A Clinical Trial of an Quadrivalent Inactivated Influenza Vaccine in Healthy Children Aged 6 to 35 Months

Inclusion criteria

• Healthy infants and young children aged 6-35 months, provide vaccination certificate and birth medical certificate.
• The subject or legal guardian can provide with informed consent and sign the informed consent form.
• The subjects or legal guardians are able to and willing to use a thermometer, a scale and fill in a diary card/contact card as required, and be able to comply with the requirements of the clinical trial protocol to complete clinical research.

Exclusion criteria

• st dose:

• Axillary temperature>37.0℃
• Participants aged 24-35 months, with abnormal blood routine, blood biochemical and urine routine indexes and judged by the researchers as having clinical significance.
• Influenza within the past 3 months (confirmed clinically, serologically or microbiological).
• Have previously received any influenza vaccine (registered or experimental) or planned to receive any influenza vaccine during the study.
• Allergy to any component of the study vaccine, history of allergic reaction to eating eggs or using gentamicin sulfate.
• History of severe allergies to any vaccines or drugs.
• Preterm (delivered before 37 weeks of gestation), low birth weight (birth weight <2500g) infants (only for volunteers aged 6 months to 12 months).
• Dystocia, suffocation rescue, nervous system damage history.
• Congenital malformations or developmental disorders affecting organ function, genetic defects, severe malnutrition, etc..
• Acute illness, severe chronic illness, or acute exacerbation of chronic illness on the day of vaccination.
• History of vaccination with the live attenuated vaccine within 14 days prior to vaccination and other vaccination within 7 days.
• Those receiving immune enhancement or inhibitor therapy within 3 months (continuous oral or infusion for more than 14 days).
• Have congenital or acquired immunodeficiency, HIV infection, lymphoma, leukemia, or other autoimmune diseases.
• History of asthma, unstable in the past two years requiring urgent treatment, hospitalization, intubation, oral or intravenous corticosteroids.
• Receive blood or blood-related products within 3 months.
• Have a medical history or family history of convulsion, epilepsy, encephalopathy and psychosis.
• History of coagulation abnormalities (eg, coagulation factor deficiency, coagulation disorder)
• Plan to relocate before the end of the study or to be away from home for an extended period of time during scheduled study visits
• Participating in or planning to participate in other clinical trials in the near future
• Abnormal laboratory test indicators, except for minor abnormalities that have no clinical significance as judged by the doctor.
• The investigator judges any situation that is inappropriate to participate in this clinical trial
• nd dose:

• Severe allergic reaction after the first dose of the vaccine.
• Serious adverse reactions causally related to the first dose of the vaccine.
• After the first vaccination, newly discovered or newly occurred do not meet the first-dose inclusion criteria or meet the first-dose exclusion criteria will be determined by the investigator whether to continue participating in the study.
• Other reasons for exclusion in the opinion of the investigator.