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A Study to Evaluate Safety and Immunogenicity of One or Two Booster Vaccinations With H5N6 Influenza Vaccine in Adults Primed With H5N1 Influenza Vaccine or Unprimed

NCT05422326 · Status: COMPLETED · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 260

Last updated 2026-05-13

Study results available
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Summary

This is a Phase 2, randomized, multi-center study in approximately 300 adults who received 2 doses of aH5N1c or placebo in and completed the parent study V89\_18 in the \<65 years of age cohort. The study investigates whether two priming doses of MF59-adjuvanted H5N1 cell culture-derived vaccine (aH5N1c) followed by one or two booster vaccinations with a MF59-adjuvanted H5N6 cell culture derived vaccine (aH5N6c) 3 weeks apart elicit immune responses to the antigens used for priming (H5N1) and boosting (H5N6) after first and second heterologous booster vaccination.

Eligible subjects, who received 2 doses of aH5N1c in the parent study V89\_18 are randomized in a 1:1 ratio to receive either two aH5N6c vaccinations, 3 weeks apart (group 1) or an aH5N6c vaccination on Day 1 and saline placebo on Day 22 (group 2). Eligible subjects, who received placebo in the parent study will receive two aH5N6c vaccinations, 3 weeks apart (group 3). After the second vaccine administration, subjects are monitored for approximately 6 months for safety and antibody persistence. The total study duration will be approximately 7 months per subject.

Conditions

  • Influenza, Human
  • Influenza in Birds
  • Respiratory Tract Infections
  • Infections
  • Orthomyxoviridae Infections
  • RNA Virus Infections
  • Virus Diseases
  • Respiratory Tract Diseases

Interventions

BIOLOGICAL

aH5N6c on Day 1

MF59-adjuvanted cell-culture derived subunit inactivated monovalent A/H5N6 vaccine (aH5N6c) for intramuscular (IM) administration, containing 7.5 μg H5N6 hemagglutinin (HA) (A/Guangdong/18SF020/2018 (H5N6)-like) + 0.25 mL MF59 (approximately 0.5 mL total volume)

BIOLOGICAL

aH5N6c on Day 22

MF59-adjuvanted cell-culture derived subunit inactivated monovalent A/H5N6 vaccine (aH5N6c) for intramuscular (IM) administration, containing 7.5 μg H5N6 HA (A/Guangdong/18SF020/2018 (H5N6)-like) + 0.25 mL MF59 (approximately 0.5 mL total volume) given 3 weeks after the first aH5N6c vaccination

BIOLOGICAL

Placebo on Day 22

Saline placebo (sterile, 0.5 mL) given 3 weeks after the aH5N6c vaccination

Sponsors & Collaborators

  • Seqirus

    lead INDUSTRY

Principal Investigators

  • Therapeutic Area Head · Seqirus

Study Design

Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2022-07-18
Primary Completion
2022-10-24
Completion
2023-03-24
FDA Drug
Yes

Countries

  • United States

Study Locations

More Related Trials

Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05422326 on ClinicalTrials.gov