immunity and safety of inactivated enterovirus 71 vaccine post-marketing among children aged 6-35 months in china

Conditions: Hand, Foot and Mouth Disease

Summary: this study evaluates three batches consistency, immunity duration and safety of inactivated enterovirus 71(ev-a71) vaccine(vero cell) post-marketing among children aged 6-35months in china.3000 subjects will be recruited in this study, of who 1500 subjects will be randomly assigned in a ratio of 1:1:1 to receive one of the three batches of ev-a71 vaccines manufactured by 40l capacity reactor, other 1500 subjects will be randomly assigned in a ratio of 1:1:1 to receive one of the three batches of ev-a71 vaccines manufactured by 150l capacity reactor. vaccine wil be administrated according to a two doses of schedule given at day 0 and 28. sample will be collected at day 0, day 56 and at month 13 after vaccinaiton.


Eligibility criteria:
inclusion criteria: * healthy children aged 6-35 months * subjects who have been clinically judged to be healthy by the researcher after being asked about the medical history and related physical examination * the subjects' guardians agree the requirements of the protocol and the relevant follow up visits * the subjects' guardians agree and sign the informed consent * subjects who have no relocation or long-term travel plan within one year and are able to comply with the requirements of the clinical trial protocol. exclusion criteria: * subject who has a medical history of hfmd caused by ev71 or has been vaccinated with ev71 vaccine * subject that has a history of allergies to vaccines or vaccine ingredients, and has serious side effects on vaccines, such as allergies, urticaria, dyspnea, vascular neuroedema or abdominal pain * subject who has congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc. * subject who has a history of epilepsy, convulsion or convulsion, or a family history of mental illness * subject who has autoimmune disease or immune deficiency, or whose parents and siblings have autoimmune disease or immune deficiency * subject who has a history of asthma, vascular and neuroedema, diabetes or malignant tumor * subject who has a thyroid resection history, or received treatment due to thyroid disease in the past 12 months * subject who has an abnormal coagulation function (such as coagulation factor deficiency, coagulant disease, platelet abnormality) or obvious bruising or clotting disorder which was diagnosed by doctors. * asplenia, functional asplenia, or splenectomy due to any circumstances * acute onset of various acute or chronic diseases in the last 7 days * immunosuppressant therapy, antiallergic therapy, cytotoxicity therapy, inhaled corticosteroids (excluding corticosteroid spray therapy for allergic rhinitis, surface corticosteroid therapy for acute non-dermatitis) in the past 6 months * any prior administration of blood products in last 3 months * any prior administration of other research medicines or vaccines in last 1 month * any prior administration of attenuated live vaccine in last 15 days * any prior administration of subunit or inactivated vaccines in last 7 days * under the anti-tb prevention or therapy * underarm temperature \> 37.0 ℃ for fever before vaccination * other factors that are not suitable for clinical trials according to the judgment of researchers exclusion criteria for the second dose: * have severe allergic reaction after first dose * have severe adverse reactions related to first dose * any situation meet the exclusion criteria stated in the exclusion criteria for first dose * acute infection or illness * other factors that are not suitable for clinical trials according to the judgment of researchers