Study of Different Formulations of Vaccines Encoding the RSV Monovalent Antigen or the Flu H5 Antigen in Participants 18 to 49 Years of Age

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

The purpose of this study is to evaluate the safety and immunogenicity of different formulations of vaccines encoding the RSV monovalent antigen or the Flu hemagglutinin subtype 5 (H5) antigen in healthy participants aged 18 to 49 years.

The total duration of study participation for each participant varies by stage and treatment arm.

Stage 1:

• For Arm 1, Arm 2, and Arm 3 the duration of study participation will be approximately 7 months for each participant.
• For Arm 4, Arm 5, and Arm 6 the duration of study participation will be approximately 6 months for each participant.

Stage 2: For all arms, the duration of study participation will be approximately 7 months for each participant.

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.