Clinical Trial of Quadrivalent Subunit Influenza Vaccine (Adjuvant) in Chinese Population Aged 65 Years and Older

A Randomized, Blinded, Controlled Phase I Clinical Trial to Evaluate the Safety of a Quadrivalent Subunit Influenza Vaccine (Adjuvant) in Adults Aged 65 Years and Older

The objective of this study was to evaluate the safety of quadrivalent subunit influenza vaccine (adjuvant) in people aged 65 years and older.

Inclusion Criteria:

• Age at enrollment is ≥65 years (including the 65th birthday).
• The participant voluntarily agrees to take part in the trial and has signed the informed consent form.
• The participant is able to comply with the trial follow-up schedule as required by the protocol (i.e., no plans for long-term absence or relocation from the study site).
• Medically stable: The participant may have underlying chronic conditions such as hypertension, diabetes, ischemic heart disease, or hypothyroidism, but symptoms/signs must be controlled. If the participant is on any medication, the dosage must have remained stable for at least three weeks prior to vaccination.

Exclusion Criteria:

• Axillary temperature >37.0°C.
• Confirmed influenza virus infection by laboratory test or self-test kit positive within the past 12 months.
• Received any influenza vaccine (licensed or investigational) within the past 12 months or plans to receive any influenza vaccine during the study.
• Known or suspected allergic to any component of the investigational vaccine.
• A history of severe allergic reactions to any vaccines or medications (for example, but not limited to: anaphylactic shock, allergic laryngeal edema, allergic purpura, thrombocytopenic purpura, local allergic necrotic reaction (Arthus reaction)).
• Congenital malformations or developmental disorders, and genetic defects or severe malnutrition.
• History of convulsions or seizures, epilepsy, psychiatric disorders, or relevant family history.
• Severe liver and kidney diseases, malignant tumors, various acute diseases, or being in the acute exacerbation stage of a chronic disease.
• Diagnosed with congenital or acquired immunodeficiency, HIV infection, lymphoma, leukemia, or other immune-mediated/autoimmune diseases.
• A history of asthma, unstable within the past two years requiring emergency treatment, hospitalization, intubation, or oral/intravenous corticosteroids.
• Individuals who have received immunostimulant or immunosuppressant therapy within the past 6 months (continuously administered orally or via drip infusion for more than 14 days).
• Suffering from severe cardiovascular diseases (e.g., heart disease, cor pulmonale, pulmonary edema).
• Blood pressure ≥150/100 mmHg despite medication control.
• History of live attenuated vaccine within 28 days prior to vaccination, or any other vaccine within 14 days prior to vaccination.
• Diagnosed with progressive neurological diseases, or a history of Guillain-Barré syndrome.
• Asplenia or functional asplenia, including splenectomy due to any reason, or resection/partial removal of other vital organs.
• Received blood or blood-derived products within the past 6 months.
• A diagnosed history of coagulation disorders (e.g., coagulation factor deficiencies, coagulopathies, platelet disorders).
• Currently undergoing anti-tuberculosis treatment.
• Clinically significant abnormalities in laboratory tests (blood biochemistry, blood routine and urine routine) as determined by the investigator.
• Any condition that, in the opinion of the investigator, makes the participant unsuitable for this clinical trial.