Shi Gang, Li Hong, Guo Lina, Yuan Lin, Chen Jingjing, Li Bin, Gou Jinbo, Yin Weiyan, Luo Shuquan, Ti Jing, Duan Mengqi, Cao Fang, Xu Xiao, Wang Bin
National Institutes for Food and Drug Control, NHC Key Laboratory of Research on Quality and Standardization of Biotech Products, State Key Laboratory of Drug Regulatory Science, NMPA Key Laboratory for Quality Research and Evaluation of Biological Products, Beijing 102629, China.
Walvax Biotechnology Co., Ltd., Kunming 650106, China.
Vaccines (Basel). 2025 Aug 10;13(8):847. doi: 10.3390/vaccines13080847.
BACKGROUND/OBJECTIVES: The immunogenicity of Streptococcus pneumoniae vaccines is commonly evaluated by assessing the fold increase or proportions exceeding 0.35 μg/mL in serotype-specific IgG antibody levels post-vaccination. Establishing baseline antibody levels in unvaccinated populations is therefore essential for defining serological thresholds and understanding naturally acquired immunity. This study aimed to assess the seroprevalence and baseline levels of IgG antibodies specific to 13 pneumococcal capsular polysaccharide serotypes in healthy infants and young children across multiple regions of China from 2016 to 2023, supporting evidence-based PCV13 vaccination strategies.
IgG concentrations for 13 serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) were measured in unvaccinated individuals using the WHO-recommended ELISA. Univariate and multivariate analyses were applied to evaluate regional, age, and gender effects on baseline antibody levels.
GMCs for serotypes 6B, 14, 19A, and 19F exceeded 0.35 μg/mL, with 14 being the highest (1.64 μg/mL) and serotypes 3 and 4 the lowest. Significant regional variation ( < 0.001) and a U-shaped age trend were observed, with the lowest being at 7-11 months ( = 0.003).
Baseline IgG levels varied by region and age. No significant gender differences were observed, and overall antibody levels were higher in the southern region.
背景/目的：肺炎链球菌疫苗的免疫原性通常通过评估接种疫苗后血清型特异性IgG抗体水平超过0.35μg/mL的倍数增加或比例来进行评估。因此，确定未接种疫苗人群的基线抗体水平对于定义血清学阈值和了解自然获得性免疫至关重要。本研究旨在评估2016年至2023年中国多个地区健康婴幼儿中13种肺炎球菌荚膜多糖血清型特异性IgG抗体的血清流行率和基线水平，为基于证据的PCV13疫苗接种策略提供支持。
使用世界卫生组织推荐的ELISA法测定未接种疫苗个体中13种血清型（1、3、4、5、6A、6B、7F、9V、14、18C、19A、19F和23F）的IgG浓度。采用单因素和多因素分析评估地区、年龄和性别对基线抗体水平的影响。
血清型6B、14、19A和19F的几何平均浓度（GMC）超过0.35μg/mL，其中14型最高（1.64μg/mL），3型和4型最低。观察到显著的地区差异（<0.001）和U型年龄趋势，最低值出现在7至11个月（=0.003）。
基线IgG水平因地区和年龄而异。未观察到显著的性别差异，且南部地区的总体抗体水平较高。
