This is a randomized, blinded, controlled phase I clinical trial with a total of 120 participants aged ≥ 60 years. Experimental group: Influenza virus split vaccine (0.7mL/vial), control group 1: Influenza virus split vaccine, control group 2: placebo group. The three groups were recruited at a ratio of 1:1:1, and 40 individuals were randomly vaccinated in each group. Each person was injected with one dose of the vaccine into the deltoid muscle of the upper arm. Participants in each study group are required to undergo laboratory indicator tests before and on the 4th day after vaccination.

Inclusion Criteria:

• Age over 60 years old, gender not limited, and able to provide legal identification;
• Volunteers voluntarily participate in the study and sign an informed consent form;
• Volunteers have the ability to understand research procedures, use thermometers, scales, and fill out diary cards as required, and can participate in all planned follow-up visits.

Exclusion Criteria:

• On the day of enrollment, the axillary temperature was ≥ 37.3 ℃;
• Those who have had influenza in the past 6 months or meet the definition of influenza like cases;
• Have received any influenza vaccine within the past 12 months or have planned to receive any influenza vaccine during the study period;
• Allergies to any components of the research vaccine, history of allergic reactions to the use of gentamicin sulfate, history of severe allergies to any vaccine/drug, or history of asthma;
• Suffering from a serious illness that prevents the completion of the entire study; Within 3 days prior to vaccination, there is an acute illness or an acute exacerbation of a chronic disease;
• Have used antipyretic or analgesic drugs or anti allergic drugs within 3 days before vaccination;
• Have received any vaccine within 2 weeks prior to vaccination;
• Have received immunosuppressive therapy or other immunomodulatory drugs within 6 months prior to receiving the experimental vaccine, For example, immunosuppressive doses of glucocorticoids, monoclonal antibodies, thymosin, interferon, etc., or planned to receive such treatment within one month after the first dose of vaccination to full immunization, but local medication is allowed;
• Suffering from congenital or acquired immunodeficiency, human immunodeficiency virus (HIV) infection, lymphoma, leukemia, or other autoimmune diseases;
• Suffering from serious chronic diseases, serious cardiovascular diseases, such as hypertension that cannot be controlled by drugs, diabetes that cannot be controlled by drugs or has serious complications, liver and kidney diseases, pulmonary edema, malignant tumors, etc;
• Have received blood or blood related products within the past 6 months;
• Individuals with progressive neurological disorders, including a history of seizures, epilepsy, encephalopathy, Guillain Barr é syndrome, psychiatric or family history;
• Have a history of abnormal coagulation function and have been using anticoagulants within 3 weeks before vaccination;
• Patients with splenectomy, functional splenectomy, splenectomy, or other important organ resection or partial resection;
• Plan to move before the end of the study or leave the local area for a long time during the scheduled study visit;
• Currently or recently planning to participate in other clinical trials;
• Abnormal laboratory test indicators before vaccination;
• Researchers determine any situation that is not suitable for clinical trials.