Inclusion Criteria:
1. Healthy infants or children who are aged 2 months (at least 6 weeks), 7-11 months, 12-23 months and 2-5 years (before the 6th birthday);
2. Participants' guardians provide legal identity document and participants' vaccination record;
3. Participants' guardians understand and voluntarily sign the informed consent form;
4. Participants' guardians can follow all study procedures and stay in contact during the study.
Exclusion Criteria:
1. Received any pneumococcal vaccine prior to enrollment;
2. History of bacterial pneumonia or invasive pneumococcal diseases (IPDs) caused by Streptococcus pneumoniae, as confirmed by laboratory tests;
3. History of allergy or adverse reactions to the vaccine or vaccine components, or history of allergy, such as urticaria, dyspnea, angioedema and abdominal pain;
4. History of dystocia, asphyxia rescue and nervous system damage at birth for infants under 2 years of age;
5. Congenital malformations or developmental disorders, genetic defects, severe malnutrition, history of asthma;
6. Autoimmune diseases (such as systemic lupus erythematosus), immunodeficiency diseases or immunosuppressive diseases (such as AIDS, organ transplantation);
7. Severe cardiovascular diseases, diabetes, liver diseases, kidney diseases, malignant tumours.
8. Have/have suffered from a serious neurological disorder (epilepsy or convulsions) or mental illness or have a family history of such diseases.
9. History of thyroidectomy, asplenia, functional asplenia; asplenia or splenectomy caused by any reasons;
10. Diagnosed abnormal blood coagulation function (eg, lack of blood coagulation factors, blood coagulopathy, abnormal platelets level), history of obvious bleeding, hematoma or bruising after intramuscular injection or venipuncture.
11. Consecutively received ≥14 days of corticosteroid, any other immunosuppressive therapy (excluding corticosteroid spray therapy for allergic rhinitis and surface corticosteroid therapy for acute non-concurrent dermatitis), or cytotoxic therapy prior to enrollment for infants aged 6 weeks to 2 months or within 6 months prior to enrollment for children aged 7 months to 5 years.
12. Received blood products prior to enrollment for children aged 2 months or within 3 months prior to enrollment for children aged 7 months to 5 years. Receipt of Hepatitis B immunoglobulin one month prior to enrollment is an exception.
13. Received other investigational drugs within 60 days prior to enrollment, or plan to receive such drugs during the study;
14. Received live attenuated vaccine within 14 days prior to enrollment;
15. Received subunit or inactivated or other vaccine within 7 days prior to enrollment;
16. Acute diseases or acute onset of chronic diseases within 7 days prior to enrollment;
17. Had fever (axillary temperature≥ 37.3 Degree Celsius) before vaccination;
18. In the investigator's judgment, the participant has any other factors that make him or her unfit to participate in the clinical trial.
