Adjuvanted and standard influenza vaccines: an evaluation of their immunogenicity in healthy younger adults (The ADJUSTIVE Study)

Status

Not yet recruiting

Phases

Phase 3

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12626000334303

Enrollment

Registered

2026-03-17

Start date

2026-06-30

Completion date

2026-11-30

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

This study is a randomised open-label trial of adminstering either Flucelvax (standard) and Fluad (adjuvanted) influenza vaccines. We will enrol healthy participants aged 18-49 years who did not receive any influenza vaccine in the 15 months preceding study entry and who would like to receive a 2026 influenza vaccine. We will randomise participants to receive either Flucelvax or Fluad Influenza vaccines and have blood, saliva and nasal fluid tests to follow their immune responses to the vaccines. Participants have study visits just prior to vaccination and on days 6, 28 and 180 post-vaccination. We are testing the idea that younger people who receive an adjuvanted influenza vaccine may have stronger immune reponses against a larger range of influenza virus strains

Interventions

Fluad (adjuvanted) influenza vaccine Participants will be randomised to receive either a Flucelvax or Fluad influenza vaccine at study entry, Fluad is adminstered as a 0.5ml single dose, as an intramuscular injection. The vaccine is administered by study medical staff.

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Prevention

Masking

Open (masking not used)

Eligibility

Sex/Gender

All

Age

18 Years to 50 Years

Healthy volunteers

Yes

Inclusion criteria

• Aged 18-50 years • Healthy with no significant immunosuppressive illnesses. These include but are not limited to: - cancer or treatment of cancer or organ transplantation - treatment of auto-immune or inflammatory conditions such as inflammatory arthritis or inflammatory bowel disease - use of corticosteroid, TNF inhibitor, interleukins, interferons, cyclosporine or other immunosuppressive medications - significant renal or liver disease • No previous significant adverse events to prior Influenza vaccines, according to the criteria below. Severe grading indicates the event prevented daily activity, temperature >40.0°C or >10.0 cm in diameter for redness and swelling at the site of injection - severe systemic events (fatigue, headache, fever, muscle or joint pain) - severe local events (pain at injection site, redness and swelling - any event requiring emergency department visit or hospitalisation • No prior anaphylaxis to any cause, including to prior Influenza vaccines • Willing and available to have blood, saliva and nasal fluid samples taken per the schedule of events • Willing to be randomly assigned to receive either Afluria Quad (standard) or Fluad (adjuvanted) influenza vaccine • Willing to provide a signed and dated informed consent form.

Exclusion criteria

• Receipt of any influenza vaccine in the 15 months preceding study entry • Pregnant or breastfeeding women and women planning to become pregnant • Receiving medication that might reduce immune responses. These include but are not limited to: - systemic corticosteroids - interleukins - interferons - cyclosporine - systemic chemotherapy

Outcome results