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
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:
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).
2,356 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.
This study's enrollment of 33 is below the median of 227 across 1,957 interventional studies indexed under Influenza, Human.
Browse Influenza, Human studies →Hvivo is the lead sponsor of 13 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
FEV1
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
Optional: TBD, depending on outcome of Part A
Other: Influenza A H3N2 virus dose arm 3
Medium dose, approximately 10\^4.5 TCID50/mL
High dose, approximately 10\^5.5 TCID50/mL
TBD, depending on outcome of Part A
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).
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
| Milestone | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Started | 5 | 5 | 4 | 19 |
| Completed | 5 | 5 | 4 | 19 |
| Not completed | 0 | 0 | 0 | 0 |
Occurrence of adverse events (AEs) related to the viral challenge from viral challenge (Day 0) to the Day 28 follow-up visit.
| Occurrence of adverse events | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Occurrence of Adverse Events Related to the Viral Challenge | 0 | 0 | 1 | 6 |
Occurrence of serious adverse events (SAEs) related to the viral challenge from viral challenge (Day 0) to the Day 28 follow-up visit.
| Occurrence of serious adverse events | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Occurrence of Serious Adverse Events Related to the Viral Challenge | 0 | 0 | 0 | 0 |
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).
| Participants | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Induces Laboratory-confirmed Infection in ≥40% of Inoculated Participants | 3 | 3 | 3 | 12 |
Viral culture-confirmed influenza infection, defined as a quantifiable viral culture measurement, from Day 1 pm to planned discharge from quarantine (Day 8 am).
| Participants | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Incidence of Viral Culture-confirmed Influenza Infection. | 2 | 2 | 1 | 10 |
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)
| log10 copies/mL*days | Medium Dose, Pipette Administration - Nasal Samples | Medium Dose, MAD Administration - Nasal Samples | High Dose, Pipette Administration - Nasal Samples | High Dose, MAD Administration - Nasal Samples | High Dose, MAD Administration (Part B Only) - Throat Samples |
|---|---|---|---|---|---|
| VL-AUC of Influenza Challenge Virus as Determined by qRT-PCR | 20.03 ± 15.52 | 18.40 ± 12.50 | 14.61 ± 10.82 | 22.21 ± 14.30 | 10.10 ± 6.61 |
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).
| log10 copies/mL | Medium Dose, Pipette Administration - Nasal Samples | Medium Dose, MAD Administration - Nasal Samples | High Dose, Pipette Administration - Nasal Samples | High Dose, MAD Administration - Nasal Samples | High Dose, MAD Administration (Part B Only) - Throat Samples |
|---|---|---|---|---|---|
| Peak Viral Load of Influenza Challenge Virus as Determined by qRT-PCR | 4.69 ± 3.67 | 4.75 ± 3.77 | 4.26 ± 2.58 | 5.52 ± 320 | 3.86 ± 2.97 |
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)
| log10TCID50/mL*days | Medium Dose, Pipette Administration - Nasal Samples | Medium Dose, MAD Administration - Nasal Samples | High Dose, Pipette Administration - Nasal Samples | High Dose, MAD Administration - Nasal Samples | High Dose, MAD Administration (Part B Only) - Throat Samples |
|---|---|---|---|---|---|
| VL-AUC of Influenza Challenge Virus as Determined by Viral Culture | 9.72 ± 7.26 | 6.05 ± 2.66 | 6.19 ± 3.53 | 7.50 ± 3.95 | 5.36 ± 2.26 |
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).
| log10TCID50/mL | Medium Dose, Pipette Administration - Nasal Samples | Medium Dose, MAD Administration - Nasal Samples | High Dose, Pipette Administration - Nasal Samples | High Dose, MAD Administration - Nasal Samples | High Dose, MAD Administration (Part B Only) - Throat Samples |
|---|---|---|---|---|---|
| Peak Viral Load of Influenza Challenge Virus as Determined by Viral Culture | 2.35 ± 1.99 | 2.20 ± 1.95 | 1.52 ± 1.68 | 2.66 ± 1.89 | 1.50 ± 1.63 |
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).
| score*days | Medium 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 ± 5.32 | 10.91 ± 7.14 | 3.05 ± 4.27 | 10.23 ± 10.99 |
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).
| Peak TSS | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Peak Total Symptoms Diary Card Score | 3.20 ± 2.39 | 5.40 ± 2.97 | 2.75 ± 3.10 | 4.05 ± 3.70 |
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).
| Peak TSS | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Day 1 | 0.80 ± 0.84 | 0.40 ± 0.89 | 1.25 ± 2.50 | 0.95 ± 1.90 |
| Day 2 | 0.40 ± 0.89 | 2.80 ± 1.92 | 1.00 ± 2.00 | 2.84 ± 3.18 |
| Day 3 | 0.80 ± 0.45 | 2.20 ± 2.39 | 1.50 ± 1.29 | 3.16 ± 3.44 |
| Day 4 | 2.20 ± 1.48 | 3.00 ± 3.74 | 0.50 ± 1.00 | 2.63 ± 2.99 |
| Day 5 | 1.60 ± 1.14 | 2.40 ± 2.79 | 0 ± 0 | 2.32 ± 2.47 |
| Day 6 | 1.80 ± 3.03 | 2.00 ± 1.58 | 1.75 ± 3.50 | 1.26 ± 1.69 |
| Day 7 | 1.40 ± 2.61 | 2.00 ± 3.39 | 0.50 ± 1.00 | 1.00 ± 1.29 |
| Day 8 | 1.20 ± 2.68 | 1.60 ± 3.58 | 0 ± 0 | 0.26 ± 0.65 |
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).
| Participants | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Laboratory-confirmed Febrile Influenza Infection | 1 | 1 | 0 | 2 |
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.
| Participants | Medium 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]) | 1 | 0 | 0 | 2 |
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).
| Participants | Medium 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]) | 1 | 0 | 0 | 1 |
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).
| Participants | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection | 1 | 3 | 0 | 7 |
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).
| Participants | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Laboratory-confirmed Symptomatic Influenza Infection | 3 | 3 | 2 | 9 |
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).
| Participants | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Viral Culture Laboratory-confirmed Moderately Severe Symptomatic Influenza Infection | 1 | 2 | 0 | 7 |
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.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| 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%) |
| Event | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. |
|---|---|---|---|---|
| Tooth infectionInfections and infestations | 0/5 | 0/5 | 1/4 | 0/19 |
| NeutropeniaBlood and lymphatic system disorders | 0/5 | 0/5 | 1/4 | 0/19 |
| HeadacheNervous system disorders | 0/5 | 0/5 | 0/4 | 4/19 |
| Aspartate aminotransferase increasedInvestigations | 0/5 | 1/5 | 0/4 | 1/19 |
| NasopharyngitisInfections and infestations | 0/5 | 1/5 | 0/4 | 1/19 |
| WheezingRespiratory, thoracic and mediastinal disorders | 0/5 | 1/5 | 0/4 | 0/19 |
| Non-cardiac chest painGeneral disorders | 0/5 | 1/5 | 0/4 | 0/19 |
| Dermatitis contactSkin and subcutaneous tissue disorders | 0/5 | 1/5 | 0/4 | 0/19 |
| Alanine aminotransferase increasedInvestigations | 0/5 | 0/5 | 0/4 | 3/19 |
| DiarrhoeaGastrointestinal disorders | 0/5 | 0/5 | 0/4 | 2/19 |
| Age, Continuous(years) | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. | Total |
|---|---|---|---|---|---|
| Mean | 29.60 ± 8.44 | 29.60 ± 7.92 | 25.75 ± 6.24 | 29.37 ± 7.73 | 29.00 ± 7.45 |
| Sex: Female, Male(Participants) | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. | Total |
|---|---|---|---|---|---|
| Female | 1 | 0 | 2 | 4 | 7 |
| Male | 4 | 5 | 2 | 15 | 26 |
| Ethnicity (NIH/OMB)(Participants) | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. | Total |
|---|---|---|---|---|---|
| Hispanic or Latino | 0 | 1 | 0 | 0 | 1 |
| Not Hispanic or Latino | 5 | 4 | 4 | 19 | 32 |
| Unknown or Not Reported | 0 | 0 | 0 | 0 | 0 |
| Race/Ethnicity, Customized(Participants) | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. | Total |
|---|---|---|---|---|---|
| Asian | 1 | 0 | 0 | 0 | 1 |
| Black or African American | 0 | 0 | 0 | 2 | 2 |
| White | 4 | 3 | 3 | 14 | 24 |
| Multiple | 0 | 1 | 0 | 0 | 1 |
| Other | 0 | 1 | 1 | 3 | 5 |
| Region of Enrollment(participants) | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. | Total |
|---|---|---|---|---|---|
| United Kingdom | 5 | 5 | 4 | 19 | 33 |
| Body Mass Index (BMI)(kg/m^2) | Medium Dose, Pipette Administration. | Medium Dose, MAD Administration. | High Dose, Pipette Administration. | High Dose, MAD Administration. | Total |
|---|---|---|---|---|---|
| Mean | 27.18 ± 3.14 | 25.82 ± 2.67 | 25.70 ± 1.99 | 26.34 ± 3.38 | 26.31 ± 3.02 |
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