Phase I/II Clinical Trial of 26-valent Pneumococcal Conjugate Vaccine

Inclusion Criteria: * The subject is 2-3 months old (minimum 6 weeks old), 7 months old and above at the time of enrollment, and the legal guardian and/or the subject can provide legal identification certificate; * The subjects themselves and/or their legal guardians understand the vaccination and trial procedures, voluntarily participate in the trial and sign the informed consent form; * The subject and/or legal guardian can comply with the clinical trial protocol, have the ability to use thermometer, scale and fill in diary card and contact card as required; * Female subjects of childbearing potential agree to take effective contraceptive measures from enrollment to 6 months after vaccination. * For calibration group subjects: 18 to 55 years of age, ≥ 50 kg for males or ≥ 45 kg for females. Exclusion Criteria: * Axillary body temperature ≥ 37.3 ℃ on the day of enrollment; * History of infectious diseases caused by Streptococcus pneumoniae confirmed by bacterial culture within 3 years; * Have received or plan to receive a Streptococcus pneumoniae vaccine outside the trial protocol, including marketed or other investigational Streptococcus pneumoniae vaccines; * Pregnant or lactating women; Previous history of severe allergy to any vaccine or drug, such as urticaria, dyspnea, angioneurotic edema, anaphylactic shock, Henoch-Schonlein purpura, thrombocytopenic purpura; * Allergic to any component of the investigational vaccine; * Suffering from severe respiratory diseases (such as severe asthma), heart diseases, liver diseases, kidney diseases, congenital malformations, developmental disorders and genetic defects (including but not limited to: down syndrome, thalassemia major, etc.) that may interfere with the conduct or completion of the trial; * Diagnosed with congenital or acquired immunodeficiency, or suspected to have serious chronic disease or systemic disease that may interfere with the conduct or completion of the trial, such as: active tuberculosis, human immunodeficiency virus (HIV) infection, etc.; * Encephalopathy, uncontrolled epilepsy, convulsion and other progressive neurological diseases, or a history or family history of mental illness; * Contraindications for intramuscular injection such as thrombocytopenia, any coagulation disorder or receiving anticoagulant therapy; * Asplenia or splenectomy, functional asplenia due to any condition; * Immunosuppressant therapy, cytotoxic therapy or corticosteroid therapy within 3 months prior to vaccination, such as systemic glucocorticoid therapy for more than 2 consecutive weeks, such as prednisone or similar drugs \> 5 mg/day (excluding corticosteroid spray therapy for allergic rhinitis, surface corticosteroid therapy for acute non-complicated dermatitis); * Received blood products or immunoglobulins within 3 months prior to enrollment (hepatitis B immunoglobulin is acceptable), or planned to be used during the trial (before the last immunogenicity blood sample collection); * Within 3 days before the first dose of vaccine, the patient has acute illness or is in acute attack of chronic disease, or has used antipyretic, analgesic or anti-allergic drugs (such as: acetaminophen, ibuprofen, aspirin, etc.); * Received non-live vaccine within 7 days (≤ 7 days) or live attenuated vaccine within 14 days (≤ 14 days) prior to enrollment; * Hypertension (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg, applicable to adults); * Abnormal and clinically significant laboratory test results, which are not suitable for enrollment as determined by the investigator (applicable to subjects aged 2 years and older in Phase I); * Birth weight \< 2.5 kg, premature delivery (gestational age \< 37 weeks), history of abnormal labor process, history of asphyxia rescue, history of nerve organ damage, history of pathological jaundice confirmed by diagnosis; * For Standardised Subjects: ① Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≥ 50 U/L; Or hemoglobin ≤ 115 g/L (female)/120g/L (male); Any positive serology for hepatitis B, hepatitis C, HIV, or syphilis. * Plans to move before the end of the trial or leave the area for an extended period of time during scheduled trial visits; * Ongoing participation or planning to participate in other clinical trials (vaccines, drugs, medical devices, etc.) in the near future; * Subject has any condition that, in the opinion of the investigator, may interfere with the evaluation of the objectives of the trial.