RecruitingPhase 4NCT07240922

The Dynamics of the Immune Responses to Repeat Influenza Vaccination Exposures (DRIVE III) Study

The Dynamics of the Immune Responses to Repeat Influenza Vaccination Exposures (DRIVE III) Study - a Randomized Controlled Trial


Sponsor

The University of Hong Kong

Enrollment

600 participants

Start Date

Oct 1, 2025

Study Type

INTERVENTIONAL

Conditions

Summary

This study will provide novel insight into the effects of repeat influenza vaccination with Flublok and FluMist on the strength and breadth of immune responses to influenza, the mechanisms underlying heterogeneity in vaccine response and vaccine failure, and biological factors that could explain variation in influenza vaccine effectiveness.


Eligibility

Min Age: 22 YearsMax Age: 50 Years

Inclusion Criteria4

  • Aged 22-50 years at enrolment.
  • A. Participated in the DRIVE I or DRIVE II studies (for DRIVE IIIa). OR B. Did not participate in the DRIVE I or DRIVE II study (for DRIVE IIIb) and has not received influenza vaccination in the prior two years.
  • Capable of providing informed consent.
  • Resident in Hong Kong in the coming 2 years.

Exclusion Criteria15

  • Included in one of the priority groups to receive influenza vaccination in Hong Kong (priority groups include pregnant women, long-stay residents of institutions for persons with disability, persons with chronic medical problems (chronic cardiovascular, lung, metabolic or kidney diseases, obesity (body mass index 30 or above) and chronic neurological condition ), healthcare workers or persons working in poultry, pig farming or pig slaughtering industry).
  • With diagnosed medical conditions related to their immune system.
  • Currently taking medication for any condition that impairs immune system.
  • Individuals who report medical conditions not suitable to receive inactivated influenza vaccines, such as:
  • Severe allergic reaction (e.g., anaphylaxis) after previous dose of any influenza vaccine; or to a vaccine component;
  • Moderate or severe acute illness with or without fever after any previous influenza vaccination; or
  • A history of Guillain-Barré syndrome (GBS) within 6 weeks of previous influenza vaccination.
  • Individuals who report medical conditions not suitable to receive live attenuated vaccines, such as:
  • having asthma;
  • having close contact with severely immunosuppressed persons who require a protected environment; or
  • having immunosuppressive treatment (e.g. high-dose steroid, anti-cancer drugs and radiotherapy).
  • Individuals who report medical conditions not suitable to receive intramuscular injection, such as
  • Bleeding disorders
  • Habitually taking anticoagulants (with the exception of antiplatelets such as aspirin).
  • Individuals who have any medical conditions not suitable to receive inactivated or live attenuated influenza vaccines as determined by a clinician.

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Interventions

BIOLOGICALLive attenuated influenza vaccine

0.2mL nasal spray live attenuated influenza vaccine (FluMist, AstraZeneca)

BIOLOGICALPlacebo nasal spray

0.2mL saline placebo nasal spray

BIOLOGICALrecombinant hemagglutinin influenza vaccine

0.5mL recombinant hemagglutinin influenza vaccine (Flublok, Sanofi)

BIOLOGICALPlacebo injection

0.5mL saline placebo injection


Locations(1)

School of Public Health, The University of Hong Kong

Hong Kong, Hong Kong

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NCT07240922


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