An Exploratory Study to Establish the Dose, Safety and Pathogenicity of a New Influenza A H3N2 Challenge Strain in Healthy Participants 18 to 55 Years of Age In Part A, up to 40 participants will be randomly allocated to one of two groups to be given one of two virus doses (Virus Dose 1 or Virus Dose 2). Based on the outcome of Part A, participants in Part B, may be given Virus Dose 1, Virus Dose 2, or another virus dose (e.g., Virus Dose 3)
This is an exploratory study of an influenza A/England/7763/2022 H3N2 challenge strain, to determine the optimum safe infectious titer of challenge agent, in healthy participants 18 to 55 years of age. A total of up to 80 participants may be given the influenza A/England/7763/2022 H3N2 challenge agent. Each participant will remain in the study for approximately 4 months from screening to the last clinic visit. The study will consist of 2 parts, in Part A of the study, up to 40 participants will be randomly allocated to one of two groups to be given one of two virus doses (Virus Dose 1 or Virus Dose 2). Based on the outcome of Part A, additional participants may be enrolled into the optional Part B of the study and may be given Virus Dose 1, Virus Dose 2, and/or another virus dose (e.g., Virus Dose 3) The study is divided into three phases: 1. Screening phase: Screening will occur between Day -90 to Day -2/-1. 2. Quarantine phase: Participants will stay in the quarantine unit for approximately 8 days (from Day -2/-1 to Day 8). One or two days prior to the day of inoculation with the challenge virus, participants will be admitted to quarantine where their eligibility will be reassessed. If participants remain eligible for the study, they will receive the challenge virus on Day 0. Participants will undergo a range of clinical assessments and safety monitoring for the entirety of their stay in quarantine. Participants will be discharged from the quarantine unit on Day 8 (or may remain longer at the principal investigator's discretion). 3. Outpatient phase: Following the conclusion of the quarantine phase, participants will attend a Follow-Up visit, approximately 28 days after they received the study virus. Their symptoms will be reassessed, and a complete safety examination performed.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
33
Medium dose, approximately 10\^4.5 TCID50/mL
High dose, approximately 10\^5.5 TCID50/mL
TBD, depending on outcome of Part A
hVIVO Services Ltd, 40 Bank Street
London, United Kingdom
Occurrence of Adverse Events Related to the Viral Challenge
Occurrence of adverse events (AEs) related to the viral challenge from viral challenge (Day 0) to the Day 28 follow-up visit.
Time frame: Day 0 to Day 28
Occurrence of Serious Adverse Events Related to the Viral Challenge
Occurrence of serious adverse events (SAEs) related to the viral challenge from viral challenge (Day 0) to the Day 28 follow-up visit.
Time frame: Day 0 to Day 28
Induces Laboratory-confirmed Infection in ≥40% of Inoculated Participants
Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR)-confirmed influenza infection, defined as 2 quantifiable (≥ lower limit of quantification \[LLOQ\]) qRT-PCR measurements (reported over 4 planned consecutive assessments within 48 hours), from Day 1 pm to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
Incidence of Viral Culture-confirmed Influenza Infection.
Viral culture-confirmed influenza infection, defined as a quantifiable viral culture measurement, from Day 1 pm to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
VL-AUC of Influenza Challenge Virus as Determined by qRT-PCR
Area under the viral load-time curve (VL-AUC) of influenza challenge virus as determined by qRT-PCR on both nasal and throat (Part B only) samples, starting from Day 1 pm up to planned discharge from quarantine (Day 8 am)
Time frame: Day 1 to Day 8
Peak Viral Load of Influenza Challenge Virus as Determined by qRT-PCR
Peak viral load of influenza challenge virus defined as the maximum viral load, from qRT-PCR on nasal and throat (Part B only) samples from Day 1 pm to planned discharge from quarantine (Day 8 am).
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Time frame: Day 1 to Day 8
VL-AUC of Influenza Challenge Virus as Determined by Viral Culture
Area under the viral load-time curve (VL-AUC) of influenza challenge virus as determined by viral culture on both nasal and throat (Part B only) samples, starting from Day 1 pm up to planned discharge from quarantine (Day 8 am)
Time frame: Day 1 to Day 8
Peak Viral Load of Influenza Challenge Virus as Determined by Viral Culture
Peak viral load of influenza challenge virus defined as the maximum viral load, from by viral culture on nasal and throat (Part B only) samples from Day 1 pm to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
Area Under the Total Clinical Symptoms Score-time Curve (TSS-AUC)
Data presented is score\*days. TSS-AUC (trapezium rule) as measured by graded symptom scoring system collected 3 times daily starting Day 1 am up to Day 8 am using a participant self-reportable 13-symptoms card, the max number of diary cards included in the AUC calculation is 22, the maximum time period is 7 days. Clinical symptoms included runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze. Participants scored symptom from 0 (no symptoms) to 3 (severe). Shortness of breath and wheeze had an additional scoring option of grade 4. Dairy card total symptom scores ranged from 0 (if all symptoms graded 0) to 41 (if all symptoms graded 3 and shortness of breath and wheeze graded 4). The range of TSS AUC scores are between 0 and 287 score\*days (maximum of 41\*7).
Time frame: Day 1 to Day 8
Peak Total Symptoms Diary Card Score
Peak Total Symptom Score (TSS) for each participant is defined as the diary card total with the worst score (highest). The symptom scoring system was collected three times daily starting one day post-viral challenge (Day 1) up to discharge from quarantine (Day 8 am) using a participant self-reportable 13-symptoms card. Clinical symptoms included runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze. Participants scored symptom from 0 (no symptoms) to 3 (severe). Shortness of breath and wheeze had an additional scoring option of grade 4. Dairy card total symptom scores ranged from 0 (if all symptoms graded 0) to 41 (if all symptoms graded 3 and shortness of breath and wheeze graded 4).
Time frame: Day 1 to Day 8
Peak Daily Symptoms Diary Card Score
Peak daily symptom score was derived, for each day from Day 1 to Day 8, as the maximum of the 3 total symptoms scores on that day. The symptoms were collected three times daily starting one day post-viral challenge (Day 1) up to planned discharge from quarantine (Day 8 am) using a participant self-reportable 13-symptoms card. Clinical symptoms included runny nose, stuffy nose, sneezing, sore throat, earache, malaise/tiredness, headache, muscle and/or joint ache, chilliness/feverishness, cough, chest tightness, shortness of breath, and wheeze. Participants scored symptom from 0 (no symptoms) to 3 (severe). Shortness of breath and wheeze had an additional scoring option of grade 4. Dairy card total symptom scores ranged from 0 (if all symptoms graded 0) to 41 (if all symptoms graded 3 and shortness of breath and wheeze graded 4).
Time frame: Day 1 to Day 8
Laboratory-confirmed Febrile Influenza Infection
A qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥LLOQ) qRT-PCR measurements (reported on 2 or more independent samples over 4 planned consecutive assessments within 48 hours), from Day 1 pm to planned discharge from quarantine (Day 8 am) AND, a febrile episode, defined as a temperature of ≥37.9°C, from Day 1 am to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
qRT-PCR-confirmed Influenza-like Illness (Centers for Disease and Control [CDC])
A qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥LLOQ) qRT-PCR measurements (reported on 2 or more independent samples over 4 planned consecutive assessments within 48 hours), from Day 1 pm to planned discharge from quarantine (Day 8 am) AND, a febrile episode, defined as a temperature of ≥37.8ºC, and a cough and/or sore throat (symptoms and signs), from Day 1 am to planned discharge from quarantine (Day 8 am), in the absence of a known cause other than influenza.
Time frame: Day 1 to Day 8
qRT-PCR-confirmed Influenza-like Illness (World Health Organization [WHO])
A qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥LLOQ) qRT-PCR measurements (reported on 2 or more independent samples over 4 planned consecutive assessments within 48 hours), from Day 1 pm to planned discharge from quarantine (Day 8 am) AND, a febrile episode, defined as a temperature of ≥38.0ºC and a cough, from Day 1 am to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection
A qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥LLOQ) qRT-PCR measurements (reported on 2 or more independent samples over 4 planned consecutive assessments within 48 hours), from Day 1 pm to planned discharge from quarantine (Day 8 am) AND, any symptoms from the symptom diary card of grade ≥2 at a single time point, from Day 1 am to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
Laboratory-confirmed Symptomatic Influenza Infection
A qRT-PCR-confirmed influenza infection, defined as 2 quantifiable (≥LLOQ) qRT-PCR measurements (reported on 2 or more independent samples over 4 planned consecutive assessments within 48 hours), from Day 1 pm to planned discharge from quarantine (Day 8 am) AND, a total symptom score of ≥2 at a single time point, from Day 1 am to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8
Viral Culture Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection
Viral culture laboratory-confirmed infection, AND any symptoms from the symptom diary card of grade ≥2 at a single time point, from Day 1 am to planned discharge from quarantine (Day 8 am).
Time frame: Day 1 to Day 8