NCT06972810

Human Infection Study of H3N2 Influenza in Healthy Adults

A Controlled Human Infection Study of a Recombinant H3N2 (A/Texas/71/2017, Clade 3C3a) Influenza Virus in Healthy Adults in Australia

• Status: Active Not Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 12 (estimated)
• Sponsor: University of Melbourne · Academic / Other
• Sex: All
• Age: 18 Years – 50 Years
• Healthy volunteers: Accepted

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 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.

Conditions

• Influenza

Interventions

Type	Name	Description
OTHER	A/Texas/71/2017, clade 3C3a H3N2 influenza virus	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.

Timeline

• Start date: 2025-05-05
• Primary completion: 2026-01-30
• Completion: 2026-06-30
• First posted: 2025-05-15
• Last updated: 2025-06-12

Locations

1 site across 1 country: Australia