Live attenuated and vero-cell-inactivated Japanese Encephalitis vaccines (LJEV, IJEV) have been in common use in young children in China since 1989 and 2004, associated with large reductions in Japanese encephalitis (JE) incidence. In 2013, northern China reported JE outbreaks among adults born before JE vaccine availability, a trend that worsened in 2017-2018. We conducted an open-label, randomized, controlled trial (ChiCTR2500103235) to assess the immunogenicity, immune persistence, and safety of three JE vaccine schedules in 40-69-year-olds to provide evidence for adult targeted JE immunization efforts. Outcomes were seroconversion proportions and seropositive prevalences; adverse events were monitored. The vaccines were immunogenic with no significant difference between vaccination groups. Seropositivity remained above 80% at one year post-vaccination. No serious adverse events occurred. All three schedules had good, persistent immunogenicity and favorable safety profiles in 40-69-year-old adults, providing evidence supporting vaccinating adults in response to the emergence of adult JE in northern China.

What is already known about this topic?:The incidences of vaccine-preventable diseases (VPDs) included in the Expanded Program on Immunization in China have decreased significantly in recent decades.What is added by this report?:This study summarizes the national incidences of nine VPDs and the seroprevalence of hepatitis B surface antigen (HBsAg) under different immunization strategies from 1950 through 2021 in China. The sharpest decreases in VPD incidence and under-5-year HBsAg seroprevalence occurred during the latest stage of the National Immunization Program. The decreases in VPD incidence were most prominent among children under five years of age.What are the implications for public health practice?:These findings provide valuable insights for vaccine value assessment and emphasize the importance of implementing immunization strategies in targeted populations.

Background:Since 1992, when recombinant hepatitis B vaccine was introduced in China, government health officials have used nationally representative serological surveys to monitor progress in prevention and control of hepatitis B. In 2020, we conducted the fourth seroepidemiological survey, which for the first time included medical evaluation of the clinical status of HBsAg positive subjects over the age of 15 and their medical management. We report survey results in comparison with the three previous surveys. Methods:Consistent with previous national surveys, the 2020 survey used a stratified, three-stage cluster random sampling method to select for evaluation 1-69-year-olds in 120 national disease surveillance points. Blood samples were tested for HBsAg, anti-HBV surface antigen (anti-HBs), and anti-HBV core antigen (anti-HBc) in the National Hepatitis Laboratory of the Institute for Viral Disease Control and Prevention of China CDC. HBsAg positive subjects aged ≥15-year were evaluated for evidence of liver disease, and through face-to-face questionnaire-based survey, we determined the healthcare management cascade of HBV-infected individuals. Findings:HBsAg prevalence in 1-69-year-olds was 5.86%; in children 1-4 years of age, seroprevalence was 0.30%; 75 million people were living with HBV nationwide. Among HBsAg-positive individuals 15 years and older, expert medical examination found that 78.03% were HBsAg carriers with no evidence of liver damage, 19.63% had chronic HBV with liver enzyme abnormalities, 0.84% had evidence of cirrhosis, and 0.15% had evidence of liver cancer. 59.78% of HBsAg + individuals were aware that they were positive before the survey, 30 million were unaware; 38.25% of those who knew they were positive (17 million) had medical indications for antiviral treatment, and 17.33% of these individuals (3 million) were being treated with antivirals. Interpretation:The decline in HBsAg prevalence in the general population, from 9.72% in 1992 to 5.86% in 2020, and in 1-4-year-olds from 9.67% in 1992 to 0.30% in 2020, shows progress that continues on track toward WHO targets for prevention of new infections. Implementation of acceptable strategies to identify infected individuals and offer long-term medical monitoring and management will be important to prevent complications from hepatitis B infection and for meeting WHO cascade-of-care targets. Funding:The study was funded by the Major Science and Technology Special Project of China's 13th 5-Year Plan (grant no. 2017ZX10105015); Central finance-operation of public health emergency response mechanism of Chinese Center for Disease Control and Prevention (131031001000200001, 102393220020010000017).

Objectives: This study aimed to evaluate the health and economic impact of diphtheria, tetanus, whole-cell pertussis vaccine (DTwP) and diphtheria-tetanus-acellular pertussis vaccine (DTaP) vaccination on pertussis prevention and control in China during the 40 years from 1978 to 2017.Methods: We conducted cost-benefit analyses with a decision tree model populated with historical vaccination coverage levels and pertussis incidence and mortality data from before 1978 and during 1978 to 2017. We modeled 40 birth cohorts from birth until death. Costs and benefits were estimated from direct cost and societal perspectives (direct and indirect costs). Costs and benefits were adjusted to 2017 US dollars (USD), and future values were discounted at a 3% annual rate. We calculated net benefit values (net savings) and benefit-cost ratios of pertussis vaccination of children younger than 5 years. We conducted sensitivity analyses by varying key parameters within plausible ranges.Results: Without DTwP and DTaP vaccination, there would be an estimated 115.76 million pertussis cases and 426 650 pertussis deaths in the 40 cohorts. With DTwP/DTaP vaccination, pertussis cases and deaths were decreased by an estimated 92.57% and 97.43%, saving 46 987.81 million USD in direct costs and 82 013.37 million USD from societal perspective. Pertussis vaccination program costs were 2168.76 million USD and 3961.28 million USD from direct cost and societal perspectives. Benefit-cost ratios were 21.67:1 from the direct cost perspective and 20.70:1 from the societal perspective. Sensitivity analyses showed the results to be robust.Conclusions: Over the lifetime of 40 birth cohorts, China's immunization program is preventing 93% of pertussis cases and 97% of pertussis deaths, resulting in substantial savings to the healthcare system and society.

Objective To analyze pertussis incidence trends and their influencing factors in several areas of China.Methods We obtained pertussis case data reported in 10 prefectures of 5 provinces during 2004-2021 from the Chinese Disease Control and Prevention Information System and obtained information on diphtheria, tetanus and acellular pertussis combined vaccine（DTaP） immunization and pertussis surveillance strategies with a questionnaire-based survey. We used a Joinpoint regression model to estimate the age-standardized incidence rate（ASIR） of pertussis and its annual percent change（APC） and average annual percent change（AAPC）.Results All study prefectures replaced diphtheria, tetanus and whole-cell pertussis combined vaccine with DTaP before 2010. Four of the five study provinces conducted intensive pertussis surveillance or pertussis-specific research during 2011 to 2021. Annual arerage ASIRs ranged from 0.20 to 3.50 per 100 000 population during 2004-2021, with AAPCs ranging from 4.06% to 44.15% in 6 areas and from-8.77% to-1.11% in 4 areas. APCs ranged from 31.20% to 132.70% between the first regression turning point and the second turning point and from-28.77% to-80.70% between the second turning point and 2021, the end of the study period.Conclusions The incidence of pertussis initially increased and subsequently decreased during 2004-2021 in all study areas. The increasing incidence may have been associated with waning protection from DTaP and intensive pertussis surveillance or specific research on pertussis.

Mainland China included Japanese encephalitis (JE) vaccine in the national immunization program in 2008 to control the JE epidemic. However, Gansu province in Western China experienced the largest JE outbreak since 1958 in 2018. We conducted a retrospective epidemiological study to explore the causes of this outbreak. We found that adults aged ≥20 years (especially those in rural areas) were the main JE cases in Gansu Province, with a significant increase in the JE incidence in older adults aged ≥60 years in 2017 and 2018. In addition, JE outbreaks in Gansu Province were mainly located in the southeastern region, while the temperature and precipitation in Gansu Province were gradually increasing in recent years, which made the JE epidemic areas in Gansu Province gradually spread to the western of Gansu Province. We also found that adults aged ≥20 years in Gansu Province had lower JE antibody positivity than children and infants, and the antibody positivity rate decreased with age. In the summer of 2017 and 2018, the density of mosquitoes (mainly the Culex tritaeniorhynchus ) in Gansu Province was significantly higher than in other years, and the genotype of JEV was mainly Genotype‐G1. Therefore, in the future JE control in Gansu Province, we need to strengthen JE vaccination for adults. Moreover, strengthening mosquito surveillance can provide early warning of JE outbreaks and the spread of epidemic areas in Gansu Province. At the same time, strengthening JE antibody surveillance is also necessary for JE control.

Objective To explore meningococcal vaccine（MenV） coverage among children in China.Methods We used a multi-stage cluster random sampling strategy to select children 1-13 years of age（born between 2008 and 2019） in 120 national monitoring counties for a questionnaire-based survey of MenV administration to determine first and second dose（MenV 1 , MenV 2 ） coverage levels in 1-13-year-olds, third dose（MenV 3 ） coverage in 4-13-year-olds, and fourth dose（MenV 4 ） coverage in 7-13-year-olds, and rates at which non-Expanded Program on Immunization（EPI） MenV replaced EPI MenV.Results MenV 1 , MenV 2 , MenV 3 , and MenV 4 coverage levels were 95.66%（18 892/19 749）, 92.79%（18 326/19 749）, 89.41%（12 087/13 518）, and 76.98%（6 148/7 987）, respectively. Among the MenV 1 , MenV 2 , MenV 3 , and MenV 4 doses administered, 7.00%, 8.08%, 13.49%, and 12.51% were non-EPI MenV doses that replaced EPI MenV doses. The overall replacement rate was 9.60%, and increased from 7.17% among children born in 2008 to 15.33% among children born in 2019（trend Z=13.20, P＜0.001）.Conclusions MenV 1 and MenV 2 coverage levels were high but coverage of MenV 3 and MenV 4 was low. The rate at which non-EPI MenV replaced EPI MenV increased over time. We should strengthen routine MenV vaccination of age-eligible children and strengthen school entry vaccination certificate examination to identify and vaccinate children missing one or more of their recommended doses.

What is already known about this topic?:Vaccine effectiveness (VE) is positively correlated with the number of administered co-purified diphtheria, tetanus, and acellular pertussis vaccine (DTaP) doses. A matched case-control study conducted in Zhongshan City revealed that the co-purified DTaP VE against pertussis-related illnesses in children aged 4-11 months was 42% for one dose, 88% for two doses, and 95% for three doses, respectively.What is added by this report?:The results of this study contribute to the current body of research. We found that the VE of co-purified DTaP against pertussis-related illness and hospitalization increased substantially, ranging from 24%-26% after one dose to 86%-87% after four doses.What are the implications for public health practice?:The results of this study underscore the significance of prompt and comprehensive immunization using co-purified DTaP to decrease the incidence of pertussis. Additionally, these findings offer evidence supporting the modification of China's pertussis vaccination approach.

疫苗保护效果(Vaccine effectiveness,VE)评价是疫苗在真实世界应用后预防控制针对疾病效果的流行病学评估.病例队列研究(Case-cohort study,CCS)是一种基于队列研究和病例对照研究的高效研究设计,可以降低研究成本、克服常用VE评价方法的诸多困难,结果可信度高.本文对CCS设计的原理、方法、适用情形、优势和局限性、在VE评价中的应用等进行综述,旨在帮助研究人员更好地了解和合理运用CCS设计.

全细胞百日咳疫苗向无细胞百日咳疫苗转换后,越来越多疫苗覆盖率较高的国家出现"百日咳再现",报告百日咳病例增加且向青少年和成人转移.疫苗的转换被认为是百日咳发病率增高的原因之一,疫苗抗原的种类和数量、生产工艺和佐剂的差异可能对疫苗的质量和效果产生影响.本文对国外百日咳疫苗抗原成分及其免疫机制、疫苗免疫原性与保护效果的关系进行综述,为优化现有百日咳疫苗免疫策略和新疫苗研发提供支持.

根据预防接种工作需要并受国家卫生健康委员会疾病预防控制局委托,2019-2020年中国疾病预防控制中心国家免疫规划技术工作组在《国家免疫规划疫苗儿童免疫程序及说明（2016年版）》基础上,整合相关疫苗和疾病防控最新证据,组织对该文件进行了修订。经国家免疫规划专家咨询委员会审议后,国家卫生健康委员会于2021年2月印发了《国家免疫规划疫苗儿童免疫程序及说明（2021年版）》。本文对该新版文件的主要内容及其修订情况进行了解析。

Objective: To analyze the antimicrobial resistance characteristics of 538 Neisseria meningitidis isolated from 2005 to 2019 in China. Method: Total of 538 Neisseria meningitidis strains collected from 30 provinces in China from 2005 to 2019. Antimicrobial susceptibility test were performed based on the standards of clinical and laboratory standardization association (CLSI) including 11 recommended antibiotics. Gradient diffusion method was used to detect the antibiotic sensitivity of Neisseria meningitidis. Results: All 538 strains were sensitive to azithromycin, meropenem, chloramphenicol, rifampicin and ceftriaxone. As to other six antibiotics, the antibiotics sensitivity rates were cefotaxime (97.4%, 524 strains), ampicillin (87.7%, 472 strains), penicillin (84.8%, 456 strains), minocycline (95.2%, 512 strains), ciprofloxacin (24.9%, 134 strains) and trimethoprim/sulfamethoxazole (11.2%, 60 strains) respectively. Conclusions: Neisseria meningitidis isolated from 2005-2019 in China were all sensitive to azithromycin, meropenem, chloramphenicol, rifampicin and ceftriaxone. It should highlight Neisseria meningitidis resistant to cefotaxime, ampicillin and penicillin. Ciprofloxacin and sulfamethoxazole are not recommended as the priority choice for clinical treatment and prophylactic medication.

目的 调查宁夏回族自治区北部地区健康人群乙型脑炎病毒(Japanese encephalitis virus,JEV)中和抗体阳性率.方法 2018年在宁夏北部地区的4个县区采集≥1岁健康人群血清标本,采用嗜斑减少中和试验检测JEV中和抗体,分析抗体阳性率.结果 调查对象JEV中和抗体总阳性率为43.73％ (279/638).1-10岁、11-20岁、21-30岁、31-40岁、41-50岁、51-60岁、61-70岁、≥71岁年龄组阳性率分别为65.52％、37.14％、35.82％、34.72％、42.86％、32.79％、42.37％、36.17％(x2=38.50,P＜0.05);4个县区人群阳性率分别为53.89％、39.01％、43.30％、38.55％(x2=11.16,P＜0.05).结论 宁夏北部地区健康人群JEV中和抗体阳性率低,建议当地开展＞40岁人群乙脑疫苗接种.

群体免疫是指基于病原传播动力学,旨在通过足够高的群体免疫水平产生社区保护以阻止病原传播的流行病学概念.实现群体免疫需要满足一定的理论条件.本文介绍了群体免疫的发现和概念、实现的理论基础和计算方法、在传染病防控中的应用,以及在2019冠状病毒病(COVID-19)疫情防控中的考虑.

In late December 2019, clinicians in Hubei Province noticed and reported to health authorities a cluster of cases of pneumonia of unknown etiology (PUE) that turned out to be the start of the coronavirus disease 2019 (COVID-19) pandemic (1).By January 29, 2020, all provincial-level administrative divisions (PLADs) across the country had launched their highest public health emergency responses (Level 1 responses) (2-3).Vaccination service delivery was impeded by social distancing measures and restrictions on gatherings of people required in the Level 1 response protocols.Although vaccination services continued to be available in some areas, and four vaccines -rabies vaccine for postexposure prophylaxis, the birth doses of hepatitis B vaccine and bacille calmette-guerin (BCG) vaccine, and tetanus toxoid for wound prophylaxiscontinued to be administered on time in all areas, most vaccination services were stopped as part of the response (4-6).On February 3, China CDC published interim guidelines for vaccinations during the COVID-19 epidemic based on local epidemiological circumstances (7).In early March 2020, the COVID-19 epidemic in PLADs outside of Hubei Province was coming under control, and in mid-march, China's National Health Commission issued a notice to resume routine vaccination services in an orderly manner (8).Eighty percent of the country's vaccination venues (China CDC, unpublished data) had suspended immunization services for up to two months for vaccines other than BCG, the first dose of hepatitis B, rabies, and tetanus toxoid for wound management.China CDC developed guidelines for resumption of routine immunization services and catch-up vaccinations for children who missed or delayed vaccine doses due to COVID-19.We describe the China CDC guidelines for during and after the COVID-19 epidemic in China.

目的 分析中国2015-2019年流行性脑脊髓膜炎(流脑)病例的脑膜炎奈瑟菌(Neisseria meningitidis,Nm)血清群分布特征.方法 通过中国法定传染病报告系统和流脑监测信息报告管理系统收集2015-2019年流脑病例和Nm血清群实验室检测数据,进行描述流行病学分析.结果 中国2015-2019年报告流脑540例,年均发病率为0.78/1 000万;在296例Nm血清群阳性病例中,A、B、C、W、Y、其他及不可分群分别占4.73％、36.15％、22.97％、6.08％、1.69％、28.38％;各血清群检出省份数分别为4个、19个、17个、10个、4个、20个;0-4岁、5-9岁病例中B群病例分别占58.56％、55.00％,10-14岁病例中C群病例占57.81％,≥ 15岁病例中其他及不可分群病例占33.66％;2015年vs 2019年A、C、B、W群病例比例分别为2.33％ vs 1.28％、16.28％ vs 37.18％、30.23％ vs 32.05％、4.65％ vs 10.26％.结论 中国流脑优势流行Nm血清群呈多元化变迁趋势以及地域和年龄分布差异;建议研发和应用B群脑膜炎球菌疫苗.

目的 分析中国2014-2018年流行性乙型脑炎(乙脑)流行病学特征.方法 通过中国疾病预防控制信息系统和乙脑监测信息报告管理系统收集2014-2018年乙脑病例,进行描述性流行病学分析.结果 中国2014-2018年共报告乙脑5 666例,年均发病率为0.083/10万;死亡309例,病死率为5.45％.年均发病率居前5位的省份为甘肃(0.76/10万)、宁夏(0.50/10万)、陕西(0.31/10万)、云南(0.23/10万)和四川(0.17/10万).7-9月份病例数占90.31％.0-14岁、15-39岁、≥40岁病例分别占42.53％、14.83％、42.64％,其中≥40岁病例构成比从2014年的14.45％上升至2018年的64.04％,0-4岁、5-9岁乙脑发病率分别从2014年的0.28/10万、0.36/10万降至2018年的0.11/10万、0.17/10万;≥40岁各年龄组发病率均上升.在4 007例随访病例中,痊愈、好转、有后遗症、死亡分别占48.91％、18.27％、16.45％、16.37％,其中≥40岁病例中死亡占26.70％.结论 中国2014-2018年儿童乙脑发病率持续下降.建议在成人乙脑高发地区开展乙脑疫苗接种和相关研究,持续开展蚊种密度和健康人群乙脑抗体水平监测.

目的 了解烟台市2017-2018年百日咳经济负担和影响因素.方法 采用分层随机抽样方法抽取烟台市2017-2018年百日咳报告病例,通过访谈和医院收费系统收集病例的医疗费用和间接花费,分析平均经济负担和影响因素.结果 共纳入百日咳病例106例,其中门诊、住院病例分别为25例、81例.所有病例的平均(中位数)总经济负担为8 603元,平均(中位数)直接医疗费用、直接非医疗费用、间接费用分别为5 394元、288元、1 080元.门诊、住院病例的总平均(中位数)经济负担为1 253元、10 580元.农村、城市病例分别为5 353元、10 148元(Z=2.69,P=0.007),＜1岁、1-9岁、＞9岁病例分别为11 516元、8 830元、1 825元(Z=37.88,P＜0.001),初诊医疗机构为乡镇级及以下、县级及以上分别为1 820元、10 918元(Z=5.83,P＜0.001),就诊1次、2次、≥ 3次病例分别为7 165元、7 105元、11 780元(Z=11.06,P=0.004).结论 烟台市百日咳患者经济负担较重,城市地区、初诊医疗机构级别高、就诊次数多的小年龄组儿童经济负担较重.

目的 观察儿童A群C群脑膜炎球菌多糖结合疫苗(Group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)基础免疫后A群C群脑膜炎球菌多糖疫苗(Group A and group C meningococcal polysaccharide vaccine,MPV-AC)加强免疫的免疫原性和持久性.方法 在安徽省部分乡镇选择已完成2剂次MPCV-AC基础免疫的3岁儿童进行1剂次MPV-AC加强免疫,采集免疫前和免疫后1个月血标本;选择已完成2剂次MPCV-AC基础免疫和1剂次MPV-AC加强免疫的6岁儿童在第2剂MPV-AC加强免疫前采集血标本;检测所有儿童的A群和C群脑膜炎奈瑟菌血清功能性杀菌抗体,分析抗体阳性率、阳转率和几何平均滴度(Geometric mean titer,GMT).结果 在69名3岁儿童中,MPV-AC免疫前A、C群抗体阳性率分别为73.91％、47.83％;免疫后阳性率均为100％,阳转率分别为75.36％、94.20％,GMT分别为1∶1 109.69、1∶2 632.68.在75名6岁儿童中,A、C群抗体阳性率分别为94.67％、64.00％(与3岁儿童免疫后相比,Fisher精确概率法,P=0.121;x2=30.57,P=0.000),GMT分别为1∶149.78、1∶42.22(与3岁儿童免疫后相比,U=866.00,P=0.000;U=570.00,P=0.000).结论 完成MPCV-AC基础免疫的3岁儿童进行1剂次MPV-AC加强免疫的免疫原性良好但免疫持久性不足3年,建议增加第2剂次加强免疫.