Assessment of immunogenicity of a Shigella bivalents conjugate vaccine ZF0901 in Chinese children aged 3 months to 5 years using in vitro serotype-specific serum bactericidal assay
10.13200/j.cnki.cjb.004750
- VernacularTitle:特异性体外血清杀菌试验考察福氏宋内氏痢疾双价结合疫苗ZF0901对中国3月龄～5岁婴幼儿的免疫效果
- Author:
Xiaohua HU
- Publication Type:Journal Article
- Keywords:
Shigella bivalents conjugate vaccine;
Immunogenicity;
Clinical trial;
Infants and young children;
Serotype-specific serum bactericidal assay(SBA)
- From:
Chinese Journal of Biologicals
2026;39(08):943-950+958
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo assess the immunogenicity of a Shigella bivalents conjugate vaccine(ZF0901) in Chinese children aged 3 months to 5 years based on bactericidal antibody levels, so as to provide reference for the next phaseⅢclinical study.MethodsInfants and young children participating in the study were divided into three age groups: 3 to <6 months old(250 subjects were randomly assigned at a 2∶2∶1 ratio to receive the test vaccine at a half dose or full dose, or the Hib control vaccine, 1 dose each on days 0, 30 and 60), 6 to <12 months old(350 subjects were randomly assigned to receive half-dose,full-dose vaccine, non-adjuvanted full-dose vaccine, or Hib control vaccine at a ratio of 2∶2∶2∶1, 1 dose each on days 0 and 30) and 1 to 5 years old(350 subjects were randomly assigned at a ratio of 2∶2∶2∶1 to receive 1 dose of half-dose,full-dose vaccine, non-adjuvanted full-dose vaccine, or Hib control vaccine on day 0), which were all injected intramuscularly into the deltoid region of the upper arm.Blood samples were collected before the first injection(day 0) and 30 days after the last vaccination, and the serum was separated.The serotype-specific in vitro serum bactericidal assay(SBA)was employed to determine the bactericidal antibody titers of the serum.By comparing the bactericidal antibody titers and seroconversion rates, the immunogenicity of the vaccine was evaluated, and the correlation between the bactericidal antibody titers and the serum-specific IgG antibody levels determined by ELISA was analyzed.ResultsAt day 30 post final vaccination, the ZF0901 vaccine could elicit specific functional antibodies against both Shigella serotypes across all age groups.The geometric mean titers(GMTs) of antibodies were as follows: for the 3-<6 months age group, Shigella flexneri 2a ranged from 5.63 to 5.77, and Shigella sonnei from 6.63 to 6.78; for the 6- <12 months age group, S.flexneri 2a ranged from 6.02 to 6.62, and S.sonnei from 5.92 to 6.18; for the 1-5 years age group, S.flexneri 2a ranged from 6.75 to 7.44, and S.sonnei from 6.36 to 7.12.These bactericidal antibody titers were significantly higher compared to pre-immunization levels or the Hib control group(P<0.001).There was a good correlation between the antibody levels detected by ELISA and the bactericidal titers representing the bactericidal ability for the two serotypes, especially for S.sonnei serotype with a correlation coefficient(R~2) ≥ 0.936.Conclusion Shigellabivalents conjugate vaccine, ZF0901, could induce robust specific bactericidal antibodies with good immunogenicity in infants and children aged 3 months to 5 years, which is consistent with previous studies of binding antibodies.
