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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.
Full 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.
Enrollment
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Inclusion criteria
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.
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).
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.
Exclusion criteria
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:
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:
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:
Participants who share a household with someone at higher risk for influenza-related complications, including:
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.
Primary purpose
Allocation
Interventional model
Masking
12 participants in 1 patient group
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Central trial contact
Dr Gail Cross, MBSS (BSc), FRACP
Data sourced from clinicaltrials.gov
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