Evaluation of Safety and Immunogenicity of Combined Immunization of PPV23 and IIV4

To evaluate the safety and immunogenicity of simultaneously immunization of 23-valent pneumococcal polysaccharide vaccine (PPV23) and quadrivalent inactivated influenza vaccine (IIV4) , we design this randomized, parallel controlled study . 1224 subjects are divided into 3 groups, including 1 experimental group and 2 control groups (control group A and B), each group includes 408 subjects respectively. Each 408-subject group is divided again into 4 age-based subgroups: ① 3-8 years old; ② 9-18 years old; ③ 19-49 years old ; ④ over 50 years old; each subgroup includes 102 subjects respectively. 408 subjects from experimental group will be simultaneously administrated with one dose of IIV (0.5 ml) and one dose of PPV23 (0.5 ml). Blood samples are collected before vaccination and one month (30 days) later. 408 subjects from control group A will be only administrated with one dose of IIV (0.5 ml). Blood samples are collected before vaccination and one month (30 days) later. 408 subjects from control group B will be only administrated with one dose of PPV23 (0.5 ml). Blood samples are collected before vaccination and one month (30 days) later. To evaluate the immunogenicity, we will detect and compare the neutralization antibody levels, the seroprotection rates, and antibody geometric mean concentrations. The safety of all groups will be monitored as well.