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Influenza A H3N2NCT06613737

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

A study testing Influenza A H3N2 virus dose arm 1, Influenza A H3N2 virus dose arm 2 and Influenza A H3N2 virus dose arm 3 in people with Influenza A H3N2, run by Hvivo at 1 site in United Kingdom.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial 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). Read more about this study

Who is it for?
Ages 18 to 55 yearsHealthy volunteers can take part
Conditions the study is for
Influenza A H3N2
What is being tested?
Influenza A H3N2 virus dose arm 1, Influenza A H3N2 virus dose arm 2 and Influenza A H3N2 virus dose arm 3
Could I receive a placebo?
No, everyone receives an active treatment
How many people
33 participants
Where
1 siteUnited Kingdom
Study dates
11 Sep 2024to 10 Mar 2025
Phase
Interventional
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 55 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • 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

Who cannot join

  • 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.
Show all 18Show fewer
  • 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

Trial locations and contacts

1 site in 1 country.

United Kingdom1 site
  • hVIVO Services Ltd, 40 Bank Street

    London, E14 5NR

Other trials in United Kingdom

About this study

Official title: 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

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.
Being tested
Influenza A H3N2 virus dose arm 1, Influenza A H3N2 virus dose arm 2, Influenza A H3N2 virus dose arm 3
Keywords
Influenza, Flu, H3N2, Human Challenge Trial
Medical subject headings
Influenza, Human

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Influenza A H3N2 virus dose arm 1Other

    Medium dose, approximately 10^4.5 TCID50/mL

  • Influenza A H3N2 virus dose arm 2Other

    High dose, approximately 10^5.5 TCID50/mL

  • Influenza A H3N2 virus dose arm 3Other

    TBD, depending on outcome of Part A

Study groups in NCT06613737
Study groupRoleWhat they receive
Dose 1ExperimentalMedium dose, expected to be approximately 10^4.5 tissue culture infective dose 50% (TCID50)/mL (titer may be adjusted based on stock titer)
Receives: Other: Influenza A H3N2 virus dose arm 1
Dose 2ExperimentalHigh dose, expected to be approximately 10^5.5 tissue culture infective dose 50% (TCID50)/mL (titer may be adjusted based on stock titer)
Receives: Other: Influenza A H3N2 virus dose arm 2
Dose 3ExperimentalOptional: TBD, depending on outcome of Part A
Receives: Other: Influenza A H3N2 virus dose arm 3

What is being measured

The primary outcome is the main question the study is designed to answer.

  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.

    Measured: 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.

    Measured: 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).

    Measured: Day 1 to Day 8

Secondary outcomes (14)
  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).

    Measured: 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)

    Measured: 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).

    Measured: 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)

    Measured: 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).

    Measured: 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).

    Measured: 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).

    Measured: 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).

    Measured: 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).

    Measured: 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.

    Measured: 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).

    Measured: 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).

    Measured: 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).

    Measured: 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).

    Measured: Day 1 to Day 8

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted26 Sep 2024
  2. Study start11 Sep 2024
  3. Primary completion10 Mar 2025
  4. Study completion10 Mar 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Other
Allocation
Randomised
Intervention model
Parallel groups
Masking
Single blind
Who is masked
Participant
Enrolment
33 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06613737
Sponsor's protocol ID
HRD-vCS-006
Status last verified
Aug 2025
First submitted
23 Sep 2024
Last updated
23 Apr 2026
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Influenza A H3N2 virus dose arm 1, Influenza A H3N2 virus dose arm 2 and Influenza A H3N2 virus dose arm 3 in people with Influenza A H3N2, run by Hvivo at 1 site in United Kingdom.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 7 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 23 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 23 Apr 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Occurrence of Adverse Events Related to the Viral Challenge (time frame: Day 0 to Day 28). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Apr 2026.

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