1996-2005年慈溪市成人麻疹流行病学特征

目的了解慈溪市≥18岁成人麻疹的流行病学特征,控制探讨麻疹的措施。方法应用流行病学方法对1996-2005年慈溪市≥18岁成人麻疹发病情况进行分析。结果1996-2005年慈溪市共报告成人麻疹133例,发病率波动在0.20/10万～4.31/10万,构成比波动在7.69%～45.45%之间。3～5月份为麻疹发病高峰,占成人麻疹发病总数的71.43%。病例男女性别比0.49∶1。职业分布以民工、农民、工人为主,3者共占73.68%。有90.98%的成人麻疹病例无免疫史或免疫史不详。本地户籍病例83例,占发病数的62.41%,外地户籍病例50例,占发病数的37.59%。两者有免疫史比例差异无统计学意义(χ2=1.58,P>0.05)。结论无麻疹疫苗免疫史及免疫失败人群、外来人口是慈溪市成人麻疹发病的高危人群。要确保MV高接种率和免疫成功率,特别是要加强外来人口的管理,是控制成人麻疹的关键。     

沪191株麻疹疫苗的流行病学效果评价

为了评价沪1 91 株麻疹疫苗 (MV)的流行病学效果 ,1991年 10月在荆州市荆州区川店镇建立了MV免疫效果观察点 ,以 5 0 3名MV初免儿童 (其中 10 1名于 1年后进行了复种 )作为观察对象 ,1992～ 1999年连续对观察点所有发热、出疹性疾病病人进行监测 ,,并采集血清标本 ,作麻疹和风疹血清学鉴别诊断。结果显示 :1992年和 1993年各发生 1例麻疹 ,1999年发生一起麻疹和风疹混合流行 ,查 15 0例病人中的 91例血清 ,麻疹抗体阳性 5 6例 ,其中 2 6例风疹IgM抗体同时阳性。所有发热、出疹性疾病病例中 ,仅 1例为MV观察对象 ,该儿童初免未成功 ,属原发性免疫失败。流行后期 ,检测 19名MV观察对象麻疹IgG抗体 ,隐性感染率为 94 74% (18/ 19)。表明沪1 91 株MV流行病学效果是满意的     

马关县苗族村寨麻疹爆发的调查

目的了解云南省马关县苗族村寨2005年10月16日~11月12日麻疹爆发的原因。方法对麻疹疫情进行流行病学调查分析,收集患者急性期鼻咽拭子和尿标本,分离麻疹病毒;采集现症病例和未发病人群血清标本,用酶联免疫吸附试验检测抗体。结果119例麻疹分布于4个村。年龄最小的8月龄,最大32岁,0~13岁占84.87%。现症病人63.16%无麻疹减毒活疫苗(MV)免疫史,31.58%免疫史不详。疫区301名儿童MV接种率88.37%,疫苗效力88.79%,麻疹感染人群中62%有接触史。患者血清标本麻疹IgM抗体阳性率59.09%,未发病人群血清标本麻疹IgG抗体阳性率61.76%。分离到麻疹病毒4株,基因型为H1。结论马关县苗族村寨发生的经血清学和病毒学检测证实的麻疹疫情,由于卫生院报告疫情滞后,部分村寨存在免疫空白,MV接种不落实导致爆发。麻疹感染者作为传染源应引起重视。     

286例麻疹确诊病例流行病学分析

目的了解郑州市麻疹病例流行病学特征,探索麻疹流行规律,为控制麻疹提供科学依据。方法采用抗体捕捉酶联免疫吸附试验(ELISA)对疑似病例血清进行麻疹抗体(1gM)检测,对确诊病例进行个案调查和流行病学分析。结果2月~4月为麻疹的高发季节,占全年总病例的77.62%;麻疹发病主要集中在8月龄-2岁年龄组,占50.70%;麻疹疫苗(MV)预防接种史不详病例占15.73%,无免疫史的占74.13%,有免疫史的占10.14%;286例麻疹病例中,184例属于流动人口,102例属于非流动人口,流动人口与非流动人口麻疹病例的预防接种史、发病年龄构成均有显著差异。结论麻疹发病与MV实际接种率不高和免疫失败有关,其中流动人口是MV预防接种工作的薄弱环节。今后应进一步加强MV的初免和复种工作,改进对流动儿童的计划免疫服务方式,在切实提高MV及时接种率和免疫覆盖率的同时提高免疫成功率。     

陕西省2003年麻疹流行病学特征及健康人群麻疹抗体水平监测分析

为了解陕西省麻疹流行病学特征 ,评价健康人群麻疹抗体水平 ,对麻疹发病和实验室资料进行分析。结果显示 :陕西省 2 0 0 3年麻疹流行模式为爆发和散发并存 ,局部地区麻疹爆发影响着全省麻疹发病水平 ,发病年龄和免疫史状况说明 8月龄～ 7岁为高发年龄段 ,该年龄段病例麻疹疫苗 (MV)接种率为 4 3%。 4、5月为麻疹高发月 ,病例数占全年病例总数的 6 0 %。麻疹抗体水平监测结果显示 :2 0 0 3年健康人群麻疹抗体阳性率和几何平均滴度倒数 (GMRT)较 2 0 0 1年上升明显 ,处于较高水平。 2～ 4岁麻疹抗体GMRT较低。提示MV初种和复种均必须加强 ,有效接种率有待提高。应对 1 5～ 2岁儿童增加 1次MV免疫 ,8月龄～ 14岁儿童开展MV的强化免疫。     

IgG抗体亲和力方法用于鉴别麻疹原发和继发性免疫失败

目的探讨麻疹消除阶段IgG抗体亲和力应用于区分原发和继发性免疫失败麻疹病例的意义。方法采用酶联免疫吸附方法检测92例麻疹诊断病例(其中17例为一起学校麻疹暴发疫情病例)的血清IgM和IgG抗体水平,测定IgG抗体亲和力,计算相对亲和力指数。结果 17例暴发疫情病例的血清IgM阳性率为41.18%(7/17),IgG阳性率为100%(17/17),全部为高亲和力IgG抗体。在另75例IgM阳性病例中,IgG阳性率为76.00%(57/75),有高亲和力IgG抗体的病例占61.4%(35/57)。92例病例中未接种含麻疹成分疫苗(MCV)25例,有高亲和力IgG抗体的病例占48%(12/25);22例病例接种≥1剂MCV,有高亲和力IgG抗体的病例占77.27%(17/22)。MCV接种病例中继发性免疫失败麻疹病例17例,原发性免疫失败麻疹病例5例。结论麻疹IgG抗体亲和力测定可用于鉴别麻疹原发和继发性免疫失败病例,解决了中国消除麻疹的这一关键技术问题。     

滁州市2004年麻疹流行病学分析

目的了解滁州市麻疹流行病学特征,探讨麻疹控制策略。方法对滁州市2004年175例病例进行回顾性分析。结果滁州市2004年麻疹发病率4.04/10万,高于1999~2003年平均水平,3~6月份为麻疹高发季节,≤2岁和7~9岁为麻疹高发年龄组,学生和散居儿童为高发人群。对麻疹病例免疫接种史分析表明,接种MV者占40.57%,未接种者占12.57%,不详占42.86%;未满8月龄7例,占4.00%。结论应进一步加强MV基础免疫与强化免疫工作,提高免疫覆盖率,同时应考虑对大年龄组人群接种MV。     

福建省2015—2019年麻疹实验室确诊病例免疫失败类型分析

目的 分析福建省2015—2019年麻疹实验室确诊病例免疫失败类型分布特征,探讨麻疹疫苗高接种率人群发病的危险因素。方法 用酶联免疫吸附试验,检测330例8月龄以上麻疹病例的急性期血清IgM和IgG抗体水平,以判定免疫失败类型。结果 330例中34.2%(113例)为原发性免疫失败(primary vaccination failure, PVF)、65.8%(217例)为继发性免疫失败(secondary vaccination failure, SVF);2015—2019年SVF占比呈上升趋势(趋势χ² =15.24,P<0.01),尤其2018—2019年SVF占82.9%(63/76)高于2015—2017年的60.6%(154/254,χ² =12.88,P<0.01);含麻疹成份疫苗(MCV)接种病例中,1剂次和2剂次SVF占比(89.3%和80.0%)高于无免疫史病例(49.1%,χ²=113.86,P<0.01);IgM阴性的42例中66.7%(28例)为SVF。结论 SVF是免疫接种...     

绵阳市2005年7起麻疹暴发疫情流行因素分析

[目的]了解绵阳市2005年麻疹暴发疫情的流行因素,总结控制工作中的经验。[方法]根据绵阳市麻疹监测系统资料,对2005年麻疹疫情进行描述流行病学分析。描述绵阳市麻疹流行近况;流行病学分析麻疹的流行因素,包括人群免疫状况、感染方式、传染源管理、麻疹疫苗（MV）保护效力,对免疫干预预防措施效果进行评价。[结果]2005年共发生麻疹348例,发病率为6.73/10万,较2004年上升7.74倍;发生暴发疫情7起154例;72.41%的病例﹤15岁;86.21%的病例发生在3～6月份和9月份;72.13%的病例无麻疹疫苗（MV）免疫史或免疫史不详;麻疹监测指标达到监测方案要求。[结论]流动儿童MV接种率低于常住儿童,是供方未及时对流动儿童提供第1针MV免疫服务的重要原因;不在学校接种MV,后期又无督促机制,严重影响MV第2针接种率。麻疹发病率上升的原因主要与存在免疫空白和免疫失败人群有关,控制麻疹暴发的重点在学校,高质量的麻疹疫苗常规免疫接种是减少麻疹发病和控制麻疹暴发的重要措施之一。感染麻疹的主要因素为医院暴露、与病例接触、未接种MV。传染源管理目前存在薄弱环节。按卫生部新免疫程序针对6岁以上儿童不开展MV接种,绵阳市可通过对入托、入学查验预防接种证确保所有儿童完成全程接种。针对≥15岁成人麻疹的控制,尚需现场证据证明其有效和可行性。减少暴露机会、控制传染源等措施引起重视。     

福建省2000年麻疹病例流行病学监测分析

[目的]使麻疹监测系统更加完善,为分析和预测麻疹流行趋势、判定高危人群、制订和调整有关策略与措施等服务。[方法]建立数据库,用EpiInfo软件进行流行病学统计分析。[结果]2000年人群麻疹IgG抗体阳性率为93.1%,在已知免疫史麻疹病例中未免疫仅占23.1%。各县递交完整麻疹监测月报告数占应报数的88.5%,麻疹监测系统报告病例占大疫情系统年报报告病例的85.2%,监测系统报告病例中有报告个案调查表占53.8%,免疫史不详占41.7%,仅17例经实验室确诊,咳嗽等主要症状不详比例均达到10%以上,暴发病例占总病例的22.8%,经实验室确诊的麻疹暴发次数占麻疹暴发次数的百分比为60%,[结论]人群的麻疹免疫水平有明显提高,发病以原发性和继发性（免疫失败）为主,福建省较为有效地控制了麻疹的流行,麻疹监测系统的敏感性有明显提高,但资料的完整性较差,现阶段每月及时递交完整麻疹监测报告仍是麻疹监测的重点,各地还应加强实验室检测工作。     

A measles outbreak from an index case with immunologically confirmed secondary vaccine failure

During the elimination stage of measles, the development of such disease in individuals who received measles-containing vaccine (MCV) is a concern from an epidemiological standpoint. A few cases in which measles was transmitted from a patient who received two doses of MCV have been reported. However, whether such transmissions were caused by primary vaccine failure (PVF) or secondary vaccine failure (SVF) remains unclear. All patients suspected of measles in Osaka Prefecture between November and December 2018 were enrolled. Data about age, gender, immunization record, and clinical signs were obtained. Laboratory examinations were performed, which included virus isolation in tissue culture, a nucleic acid test based on virus-specific real-time polymerase chain reaction and humoral responses to the measles virus measuring immunoglobulin (Ig) M, IgG, avidity of IgG, and neutralizing antibody concentration. The measles outbreak comprised 10 laboratory confirmed cases, including three secondary and six tertiary patients. Among them, three secondary patients were unvaccinated. The index case had received two MCV doses, and the six tertiary patients were vaccinated. Both the index and tertiary patients had high specific IgG concentration with high avidity. In particular, the index patient had a markedly high neutralization antibody concentration of 425,590 mIU/mL, which indicated immunological SVF. This study first reported about measles transmission from an individual with SVF who received two vaccination doses. To prevent measles transmission and outbreak particularly in countries where measles was almost eliminated, patients with SVF for measles should be cautiously monitored.     

Measles epidemic in Romania, 1996-1998: assessment of vaccine effectiveness by case-control and cohort studies

A measles epidemic occurred in Romania with 32,915 cases and 21 deaths reported between November 1996 and June 1998, despite high vaccination coverage since the early 1980s. Most cases were unvaccinated children aged <2 years and vaccinated school-aged children. A case-control study among preschool children and a cohort study among primary-school children were conducted to estimate effectiveness of Romanian-produced measles vaccine, and to evaluate age at vaccination and waning immunity as risk factors for vaccine failure. Both studies indicated that measles vaccine was highly effective. One dose reduced the risk for measles by 89% (95% confidence interval (CI) 85, 91); two doses reduced the risk by 96% (95% CI 92, 98). Children vaccinated at <1 year of age were not at increased risk for measles compared with children vaccinated at > or =1 year. Waning immunity was not identified as a risk factor since vaccine effectiveness was similar for children vaccinated 6-8, 9-11, and 12-14 years in the past. Because specific groups were not at risk for vaccine failure, an immunization campaign that targets all school-aged children who lack two doses may be an effective strategy for preventing outbreaks. A mass campaign followed by increased first-dose coverage should provide the population immunity required to interrupt indigenous measles virus transmission in Romania.     

Measles infection in persons with secondary vaccine failure,New York City, 2018–19

A large measles outbreak in New York City, which included cases among vaccinated persons and adults presumed to be immune, provided the opportunity to better understand vaccine failure and the potential impact on measles transmission. Immunoglobulin G (IgG) avidity can distinguish primary (low avidity IgG, indicating no evidence of prior immunity) versus secondary vaccine failure (high avidity IgG, indicating prior immune response and waning antibody). Measles IgG avidity was measured on samples from 62 persons: avidity was high in 53 (16 vaccinated and 37 with unknown vaccination history) and low in 9 (1 recently vaccinated and 8 with unknown vaccination history). Secondary transmission from 2 persons with high-avidity IgG results occurred. These findings illustrate that in settings of sustained measles elimination, measles infection and transmission can occur in persons with secondary vaccine failure, underscoring the need to maintain a high index of suspicion for measles during an outbreak despite prior or presumed prior vaccination.     

北京地区SARS康复者冠状病毒IgM、IgG抗体水平的变化

目的探讨SARS康复者康复后及其1年内血清冠状病毒IgG、IgM抗体的产生水平及动态变化,为该病的下一步预防和疫苗的保护效力提供依据.方法采用ELISA法对SARS康复者冠状病毒IgG、IgM抗体进行检测,对IgG或IgM抗体连续两次检测都为阳性者继续随访1年;对二者连续两次都为阴性者放弃随访;随访结果用stata 7.0软件分析.结果 81.2%的康复者连续两次IgG抗体检测阳性;18.8%的康复者连续两次IgG抗体阴性;对311例IgG抗体阳性者进行了1年的随访,除1例在出院后85 d时抗体变为阴性外,其他310例康复者1年后IgG抗体仍为阳性,但抗体平均水平下降了约35.8%;22例IgG抗体阳性康复者(2003年4月3日～5月21日出院)进行了IgM抗体检测,2003年5月30日检测时,22.7%的康复者IgM抗体阳性,2003年6月14日检测时,IgM抗体全为阴性.结论 IgM抗体在康复后短期内很快消失;约有81.2%的康复者能够产生IgG抗体;1年随访中,除1例康复者IgG抗体由阳性转为阴性外,其他IgG抗体阳性者1年后该抗体仍为阳性,但抗体水平有所下降.     

Mumps outbreak and MMR IgG surveillance as a predictor for immunity in military trainees

In 2017, a mumps outbreak occurred in a barrack holding 249 service members. Suspected cases were evaluated with a combination of mumps IgG, IgM, viral culture, PCR and sequencing. Seven cases were diagnosed in febrile patients presenting with parotitis or orchitis. Mumps infection was confirmed by IgM or positive PCR with 5/7 cases having notable IgG levels before infection. Sequencing confirmed mumps genotype G strain. Serum from all 249 service members collected prior to the outbreak was withdrawn from the Department of Defense (DoD) Serum Repository and the IgG values of measles, mumps and rubella determined with 20.2%, 12.3% and 9.7% service members being seronegative, respectively. No specific IgG seronegativity combination predicted IgG marker levels to another virus within the same vaccine. This paper provides additional evidence that mumps serology is not a reliable surrogate for mumps immunity and that we need better laboratory correlates to confirm immunity.     

Investigation of the effectiveness of measles vaccination in children in Kenya

Laboratory studies were performed on 128 children clinically diagnosed as measles when seen at the Infectious Diseases Hospital, Kenyatta National Hospital (IDH), Nairobi (86 cases) and the Rural Health Training Centre, Maragua, Central Province (42 cases) between 9 July and 31 August 1984. A concurrent measles infection was confirmed in 95% of the children seen at IDH and in 85% of those seen at Maragua, with similar proportions of confirmations in children who had, and who had not, received measles vaccine. No differences in the number of sero-conversions nor in the absolute levels of acute or convalescent HI antibody titres could be detected between vaccinated and unvaccinated children. Analysis of the cases seen at Maragua indicates that about two thirds of the children who had received vaccine were protected. A pilot study of vaccinating children at 8 months and again at 12-13 months is suggested in an attempt to eradicate measles.     

Serological response to measles revaccination in a highly immunized military dependent adolescent population

In the spring of 1986, there was a measles outbreak in the city of El Paso, Texas, with 92 cases reported to the City-County Health Department. Of those 92 cases, 31 (32%) occurred within a public high school's student population of 2524. A mass measles vaccination program was undertaken at that high school in order to limit the outbreak. The student enrollment included a military dependent population of 368 students. Despite documented histories of prior measles immunizations in this military dependent subgroup, three individuals contracted the disease. Since this subgroup of students represented a highly immunized adolescent population, it was of interest to serologically determine their immune status prior to and following reimmunization with the expectation that such a study would provide information relating to the level of "protective" immunity. Prevaccination and postvaccination sera were obtained from 95 students. Results of measuring anti-measles antibody activity by ELISA indicate that 13 (14%) students responded to revaccination and experienced a fourfold or greater rise in IgG antibody levels. There were no detectable IgM responses. All of the students who responded to revaccination produced an anamnestic response (IgG boost only). Since most of these individuals had received first immunizations at 15 months of age or older, these findings suggest that secondary vaccine failure (waning immunity) was responsible for the putative "lowered" immunity in these individuals, instead of primary vaccine failure (maternal antibody suppression). These findings support current recommendations for measles booster revaccination of school-age children and adolescents.     

Measles immunity and response to revaccination among secondary school children in Cumbria.

The prevalence of antibody to measles virus in 759 children aged 11-18 years attending a secondary school in Cumbria was measured using a salivary IgG antibody capture assay. Serum IgG antibody levels were measured using a plaque reduction neutralization assay in subjects whose saliva was antibody negative. Vaccination histories were obtained from the child health computer and general practice record. A total of 662 pupils (87% of those tested) had detectable measles-specific IgG in saliva. Of the remaining 97, 82 provided blood samples and 29 had serum neutralizing antibody levels above 200 mIU/ml. Afer adjusting for non-participation rates, the proportion considered non-immune (no IgG in saliva and < or = 200 mIU/ml in serum) was 9% overall, ranging from 6% in vaccinated children to 20% in unvaccinated children. Measles-mumps-rubella vaccine was given to 50 children of whom 38 provided post-vaccination serum and 32 saliva samples. Thirty (79%) had a fourfold or greater rise in serum neutralizing antibody and 28 (88%) developed IgG antibody in saliva. Half of the children considered non-immune by antibody testing would have been overlooked in a selective vaccination programme targeted at those without a history of prior vaccination. A programme targeted at all school children should substantially reduce the proportion non-immune since a primary or booster response was achieved in three quarters of previously vaccinated children with low antibody levels and in all unvaccinated children. While it is feasible to screen a school-sized population for immunity to measles relatively quickly using a salivary IgG assay, a simple inexpensive field assay would need to be developed before salivary screening and selective vaccination could substitute for universal vaccination of populations at risk of measles outbreaks. The salivary IgG assay provided a sensitive measure of a booster response to vaccination.     

Inadequate immunity to measles in children vaccinated at an early age: effect of revaccination

This report describes a follow-up serological study of 79 Brazilian children who, because of their young age, had failed to develop protective levels of immunity after vaccination against measles. There was serological evidence that infection with wild virus had occurred at a rate of about 17% per annum. Approximately 1½ years after the initial vaccination, 46% of the uninfected children maintained very low levels of neutralizing antibody, but did not have a measurable haemagglutination-inhibition titre. Revaccination did not elicit an IgM response in most children, but stimulated anti-measles IgG production in all of them. In 36% of the children, the IgG titres fell again within three months to levels that may permit reinfection. If it is assumed that some of the persistent titres can be attributed to wild virus infection, the actual effect of revaccination would have been to immunize no more than 60% of the susceptible group. The results suggest that early administration of measles vaccine may produce a cohort of children with inadequate immunity who cannot be fully immunized by revaccination. The implications of these findings for measles immunization programmes are discussed.