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CompletedNCT06613737Updated Apr 23, 2026Results posted

Dose, Safety, and Pathogenicity of a New Influenza A H3N2 Challenge Strain

An interventional study of Influenza A H3N2 virus dose arm 1 and Influenza A H3N2 virus dose arm 2 in Influenza A H3N2, sponsored by Hvivo. Completed at 1 site in United Kingdom. Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-23.

Sponsored by Hvivo · Not applicable, Interventional, and Other

Phase
Not applicable
Study type
Interventional
Enrollment
33
Allocation
Randomized
Ages
18 Years to 55 Years
Sex
All
01

Study summary

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)

Read the detailed description

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.
02

Conditions studied

  • Influenza A H3N2

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Keywords

  • Influenza
  • Flu
  • H3N2
  • Human Challenge Trial
03

Who can participate

Ages eligible
18 Years to 55 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Written informed consent
  • Adult male or female aged between 18 and 55 years
  • A total body weight ≥50 kg and body mass index (BMI) ≥18 kg/m2 and ≤35kg/m2.
  • In good health with no history, or current evidence, of clinically significant medical conditions, and no clinically significant test abnormalities that will interfere with participant safety.
  • Documented medical history
  • Adherence to contraception requirements
  • Serosuitable for the challenge virus

Exclusion criteria

Exclusion Criteria:

  • History of, or currently active, symptoms or signs suggestive of upper or lower respiratory tract (LRT) infection within 4 weeks prior to the first study visit.
  • Any history or evidence of any clinically significant or currently active disease.
  • Any participants who have smoked ≥10 pack years at any time.
  • Female participants who are breastfeeding, or have been pregnant within 6 months prior to the study, or have a positive pregnancy test at any point during screening or prior to inoculation.
  • Any history of anaphylaxis and/or a any history of severe allergic reaction.
  • Venous access deemed inadequate for the phlebotomy and cannulation demands of the study.
  • Lifetime history of anaphylaxis and/or a lifetime history of severe allergic reaction.
  • Significant abnormality of the nose, includes loss of or alterations in smell or taste, nasal polyps, epistaxis, nasal or sinus surgery.
  • Recent vaccinations or intention to receive vaccination before the Day 28 follow up visit.
  • Receipt of blood or blood products, or loss (including blood donations) of 550 mL or more of blood during the 3 months prior to the planned inoculation or planned during the 3 months after the final visit.
  • Recent receipt of investigational drugs or challenge viruses.
  • Use or anticipated use during the conduct of the study of concomitant medications (prescription and/or non-prescription), including vitamins or herbal and dietary supplements within the specified windows.
  • Positive drugs of abuse test, recent history or presence of alcohol addiction, excessive consumption of xanthine containing substances or a presence of significant signs and symptoms of nicotine withdrawal on first study visit.
  • A forced expiratory volume in 1 second (FEV1) \<80%.
  • Positive HIV, hepatitis B virus, or hepatitis C virus test.
  • Presence of fever, defined as participant presenting with a temperature reading of ≥37.9°C on Day -2/-1 and/or pre-inoculation on Day 0.
  • Those employed or immediate relatives of those employed at hVIVO or the sponsor.
  • Any other reason, in the opinion of the investigator deems the participant unsuitable for the study
04

Study design

Phase
Not applicable
Primary purpose
Other
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Participant)
Enrollment
33 participants (actual)

Study arms

  • Experimental
    Dose 1

    Medium dose, expected to be approximately 10\^4.5 tissue culture infective dose 50% (TCID50)/mL (titer may be adjusted based on stock titer)

    Other: Influenza A H3N2 virus dose arm 1

  • Experimental
    Dose 2

    High dose, expected to be approximately 10\^5.5 tissue culture infective dose 50% (TCID50)/mL (titer may be adjusted based on stock titer)

    Other: Influenza A H3N2 virus dose arm 2

  • Experimental
    Dose 3

    Optional: TBD, depending on outcome of Part A

    Other: Influenza A H3N2 virus dose arm 3

Interventions

  • OtherInfluenza A H3N2 virus dose arm 1

    Medium dose, approximately 10\^4.5 TCID50/mL

  • OtherInfluenza A H3N2 virus dose arm 2

    High dose, approximately 10\^5.5 TCID50/mL

  • OtherInfluenza A H3N2 virus dose arm 3

    TBD, depending on outcome of Part A

05

What researchers measure

Primary outcomes

  1. 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

  2. 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

  3. 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

Secondary outcomes

  1. 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

  2. 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

  3. 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).

    Time frame: Day 1 to Day 8

  4. 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

  5. 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

  6. 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

  7. 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

  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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

06

Results

Posted Apr 23, 2026

Participant flow

Participant flow — Overall Study
MilestoneMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Started55419
Completed55419
Not completed0000

Outcome measures

PrimaryOccurrence 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
Reported as:
Number · Occurrence of adverse events
Occurrence of Adverse Events Related to the Viral Challenge
Occurrence of adverse eventsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Occurrence of Adverse Events Related to the Viral Challenge0016
PrimaryOccurrence 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
Reported as:
Number · Occurrence of serious adverse events
Occurrence of Serious Adverse Events Related to the Viral Challenge
Occurrence of serious adverse eventsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Occurrence of Serious Adverse Events Related to the Viral Challenge0000
PrimaryInduces 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
Reported as:
Count of participants · Participants
Induces Laboratory-confirmed Infection in ≥40% of Inoculated Participants
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Induces Laboratory-confirmed Infection in ≥40% of Inoculated Participants33312
SecondaryIncidence 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
Reported as:
Count of participants · Participants
Incidence of Viral Culture-confirmed Influenza Infection.
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Incidence of Viral Culture-confirmed Influenza Infection.22110
SecondaryVL-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
Reported as:
Mean · log10 copies/mL*days
VL-AUC of Influenza Challenge Virus as Determined by qRT-PCR
log10 copies/mL*daysMedium Dose, Pipette Administration - Nasal SamplesMedium Dose, MAD Administration - Nasal SamplesHigh Dose, Pipette Administration - Nasal SamplesHigh Dose, MAD Administration - Nasal SamplesHigh Dose, MAD Administration (Part B Only) - Throat Samples
VL-AUC of Influenza Challenge Virus as Determined by qRT-PCR20.03 ± 15.5218.40 ± 12.5014.61 ± 10.8222.21 ± 14.3010.10 ± 6.61
SecondaryPeak 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).

Time frame:
Day 1 to Day 8
Reported as:
Mean · log10 copies/mL
Peak Viral Load of Influenza Challenge Virus as Determined by qRT-PCR
log10 copies/mLMedium Dose, Pipette Administration - Nasal SamplesMedium Dose, MAD Administration - Nasal SamplesHigh Dose, Pipette Administration - Nasal SamplesHigh Dose, MAD Administration - Nasal SamplesHigh Dose, MAD Administration (Part B Only) - Throat Samples
Peak Viral Load of Influenza Challenge Virus as Determined by qRT-PCR4.69 ± 3.674.75 ± 3.774.26 ± 2.585.52 ± 3203.86 ± 2.97
SecondaryVL-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
Reported as:
Mean · log10TCID50/mL*days
VL-AUC of Influenza Challenge Virus as Determined by Viral Culture
log10TCID50/mL*daysMedium Dose, Pipette Administration - Nasal SamplesMedium Dose, MAD Administration - Nasal SamplesHigh Dose, Pipette Administration - Nasal SamplesHigh Dose, MAD Administration - Nasal SamplesHigh Dose, MAD Administration (Part B Only) - Throat Samples
VL-AUC of Influenza Challenge Virus as Determined by Viral Culture9.72 ± 7.266.05 ± 2.666.19 ± 3.537.50 ± 3.955.36 ± 2.26
SecondaryPeak 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
Reported as:
Mean · log10TCID50/mL
Peak Viral Load of Influenza Challenge Virus as Determined by Viral Culture
log10TCID50/mLMedium Dose, Pipette Administration - Nasal SamplesMedium Dose, MAD Administration - Nasal SamplesHigh Dose, Pipette Administration - Nasal SamplesHigh Dose, MAD Administration - Nasal SamplesHigh Dose, MAD Administration (Part B Only) - Throat Samples
Peak Viral Load of Influenza Challenge Virus as Determined by Viral Culture2.35 ± 1.992.20 ± 1.951.52 ± 1.682.66 ± 1.891.50 ± 1.63
SecondaryArea 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
Reported as:
Mean · score*days
Area Under the Total Clinical Symptoms Score-time Curve (TSS-AUC)
score*daysMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Area Under the Total Clinical Symptoms Score-time Curve (TSS-AUC)5.88 ± 5.3210.91 ± 7.143.05 ± 4.2710.23 ± 10.99
SecondaryPeak 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
Reported as:
Mean · Peak TSS
Peak Total Symptoms Diary Card Score
Peak TSSMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Peak Total Symptoms Diary Card Score3.20 ± 2.395.40 ± 2.972.75 ± 3.104.05 ± 3.70
SecondaryPeak 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
Reported as:
Mean · Peak TSS
Peak Daily Symptoms Diary Card Score
Peak TSSMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Day 10.80 ± 0.840.40 ± 0.891.25 ± 2.500.95 ± 1.90
Day 20.40 ± 0.892.80 ± 1.921.00 ± 2.002.84 ± 3.18
Day 30.80 ± 0.452.20 ± 2.391.50 ± 1.293.16 ± 3.44
Day 42.20 ± 1.483.00 ± 3.740.50 ± 1.002.63 ± 2.99
Day 51.60 ± 1.142.40 ± 2.790 ± 02.32 ± 2.47
Day 61.80 ± 3.032.00 ± 1.581.75 ± 3.501.26 ± 1.69
Day 71.40 ± 2.612.00 ± 3.390.50 ± 1.001.00 ± 1.29
Day 81.20 ± 2.681.60 ± 3.580 ± 00.26 ± 0.65
SecondaryLaboratory-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
Reported as:
Count of participants · Participants
Laboratory-confirmed Febrile Influenza Infection
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Laboratory-confirmed Febrile Influenza Infection1102
SecondaryqRT-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
Reported as:
Count of participants · Participants
qRT-PCR-confirmed Influenza-like Illness (Centers for Disease and Control [CDC])
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
qRT-PCR-confirmed Influenza-like Illness (Centers for Disease and Control [CDC])1002
SecondaryqRT-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
Reported as:
Count of participants · Participants
qRT-PCR-confirmed Influenza-like Illness (World Health Organization [WHO])
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
qRT-PCR-confirmed Influenza-like Illness (World Health Organization [WHO])1001
SecondaryLaboratory-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
Reported as:
Count of participants · Participants
Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection1307
SecondaryLaboratory-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
Reported as:
Count of participants · Participants
Laboratory-confirmed Symptomatic Influenza Infection
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Laboratory-confirmed Symptomatic Influenza Infection3329
SecondaryViral 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
Reported as:
Count of participants · Participants
Viral Culture Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection
ParticipantsMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Viral Culture Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection1207

Adverse events

Collected over Challenge agent-emergent adverse events were collected from inoculation of the challenge virus till the day 28 follow up visit (29 days).. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Medium Dose, Pipette Administration.0/5 (0%)0/5 (0%)0/5 (0%)
Medium Dose, MAD Administration.0/5 (0%)0/5 (0%)4/5 (80%)
High Dose, Pipette Administration.0/4 (0%)0/4 (0%)2/4 (50%)
High Dose, MAD Administration.0/19 (0%)0/19 (0%)9/19 (47.4%)
Most frequent other events
Showing 10 of 14
Most frequent other events
EventMedium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.
Tooth infectionInfections and infestations0/50/51/40/19
NeutropeniaBlood and lymphatic system disorders0/50/51/40/19
HeadacheNervous system disorders0/50/50/44/19
Aspartate aminotransferase increasedInvestigations0/51/50/41/19
NasopharyngitisInfections and infestations0/51/50/41/19
WheezingRespiratory, thoracic and mediastinal disorders0/51/50/40/19
Non-cardiac chest painGeneral disorders0/51/50/40/19
Dermatitis contactSkin and subcutaneous tissue disorders0/51/50/40/19
Alanine aminotransferase increasedInvestigations0/50/50/43/19
DiarrhoeaGastrointestinal disorders0/50/50/42/19

Baseline characteristics

Age, Continuous
Age, Continuous(years)Medium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.Total
Mean29.60 ± 8.4429.60 ± 7.9225.75 ± 6.2429.37 ± 7.7329.00 ± 7.45
Sex: Female, Male
Sex: Female, Male(Participants)Medium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.Total
Female10247
Male4521526
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)Medium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.Total
Hispanic or Latino01001
Not Hispanic or Latino5441932
Unknown or Not Reported00000
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)Medium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.Total
Asian10001
Black or African American00022
White4331424
Multiple01001
Other01135
Region of Enrollment
Region of Enrollment(participants)Medium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.Total
United Kingdom5541933
Body Mass Index (BMI)
Body Mass Index (BMI)(kg/m^2)Medium Dose, Pipette Administration.Medium Dose, MAD Administration.High Dose, Pipette Administration.High Dose, MAD Administration.Total
Mean27.18 ± 3.1425.82 ± 2.6725.70 ± 1.9926.34 ± 3.3826.31 ± 3.02
07

Study locations

1 site
  • hVIVO Services Ltd, 40 Bank Street
    London, E14 5NR, United Kingdom
08

References and documents

Study documents

  • Protocol and statistical analysis plan · Dec 20, 2024

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: No

09

Registry details

Key details

Study ID
NCT06613737
Lead sponsor
Hvivo
Responsible party
Sponsor
First posted
Sep 26, 2024
Start date
Sep 11, 2024
Primary completion
Mar 10, 2025
Completion
Mar 10, 2025
Results posted
Apr 23, 2026
Last update
Apr 23, 2026

Study contacts

Alexandre Lima, MD-PhD
principal investigator · hVIVO Services Ltd.

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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