贵州省成人流行性乙型脑炎病毒中和抗体水平调查

  目的  调查贵州省成人流行性乙型脑炎（乙脑）病毒中和抗体水平。  方法  采用多阶段随机抽样的方法,在2017年5~6月采集3个市（州）6个年龄组健康成人血清共360份,应用蚀斑减少中和试验法检测乙脑病毒中和抗体。  结果  360名调查对象中乙脑病毒中和抗体阳性率为55.28%,几何平均滴度（GMT）为1 ∶17.52。不同性别（χ2=10.798,P=0.001）、不同发病率地区（χ2=6.090,P=0.048）成人乙脑病毒中和抗体阳性率差异具有统计学意义（均有P<0.05）;不同年龄成人乙脑病毒中和抗体阳性率在45.00%~60.00%之间（χ2=4.236,P=0.516）;不同民族中,布依族成人乙脑病毒中和抗体阳性率最高（79.17%）。  结论  贵州省成人乙脑病毒中和抗体水平较低,存在成人乙脑流行风险。     

浙江省仙居县2012-2013年流行性乙型脑炎病毒基因特征和人群血清学研究

目的：分析浙江省仙居县媒介蚊虫中流行性乙型脑炎（乙脑）病毒（JEV）基因型别和健康人群乙脑抗体水平。方法2012-2013年在浙江省仙居乙脑监测点采集蚊虫,分离JEV,测定其E基因核苷酸序列,并进行同源性与进化分析;对监测点的642名健康人群,在乙脑流行季节前后,分别采集双份血清,共计样本1263份,检测JEV中和抗体。结果采集11650只蚊虫标本,分离25株JEV,同源性分析显示,2012-2013年分离到的JEV与浙江省1982-2010年JEV之间E基因核苷酸同源性为87.8%～99.7%,与乙脑疫苗株SA14-14-2之间核苷酸同源性为87.7%～88.0%。E基因进化分析显示,2012-2013年JEV属于基因Ⅰ型,E基因编码病毒毒力和抗原表位的位点未发生改变。健康人群JEV中和抗体阳性率为31.5%～42.0%,抗体几何平均滴度（GMT）为1∶2.56～1∶3.53,流行前后人群抗体阳性率（χ2≤1.76,P＞0.05）和GMT（u≤0.64,P＞0.5）差异均无统计学意义。结论2012-2013年浙江省仙居县蚊媒中携带基因Ⅰ型JEV,健康人群JEV中和抗体阳性率≤42.0%,流行前后抗体阳性率和中和GMT均无明显变化。     

2012年北京市密云县健康人群乙脑抗体水平监测

目的分析2012年北京市密云县健康人群乙型脑炎抗体水平特征及影响因素。方法按照随机抽样的方法抽取密云县10个行政村（居委会）作为调查点,选择在当地连续居住6个月以上的健康人群共268人,采用反向被动血凝抑制方法测定乙脑中和抗体,抗体滴度≥1∶10判断阳性。结果健康人群乙脑抗体监测阳性率为68.28%,其中0岁~组抗体阳性率最低为12.00%,1岁~组抗体阳性率最高,为100%,不同年龄组抗体阳性率差异有统计学意义（χ2=68.731,P=0.000）;不同户籍抗体阳性率分别为72.06%和64.39%;不同免疫次数人群乙脑抗体阳性率差异有统计学意义（χ2=55.919,P=0.000）结论该县有可能发生乙脑流行,主要是因为0岁~,25岁~年龄组的抗体水平偏低,此结果提示应探讨育龄期妇女及成人乙脑疫苗免疫策略,同时应做好防蚊灭蚊工作,防止乙脑流行。     

汕头市人群肠道病毒70型中和抗体调查

目的观察近阶段人群中肠道病毒70型(EV-70)感染状态.方法采用中和试验测定人群中血清抗体.结果 EV-70中和抗体阳性率、抗体几何平均滴度(GMT)分别为45.5%、9.89,其中以7～14岁年龄组最高(59.1% ),3～6岁组次之(53.3%),0～2岁组最低(31.8%).GMT以51～90岁组最高(131.8),7～14岁组次之(124.8),0～2岁组最低(8.90).各年龄组抗体阳性率比较,差异有显著性(χ2=9.891,P＜0.05);男女阳性率比较,差异无显著性(χ2=4.458,P＞0.05).结论反映人群受EV-70感染状态,EV-70在该地区人群中仍有一定程度的传播.应引起当地临床和预防医学工作者的重视.     

2014年扬州市健康人群流行性乙型脑炎抗体水平监测结果

目的了解扬州市健康人群流行性乙型脑炎(乙脑)抗体水平,为制定预防控制策略提供依据。方法 2014年6月乙脑流行季节前,分7个年龄组,每组随机抽取50名健康人,采用蚀斑减少中和试验法检测乙脑中和抗体。结果共检测356人,乙脑抗体阳性率为60.11%,GMT为1∶10.36。抗体阳性率、GMT<8月龄组最低,>20岁组最高,不同年龄组差异有统计学意义(χ2=91.18,P<0.05;F=23.82,P<0.05);有乙脑疫苗免疫史人群抗体阳性率高于无免疫史人群(χ2=27.68,P<0.05;F=16.19,P<0.05),且随着免疫剂次的增加而增加;不同性别抗体阳性率、GMT之间差异无统计学意义(χ2=0.76,P>0.05;F=1.25,P>0.05)。结论扬州市健康人群乙脑抗体水平主要受疫苗接种及由流行季节造成的隐性感染影响,2岁儿童乙脑抗体水平较低,建议增加6岁儿童复种1剂次乙脑疫苗的接种程序。     

江苏省2007年乙脑正常人群免疫水平监测分析

目的:对江苏省2007年正常人群乙脑免疫水平进行监测,为正常人群的乙脑防控提供依据。方法:采用蚀斑减少中和实验,测定正常人群的乙脑抗体水平。结果:2007年共调查1 065人,乙脑抗体阳性率为69.95%,GMT为1∶14.44。阳性率最高的为20～岁组,为93.42%;低滴度抗体≤1∶10占44.98%,0～岁组最高,占85.81%;高滴度抗体≥1∶80占19%,0～岁组最低,占2.58%。3个监测点无锡江阴阳性率为79.24%,GMT为1∶18.93;宿迁宿豫阳性率为75.34%,GMT为1∶19.27;泰州姜堰阳性率为55.14%,GMT为1∶8.15。结论:乙脑低滴度抗体水平主要集中在小年龄组,应加强儿童免疫。3个监测点以苏中免疫水平较低,应加强免疫。     

崇左市边境地区儿童疫苗可预防疾病免疫状况及居民知识水平调查研究

目的 了解崇左市边境地区儿童疫苗可预防疾病免疫状况及居民知识水平,为中越边境地区制定免疫规划策略和措施提供科学依据。方法 随机分层抽取3个中越边境县（市）2～7岁儿童444人,分析麻疹（MV）IgG抗体、白喉(DP)IgG 抗体、脊髓灰质炎(PV)总抗体、乙肝表面抗体(HBsAb)、乙肝表面抗原(HBsAg)的水平。结果 中越边境地区儿童的乙肝抗原及乙肝、脊灰、麻疹、白喉抗体阳性率分别为1.1%、53.6%、97.1%、95.7%、95.3%,抗体几何平均滴度 （GMT） 分别为 1∶67.47、1∶1 385.08、1∶0.13、1∶39.74。不同年龄组间脊灰抗体阳性率差异具有统计学意义（χ2 = 25.892,P＜0.001）;不同地区组间乙肝抗体、白喉抗体阳性率差异具有统计学意义（χ2HBsAb = 12.084,χ2DPIgG = 7.452,P＜0.05）;常住儿童脊灰、麻疹、白喉抗体阳性率均大于流动儿童（χ2PVIgG = 7.551,χ2MVIgG = 12.771,χ2DPIgG = 14.564,P＜0.05）。本地儿童乙肝、麻疹、白喉、乙脑接种率均大于外地儿童（P＜0.05）;儿童监护人对免疫规划知识、态度、行为调查问卷正确率均大于80%,信息获取主要渠道是预防接种门诊。结论 崇左市边境地区2～7岁儿童免疫规划疫苗抗体水平和接种率维持在较高水平,儿童监护人对疫苗可预防疾病知识水平达标。流动儿童和边远地区儿童为免疫规划管理薄弱人群,应结合抗体水平监测加强重点人群、重点地区的疫苗接种工作。     

江苏省2009年健康人群流行性乙型脑炎免疫水平监测分析

目的了解江苏省2009年健康人群乙脑免疫水平。方法采用蚀斑减少中和实验,选择两个监测点,分7个年龄组测定健康人群乙脑抗体水平。结果共检测741人,乙脑抗体阳性率为74.76%,GMT为1∶13.54。阳性率最高为20-岁组(94.00%),最低为1-岁组(49.50%),各年龄组阳性率差异有统计学意义(P<0.01)。两监测点阳性率分别为67.26%、83.14%,GMT分别为1∶10.80、1∶17.44,差异有统计学意义(P<0.01)。结论小年龄组儿童乙脑抗体阳性率较低,应重点加强这部分儿童的乙脑疫苗免疫接种工作,提高其抗体水平。     

微量细胞病变法检测健康人群EV71和CVA16中和抗体水平

目的了解深圳市福田区健康人群中肠道病毒71型(EV71)和柯萨奇A16型(CVA16)隐性感染情况。方法应用微量细胞病变法,对2011年和2012年一般人群流感抗体水平调查采集的471份血清标本进行EV71和CVA16中和抗体检测,并对检测结果进行统计学分析。结果 471份健康人群血清中EV71和CVA16中和抗体阳性率分别为25.50%和33.10%;EV71抗体由0～岁组的7.14%上升至15～岁组的42.65%(χ2=42.12,P<0.01),上升5.97倍,抗体几何平均滴度(GMT)呈缓慢上升趋势;CVA16抗体由0～岁组的9.18%上升至5～岁组的58.73%(χ2=61.87,P<0.01),上升6.39倍,抗体GMT呈波峰状;各年龄组两种抗体混合感染阳性率为11.25%(χ2=64.95,P<0.01)。结论本地区健康人群中存在肠道病毒隐性感染,各年龄组CVA16抗体阳性率均高于EV71;5～25年龄人群EV71和CVA16中和抗体阳性率、GMT和混合感染情况均高于其他年龄组,应加强5～25年龄人群的流行病学监测。     

江苏省自然人群乙型脑炎抗体血清学监测

目的了解江苏省正常人群流行性乙型脑炎(乙脑)免疫状况。方法采用蚀斑减少中和试验对2006-2009年收集的0～20岁血清标本3258份进行乙脑抗体检测。结果乙脑抗体总的阳性率为70.35%,GMT为1:13.56。结论江苏省3岁以上人群乙脑抗体有保护作用,其阳性率及效价随年龄增加而增加,0和1岁组抗体水平较低,应该加强该年龄段人群的保护。     

Long-term immunogenicity of an initial booster dose of an inactivated,Vero cell culture-derived Japanese encephalitis vaccine (JE-VC) and the safety and immunogenicity of a second JE-VC booster dose in children previously vaccinated with an inactivated,mouse brain-derived Japanese encephalitis vaccine

BackgroundThis study was performed with the aim of determining the long-term immunogenicity of an inactivated, Vero cell culture-derived Japanese encephalitis (JE) vaccine (JE-VC) and an inactivated, mouse brain-derived JE vaccine (JE-MB) after the 1st booster dose at 2 years of age, as well as the safety and immunogenicity of the 2nd booster dose of JE-VC at 6 years of age, in children primed and given a 1st booster dose of either JE-VC or JE-MB.MethodIn this multicenter, open-label clinical trial, the study population consisted of healthy Korean children (aged 6 years) who participated in the previous JE vaccine trial. All subjects were subcutaneously vaccinated once for the booster immunization with Boryung Cell Culture Japanese Encephalitis Vaccine® (JE-VC).ResultApproximately 4 years after the 1st booster dose of JE-VC, the seroprotection rate (SPR) and geometric mean titer (GMT) of the neutralizing antibody were 100% and 1113.8, respectively. In children primed and given a 1st booster dose of JE-MB, the SPR and GMT were 88.5% and 56.3, respectively. After the 2nd booster dose of JE-VC, all participants primed and given a 1st booster dose of either JE-MB or JE-VC were seroprotective against JE virus. The GMT of the neutralizing antibody was higher in children primed and given a 1st booster dose of JE-VC (8144.1) than in those primed and given a 1st booster dose of JE-MB (942.5) after the vaccination (p < 0.001). In addition, the 2nd booster dose of JE-VC showed a good safety profile with no serious vaccine-related adverse events.ConclusionThe 1st booster dose of JE-VC and JE-MB showed long-term immunogenicity of at least 4 years, and the 2nd booster dose of JE-VC showed a good safety and immunogenicity profile in children primed and given a 1st booster dose of either JE-VC or JE-MB.ClinicalTtrials.gov Identifier: NCT02532569     

黑龙江省人群2006年流行性乙型脑炎抗体水平监测

目的 了解黑龙江省健康人群流行性乙型脑炎(乙脑)病毒的感染状况和分布特点,分析人群乙脑抗体阳性率的影响因素.方法　2006年在全省7个国家级疾病监测点1～59岁人群中,分1～、3～、6～、11～、≥21岁5个年龄组,每个监测点每年龄组随机抽取30人,共1050名调查对象,应用定量ELISA方法检测乙脑IgG抗体.结果 调查地区1～59岁人群乙脑IgG抗体标化调整阳性率为70.62%,平均阳性率以3～岁组最低,并有随年龄上升而升高的趋势,趋势检验x2=40.52,P＜0.001.人群中乙脑IgG抗体整体水平较低,不同年龄抗体滴度水平不同,经Kruskal-Wallis非参数检验x2=76.9,P＜0.001,呈随年龄增长而增高的趋势.logistic分析结果显示,除年龄之外,居住地区纬度也是影响乙脑IgG阳性的因素,纬度越高,阳性率越低.结论 乙脑病毒感染在黑龙江省部分地区呈低水平长期存在,年龄增长和纬度降低是乙脑病毒抗体阳性率升高的影响因素.建议在重点地区加强乙脑病例、宿主动物和蚊虫带病毒情况监测.     

Assessment of neutralizing antibodies elicited by a vaccine (Nakayama) strain of Japanese encephalitis virus in Taiwan.

A total of 368 blood specimens were resampled from a serum collection containing 2914 blood samples which were collected by a random sampling in Taiwan in 1991. The plaque reduction neutralization test was applied to evaluate the neutralizing ability to two strains of Japanese encephalitis viruses, i.e. Nakayama (the present vaccine strain) and JE5 (a Taiwan isolate). The result revealed that antibodies against JE virus were present in each stratified age group. Antibody positive rates were both highest in the group older than 70 years although the lowest rates were located in different groups. In addition, the result showed that the immunogenicity potency of the antibody induced by the vaccine strain did not have a good coverage against JE5. The rate of neutralizing antibodies above the level of protective efficacy of the present vaccine was limited as low as 37.93%. Efficacy of the vaccine used at present was apparently not efficient. Consideration of a more promising vaccine may be necessary.     

河南省部分地区病毒性脑炎监测分析

目的分析河南省部分地区病毒性脑炎的病原种类及流行特点。方法对2008年新乡、开封、洛阳监测的病毒性脑炎病例进行流行病学调查,采集血液和脑脊液标本,采用ELISA方法检测流行性乙型脑炎(乙脑)IgM,对其中乙脑IgM阴性病例脑脊液标本进行细胞培养分离,采用逆转录聚合酶链反应(RT-PCR)检测其他病毒。结果从215例病毒性脑炎病例中检出乙脑IgM抗体阳性47例,阳性率为21.86%;从乙脑IgM阴性的168例脑脊液中分离到肠道病毒24株,阳性率为14.29%;24株肠道病毒中,埃可病毒30(ECHO30)12株,埃可病毒6(ECHO6)7株,埃可病毒25(ECHO25)4株,柯萨奇病毒B5(CoxB5)1株;47例乙脑和168例肠道病毒等病毒性脑炎发病高峰为7～9月,分别占93.62%和70.24%;新乡、开封的乙脑和肠道病毒等病毒性脑炎以0～14岁儿童为主,分别为91.91%、92.31%和97.92%、98.41%;洛阳的肠道病毒等病毒性脑炎0～14岁占92.99%,乙脑≥15岁发病明显上升,占56.52%,差异有统计学意义(χ2=21.13,P<0.05);洛阳乙脑病例以农民为主,新乡、开封乙脑病例及3地肠道病毒等病毒性脑炎病例均以散居、托幼儿童和学生为主。结论病毒性脑炎病原体以乙脑病毒和肠道病毒为主;乙脑与肠道病毒等病毒性脑炎高发季节一致;不同地区2类脑炎发病年龄、职业有差别。     

Immunogenicity and protective efficacy of the current inactivated Japanese encephalitis vaccine against different Japanese encephalitis virus strains

Mouse brain-derived, inactivated Japanese encephalitis (JE) vaccine has been internationally used for many years. It is believed that this vaccine made a great contribution to the reduction of JE patients in several countries. Mouse brain-derived, Beijing-1 and Nakayama JE vaccines induce high levels of neutralizing antibodies. High levels of induced antibodies are maintained at least for 3-4 yr. The induced antibodies are cross-reactive to heterologous strains; however, the neutralizing antibody titers against heterologous strains are usually lower than those against homologous strains. Considering that both Nakayama and Beijing-1 JE vaccines showed high levels of protective efficacy in Taiwan and Thailand where strains other than Nakayama and Beijing-1 were circulating, we conclude that the current inactivated JE vaccine can induce high levels of protective immunity against heterologous JE virus strains.     

High antibody prevalence in an unconventional ecosystem is related to circulation of a low-virulent strain of Japanese encephalitis virus

Liu-Chiu islet, a relatively isolated ecosystem that is free of rice cultivation, has long considered free of Japanese encephalitis (JE). However, a new strain (T1P1) of JE virus was isolated from the mosquito, Armigeres subalbatus, and a rather broad distribution of neutralizing antibody has been reported on the islet, suggesting that the circulating virus could be an attenuated strain. In an assessment on 219 blood samples obtained from residents of Liu-Chiu islet, the positive rate of JEV-specific IgM antibodies decreased with age while that of neutralizing antibodies increased with age. Both antibodies were mainly responsive to the T1P1 strain since higher positive rates and titers of specific neutralizing antibodies are shown in this investigation. Importantly, the T1P1 strain is herein characterized as being broader in neutralizing virus strains, stable in genetic traits, and productive in Vero cells. Taken together, the JE virus strain endemically circulating on Liu-Chiu islet may have served as a natural form of a live-attenuated vaccine. As a result, it possibly can be utilized as a new and effective vaccine candidate in the future.     

Needle-free jet injection of small doses of Japanese encephalitis DNA and inactivated vaccine mixture induces neutralizing antibodies in miniature pigs and protects against fetal death and mummification in pregnant sows

Japanese encephalitis (JE) virus causes abortion and stillbirth in swine, and encephalitis in humans and horses. We have previously reported that immunogenicity of a DNA vaccine against JE was synergistically enhanced in mice by co-immunization with a commercial inactivated JE vaccine (JEVAX) under a needle-free injection system. Here, we found that this immunization strategy was also effective in miniature pigs. Because of the synergism, miniature pigs immunized twice with a mixture of 10 μg of DNA and a 1/100 dose of JEVAX developed a high neutralizing antibody titer (1:190 at 90% plaque reduction assay). Even using 1 μg of DNA, 3 of 4 pigs developed neutralizing antibodies. Following challenge, all miniature pigs with detectable neutralizing antibodies were protected against viremia. Pregnant sows inoculated with 10 or 1 μg of DNA mixed with JEVAX (1/100 dose) developed antibody titers of 1:40–1:320. Following challenge, fetal death and mummification were protected against in DNA/JEVAX-immunized sows.