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Influenza Challenge Study to Determine the Optimal Infection Dose and Safety of a Recombinant H3N2 (A/Texas/71/2017 (H3N2, Clade 3C3a) Influenza Strain

NCT04978454 · Status: COMPLETED · Phase: PHASE1 · Type: INTERVENTIONAL · Enrollment: 60

Last updated 2025-08-28

Study results available
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Summary

An open-label, dose-ranging influenza challenge study in healthy adult volunteers to determine the optimal infection dose and safety of a recombinant H3N2 (A/Texas/ A/Texas/71/2017 (H3N2, clade 3C3a) influenza strain. The goal of this study is to find a challenge virus dose that is safe and can achieve a symptomatic influenza Attack Rate (AR) that will be sufficiently high for utilization in future vaccine or intervention studies. The optimal dose of the three considered is broadly defined as the minimum challenge virus dose that elicits the highest AR without meeting safety-stopping criteria. Additionally, viral recovery, clinical symptoms, and immune responses over the post-challenge period will be described by challenge dose group. This study will last for up to 1 year depending upon the number of challenge cohorts enrolled given the adaptive dose-escalation design. The populations are healthy males and non-pregnant, non-breastfeeding females aged = 18 and \< 46 years of age with a serum HAI antibody titer of \</=1:40 against influenza A/Texas/71/2017 (H3N2), clade 3C3a. The study will enroll and challenge up to 106 (plus 8 shams) healthy adult volunteers with the H3N2 (A/Texas/71/2017 (H3N2), clade 3C3a) influenza virus challenge strain. The primary objectives are: 1) To determine the optimal infectious dose of a recombinant influenza virus (A/Texas/71/2017 (H3N2), clade 3C3a) to be used as a clinical challenge strain in future vaccine efficacy or intervention studies as assessed by viral shedding and clinical symptoms. 2) To describe viral detection by quantitative and qualitative Reverse Transcription - Polymerase Chain Reaction (RT-PCR) from study subjects at baseline and post-challenge. 3) To document clinical symptoms from self-reported surveys and standardized symptom scales at baseline and post-challenge.

Conditions

Interventions

BIOLOGICAL

Influenza RG-A/Texas/71/2017 (H3N2) Challenge

RG-A/Texas/71/2017 (H3N2) is an infectious influenza virus and requires handling at BioSafety Level 2. The challenge virus will be administered intranasally in a volume of approximately 0.5 mL per nostril. Intranasal challenge will be carried out using the Intranasal Mucosal Atomization ( MAD Nasa(TM)) Device attached to a 1 mL syringe.

OTHER

Placebo

Sucrose phosphate glutamate (SPG) inoculum

Sponsors & Collaborators

  • National Institute of Allergy and Infectious Diseases (NIAID)

    lead NIH

Study Design

Allocation
RANDOMIZED
Purpose
OTHER
Masking
TRIPLE
Model
SEQUENTIAL

Eligibility

Min Age
18 Years
Max Age
45 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2021-08-19
Primary Completion
2022-09-22
Completion
2022-09-22
FDA Drug
Yes

Countries

  • United States

Study Locations

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT04978454 on ClinicalTrials.gov