2011-2017年河北省甲型H1N1流感流行特征分析

目的掌握河北省甲型H1N1流感的流行特征,为流感防控提供科学依据.方法通过中国流感监测信息系统收集河北省2011年4月至2017年3月流感及流感样病例(influenza-likeillness,ILI)监测数据进行统计分析.结果共检测ILI标本77 008份,甲型H1N1流感病毒核酸阳性2 699份,阳性率3.50％.对2 699例甲型H1N1流感病例进一步分析显示:全省11个地市均有该病例检出,男女比例为1.09:1,各年龄组均可发病,检出率最高的是25～59岁组,最低0～4岁组.2011年11月至2017年3月共出现4次流行,具有明显的季节性,且呈单峰性.各年度均有甲型H1N1流感病例检出,甲型H1N1流感分别是2012-2013、2013-2014和2016-2017年度的优势病原.结论河北省甲型N1N1流感流行具有明显的季节性,冬春季流行,近年来感染以5～14岁年龄组为主.     

应用CUSUM和EWMA模型探测甲型H1N1流感流行起始的预警研究

目的 探讨累计和( CUSUM)和指数加权移动平均(EWMA)模型探测甲型H1 N1流感流行起始的功效.方法 利用北京市2009年流感样病例监测数据,分别采用CUSUM和EWMA模型对数据进行分析,与流感病原学监测数据进行对比,分析了不同参数组合下2种模型探测甲型H1N1流感流行起始的效果.结果 流感病原学监测显示20...     

2009甲型H1N1流感大流行期间北京儿童的流感监测

目的 了解2009年甲型H1N1流感大流行期间北京地区儿童中流感流行的情况.方法 采用WHO推荐的实时荧光定量RT-PCR和国家流感中心推荐的分型方法,对2009年甲型H1N1流感大流行期间因流感样症状来首都儿科研究所附属儿童医院就诊患儿的咽拭子标本进行流感病毒核酸检测.结果 2009年6月1日至2010年2月28日期间共检测了4363份咽拭子标本,其中623例为甲型H1N1阳性,阳性率为14.3%,657例为其他甲型流感病毒阳性(15.1%),所有甲型流感病毒的总阳性率为29.3%.623例中有23例为危重症病例(占阳性患者的3.7%),其中5例死亡.618例信息完整的甲型H1N1病例中,患儿年龄为14天～16岁,性别比例为男比女为1.3:1.1～3岁儿童占25.2%,3～6岁学龄前儿童和6～12岁学龄儿童所占比例相近,各约占30%.在监测期间,仅呈现了一个甲型H1N1的流行波.2009年11月达到最高峰,随后减弱,2010年2月快速下降至2.7%.对监测期间每周20～30份临床标本同时进行季节性流感的监测显示,季节性H3N2、甲型H1N1和乙型流感交替流行.呼吸道合胞病毒(RSV)在甲型H1N1流行趋势减缓后逐渐流行成为流行优势株.结论 2009年6月至2010年2月北京地区儿童中出现甲型H1N1的流行,主要累及学龄前和学龄儿童.季节性流感和RSV与甲型H1N1交替流行.     

河北省2009-2014年甲型H1N1流感流行特征分析

目的 分析河北省2009-2014年度甲型H1N1流感的流行特征.方法 采用描述性流行病学方法对2009年4月1日-2014年3月31日的流感监测结果进行分析.结果 采集的47949例流感样病例(influenza-like illness,ILI)标本经流感病毒核酸检测,8248例阳性(阳性率为17.20％),其中甲型H1N1 4168例,季节性H3 2006例,B型1820例,季节性H1等254例.各年度优势病原不同,除2010-2011年度外,其他年度均存在甲型H1N1流感病毒流行.对4168例甲型H1N1病例进一步分析显示:全省11个地市均有该病例检出,男女性别比1.09:1.自2009年甲流大流行后,2011年11月至2014年3月共出现3次流行,具有明显的季节性,且呈单峰分布.结论 河北省甲型N1N1流感的流行趋势已趋于季节性,无明显的地域性,除2010-2011年度外,其他年度都是优势病原之一,近年来感染以25-59岁年龄组为主.     

2009-2010年山西省流感／甲型H1N1流感的病原学监测分析

目的分析掌握山西省2009--2010年流感／甲型H1N1流感的流行特征,为预测和防控流感／甲型H1N1流感流行提供科学依据。方法对哨点医院和集体发热疫情进行监测采样,采用病毒核酸检测法和细胞培养法分离鉴定流感／甲型H1N1流感病毒,并对2009年5月至2010年4月山西省录入“中国流感监测信息系统”的流感样病例监测报告数据及其样本病原学监测数据进行统计分析。结果山西省全年均有流感病毒活动,2009年流行优势毒株为甲型H1N1流感病毒,流行最高峰在11月（阳性率为58．1％,甲型H1N1占88．1％）,主要导致59岁以下人群发病,其中5-24岁年龄组阳性率较高,进入2010年后乙型（Victoria系）流感病毒的活动有所增加,成为流行株。结论流感样病例监测和病原学监测,可以及时反映流感活动状况,对于掌握该省流感／甲型H1N1流感流行规律有着重要意义。     

广东从化市首起甲型H1N1流感疫情的调查

目的探讨从化市首例甲型H1N1流感病例的发生过程,为制订防控措施提供依据。方法按照2009年卫生部《甲型H1N1流感流行病学调查和暴发疫情处理技术指南（试行）》的要求进行现场流行病学调查。结果病例潜伏期74h,体温37.5℃,无明显呼吸道症状;临床症状较轻;咽拭子样本检测,甲型H1N1流感病毒核酸阳性,确诊为甲型H1N1流感病例;未见续发二代病例。结论本事件为输入性二代病例引发本地感染甲型H1N1流感疫情,感染者在无防护的环境下,接触保留带有甲型H1N1流感病毒的被褥或尘埃后导致感染。     

402例甲型H1N1流感病例流行病学特征分析

目的了解深圳市福田区甲型H1N1流感病例的流行病学特征,为甲型H1N1流感预防控制提供科学依据。方法应用描述性流行病学方法分析402例甲型H1N1流感病例的流行病学特征,包括病例的年龄、性别、职业分布、地区分布等。结果 402例甲型H1N1流感病例男性占58.71%,女性占41.29%;90.55%的病例集中在0～30岁年龄段,11～20岁年龄段病例最多,占总病例数的41.79%;从职业构成看,所有病例中,绝大多数为学生,占总病例数的64.18%。结论学生是甲型H1N1流感的危险人群,应当注重学校等场所的甲型H1N1流感防控工作。     

中国首例甲型H1N1流感二代病例的临床特征

目的了解2009年我国首例甲型H1N1流感二代病例的流行病学、临床、病原学检查特点及预后转归。方法对患者流行病学及临床资料进行回顾性分析,并采用实时荧光聚合酶链反应测定甲型H1N1流感病毒核酸。结果患者与甲型H1N1流感输入病例接触1天后发病。以发热、咽痛、咳嗽起病,白细胞及CD4＋T淋巴细胞计数降低,无肺炎等并发症。多级机构检测咽拭子甲型H1N1流感病毒核酸阳性确诊甲型H1N1流感。RT-PCR测序证实其病毒核苷酸序列与一代输入病例的一致,同源性为100%。经奥司他韦抗病毒及对症治疗痊愈出院。结论本病例的传染源明确,为我国首例报告的甲型H1N1流感二代确诊病例,其临床表现轻,病情恢复快。未发生院内感染,早隔离早诊断等防控措施有效。     

广东省深圳市流感流行特征分析

目的 掌握深圳市流感流行规律,了解甲流大流行以后流感的流行趋势.方法 对深圳市流感样病例监测数据、病原学检测结果和暴发疫情资料进行分析.结果 深圳市的流感样病例百分比(ILI％)为4.67％,呈逐年下降趋势,ILI年龄构成以0-4岁为主(占54.2％).流感病毒分离平均阳性率为10.6％,按月分析流感病毒分离阳性率与ILI％变化趋势呈正相关(r=0.447,P =0.001).全市报告了482起ILI暴发疫情,以乙型流感为主(占63.9％).2010年深圳市季节性流感出现了春季和夏季流行高峰,分别以乙型Victoria系和甲型H1N1亚型为优势株;2011年为冬春季和秋季高峰,以甲型H1N1和季节性H3亚型为优势株;2012年出现了冬春季和夏季高峰,以乙型(Victoria系和Yamagata系)和季节性H3亚型为优势株;2013年出现了春、秋、冬季三个流行高峰,分别以甲型H1N1、季节性H3和乙型Yamagata系为优势株.结论 深圳市季节性流感每年均出现2-3个流行高峰,分别在冬春季和夏秋季,每年流行高峰出现的时间不同,每年流行的型别不同.     

卫生部办公厅关于印发《甲型H1N1流感密切接触者中相关人员预防性用药指南（2009年试行版）》的通知

为做好甲型H1N1流感疫情防控工作,尽可能防止密切接触者中相关人员感染,延缓、减少续发病例,参考美国疾病预防控制中心《甲型H1N1流感患者和密切接触者抗病毒治疗临时指导意见（2009年5月6日版）》和世界卫生组织《流感大流行期间疫苗及抗病毒药物应用指南（2004年版）》,结合我国防治甲型H1N1流感初步经验,卫生部于2009年6月1日印发《甲型H1N1流感密切接触者中相关人员预防性用药指南（2009年试行版）》（以下简称《指南》）,供甲型H1N1流感防控工作中参考。随着对甲型H1N1流感认识的不断深入和防控形势变化,卫生部将适时组织专家对《指南》进行修订。     

北京市中小学生甲型H1N1流感感染影响因素的病例对照研究

目的 探讨北京市中、小学生甲型H1N1流感感染的相关影响因素.方法采用1∶2病例-对照研究方法,通过问卷调查,在6个区县收集304对病例和对照的个人卫生习惯、疫苗接种史、搭乘交通工具等信息.结果多因素logistic回归结果显示,教室内学生密度,教室通风情况,课间活动范围,打喷嚏后是否洗手,睡眠时间,上学交通方式,接种...     

北京市中小学生甲型H1N1流感感染影响因素的病例对照研究

目的 探讨北京市中、小学生甲型H1N1流感感染的相关影响因素.方法采用1∶2病例-对照研究方法,通过问卷调查,在6个区县收集304对病例和对照的个人卫生习惯、疫苗接种史、搭乘交通工具等信息.结果多因素logistic回归结果显示,教室内学生密度,教室通风情况,课间活动范围,打喷嚏后是否洗手,睡眠时间,上学交通方式,接种甲流疫苗和不带病上课与甲型H1N1流感感染有关.结论参加户外活动、加强教室通风、注意手卫生、保证睡眠允足、不乘坐密闭的交通工具、接种甲型H1N1流感疫苗是预防中小学生甲型H1N1流感感染的重要手段.     

Characterization and long-term persistence of immune response following two doses of an AS03A-adjuvanted H1N1 influenza vaccine in healthy Japanese adults

Background Long-term persistence of immune response and safety of two doses of an A/California/07/2009 H1N1 pandemic influenza vaccine adjuvanted with AS03 (an α-tocopherol oil-in-water emulsion-based Adjuvant System) administered 21 d apart was evaluated in Japanese adults [NCT00989612]. Methods One-hundred healthy subjects aged 20-64 y (stratified [1:1] into two age strata 20-40 y and 41-64 y) received 21 d apart, two doses of AS03-adjuvanted 3.75μg haemagglutinin (HA) H1N1 2009 vaccine. Immunogenicity data by haemagglutination inhibition (HI) assay six months after the first vaccine dose (Day 182) and microneutralization assay following each of the two vaccine doses (Days 21 and 42) and at Day 182 are reported here. Results Persistence of strong HI immune response was observed at Day 182 that met the US and European regulatory thresholds for pandemic influenza vaccines (seroprotection rate: 95%; seroconversion rate: 93%; geometric mean fold-rise: 20). The neutralizing antibody response against the A/Netherlands/602/2009 strain (antigenically similar to vaccine-strain) persisted for at least up to Day 182 (vaccine response rate: 76%; geometric mean titer: 114.4) and paralleled the HI immune response at all time points. No marked difference was observed in HI antibody persistence and neutralising antibody response between the two age strata. The vaccine had a clinically-acceptable safety profile. Conclusion Two priming doses of H1N1 2009 pandemic influenza vaccine induced an immune response persisting for at least six months after the first vaccine dose. This could be beneficial in evaluating the importance and effect of vaccination with this AS03-adjuvanted pandemic influenza vaccine.     

Duration of viral shedding in patients admitted to hospital with pandemic influenza A/H1N1 2009 infection

Little is known about the kinetics of viral shedding of pandemic influenza A/H1N1 2009 virus. Influenza RNA, as a surrogate for viral clearance, was therefore measured on days 1, 5, 7, and 10 or more in patients admitted to hospital with pandemic influenza A/H1N1 2009 infection. A total of 72 patients who were admitted to hospital with confirmed pandemic influenza A/H1N1 2009 at a tertiary care hospital, Seoul, South Korea, between 1 September and 11 November 2009 were evaluated. The median duration of viral shedding, as assessed by RT-PCR, was 9 days, as determined by the Kaplan-Meier method. Patients who were positive by RT-PCR at their last assay, but who were discharged before the next RT-PCR test due to symptom improvement, were censored from the analysis. If such patients were included, with the assumption that they had negative viral status at discharge, the median duration of viral shedding was 5 days (interquartile range, 2-8 days). These calculations thus suggest that the true median duration of viral shedding is between 5 and 9 days. Univariate analysis showed that delayed administration of antiviral therapy and comorbidity were associated with slower viral clearance. Multivariate analysis showed that oseltamivir started after the first day of symptoms (OR 2.7, 95% CI 1.2-5.7) was associated independently with slower viral clearance. These findings indicate that, in about 50% of patients admitted to hospital with pandemic influenza A/H1N1 2009, virus can be positive as tested by RT-PCR on the eighth day after developing symptoms of influenza. The present findings also indicate that starting antiviral therapy within 24 hr of the onset of symptoms is associated with more rapid viral clearance.     

La grippe A (H1N1) 2009 à Mayotte: mise en place d’une surveillance épidémiologique face à la menace de pandémie

In response to the threat of the pandemic influenza A (H1N1) 2009 virus in Mayotte Island, influenza surveillance needed to be set up in a matter of weeks, to detect the introduction of the pandemic virus and monitor its spread and impact on public health. Surveillance was based on different systems, including a sentinel practitioner network for influenza-like illness, surveillance of the activity at the hospital emergency departments, virological surveillance, surveillance of severe and fatal cases, and data collection on sale of antipyretic and anti-viral drugs. Despite some weaknesses of the surveillance, results showed a good correlation between all systems, describing an epidemic period of approximately 8-9 weeks, with a peak between weeks 37 and 40, followed by a rapid decrease. Besides allowing monitoring and describing the impact of pandemic H1N1 2009 virus in Mayotte, the surveillance system provided an opportunity to create networks and globally strengthened surveillance of infectious diseases in the Island.     

Fatal cases of 2009 pandemic influenza A (H1N1) in Korea

The aim of this study was to describe the features of deaths associated with the 2009 pandemic influenza A (H1N1) by 26 November 2009 in Korea. We collected standardized case reports on 115 confirmed deaths through a nationwide enhanced influenza surveillance system. The median age was 61 yr (interquartile range [IQR], 0.2-97 yr) and 58 (50.4%) were females. The case fatality rate was estimated as 16 per 100,000 cases. The age-related mortality rate had a J-shaped curve. Eighty-three patients (72.2%) had at least 1 underlying medical disease. Bacterial co-infections were detected in the blood or sputum specimens from 34 patients. Of the 63 patients who were hospitalized in the intensive care unit (ICU), the median time from symptom onset to hospital admission was 2 days (IQR, 0-22 days), and the median time from hospitalization to ICU admission was 1 day (IQR, 0-17 days). Neuraminidase inhibitors were administered to 100 patients (87.0%), 36% of whom began treatment within 2 days. In conclusion, fatal cases from the 2009 influenza A (H1N1) infection in Korea are mainly aged individuals with underlying disease, and associated with pneumonia, bacterial co-infections, and multi-organ failure.     

Pandemic influenza A (H1N1) 2009 vaccine: an update

The world witnessed a the first influenza pandemic in this century and fourth overall since first flu pandemic was reported during the World War I. The past experiences with influenza viruses and this pandemic of H1N1 place a consider-able strain on health services and resulted in serious illnesses and a large number of deaths. Develop-ing countries were declared more likely to be at risk from the pandemic effects, as they faced the dual problem of highly vulnerable populations and limited resources to respond H1N1. The public health experts agreed that vaccination is the most effective ways to mitigate the negative effects of the pandemic. The vaccines for H1N1 virus have been used in over 40 countries and administered to over 200 million people helped in a great way and on August 10, 2010, World Health Organization (WHO) announced H1N1 to be in postpandemic period. But based on knowledge about past pandemics, the H1N1 (2009) virus is expected to continue to circulate as a seasonal virus and may undergo some agenic-variation. As WHO strongly recommends vaccination, vigilance for regular updating of the composition of influenza vaccines, based on an assessment of the future impact of circulating viruses along with safety surveillance of the vaccines is necessary. This review has been done to take a stock of the currently available H1N1 vaccines and their possible use as public health intervention in the postpandemic period.