A Clinical Trial to Evaluate the Immunogenicity and Safety of PPV23 Vaccine Revaccinations in the Elderly

Inclusion Criteria: 1.The age was 60-65 years old on the day of enrollment;2.The subjects have signed the informed consent and signed the date;3.The subjects are able to participate in all planned follow-up visits and were able to follow all trial procedures (e.g. complete diary card / contact card, return to visit);4.The subjects in the study group had been vaccinated with 23 valent pneumococcal polysaccharide vaccine made in China for more than 5 years; 5.The control group had never been vaccinated with any pneumococcal vaccine; 6.Axillary temperature ≤37.0℃. Exclusion Criteria: 1.With a medical history with hypersensitiveness, eclampsia, epilepsy, cerebropathia and neurological illness; 2.Allergic to any ingredient of vaccine or with allergy history to any vaccine; 3.Subjects with immunodeficency or suspected impairment of immunologic function (e.g. caused by HIV), or subjects are in the process of immunosuppressor therapy(Taking orally injecting of steroid hormone); 4.Administration of immunoglobulins within 30 days prior to this study; 5.Acute febrile disease(temperature ≥ 37.0°C) or infectious disease; 6.With a clearly diagnosed history of thrombocytopenia or other coagulopathy, may cause contraindications for subcutaneous injection; 7.With any serious chronic illness, acute infectious diseases, or respiratory diseases; 8.Suffering from serious cardiovascular diseases (pulmonary heart disease, pulmonary edema, hypertension can not be controlled to normal by drugs), liver and kidney diseases, diabetes with complications;9.With any kind of infectious, purulent, or allergic skin diseases; 10.With any other factor that makes the investigator determines the subject is unsuitable for this study.