Comparing immune responses to influenza vaccination and infection in healthy adults

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This experimental study investigates the immune responses of healthy adult volunteers aged 18-40 years to influenza vaccination and infection. Participants will receive a live-attenuated influenza vaccine via nasal spray and will also be exposed to an influenza A (H3N2) viral challenge. The study aims to assess how these two methods of exposure affect immune responses in both the upper and lower respiratory tracts. The findings could provide insights into the effectiveness of vaccination versus natural infection in generating mucosal immunity.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Adults aged between 18-55 years inclusive
* Sero-suitable as defined by a serum micro-neutralisation titre \<1:20
* Female participant who is not of child-bearing potential as assessed by an investigator OR is willing and able to use contraception as described in the protocol
* Male participants who are willing to use one of the contraception methods described in the protocol
* In good health with no clinically significant medical conditions

Exclusion Criteria

* History of clinically significant/currently active conditions;

  * Cardiovascular, thromboembolic/cerebrovascular disease.
  * Types of chronic respiratory disease in adulthood.
  * Significant wheeze in the past
  * Respiratory symptoms including wheeze, resulting in hospitalisation
  * Known bronchial hyperactivity to viruses
  * Diabetes mellitus
  * Migraine with associated symptoms like hemiplegia/vision loss. Cluster headache/migraine/prophylactic treatment for migraine.
  * History of autoimmune disease/known immunodeficiency of any cause
  * Immunosuppression.
  * Known coagulation disorder/anticoagulant therapy
  * Psychiatric illness including participants with a history of depression and/or anxiety with associated psychiatric comorbidities
  * Other major disease that, under the PI's discretion, could interfere with the participant completing the study.
* Concurrent serious illness including history of malignancy that could interfere with the study or a participant completing the study.
* Known IgA deficiency/immotile cilia syndrome/Kartagener's syndrome
* Significant abnormality altering the anatomy/function of the nose or nasopharynx, a clinically significant history of epistaxis within the last 3 months, nasal/sinus surgery within 6 months of Day 0, including nasopharyngeal malignancy, arterio-venous malformation, or undiagnosed nasopharyngeal mass
* Inhaled bronchodilator/inhaled steroid use within the last 12 months before Day 0
* Acute upper respiratory tract infection in the past 6 weeks.
* Receipt of systemic glucocorticoids (in a dose ≥ 5 mg prednisone daily or equivalent) within one month, or any other cytotoxic or immunosuppressive drug within 6 months before Day 0
* Receipt of any vaccine within 30 days of Day -14
* Any significant medical condition/prescribed drug, under the PI's discretion
* Presence of cold-like symptoms and/or fever on Day -14 or Day 0.
* Receipt of blood/blood products/loss (including blood donations) of 550 mL or more of blood during the 3 months prior to Day -14.
* Significant history/presence of drug/alcohol misuse by self-report.
* Current use of drugs through nose inhalation or inhaled route including recreational drugs.
* Regular smoking and/or vaping and/or using nicotine-containing products in the past 3 months OR \>5 pack-year lifetime history by self-report (5 pack years is equivalent to one pack of 20 cigarettes per day for 5 years).
* History of anaphylaxis and/or a history of severe allergic reaction or significant intolerance to any food/drug, as assessed by the PI.
* Clinically active rhinitis (including hay fever)/history of moderate to severe rhinitis/history of seasonal allergic rhinitis likely to be active at the time of inclusion into the study and/or requiring regular nasal corticosteroids on an at least weekly basis, within 30 days of enrolment.
* Anyone with any of the following contraindications to receiving the Fluenz Tetra Vaccine:

  * Allergy to gentamicin, gelatin or the other ingredients of the fluenz vaccine.

Where it's running

• Imperial Clinical Research Facility, Imperial College Healthcare NHS Trust
  London, United Kingdom Recruiting

Study contacts

• Principal investigator: Christopher Chiu — Imperial College London
• Study coordinator: Polly Fox, MSc
• Email: polly.fox@imperial.ac.uk
• Phone: 0208383 3231

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• High-dose vs standard-dose flu vaccine in adults with blood cancers on B-cell-depleting therapy

  This study tests whether a high-dose flu shot evokes a stronger immune response than a standard-dose shot in adults with hematologic cancers who recently had B-cell-depleting therapy.

  Recruiting Phase 2 Asan Medical Center · Seoul · NCT07926217

• Abbott ID NOW at the point of care for flu-like illness in long-term care facilities

  This trial tests whether the Abbott ID NOW rapid test at the point of care in long-term care facilities can help identify influenza sooner for residents 65 and older with fever and respiratory symptoms.

  Recruiting China Medical University Hospital · Taichung · NCT07846423

• Egg-based H5N8 influenza vaccine at multiple doses with or without adjuvant in healthy adults

  This trial tests whether an egg-based H5N8 flu vaccine, given at low to high doses with or without an adjuvant, is safe and can provoke a stronger immune response in healthy adults 18 and older.

  Recruiting at 16 sites Phase 1/2 Sanofi · Tempe, Arizona and 15 other locations · NCT07779408

• Safety and PK of Ingavirin Forte vs Ingavirin in healthy adults under fasting and fed conditions

  This early-phase study tests whether Ingavirin Forte (90 mg + 20 mg) is safe and how it behaves in the body compared with Ingavirin (90 mg) in healthy adults aged 18–45, under different meal conditions.

  Recruiting Phase 1 Valenta Pharm JSC · Saint Petersburg · NCT07645534

• Light-based immune boost to help prevent viral upper respiratory infections

  A daily handheld light therapy device is tested to see if it can lower how often adults at a military medical facility get colds, flu, or other upper respiratory infections.

  Recruiting Mike O'Callaghan Military Hospital · Nellis Air Force Base, Nevada · NCT07610967

• Virological Monitoring of Seasonal Respiratory Infections in France

  This project tests how often common respiratory viruses show up in patients seen by primary care doctors in metropolitan France during the fall and winter.

  Recruiting Institut National de la Santé Et de la Recherche Médicale, France · Paris · NCT07599449

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.