A Booster Dose of Inactivated Vaccine (Vero Cell) Against EV71 in Chinese Children

Inclusion criteria

• Had participated in the previous phase II trial and received at least 1 dose of EV71 vaccine.
• Healthy children as established by medical history and clinical examination
• The subjects' guardians are able to understand and sign the informed consent
• Subjects who can and will comply with the requirements of the protocol
• Subjects with temperature <=37.0°C on axillary setting

Exclusion criteria

• Had participated in the previous phase II trial and received placebo.
• Subject who has a medical history of EV71-associated disease with specific laboratory evidence
• <= 37 weeks gestation
• Subjects with a birth weight <2.5 kg
• Subject that has a medical history of any of the following: allergic history, or allergic to any ingredient of vaccine
• Family history of seizures or progressive neurological disease
• Family history of congenital or hereditary immunodeficiency
• Severe malnutrition or dysgenopathy
• Major congenital defects or serious chronic illness, including perinatal brain damage
• Autoimmune disease
• Bleeding disorder diagnosed by a doctor or significant bruising or bleeding difficulties with IM injections or blood draws
• Any acute infections in last 7 days
• Any prior administration of immunodepressant or corticosteroids in last 6month
• Any prior administration of blood products in last 3 month
• Any prior administration of other research medicines in last 1 month
• Any prior administration of attenuated live vaccine in last 14 days
• Any prior administration of subunit or inactivated vaccines in last 7 days, such as pneumococcal vaccine
• Under the anti-TB prevention or therapy
• Any condition that in the opinion of the investigator, may interfere with the evaluation of study objectives