The purpose of this first time in humans trial is to evaluate the safety, reactogenicity and immunogenicity of repeated administrations of AVX70371 in healthy participants.

Inclusion Criteria:

• Male or female assigned at birth, inclusive of all gender identities
• Between, and including, 18 and 40 years of age on the day of the Screening Visit
• Healthy individual, as established by the Investigator
• Able to read and understand the informed consent form, and written informed consent obtained from the participant
• Participants who, in the opinion of the Investigator, can and will comply with the requirements of the protocol

Exclusion Criteria:

• Body Mass Index < 18.0 or > 32.0 kg/m2
• Use of any investigational or non-registered product other than the study vaccination within 1 month preceding study entry, or concurrent participation in another clinical study in which the participant has been or will be exposed to an investigational or non-registered product, at any time during the study period
• Administration / planned administration of any vaccine not foreseen by the study protocol within 1 month preceding the first study vaccination and up to 1 month after the last study vaccination
• Presence of serologic marker of acute, chronic or past HBV infection
• Chronic administration of immunosuppressants or other immune-modifying drugs within 6 months preceding first study vaccination, or planned chronic administration at any time during the study period
• Administration of long-acting immune-modifying drugs within 6 months or 5 half-lives (whichever is longer) preceding first study vaccination, or planned administration at any time during the study period
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history, family history or physical examination
• Administration of immunoglobulins and / or any blood or blood-derived products within 3 months preceding the first study vaccination, or planned administration during the study period
• History of or current autoimmune disease
• Malignancies or lymphoproliferative disorders within previous 5 years
• Personal or family history of thymic pathology
• History of any neurological disorders or seizures
• History of any reaction or hypersensitivity likely to be exacerbated by any component of the investigational vaccine
• Moderate or severe acute disease in the opinion of the Investigator, and / or fever, on Day 1
• Alcohol, prescription drug, or substance (ab)use that, in the opinion of the Investigator, might interfere with the study conduct and / or participant safety
• Pregnant or lactating woman
• Woman of childbearing potential who is not utilizing a highly effective birth control method for at least 1 month prior to the first study vaccination, or who is planning to discontinue highly effective contraception prior to 2 months following the last study vaccination
• Employed by the Sponsor, by the contract research organisations working on behalf of the Sponsor, by the Investigator or the study site, or close relatives of research staff working on this study
• Medical condition or use of medication(s) that can increase the risk of bleeding or haematoma
• Any other condition or finding that the Investigator judges may interfere with study procedures or study results, or renders the participant unsuitable for the study

Note: other protocol-defined inclusion / exclusion criteria may apply.