This phase IV clinical study evaluates the safety of enterovirus 71 vaccine in children aged 6-35 months old by the method of both passive and active surveillance.

Inclusion Criteria:

• Infant and toddlers aged 6 and 35 months, meeting the criteria of receiving vaccine based on the judgement of caregivers at vaccination clinic. And The legal guardian are willing to vaccination at his own expense.

Exclusion Criteria:

• History of allergy to any vaccine ingredient or gentamycin;
• Fever, or acute disease, or acute stage of chronic disease;
• Having serious chronic diseases, or allergic constitution;
• Refusal of follow-up for safety concern.