The purpose of this study is to evaluate the immunogenicity and safety of an investigational 23-valent pneumococcal polysaccharide vaccine (PPV) in healthy children, adults and elderly. The control vaccine is a commercialized 23-valent PPV.

This study is a randomized, double-blind, single-center, controlled phase III clinical trial. The purpose of this study is to evaluate the immunogenicity and safety of an investigational 23-valent pneumococcal polysaccharide vaccine (PPV) manufactured by Sinovac Biotech Co., Ltd. The primary objective of this study is to demonstrate that the immunogenicity of the investigational vaccine is non-inferior to that of a commercialized 23-valent PPV manufactured by Chengdu Institute of Biological products Co., Ltd.; the secondary objective is to assess the safety of the investigational and control vaccines. Participants will be grouped into three cohorts by age: child cohort (2 - 17 years old), adult cohort (18 - 60 years old) and elderly cohort (≥ 61 years old). In each cohort, the participants will be randomly assigned into experimental group or control group in the ratio 1:1.

Inclusion Criteria:

• Healthy volunteer ≥ 2 years old;
• Proven legal identity;
• Written consent of the guardian of participants < 18 years old, and written consent of the participant ≥ 12 years old;
• Complying with the requirement of the study protocol;

Exclusion Criteria:

• Prior vaccination with pneumococcal vaccine;

• History of bacterial pneumonia within 3 years prior to this study;

• Pregnant, breast feeding, or women expected to conceive within 60 days after vaccination;

• History of allergy to any vaccine or vaccine ingredient;

• Receipt of any of the following products:

  1. Blood product within 3 months prior to study entry;
  2. Any live attenuated vaccine within 28 days prior to study entry;
  3. Any subunit vaccine or inactivated vaccine within 14 days prior to study entry;
  4. Any immunosuppressant within 6 month prior to study entry;

• Congenital malformation, developmental disorders, serious chronic diseases, autoimmune disease, immunodeficiency, serious cardiovascular disease, diabetes, hypertension that cannot be stabilized by medication, liver or kidney disease, or malignant tumor;

• History of asthma, thyroidectomy, angioneurotic edema, severe nervous system disease or mental illness; without spleen or splenectomy; diagnosed coagulation function abnormal (e.g., coagulation factor deficiency, coagulation disorder, or platelet abnormalities), or obvious bruising or coagulation disorders;

• Acute disease or acute stage of chronic disease within 7 days prior to study entry;

• Axillaty temperature > 37.0 °C;

• Any other factor that in the opinion of the investigator suggesting the volunteer is unsuitable for this study;

• Participants with the following conditions from day 0 - 28 would be included in the full analysis set (FAS), but would be excluded from the per protocol set (PPS):

  1. Receipt of any other investigational or unregistered product (drug or vaccine);
  2. Receipt of immunosuppressant (corticosteroid dosage that equivalent to or above 0.5 mg prednisone/kg weight/day) for > 14 days, except for inhalant or locally administrated corticosteroid;
  3. Receipt of immunoglobulin and/or blood product;
  4. Newly diagnosed autoimmune disease or immunodeficiency (e.g., HIV infection);