A Phase III Clinical Trial of Quadrivalent Influenza Vaccine in Healthy Subjects Aged 6 to 35 Months

Inclusion Criteria:

• Healthy infants aged 6-35 months;

• Proven vaccination certificate and birth certificate;

• The subjects' guardians can understand and voluntarily sign the informed consentform.

Exclusion Criteria:

• Received any circulating seasonal influenza vaccine prior to enrollment or had aninfluenza vaccine schedule during the study;

• Suffering from seasonal influenza in the past 6 moths;

• Axillary temperature >37.0°C;

• History of allergy to the vaccine or vaccine components, or serious adversereactions to the vaccine, such as urticaria, dyspnea, angioedema and asthma;

• Congenital malformations or developmental disorders, genetic defects, severemalnutrition, etc.;

• Severe chronic diseases(Such as down syndrome, diabetes, sickle cell anaemia orneurological disorders);

• Severe neurological disease (epilepsy, convulsions or convulsions) or mentalillness;

• Autoimmune disease (such as systemic lupus erythematosus) or immunodeficiency /immunosuppression (such as HIV, after organ transplantation)

• Thyroid disease or history of thyroidectomy, asplenia,functional asplenia, aspleniaor splenectomy resulting from any condition;

• Diagnosed abnormal blood coagulation function (eg, lack of blood coagulationfactors, blood coagulopathy, abnormal platelets) or obvious bruising or bloodcoagulation;

• Continuous use of corticosteroids or other immunosuppressive agents for ≥ 14 dayswithin the past 6 months (excluding allergic rhinitis corticosteroid spray therapy,acute noncomplicated dermatitis superficial corticosteroid therapy) and cytotoxictherapy in the past 6 months;

• Acute diseases or acute exacerbation of chronic diseases in the past 3 days;

• Receipt of blood products within in the past 3 months;

• Receipt of other investigational drugs in the past 30 days;

• Receipt of attenuated live vaccines in the past 14 days;

• Receipt of inactivated or subunit vaccines in the past 7 days;

• Participated in other clinical trials before enrollment and in the follow-up period,or plans to participate in other clinical trials during the clinical trial;

• According to the investigator's judgment, the subject has any other factors that arenot suitable for participating in the clinical trial