This is a open label, randomized phase VI study, to assess the safety and immunogenicity of co-administration of Hepatitis E vaccine with Hepatitis B vaccine. The concomitant group (n =300) received Hepatitis B vaccine concomitantly with Hepatitis E vaccine at day 1 and months 1 and 6; The nonconcomitant group (n =150) received Hepatitis E vaccine at at day 1 and months 1 and 6. Another nonconcomitant group (n=150) received Hepatitis B vaccine at at day 1 and months 1 and 6.

Anti-HEV IgG and HBsAb were determined. Injection-site and systemic adverse events (AEs) were monitored for 30 days after any vaccination; serious AEs were monitored throughout the study.

Inclusion Criteria:

• Healthy people aged over 18 years old on the day of enrollment
• Negative in HBsAg,HBsAb and HBcAb.
• Judged as healthy and eligible for vaccination by the investigators through a selfreported medical history and some physical examinations.
• Able to understand this study information and willing to comply with all study requirements.
• Willing to participate in this study and sign informed consent form.

Exclusion Criteria:

• Pregnant or breastfeeding or planning on getting pregnant in the future 7 months
• Use of any investigational product or non-registered product (drug or vaccine)within 30 days preceding the first dose of the study vaccine or plan to use during the study period
• Received immunosuppressed, immunoregulation therapy or corticosteroid systemic therapy for more than 14 days in the 6 months before entry, exceptlocal treatment.
• Administration of any immunoglobulin or blood products within 3 months preceding the first dose of the study vaccine,or plan to use during the study period.
• Administration of any inactivated vaccines within 14 days preceding the first dose of the study or attenuated live vaccines within 21 days preceding the first dose of the study.
• Had a fever (axillary temperature over 38°C) within 3 days or acute illness requiring systemic antibiotics or antiviral treatment within 5 days before vaccination.
• Plan to participate in any other clinical trial during the study period
• Administration of HEV vaccine before the study.
• Immunodeficiency (such as HIV carriers), primary disease of important organs, malignant tumor,or any immune disease (such as systemic lupus erythematosus, arthritis pauperum, splenectomy or functional asplenia or other disease which might affect immune response).
• History of allergic disease or history of serious adverse events occurring after vaccination, i.e., allergy,urticaria, dyspnea, angioneurotic edema or abdominal pain.