Antibody Levels Against Mumps Virus in Children After Implementation of the Two-Dose MMR Vaccine Policy — Fujian Province, China, 2023

Zhifei Chen^1,2,&; Rui Chen^2,&; Ruihong Wu^1,2; Suhan Zhang¹; Xiuhui Yang^1,2; Weiyi Pan¹; Hairong Zhang¹; Mengping Zhang¹; Yong Zhou^1,2; Dong Li^1,2,#

1. Fujian Provincial Key Laboratory of Zoonosis Research, Fujian Provincial Center for Disease Control and Prevention, Fuzhou City, Fujian Province, China;

2. School of Public Health, Fujian Medical University, Fuzhou City, Fujian Province, China.

^& Joint first authors.

^# Corresponding author: Dong Li, lidong@fjcdc.com.cn.

To evaluate population immunity against the mumps virus (MuV) after China’s two-dose Measles-Mumps-Rubella (MMR) vaccine policy introduced in June 2020, we conducted a sero-epidemiological analysis among individuals aged 0–19 years. A cross-sectional survey was conducted in Fujian Province from March to June 2023. MuV IgG antibodies were detected using ELISA, and their seroprevalence and geometric mean concentrations (GMCs) were assessed. Population immunity in 2023 was compared with a 2018 survey. Overall seroprevalence and GMCs in 2023 were 79.53% and 265.61 U/mL, respectively. Both varied significantly by age: levels rose from 8 months, peaked at 2–5 years, then declined to a low point at 15–17 years. In 2023, seroprevalence and GMCs were higher in children aged 0–1 year (47.29% vs. 14.51%; 97.15 U/mL vs. 34.13 U/mL) and lower in those 15–17 years (58.06% vs. 80.73%; 126.00 U/mL vs. 289.98 U/mL) compared with 2018; 2-year-olds showed higher GMCs (554.85 U/mL vs. 353.39 U/mL). Among vaccinated individuals, antibody levels peaked 15–90 days after the latest vaccination; two-dose recipients exhibited significantly higher antibody levels than one-dose recipients within 270 days. China’s two-dose MMR vaccine policy has effectively increased seroprevalence and GMCs in children 8 months-2 years. Continuous monitoring of antibody decline is essential, particularly for those aged 6–19 years with weaker immunity.

实施2剂次MMR疫苗政策后儿童腮腺炎病毒抗体水平 — 福建省，中国，2023 年

陈致飞^1,2,&；陈睿^2,&；吴瑞红^1,2；张苏晗¹；杨秀惠^1,2；潘伟毅¹；张海荣¹；张梦萍¹；周勇^1,2；李东^1,2,#

1. 福建省人兽共患病研究重点实验室，福建省疾病预防控制中心 , 福州市，福建省，中国；

2. 公共卫生学院，福建医科大学，福州市，福建省，中国。

^& 共同第一作者。

^# 通信作者：李东，lidong@fjcdc.com.cn。

为评估中国自 2020 年 6 月实施两剂次麻疹-腮腺炎-风疹（麻腮风）疫苗政策后人群对腮腺炎病毒的免疫水平，我们在 0–19 岁人群中开展血清流行病学调查。2023 年 3 月至 6 月在福建省开展横断面调查。我们采用酶联免疫吸附试验（ELISA）检测腮腺炎病毒IgG抗体，并评估其血清阳性率及几何平均浓度（GMCs），此外，对比了 2023 年与 2018 年两次调查的人群免疫特征。2023 年人群腮腺炎病毒 IgG 抗体总体血清阳性率为 79.53%，GMCs为265.61U/mL，且不同年龄组的血清阳性率与GMCs存在显著差异。抗体血清阳性率与 GMCs 从 8 月龄开始上升，在 2–5 岁达到峰值，随后下降，在 15–17 岁降至低谷。与 2018 年相比，2023 年 0–1 岁儿童的血清阳性率（47.29% vs. 14.51%）和 GMCs（97.15 U/mL vs. 34.13 U/mL）显著更高，15–17 岁人群的血清阳性率（58.06% vs. 80.73%）和 GMCs（126 U/mL vs. 289.98 U/mL）显著更低，2 岁儿童的 GMCs 则更高（554.85 U/mL vs. 353.39 U/mL）。在接种疫苗的人群中，末次接种后 15–90 天抗体水平达到峰值；在末次接种后 270 天内，接种两剂次疫苗者的抗体水平显著高于接种一剂次者。在中国，两剂次麻腮风疫苗政策能有效提高 8 月龄–2 岁儿童腮腺炎病毒抗体的血清阳性率和几何平均浓度（GMCs）。然而持续监测抗体水平下降情况至关重要，尤其是对于免疫水平相对较弱的 6–19 岁人群。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.223

Impact of PCV13 Vaccination on Pharyngeal Detection of Streptococcus pneumoniae Among Children — Suqian City, Jiangsu Province, China, February 2023–February 2025

Lisha Ma^1,&; Mingwei Wei^2,3,&; Tao Wu³; Ran Tao³; Jinbo Gou⁴; Yue Liu¹; Manrong Zhang¹; Mengjuan Yuan²; Lunbiao Cui^3,#; Jingxin Li^1,3,#

1. School of Public Health, Southeast University, Nanjing City, Jiangsu Province, China;

2. School of Public Health, National Vaccine Innovation Platform, Nanjing Medical University, Nanjing City, Jiangsu Province, China;

3. Jiangsu Provincial Medical Innovation Center, National Health Commission Key Laboratory of Enteric Pathogenic Microbiology, Jiangsu Provincial Center for Disease Control and Prevention (Jiangsu Provincial Academy of Preventive Medicine), Nanjing City, Jiangsu Province, China;

4. CanSino Biologics Inc., Tianjin, China.

^& Joint first authors.

^# Corresponding author: Lunbiao Cui, lbcui@jscdc.cn; Jingxin Li, Lijingxin@jscdc.cn.

The 13-valent pneumococcal conjugate vaccine (PCV13) has reduced vaccine-type carriage rates, though regarding serotype replacement remain. This study conducted a 2-year prospective cohort study (February 2023–February 2025) in Suqian, Jiangsu Province, enrolling 2-month-old infants and monitoring for acute respiratory infections (ARIs). Pharyngeal swabs collected during ARIs were analyzed using targeted next-generation sequencing (tNGS) to identify respiratory pathogens, and Streptococcus pneumoniae (S. pneumoniae)-positive samples were serotyped using multiplex PCR. Risk ratios (RRs) for S. pneumoniae detection were estimated using Poisson regression, with sensitivity analysis performed using inverse probability of treatment weighting (IPTW). Among 579 children, 1,527 swabs were collected, yielding an overall S. pneumoniae detection incidence of 35.2%. Vaccinated children receiving 3–4 PCV13 doses demonstrated significantly lower detection rates than unvaccinated children [23.1% vs. 40.2%; adjusted RR=0.70; 95% confidence interval (CI): 0.50, 0.98; P=0.036]. IPTW analysis confirmed these findings. Non-vaccine serotypes predominated, particularly the 10A and 15A/15F strains. PCV13 vaccination was associated with reduced S. pneumoniae detection among children with ARIs, despite dominance of non-vaccine serotypes. Our findings emphasize the importance of ongoing surveillance for S. pneumoniae and highlight the need to expand the serotype coverage of pneumococcal vaccines.

PCV13 疫苗接种对儿童咽部检出肺炎链球菌的影响 — 宿迁市，江苏省，中国，2023年2月–2025年2月

马丽莎^1,&；魏明伟^2,3,&；吴涛³；陶然³；苟锦博⁴；刘玥¹；张曼蓉¹；袁梦娟²；崔仑标^3,#；李靖欣^1,3,#

1. 公共卫生学院，东南大学，南京市，江苏省，中国；

2. 公共卫生学院，南京医科大学国家医学攻关产教融合创新平台（疫苗研发），南京医科大学，南京市，江苏省，中国；

3. 江苏省医学创新中心，国家卫健委肠道病原重点实验室，江苏省疾病预防控制中心（江苏省预防医学科学院），南京，中国；

4. 康希诺生物股份公司，天津，中国。

^& 共同第一作者。

^# 通信作者：崔仑标，lbcui@jscdc.cn；李靖欣，Lijingxin@jscdc.cn。

13价肺炎球菌结合疫苗（PCV13）的广泛实施已显著降低疫苗型血清型的携带率。然而，非疫苗型血清型的流行比例不断上升，引发了对潜在血清型替代动态的高度关注。本研究于2023年2月至2025年2月在江苏省宿迁市开展了一项为期2年的前瞻性队列研究，招募了2月龄婴儿，并对急性呼吸道感染（ARI）进行主动监测。在ARI发作期间采集的咽拭子样本采用靶向二代测序（tNGS）检测呼吸道病原体，对检出肺炎链球菌（Streptococcus pneumoniae）的样本进一步采用多重PCR进行血清分型。我们使用稳健标准误的Poisson回归模型估算接种PCV13与未接种儿童肺炎链球菌检出发病率之间的风险比（RR），并采用倾向性评分逆概率加权（IPTW）进行敏感性分析。在24个月的监测期间，共从579名儿童采集了1,527份咽拭子样本，肺炎链球菌总体检出率为35.2%。与未接种组相比，接种3–4剂PCV13的儿童肺炎链球菌检出率显著降低（23.1% vs. 40.2%；调整后RR=0.70；95% CI：0.50，0.98；P=0.036）。IPTW敏感性分析得出了与主分析一致的结果。非疫苗型血清型在阳性样本中占据主导地位，其中以10A和15A/15F最为常见。PCV13接种与ARI儿童肺炎链球菌检出率下降相关，尽管当前流行菌株以非疫苗血清型为主。本研究强调了持续监测肺炎链球菌流行株的重要性，并提示有必要在未来疫苗中扩大血清型覆盖范围。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.222

Protective Effect and Immune Mechanism of EPCP009 Booster Immunization After BCG Prime Immunization Against Tuberculosis in Mice — China, 2024

Ruihuan Wang¹, Xueting Fan¹, Machao Li¹, Xiuqin Zhao¹, Xinyue He¹, Kanglin Wan¹, Haican Liu^1,#

1. National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.

^# Corresponding authors: Haican Liu, liuhaican@icdc.cn.

Bacillus Calmette–Guérin (BCG) is the only approved tuberculosis (TB) vaccine; however, it has partial efficacy and time-limited protection. Subunit booster vaccines may enhance the effects of BCG; however, their efficacy depends on their composition. Six-week-old Balb/c mice received primary immunization with BCG, followed by EPCP009 protein boosters (mixed with DDA/poly:IC [DP] adjuvant) once, twice, or thrice (2-week intervals). Six weeks after the first immunization, blood and spleen samples were collected. Levels of antibodies and cytokines were assessed via enzyme-linked immunosorbent assay (ELISA), Luminex, and ELISpot) The ability of splenocytes to inhibit Mycobacterium tuberculosis (Mtb) was assessed by MGIA, and pathological analyses were conducted on the liver, spleen, and lung. In addition, mice were immunized with EPCP009 or H4 protein separately. BCG was administered intravenously 6 weeks later, and spleens were collected at 3.5 weeks to quantify the BCG bacterial load. BCG combined with a single EPCP009 dose provided better short-term (6-week) and long-term (12-week) protection than multiple doses. During the long-term process, the levels of PPD-specific interferon (IFN)-γ and granulocyte-macrophage colony-stimulating factor (GM-CSF) remained relatively high. No significant differences in the BCG colony counts were observed among the EPCP009/DP, phosphate-buffered saline (PBS), and DP groups. These findings demonstrate that BCG vaccination combined with a single dose of EPCP009 enhances protective efficacy against TB. This study provides a critical theoretical basis for designing booster immunization strategies for TB vaccines.

卡介苗初免后 EPCP009 加强免疫对小鼠结核病的保护作用及免疫机制研究 — 中国，2024

王瑞欢¹；范雪亭¹；李马超¹；赵秀芹¹；何心越¹；万康林¹；刘海灿^1,#

1. 传染病溯源预警与智能决策全国重点实验室，传染病预防控制所，中国疾病预防控制中心，北京，中国。

^# 通信作者：刘海灿，liuhaican@icdc.cn。

卡介苗是目前唯一被批准的结核病疫苗，但BCG 免疫保护效果和时间有限。亚单位蛋白疫苗作为加强疫苗可能延长BCG的保护时长，但效力取决于其组成成分。将构建和表达的EPCP009蛋白与DDA/Poly:IC（DP）佐剂混合，采用6周龄Balb/c小鼠接种BCG初免疫后，分别接种EPCP009/DP加强免疫1次、2次、3次，间隔为2周，距离第一次免疫6周时，采集血液和脾脏样本。采用酶联免疫吸附试验、多重微球技术、酶联免疫斑点法检测血清抗体滴度、细胞因子分泌水平；采用体外结核分枝杆菌生长抑制试验检测小鼠脾细胞体外抑制结核分枝杆菌生长的能力；并对免疫后小鼠的肝、脾、肺进行病理分析。另外，分别用EPCP009或H4蛋白免疫小鼠，6周后静脉注射卡介苗，3.5周时取脾，定量卡介苗细菌载量。卡介苗联合EPCP009单次给药可提供较好的短期（6周）和长期（12周）保护。在长期观察过程中，PPD特异性的IFN-γ和GM-CSF细胞因子水平依然较高。EPCP009/DP组和PBS组、DP组的BCG菌落计数无显著差异。本研究表明卡介苗与单剂EPCP009联合接种可增强对结核病的保护作用，为结核病疫苗加强免疫策略的设计提供了重要的理论基础。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.225

Evaluation of Measles Vaccine Immunogenicity and Durability Using A Pseudotyped Virus Neutralization Assay

Qi Jiang¹; Xi Wu¹; Jie Zhang¹; Huiling Wang²; Fangyu Dong³; Xuelian Wu¹; Pengju Yu¹; Jianhui Nie¹; Youchun Wang⁴; Weijin Huang¹; Jiuyue Zhou³; Yaru Quan⁵; Yan Zhang^2,#; Suting Wang^6,#; Juan Li^5,#

1. Division of HIV/AIDS and Sexually Transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), State Key Laboratory of Drug Regulatory Science, Beijing, China;

2. WHO Western Pacific Regional Measles/Rubella Reference Laboratory, National Key Laboratory for Intelligent Tracking and Forecasting of Infectious Diseases, NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China;

3. Department of Research & Development, Taibang Biologics Group, Beijing, China;

4. Institute of Medical Biology, Chinese Academy of Medical Sciences, Kunming City, Yunnan Province, China;

5. Division of Respiratory Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China;

6. Shandong Center for Disease Control and Prevention, Jinan City, Shandong Province, China.

^# Corresponding author: Juan Li, lijuan@nifdc.org.cn; Suting Wang, sdsjbyfkzzx-mys@shandong.cn; Yan Zhang, zhangyan@ivdc.chinacdc.cn.

This study aimed to establish a robust method for monitoring measles vaccine-induced immunity and assessing population-level serostatus. This study constructed a vesicular stomatitis virus (VSV)-based pseudotyped virus system expressing envelope proteins from seven major circulating measles genotypes (H1, B3, D4, D8, D9, D11, G3) and the Schwarz vaccine strain (genotype A), thereby enabling a high-throughput neutralization assay for antibody detection. Vaccination induced a substantial increase in neutralizing antibody geometric mean titers (GMT) post-immunization (4,808 after the first dose; 5,326 after the second dose), with antibody levels remaining elevated in 4-year-old children (GMT: 3,834). Cross-neutralization activity against different genotypes varied by less than 6.4-fold, demonstrating broad protective immunity. However, 12% of adult sera tested were seronegative, revealing the presence of susceptible populations. This study confirms the robust immunogenicity of the current measles vaccine and establishes a valuable tool for serosurveillance and long-term immunity assessment.

基于假病毒中和试验的麻疹疫苗免疫原性和持久性评价

姜奇¹；吴曦¹；张洁¹；王慧玲²；董方玉³；吴雪莲¹；余鹏举¹；聂建辉¹；王佑春⁴；黄维金¹；周久越³；权娅茹⁵；张燕^2,#；王素婷^6,#；李娟^5,#

1. 艾滋病性病病毒疫苗室，生物制品检定所，中国食品药品检定研究院，药品监管科学国家重点实验室，北京，中国；

2. WHO西太平洋地区麻疹/风疹实验室，传染病溯源预警与智能决策全国重点实验室，医学分子病毒学教育部/卫生部重点实验室，病毒病预防控制所，中国疾病预防控制中心，北京，中国；

3. 研究发展部，山东泰邦生物制品有限公司，北京，中国；

4. 中国医学科学院医学生物学研究所，昆明市，云南省，中国；

5. 呼吸道病毒疫苗室，中国食品药品检定研究院，北京，中国；

6. 山东省疾病预防控制中心；济南市，山东省，中国。

^# 通讯作者: 李娟，lijuan@nifdc.org.cn; 王素婷，sdsjbyfkzzx-mys@shandong.cn; 张燕，zhangyan@ivdc.chinacdc.cn。

监测麻疹疫苗免疫效果及人群抗体水平。本研究构建了基于水泡性口炎病毒（VSV）的麻疹假病毒系统，覆盖七大流行基因型（H1, B3, D4, D8, D9, D11, G3）及Schwarz疫苗株，并据此建立了高通量中和抗体检测法。应用该方法发现，接种疫苗后抗体滴度显著上升（首剂后GMT：4,808；次剂后：5,326），并可维持至4岁（GMT：3,834）。针对不同基因型的交叉中和活性差异小于6.4倍，表明疫苗可诱导广谱保护。然而，成人血清中有12%为抗体阴性，提示免疫空白存在。本研究证实当前疫苗免疫原性良好，所建立的方法为血清流行病学监测与免疫持久性评估提供了有效工具。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.224