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

1. Antibody double growth rate in 28-40 days after immunization;
2. Antibody GMC level in 28-40days after immunization;
3. Incidence of adverse reactions in 0-30days.

• 23-valent pneumococcal polysaccharide vaccine (Biological): The study group and the control group were injected with a dose of 23-valent pneumococcal polysaccharide vaccine. One month later, blood was collected and serum was separated.

Primary outcomes

• 2-fold growth rate of antibody [The blood collection time was 28-40 days after vaccination.]: The serum antibody level of pneumococci was determined by modified enzyme-linked immunosorbent assay. The double growth rate of serum antibody level was calculated.

Secondary outcomes

• Antibody GMC level [The blood collection time was 28-40 days after vaccination.]: The serum antibody level of pneumococci was determined by modified enzyme-linked immunosorbent assay.
• Incidence of adverse reactions [Within 30 days after vaccination.]: Adverse reactions were collected during the observation period.

Sex: All, ages: 60 Years to 65 Years, accepts healthy volunteers

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.

• Results publication: Qiu J, Li Z, Huang F, Huang Z, Liang X, Li J, Liao Y, Guo X, Sun X. Immunogenicity and safety study of 23-valent pneumococcal polysaccharide vaccine revaccination among elderly individuals aged 60-70 years in Shanghai, China. Front Immunol. 2025 Jul 17;16:1623611. doi: 10.3389/fimmu.2025.1623611. eCollection 2025. PMID 40746543

• Qianli Ma, Study director, Sichuan Center for Disease Control and Prevention