Different vaccine formulations for RSV or H5 flu in adults 18–49

A Phase 1, Randomized, Multi-center Study to Evaluate the Safety and Immunogenicity of Different Formulations of Vaccines Encoding the RSV Monovalent Antigen or the Flu H5 Antigen in Healthy Participants 18 to 49 Years of Age

Phase 1 Interventional Sanofi · NCT07516418

This trial will try several vaccine formulations that produce either the RSV antigen or the H5 flu antigen in healthy adults 18 to 49 to see if they are safe and trigger immune responses.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment570 (estimated)
Ages18 Years to 49 Years
SexAll
SponsorSanofi Industry-sponsored
Locations6 sites (Griffith, Queensland and 5 other locations)
Trial IDNCT07516418 on ClinicalTrials.gov

What this trial studies

This is a Phase 1, interventional trial enrolling healthy adults aged 18 to 49 to receive one of several investigational vaccine formulations encoding either an RSV monovalent antigen or the influenza H5 hemagglutinin antigen. Participants are assigned to arms across two stages and followed for approximately 6–7 months depending on their arm to monitor safety and immune responses. The study collects safety data and measures immunogenicity, primarily antibody responses, after vaccination. Multiple investigational product formulations are compared to identify tolerable formulations that elicit biologically meaningful immune signals.

Who should consider this trial

Good fit: Healthy adults aged 18 to 49 who are not pregnant or breastfeeding and who meet contraception requirements if of child-bearing potential are eligible.

Not a fit: People outside the 18–49 age range, pregnant or breastfeeding individuals, and those with conditions that interfere with study evaluations (including many immunocompromised patients) are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, the tested formulations could identify safe vaccine candidates that induce protective immune responses against RSV or H5 influenza in adults.

How similar studies have performed: Early-phase vaccine studies for RSV and H5 influenza have previously produced measurable immune responses in adults, but broadly protective, widely licensed vaccines for these targets remain limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Aged 18 to 49 years on the day of inclusion
* A female participant is eligible to participate if she is not pregnant or breastfeeding and of the following conditions applies:
* Is of NCBP (Non-Child-Bearing Potential). To be considered of NCBP, a female must be post-menopausal for at least 1 year, or surgically sterile. OR
* Is of CBP (Child-Bearing Potential) and uses an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 12 weeks after the last study intervention administration.

Exclusion Criteria:

• Any condition which, in the opinion of the Investigator, might interfere with the evaluation of the study objectives

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Where this trial is running

Griffith, Queensland and 5 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Respiratory Syncytial VirusInfluenza ARSVRSV InfectionRSV VaccineFluFlu InfectionFlu Vaccine
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.