This study is a double-blind randomized controlled trial designed to establish the non-inferiority of Sci-B-Vac® compared to Engerix-B® in adults ≥ 18 years old and the superiority of Sci-B-Vac® compared to Engerix-B® in ≥ 45 years old.

This study is a double-blind randomized controlled trial designed to establish the non-inferiority of Sci-B-Vac® compared to Engerix-B® in adults ≥ 18 years old and the superiority of Sci-B-Vac® compared to Engerix-B® in adults ≥ 45 years old. Study subjects are randomized 1:1 to receive either a total of 3 injections of Sci-B-Vac® or 3 injections of Engerix-B® intra-muscularly (IM) on Days 0, 28, and 168.

Inclusion Criteria:

• Any gender.
• Age ≥ 18 years
• In stable health as determined by a physical examination and laboratory tests values. Common chronic conditions such as, but not limited to, type 2 diabetes, high blood pressure, Chronic Obstructive Pulmonary Disease (COPD) and asthma will be accepted if the condition is well controlled, as determined by the investigator, and not meeting the exclusion criteria. For subjects > 65 years old, Frailty Index ≤3
• If female, either is not of childbearing potential or is of childbearing potential and must agree to use an adequate birth control method during the screening period and until the end of her participation in the study
• Able and willing to give consent.

Exclusion Criteria:

• Previous vaccination with any Hep B vaccine (licensed or experimental).
• Treatment by immunosuppressant within 30 days of enrollment including but not limited to corticosteroids at a dose that is higher than an oral or injected physiological dose, or a prednisolone-equivalent dose > 20 mg /day (Inhaled and topical steroids are allowed).
• Known history of immunological function impairment
• Pregnancy or breastfeeding
• Immunization with attenuated vaccines (e.g. MMR) within 4 weeks prior to enrollment
• Immunization with inactivated vaccines (e.g. influenza) within 2 weeks prior to enrolment
• Has received blood products or immunoglobulin within 90 days of enrollment or is likely to require blood products during the study period
• Subject in another clinical trial with an investigational drug or a biologic within 30 days of enrollment
• Has received granulocyte-macrophage colony stimulating factor (G/GM-CSF) or erythropoietin (EPO) within 30 days of enrollment or likely to require GM-CSF or erythropoietin during the study period
• Any history of cancer requiring chemotherapy or radiation within 5 years of randomization or current disease.
• Any skin abnormality or tattoo that would limit post-vaccination injection site assessment
• History of allergic reactions or anaphylactic reaction to any vaccine component (Engerix-B® or Sci-B-Vac®)
• Unwilling, or unable in the opinion of the investigator, to comply with study requirements, including the use of an adequate birth control method
• Immediate family members of study center staff (parents, sibling, children)
• Current or past hepatitis B infection or prior vaccination as evidenced by HBV markers at screening
• Known hepatitis C infection or positive Hepatitis C serology at screening, unless treated and cured
• Known human immunodeficiency virus (HIV) infection or positive HIV serology at screening
• Renal impairment at screening
• Uncontrolled diabetes mellitus
• Uncontrolled hypertension
• Any laboratory test abnormality that would be considered of Grade 1 severity and is considered as clinically significant by the investigator. Grade 3 severity or above is exclusionary, regardless of clinical assessment.
• Diagnosis of advanced stage heart failure or Unstable Angina.