The research objective is to evaluate lot-to-lot consistency and immune persistence of three commercial batches of 23 valent pneumococcal polysaccharide vaccine.

This study adopted a randomized, double-blind, equivalency design with different batches of experimental vaccine. 990 individuals aged 18-59 were included and divided into three groups at a ratio of 1:1:1, with 330 individuals in each group receiving three batches of experimental vaccines, respectively. All subjects were vaccinated with 1 dose of 0.5ml, intramuscularly injected into the lateral deltoid muscle of the upper arm.

Inclusion Criteria:

• Healthy volunteers aged 18-59;
• Voluntarily participate and sign an informed consent form;
• Subjects are able to comply with the requirements of the clinical study protocol and complete the prescribed follow-up;
• Has not received pneumococcal vaccine or any other preventive products recently (has not received attenuated live vaccine within 14 days, has not received inactivated vaccine within 7 days);
• Underarm temperature ≤ 37.0 ℃;
• Female participants of childbearing age agree to take effective contraceptive measures within 3 months from the start of the study until the full vaccination period.

Exclusion Criteria:

• Subjects with a history or family history of progressive neurological disorders such as epilepsy, encephalopathy, and mental illness;
• Has a history of severe allergies to any drugs or vaccines in the past;
• Has a allergy history to any component of the experimental vaccine (the main components of the vaccine include type 23 pneumococcal polysaccharides, sodium chloride, sodium dihydrogen phosphate, and sodium dihydrogen phosphate);
• Suffering from severe cardiovascular diseases (heart disease, pulmonary heart disease, pulmonary edema, drug-resistant hypertension (systolic blood pressure ≥ 160mmHg and/or diastolic blood pressure ≥ 100mmHg)); drug-resistant diabetes;
• Subjects with a history of thrombocytopenia or other coagulation disorders that may cause contraindications for subcutaneous injection;
• Subjects with known immunological dysfunction or low levels, or HIV infection;
• Any situation leading to splenomegaly, splenectomy, or functional splenomegaly;
• Malignant tumors, active or treated tumors that have not been clearly cured, or are likely to recur during the study period;
• Anti tuberculosis prevention or treatment is under way;
• Subjects who are participating in or planning to participate in clinical trials of other drugs or vaccine clinical trials throughout the entire observation period;
• Women of childbearing age are in pregnancy (positive urine pregnancy test) or lactation period;
• Any situation that the researcher believes may affect the evaluation of the study.