according to the WHO. Transmission occurs via respiratory droplets, with most healthy adults recovering within a week. However, severe illness can occur in high-risk groups such as young children, the elderly, pregnant women, and individuals with comorbidities.
The self-limiting nature of influenza in healthy adults lends itself to controlled human infection models (CHIM) which offer key advantages for influenza research, including precise control over the virus strain, timing of infection, and the ability to collect well-timed pre- and post-infection samples.
Influenza challenge studies have provided key insights into host immune responses and supported the development of vaccines and antivirals.
This first-in-Australia influenza challenge study aims to evaluate the safety and infectivity of recombinant H3N2 (A/Texas/71/2017, clade 3C3a) in a serosusceptible cohort. The study will also explore early host-virus interactions using advanced immunological techniques, alongside viral shedding into the air through environmental sampling, the kinetics of viral transmission and microbiome changes.
- Conditions
- Influenza
- Being tested
- A/Texas/71/2017, clade 3C3a H3N2 influenza virus
- Keywords
- Influenza virus type A (H3N2), Challenge
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
A/Texas/71/2017, clade 3C3a H3N2 influenza virusOther
Also called A/Texas/71/2017, clade 3C3a H3N2
The intervention product is a live challenge virus that is manufactured in the USA under Good Manufacturing Practice (GMP). The challenge will be administered intranasally using a sprayer device. Participants will be admitted into an inpatient facility prior to the administration of the flu virus. Following inoculation, they will be quarantined for a minimum of 8 days prior to discharge. Participants will receive supportive care and PCR positive participants will receive an effective antiviral medication. Participants will be followed for a total of 6 months.
| Study group | Role | What they receive |
|---|---|---|
| Influenza Challenge Model with Influenza A H3N2 virus strain | Experimental | Not described Receives: Other: A/Texas/71/2017, clade 3C3a H3N2 influenza virus |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of participants who become infected with the virus
Confirmation of the challenge dose of virus to achieve a symptomatic influenza attack rate (AR) of 78% defined as:
Percentage of participants with detectable shedding in nasopharyngeal (NP) swab(s) identified on RT-PCR over any 2 days between days 1-7 post challenge.
AND Symptom score that meets the clinical case definition for symptomatic infection (modified Jackson score ≥ 6).
Measured: Day 1 to Day 7 post challenge
Safety of the H3N2 challenge model
Frequency and severity of adverse events (AEs) events, either self-reported, or observations, during inpatient confinement and at clinic visits throughout the study period.
Measured: Day 0 to 6 months post challenge
Secondary outcomes (2)
Detection of asymptomatic infection
Percentage of participants who have detectable viral shedding in nasopharyngeal swabs by RT-PCR on any 2 days between days 1-7 post challenge AND who record a modified Jackson score < 6
Measured: Day 1 to 7 post challenge
Percentage of participants who develop influenza antibodies
Percentage of participants who develop serological evidence of infection defined as a ≥ 4-fold rise in influenza-specific serum antibody
Measured: Day 0 - 14 post challenge
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 May 2025
- Study start5 May 2025
- Primary completion26 Nov 2025
- Study completion26 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for InfluenzaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Melbourne
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute of Allergy and Infectious Diseases (NIAID), World Health Organization
- Responsible party
- Sponsor
- Investigators
- Dr Gail Cross, MBSS (BSc), FRACP, Principal investigator, University of Melbourne
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06972810
- Sponsor's protocol ID
- 27338
- Acronym
- FluCHIM
- Status last verified
- Jun 2025
- First submitted
- 27 Apr 2025
- Last updated
- 30 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 30 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Controlled Human Infection Study of a Recombinant H3N2 (A/Texas/71/2017, Clade 3C3a) Influenza Virus in Healthy Adults in Australia
- ClinicalTrials.gov ID
- NCT06972810
- Acronym / sponsor ID
- FluCHIM / 27338
- Conditions
- Influenza
- Keywords
- Influenza virus type A (H3N2), Challenge
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- University of MelbourneUniversity, hospital or other
- Collaborators
- National Institute of Allergy and Infectious Diseases (NIAID), World Health Organization
- Study start
- 5 May 2025 (actual)
- Primary completion
- 26 Nov 2025 (actual)
- Study completion
- 26 Nov 2025 (actual)
- First posted
- 15 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will examine how the immune system responds to a flu virus (H3N2) during and after infection in health adults aged between 18 and 50 while in an inpatient facility.
The study uses a specific flu virus called the H3N2 influenza challenge virus, that was produced specifically for use in clinical research in controlled conditions. From a previous study, mild to moderate symptoms are expected.
This is the first time that a flu challenge study has been undertaken in Australia.
Detailed description
Influenza A and B viruses cause seasonal outbreaks that affect 2-10% of people in developed countries annually and contribute to up to 650,000 global deaths, according to the WHO. Transmission occurs via respiratory droplets, with most healthy adults recovering within a week. However, severe illness can occur in high-risk groups such as young children, the elderly, pregnant women, and individuals with comorbidities.
The self-limiting nature of influenza in healthy adults lends itself to controlled human infection models (CHIM) which offer key advantages for influenza research, including precise control over the virus strain, timing of infection, and the ability to collect well-timed pre- and post-infection samples.
Influenza challenge studies have provided key insights into host immune responses and supported the development of vaccines and antivirals.
This first-in-Australia influenza challenge study aims to evaluate the safety and infectivity of recombinant H3N2 (A/Texas/71/2017, clade 3C3a) in a serosusceptible cohort. The study will also explore early host-virus interactions using advanced immunological techniques, alongside viral shedding into the air through environmental sampling, the kinetics of viral transmission and microbiome changes.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Influenza Challenge Model with Influenza A H3N2 virus strain | Experimental | Other: A/Texas/71/2017, clade 3C3a H3N2 influenza virus |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (13 listed)
- General good health, without significant medical conditions that would interfere with participant safety, as defined by medical history, physical examination, screening laboratory tests, and ECG at a screening evaluation.
- Susceptible to the challenge virus as determined by a baseline serum HAI and NAI antibody titer to the RG-A/Texas/71/2017 (H3N2; clade 3c3a) virus of 1:40 or less.
- Able to understand and comply with planned study procedures and available for the duration of the trial.
- Willing to participate in the study and adhere to all trial requirements, including providing written consent to remain at the trial site for at least seven days after administration of the challenge virus. This willingness must be demonstrated by signing the informed consent document.
- Willing to allow the investigators to discuss the participant's medical history with their General Practitioner or any relevant health professional.
Key exclusion criteria (51 listed)
- History of clinically significant or currently active neurological, cardiac, respiratory, hepatic, rheumatological, autoimmune, or renal disease. Specifically:
- Any clinical laboratory test parameters ≥ 1.5x upper limit of normal (ULN) unless deemed by the investigator to have no clinical significance.
- Body Mass Index (BMI) of less than 18.5 or greater than 32.
- Behavioral or cognitive impairment that in the opinion of the investigator affects the ability of the participant to understand and cooperate with the study protocol.
- The use of alcohol or psychoactive drugs/controlled substances in the past 12 months that:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| A/Texas/71/2017, clade 3C3a H3N2 influenza virusAlso: A/Texas/71/2017, clade 3C3a H3N2The intervention product is a live challenge virus that is manufactured in the USA under Good Manufacturing Practice (GMP). The challenge will be administered intranasally using a sprayer device. Participants will be admitted into an inpatient facility prior to the administration of the flu virus. Following inoculation, they will be quarantined for a minimum of 8 days prior to discharge. Participants will receive supportive care and PCR positive participants will receive an effective antiviral medication. Participants will be followed for a total of 6 months. | Other | Influenza Challenge Model with Influenza A H3N2 virus strain |
Primary outcome
Percentage of participants who become infected with the virus
Time frame: Day 1 to Day 7 post challenge
Confirmation of the challenge dose of virus to achieve a symptomatic influenza attack rate (AR) of 78% defined as: Percentage of participants with detectable shedding in nasopharyngeal (NP) swab(s) identified on RT-PCR over any 2 days between days 1-7 post challenge. AND Symptom score that meets the clinical case definition for symptomatic infection (modified Jackson score ≥ 6).
Safety of the H3N2 challenge model
Time frame: Day 0 to 6 months post challenge
Frequency and severity of adverse events (AEs) events, either self-reported, or observations, during inpatient confinement and at clinic visits throughout the study period.
2 secondary outcomes
Detection of asymptomatic infection
Time frame: Day 1 to 7 post challenge
Percentage of participants who develop influenza antibodies
Time frame: Day 0 - 14 post challenge
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Apr 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Dr Gail Cross, MBSS (BSc), FRACP principal investigator
University of Melbourne
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing A/Texas/71/2017, clade 3C3a H3N2 influenza virus in people with Influenza, run by University of Melbourne at 1 site in Australia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 13 inclusion and 51 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of participants who become infected with the virus (time frame: Day 1 to Day 7 post challenge). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Apr 2026.