Phase III Clinical Trial of Quadrivalent Influenza Virus Split Vaccine

Inclusion Criteria: * Age Requirement: volunteers aged 3 years and above at the time of enrollment. * Provision of Legal Identification: Volunteers and their legal guardians or appointed representatives must provide valid legal identification documents. * Informed Consent: Volutters, legal guardians, or appointed representatives of volunteers must have the capacity to understand the informed consent document and the research process, voluntarily participate, sign the informed consent form, and be able to comply with the requirements in the study as well as complete relevant visits on time. * Requirements for contraception: agree to take contraception actions in 6 months. * Temperature Requirement: Axillary body temperature is less than 37.3°C. * Previous Vaccination Requirements: (a) Received at least 1 dose of influenza vaccine within 1 year before screening in children aged 3-8 years; (b) Never received any influenza vaccine 1 year before screening in children aged over 3 years. Exclusion Criteria: Subjects meeting any of the following exclusion criteria will be not eligible for enrollment. * Subjects with a history of severe allergy to egg or egg protein, such as those who have had symptoms such as angioedema, dyspnea, chest distress, or repeated vomiting due to eating eggs, and even those who have used epinephrine or other emergency medical treatment, especially those who have symptoms immediately or within a short period (minutes to hours). * Subjects with influenza …