ClinicalTrials.gg
CompletedNCT05572450Updated Sep 13, 2023

Dose, Safety, and Pathogenicity of a New Influenza H1N1 Challenge Strain

An interventional study of Infectious Titre 1 and Infectious Titre 2 in Influenza A H1N1, 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 2023-09-13.

Primary conditionInfluenza, HumanRegistry: Orthomyxoviridae InfectionsReclassifiedWhy we changed it
Registry
Orthomyxoviridae Infections — the first condition term the registry derived for this study.
ClinicalTrials.gg
Influenza, Human
Why
  1. The study's listed conditions name Influenza, Human, a narrower term within Orthomyxoviridae Infections.
Confidence
High: the new condition is named in the study's own listed conditions. Of 351 hand-checked studies reclassified this way, 68% were exactly right and 84% in the right disease family; the registry's first term was right for 5% (measured 2026-10-21). How we classify →
Wrong?
Tell us the study's main condition →

Sponsored by Hvivo · Not applicable, Interventional, and Basic science

Phase
Not applicable
Study type
Interventional
Enrollment
70
Allocation
Randomized
Ages
18 Years to 55 Years
Sex
All
01

Study summary

A total of up to 90 participants may be given H1N1 influenza challenge virus.

In Part A, 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

Influenza viruses are associated with significant human disease and cause annual epidemics during autumn and winter. Although most people recover within 1 to 2 weeks without requiring medical attention, seasonal influenza yearly results in approximately 3 to 5 million cases of severe illness and up to 500,000 deaths worldwide, particularly among the very young, elderly, and chronically ill.

The H1N1 virus used for the challenge virus originated from a cell-culture derived candidate vaccine virus (ccCVV), provided by the Centers for Disease Control an Prevention (CDC) in the USA.

In Part A, 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)

02

Conditions studied

  • Influenza A H1N1

Browse trials for

Keywords

  • Influenza
  • Human Challenge Trial
  • H1N1
  • Flu
03

In context

Influenza, Human Reclassified

2,356 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.

This study's enrollment of 70 is below the median of 227 across 1,957 interventional studies indexed under Influenza, Human.

Browse Influenza, Human studies →

Lead sponsor

Hvivo is the lead sponsor of 13 studies on the registry; 2 are open to participants now.

Compared within Influenza, Human, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Orthomyxoviridae Infections. The counts are of registry records indexed under each term, refreshed daily. How we classify →

04

Who can participate

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

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.

Inclusion criteria

  • Written
  • Adult male or female aged between 18 and 55 years
  • A total body weight ≥50 kg and (BMI) ≥18 kg/m2 and ≤35kg/m2
  • In good health with no history, or current evidence, of medical conditions, and no clinically significant test abnormalities that will interfere with participant safety.
  • Documented medical history
  • Adherence to 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 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.
  • Lifetime history of anaphylaxis and/or a lifetime history of severe allergic reaction.
  • Venous access deemed inadequate for the phlebotomy and cannulation demands of the study.
  • Significant abnormality of the nose, epistaxis, nasal or sinus surgery.
  • Recent vaccinations or intention to receive vaccination before the final 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 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 or recent history or presence of alcohol addiction
  • A (FEV1) \<80%.
  • Positive , virus, or virus test.
  • Presence of fever, defined as participant presenting with a temperature reading of ≥37.9C 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
Terms in these criteria, in plain language(9)

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Participant)
Enrollment
70 participants (actual)

Study arms

  • Experimental
    Infectious Titre 1

    Dose Arm 1 (Part A): Approximately 10\^5.5 TCID50/mL (titre may be adjusted based on stock titre)

    Other: Infectious Titre 1

  • Experimental
    Infectious Titre 2

    Dose Arm 2 (Part A): Approximately 10\^4.5 TCID50/mL (titre may be adjusted based on stock titre)

    Other: Infectious Titre 2

  • Experimental
    Infectious Titre 3

    Optional Dose Arm 3 (Part B): to be determined (TBD), depending on outcome of Part A

    Other: Infectious Titre 3

  • Experimental
    Infectious Titre 4

    Optional Dose Arm 4 (Part B): TBD, depending on outcome of Part A

    Other: Infectious Titre 4

Interventions

  • OtherInfectious Titre 1

    Approximately 10\^5.5 TCID50/mL (titre may be adjusted based on stock titre)

  • OtherInfectious Titre 2

    Approximately 10\^4.5 TCID50/mL (titre may be adjusted based on stock titre)

  • OtherInfectious Titre 3

    To be determined (TBD), depending on outcome of Part A

  • OtherInfectious Titre 4

    TBD, depending on outcome of Part A

06

What researchers measure

Primary outcomes

  1. To determine the safe and optimal titre of the influenza challenge virus

    To identify a safe and infectious dose of wild-type influenza virus in healthy participants, suitable for future intervention studies that: • Has an acceptable safety profile as measured by: Occurrence of adverse events (AEs) related to the viral challenge Occurrence of serious AEs (SAEs) related to the viral challenge Induces laboratory-confirmed infection in ≥40% of inoculated participants (ideally between 50% and 80%).

    Time frame: Day 0 to Day 28

07

Study locations

1 site
  • hVIVO Services Ltd
    London, United Kingdom
08

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Sep 2022 to primary completion in Dec 2022, 3 months.

Of 166 interventional studies with no phase under Influenza, Human, half reached primary completion within 6 months of starting (the median), counting those still running; a quarter within 3 and three quarters within 16. This study's 3 months is below that.

How these figures are worked out, and which studies are left out of them.

Registered
Oct 5, 2022
First posted
Oct 7, 2022
StartActual
Sep 7, 2022
Primary completionActual
Dec 19, 2022
CompletionActual
Dec 19, 2022
Last update
Sep 13, 2023
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Sep 13, 2023, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT05572450
Lead sponsor
Hvivo
Collaborators
Pfizer
Responsible party
Sponsor
First posted
Oct 7, 2022
Start date
Sep 7, 2022
Primary completion
Dec 19, 2022
Completion
Dec 19, 2022
Last update
Sep 13, 2023

Study contacts

Alex Mann
study director · hVIVO Services Ltd.

Oversight

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

Not currently enrolling

This study is completed, as verified in Sep 2023. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion