NCT06753474

A/Texas Flu Challenge

Influenza Human Challenge Model Using H3N2 (A/Texas/71/2017 (H3N2), Clade 3C3a)

• Status: Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 50 (estimated)
• Sponsor: Emory University · Academic / Other
• Sex: All
• Age: 18 Years – 49 Years
• Healthy volunteers: Accepted

Summary

This study is designed to help us better understand how the immune system responds to the flu and how flu is transmitted in the environment. The ultimate goal is to develop better vaccines and drugs to protect against or fight the flu. This study will describe how the body's immune system responds to the flu virus during and after infection and how the flu virus is transmitted in the environment. The study will use a flu virus called A/Texas/71/2017 (H3N2), clade 3C3a produced specifically for clinical research in controlled conditions. The study will also assess the safety of the H3N2 influenza challenge in healthy participants. Mild to moderate symptoms are expected based on previous studies with this strain of influenza. Study volunteers will be recruited and screened from the general population of metro Atlanta through advertisements or identified from a database of research participants who have previously agreed to be contacted for future research studies. Participants will provide written consent before study participation. Up to 200 healthy adults, 18-49 years old, will be screened for participation. Eligible participants will take part in the study over 5 months. Enrolled participants will be admitted to Emory University Hospital during which time they will receive the influenza virus in the form of a spray in the nose or exposure to infected participants followed by an 8-12 day inpatient stay for observation. Follow-up outpatient visits will take place at the Hope Clinic of the Emory Vaccine Center. Participants will receive compensation (pro-rated for all visits completed) for their time and effort. There will be no costs to participants as a result of being in the study.

Detailed description

Influenza A continues to circulate widely in the human population and causes significant morbidity and mortality. Current vaccines have variable effectiveness year-to-year, with observable breakthrough infections each season, and have limited effectiveness in certain at-risk members of the population. Although basic and clinical influenza research has broadened our understanding of viral immunology, transmission, and pathogenesis, important questions, particularly concerning correlates of protection, viral evolution, and transmission, remain unanswered. Many of these questions can only be approached through studies in humans. As more broadly protective vaccines are developed, efficient and comprehensive methods of determining their value will be imperative. One of the key components and gap-filling measures in the National Institute of Allergy and Infectious Diseases (NIAID) strategic plan for universal influenza vaccines is to expand our capacity to conduct human challenge studies with relevant influenza challenge viruses to facilitate early evaluation of new vaccines and to further our understanding of flu pathogenesis and immunity. The goal of this study is to conduct a human challenge study to build upon our success at establishing the influenza challenge model at Emory to better understand influenza pathogenesis, immunity, transmission, and evolution using an H3N2 challenge stock. Human challenge studies for influenza are a particularly attractive modality for the development of a universal influenza vaccine. As outlined by NIAID's strategic plan, a universal flu vaccine would be at least 75% effective, maintain protection for at least one year, protect against group I (e.g., H1, H5) and II (e.g., H3, H7) influenza A virus strains, and be effective for all age groups. ix The strategic plan also states that a human challenge model could offer unique benefits to better understand the concept of imprinting, determine correlates of protection against influenza, and evaluate different universal influenza vaccine candidates. The development of universal vaccine strategies that reduce transmission potential and can protect from infection by aerosolized viruses will be a strategic advantage for reducing the public health burden from influenza viruses.

Conditions

• Influenza

Interventions

Type	Name	Description
BIOLOGICAL	Influenza Virus influenza A H3N2 strain	Live Influenza Virus RG-A/Texas/71/2017 (H3N2). It is a cell-grown, reverse genetics-derived influenza A virus manufactured to conduct clinical trials that involve controlled human infection with influenza A virus. This influenza human challenge virus was produced for the National Institute of Allergy and Infectious Diseases (NIAID). The final Drug Product Live Influenza Virus RG-A/Texas/71/2017 (H3N2) (Lot #1507-232149) vial contains 1.86 X 106 median tissue culture infectious doses (TCID50)/mL formulated in 1X sucrose-phosphate-glutamate (SPG; 7.4% sucrose, 3.8 mM KH2PO4, 7.2 mM K2HPO4, 5.4 mM L-glutamic acid) in Ex-Cellä 293 serum-free medium (Sigma-Aldrich). It is susceptible to the FDA-approved neuraminidase (NA) inhibitors (NAI) oseltamivir phosphate, zanamivir, and peramivir, and the polymerase acidic (PA) inhibitor (PAI) baloxavir marboxil.x

Timeline

• Start date: 2025-02-04
• Primary completion: 2027-12-01
• Completion: 2027-12-01
• First posted: 2024-12-31
• Last updated: 2026-03-03

Locations

2 sites across 1 country: United States

Regulatory

• FDA-regulated drug study