This study is aims to evaluate the safety, reactogenicity and immunogenicity of EV71 vaccine at a 0.25ml or 0.5ml dose in health volunteers

This is a phase I, prospective, randomized, open-label, two-center study. A total 60 healthy volunteers will be screened for baseline characteristic inclusion/exclusion criteria after providing a written informed consent. Eligible subjects will be recruited and equally randomized to either receive 2 doses of EV71 vaccine 0.25ml or 0.5ml. All subjects should be followed till Day 210.

Inclusion Criteria:

• Subject who is free of obvious health problems
• Able and willing to comply with the study procedure adn give written informed consent

Exclusion Criteria:

• Female who is pregnant/lactating or planning to be pregnant
• Body mass index(BMI) > 35
• Oral temperature > 37.5 Celsius at the time of planned vaccination
• Subject with any abnormal laboratory results at screening
• With a history of herpangina, hand-foot-mouth disease, acute hemorrhagic conjunctivitis or acute gastrointestinal illness associated with enterovirus infection in the past 3 months
• Has been diagnosed with neurological, pulmonary, cardiovascular, hematological, hepatic or renal disorder
• With a history of hypersensitivity to vaccine or allergic disease
• Use of any investigational/non-registered product within 30 days prior to vaccination
• Use of immunoglobulins or any blood products within 3 months prior to vaccination
• Chronic administration of immunosuppressants or other immunomodulators within 5 months prior to vaccination