2016-2017年度中国大陆流行性感冒监测分析

目的 对2016-2017监测年度中国内地流行性感冒的监测结果及流行形势进行分析总结。方法 统计“中国流感监测信息系统”以及“突发公共卫生事件信息管理系统”2016-2017监测年度全年中国内地的ILI监测数据以及流感样病例暴发疫情数据。结果 2016-2017监测年度,南方省份流感活动未出现明显的夏季活动高峰,南、北方省份2017年秋冬流感流行季节均早于上一个监测年度,但流行高峰水平低于2015-2016监测年度。整个年度全国的流感流行优势病毒分别就经历了B型、A(H3N2)和甲型H1N1的交替。全国报告的ILI暴发疫情总起数低于2015-2016年度,南方片区高于北方片区。结论 各地继续高度重视近期流感病毒活动情况,密切关注全球及我国疫情形势,加强监测数据的分析和利用,跟踪流感病毒的活动水平、变异和耐药性变化,及时开展流感暴发疫情的调查处置和应对工作。     

2009～2010年乌鲁木齐市流行性感冒病原学监测分析

目的了解流行性感冒病毒（流感）的流行情况,探讨流感流行规律,为制订流感控制措施提供依据。方法对乌鲁木齐市监测门诊及疫情点的疑似流感样病例采集咽拭子标本,用核酸检测和接种狗肾传代细胞（MDCK）培养进行流感病毒分离及进行血凝试验,并对阳性者进行血凝抑制试验进行分型鉴定。结果 2009年10月-2010年3月监测流感样标本与咽拭子标本共1 218份,分离出流感病毒181株,分离率3.72%,分别为甲型H1N1亚型8株、H3N2亚型32株、新甲型H1N1 104株、B型37株。结论 2009年10月-2010年1月是以新甲型H1N1亚型流感病毒流行为主,2010年2月以B型流感流行为主。     

2013-2018年我国流感流行特征分析北大核心CSCD

目的了解我国近5年流感性感冒(简称流感)流行的季节性、病毒亚型、发病率和病死率等流行病学特征。方法通过中国疾病控制中心信息系统和中国流感监测信息系统收集2013年1月-2018年3月我国流感发病数和死亡数及每周上报流感样病例(ILI)监测实验室检测数据,采用Excel 2010进行统计学分析。结果 2013-2017年全国共检测流感样病例鼻咽拭子标本1 143 123份,检出流感病毒阳性154 699份(阳性率13.53%),以甲型流感病毒(H1N1、H3N2)和乙型流感病毒为主;2018年截止4月1日共检测阳性标本102 166份,流感病毒阳性31 154份(占30.49%),主要流行毒株为甲型H1N1、乙型流感病毒和甲型H3N2。每年的流感发病高峰主要集中在上年的12月至次年的4月,但2015、2017年的7月和8月发病率均较高(>10%)。结论 2013-2017年我国流感发病呈明显季节性,以冬、春季节发病率较高,2015年和2017年夏季出现流感发病高峰期。2017年12月-2018年2月流感发病数达到近5年的最高峰,甲型H1N1和乙型流感病毒为主要流行株。     

新疆克拉玛依市流感样病例检测分析

目的分析2011─2013年新疆克拉玛依市流感样病例检测结果,探讨本地区流感流行的特征及趋势,为流感防控工作提供科学依据。方法采用Real-timeRT-PCR方法对2011—2013年克拉玛依市流感哨点医院定期采集的流感样病例咽拭子标本进行核酸检测。结果 3年共采集流感样病例标本1 161份,流感病毒核酸检出率21.5%,2011—2013年流感病毒核酸检出率分别为15.7%、33.5%、17.4%;流感病毒型别主要为甲型H1N1、季节性H3N2和B型;哨点医院监测还发现全市流感发病有明显的季节性,当年11—12月到次年1—2月为高发季节,其中12月和1月最高;流感病毒优势株2011年底至2012年初以B型为主,2012年底至2013年初以季节性H3N2型为主,2013年底以新甲型H1N1为主。结论加强哨点医院流感样病例监测,有助于掌握本地区流感病毒的流行趋势和当地流感疫情的防控。     

2016—2020 年深圳市盐田区流行性感冒流行特征分析

目的 分析深圳市盐田区流行性感冒的流行病学特征,预测其流行趋势,为流感防控提供科学依据。 方法 收集 2016—2020 年盐田区流感样病例(ILI)监测数据、辖区内流感暴发疫情数据和病原学检测结果并进行分析。结果 2016—2020 年深圳市盐田区哨点医院共报告 ILI 1 563 例,其中男性 898 例,女性 665 例;年龄以 0~ 15 岁人群为主,占 67. 31%(1 052 / 1 563)。 2016—2020 年共采集 ILI 样本 1 563 份,检出阳性样本 302 份,总阳性率为19. 32%。 2016—2020 年 ILI 样本阳性率分别为 23. 79%、21. 39%、16. 23%、31. 11%和 2. 42%,各年度阳性率差异有统计学意义( χ2 = 87. 829,P<0. 05)。 2016 年主要流行病毒株为甲型 H1N1 和 B 型 Victoria 系,2017 年为甲型 H1N1和 A(H3N2),2018 年为甲型 H1N1 和 B 型 Victoria 系,2019 年为甲型 HINI、A(H3N2)和 B 型 Victoria 系,2020 年仅 有 A(H3N2)检出。 2016—2020 年深圳市盐田区共报告 ILI 暴发疫情 82 起,采集样本 451 份,阳性 314 份,阳性率为 69. 62%。 暴发疫情全部发生在学校,以小学为主,中学次之。 结论 深圳市盐田区不同监测年份各流感亚型交替流行,0~ 15 岁人群为重点关注人群,学校是盐田区流感防控重点场所。 应提高重点人群流感疫苗接种率,加强学校流感监测工作。     

2011~2013 年成都市某哨点医院流感监测结果分析

目的 分析成都某医院2011~2013 年流感监测结果,探索流感流行特征及规律,为制订流感防治策略提供依据。方法 将内科门诊、发热门诊、内科急诊和儿内科门诊设置为监测诊室,按照国家流感监测方案开展监测工作,并对监测结果进行分析。结果 登记报告流感样病例就诊百分比（ILI%）2011 年为1.95%,2012 年为1.24%,2013 年为2.70%。2011~2013 年832 份ILI 标本中流感病毒核酸阳性率为13.82%,其中各亚型流感病毒构成比分别为：B 型19.13%、季节性A（H1N1）型0.87%、A（H3N2）型15.62%和甲型H1N1 流感64.35%。ILI 在冬春季节出现就诊高峰,与标本核酸检测阳性率高峰时间呈正相关（r＝0.457,P<0.001）;ILI 年龄组构成比以5~15 岁组最高,各年龄组核酸检测阳性率差异有统计学意义。结论 ILI 流行强度与流感病毒活动趋势一致。流感防治工作需要在冬春以及夏季加强。需注重各年龄层的采样比例,减少采样人群分布不均衡导致的监测结果差异。     

2016-2019年新疆流感监测分析

目的了解2016—2019年新疆流感样病例(influenza-like illness,ILI)的流行病学特征和病原学监测数据,为流感防控工作提供科学依据。方法通过中国流感监测信息系统收集2016—2019年新疆流感哨点医院报告的ILI、病原学监测数据和流感聚集性疫情报告资料,分析流行病学特征。结果 2016年第14 w—2019年第13 w,新疆共报告门诊病例9 820 366例,其中流感样病例405 394例,ILI%为4.1%;病例集中在15岁以下人群;检测样本38 975份,检出流感病毒阳性6 584份、阳性率16.9%,分离病毒株为新甲型H1N1型848株、H3型603株、BV型47株和BY型606株,聚集性疫情中病毒型别与当年流行的病毒型别一致。结论新疆流感疫情集中在每年的第40 w至次年第20 w,新甲型H1N1,B型和H3型交替流行;流感主要发生在冬春季,以学龄儿童为主;应加强学龄儿童的流感防控工作。     

2007—2008年新疆流感监测结果分析

目的分析2007—2008年新疆流行性感冒（流感）流行特征和流感病毒优势株的情况。方法收集、分析监测哨点医院流感样病例及实验室病原学资料,用细胞培养分离并用血球凝集抑制试验对流感病毒进行分型。结果监测哨点医院2007—2008年流感样病例处于较为平稳的水平,无明显的流行高峰,病例相对集中在2007年12月-2008年1月,此监测年度无疫情暴发报告;共收集流感样病例标本589份,分离病毒60株,阳性率为10．19％;其中B（Yamagata）型52株（86％）,H3N2亚型7株（12％）,H1N1亚型1株（2％）。结论2007—2008年新疆流感活动较为平稳,流行毒株以B（Yamagata）型病毒为主,并有向H3N2亚型转化的趋势。     

2009-2012年丽水市流感监测网络实验室结果分析北大核心CSCD

目的掌握丽水市2009-2012年流感流行特征和病原学变化规律,为流感大流行的预测和防控提供科学依据。方法采用Real—timePCR法检测流感病毒核酸,分析辖区内流感流行特征。结果丽水市2009年IL1标本流感核酸检测阳性率为62．37％,以A型H1N1流感为主,占98．31％;2010年阳性率为28．95％,以B型为主要流行株,占61．62％;2011年阳性率为25．39％,以A型H1N1和B型为主要流行株,分别占52．58％和45．36％;2012年阳性率为39．93％,主要流行株为季节性A型H3（占56．88％）和B型（占43．12％）,无A型H1N1和季节性A型H1N1流行。剔除2009年新型A型H1N1病毒的影响,丽水市流感主要流行株为季节性A型H3N2和B型,季节性A型H3N2春夏季流行较多,而B型则主要在秋冬季流行。结论丽水市流感的流行有一定的季节性,2009年以新型A型H1N1流感为主,2010-2012年以季节性A型H3N2和B型流感为主。因此应继续加强对流感的病原学监测,及时发现流感病毒变异,对人群进行规范的流感疫苗棒种及僻康新畜。     

2009～2010年北京地区甲型流感监测分析

目的了解北京地区2009～2010年甲型流感的流行情况,为预防和控制北京地区甲型流感的流行提供依据。方法以解放军总医院作为哨点医院,用Real-ti me RT-PCR从流感样病例咽拭子中检测甲型流感病毒,监测甲型流感病毒在该地区的流行情况。结果 2 134份标本中甲型流感病毒阳性575份,阳性率为26.94%,其中甲型H1N1占46.26%,季节性H3N2型占40.70%,H1N1型占3.30%,未分型占9.74%。甲型流感病毒感染者年龄分布峰值在20～30岁之间,感染时间分布的2个峰值在第37周和47周,分别以H3N2型和甲型H1N1流感病毒为主。结论 2009～2010年北京地区流行的甲型流感病毒以甲型H1N1为主,其次是H3N2,甲型H1N1取代了季节性H3N2流感病毒在冬季的流行。应加强对甲型流感病毒的监测,密切关注甲型H1N1流感病毒的抗原变化有重要意义。     

Antibody responses against influenza A(H1N1)pdm09 virus after sequential vaccination with pandemic and seasonal influenza vaccines in Finnish healthcare professionals

Background Influenza A(H1N1)pdm09 virus has been circulating in human population for three epidemic seasons. During this time, monovalent pandemic and trivalent seasonal influenza vaccination against this virus have been offered to Finnish healthcare professionals. It is, however, unclear how well vaccine‐induced antibodies recognize different strains of influenza A(H1N1)pdm09 circulating in the population and whether the booster vaccination with seasonal influenza vaccine would broaden the antibody cross‐reactivity. Objectives Influenza vaccine‐induced humoral immunity against several isolates of influenza A(H1N1)pdm09 virus was analyzed in healthcare professionals. Age‐dependent responses were also analyzed. Methods Influenza viruses were selected to represent viruses that circulated in Finland during two consecutive influenza epidemic seasons 2009–2010 and 2010–2011. Serum samples from vaccinated volunteers, age 20–64 years, were collected before and after vaccination with AS03‐adjuvanted pandemic and non‐adjuvanted trivalent seasonal influenza vaccine that was given 1 year later. Results Single dose of pandemic vaccine induced a good albeit variable antibody response. On day 21 after vaccination, depending on the virus strain, 14–75% of vaccinated had reached antibody titers (≥1:40) considered seroprotective. The booster vaccination 1 year later with a seasonal vaccine elevated the seroprotection rate to 57–98%. After primary immunization, younger individuals (20–48 years) had significantly higher antibody titers against all tested viruses than older persons (49–64 years) but this difference disappeared after the seasonal booster vaccination. Conclusions Even a few amino acid changes in influenza A HA may compromise the vaccine‐induced antibody recognition. Older adults (49 years and older) may benefit more from repeated influenza vaccinations.     

Genotypic Variants of Pandemic H1N1 Influenza A Viruses Isolated from Severe Acute Respiratory Infections in Ukraine during the 2015/16 Influenza Season

Human type A influenza viruses A(H1N1)pdm09 have caused seasonal epidemics of influenza since the 2009–2010 pandemic. A(H1N1)pdm09 viruses had a leading role in the severe epidemic season of 2015/16 in the Northern Hemisphere and caused a high incidence of acute respiratory infection (ARI) in Ukraine. Serious complications of influenza-associated severe ARI (SARI) were observed in the very young and individuals at increased risk, and 391 fatal cases occurred in the 2015/16 epidemic season. We analyzed the genetic changes in the genomes of A(H1N1)pdm09 influenza viruses isolated from SARI cases in Ukraine during the 2015/16 season. The viral hemagglutinin (HA) fell in H1 group 6B.1 for all but four isolates, with known mutations affecting glycosylation, the Sa antigenic site (S162N in all 6B.1 isolates), or virulence (D222G/N in two isolates). Other mutations occurred in antigenic site Ca (A141P and S236P), and a subgroup of four strains were in group 6B.2, with potential alterations to antigenicity in A(H1N1)pdm09 viruses circulating in 2015/16 in Ukraine. A cluster of Ukrainian isolates exhibited novel D2E and N48S mutations in the RNA binding domain, and E125D in the effector domain, of immune evasion nonstructural protein 1 (NS1). The diverse spectrum of amino-acid substitutions in HA, NS1, and other viral proteins including nucleoprotein (NP) and the polymerase complex suggested the concurrent circulation of multiple lineages of A(H1N1)pdm09 influenza viruses in the human population in Ukraine, a country with low vaccination coverage, complicating public health measures against influenza.     

Epidemiology and molecular characterization of influenza viruses in Burkina Faso,sub‐Saharan Africa

Background

The importance of influenza viruses in respiratory infections in sub‐Saharan Africa has been historically overlooked, including in Burkina Faso.

Objectives

This study therefore aimed at evaluating the prevalence and seasonal occurrence of influenza viruses in children under 5 years old, at risk of influenza‐related complications, presenting with influenza‐like illness (ILI) or severe acute respiratory infection (SARI). The study also aimed at identifying the periods with increased influenza transmission for vaccination recommendations in Burkina Faso.

Methods

From January 2014 to December 2015, ILI and SARI (2015 only) patients were recruited in six healthcare centers in Burkina Faso. Influenza A and B molecular detection and subtyping were performed. Clade clustering of a subset of A(H1N1)pdm09 and A(H3N2) strains was deduced by performing phylogenetic analyses on hemagglutinin gene sequences. Weekly surveillance data from FluNet (2011‐2013; 2016) and this study (2014‐2015) were used to identify periods of increased influenza activity.

Results

Influenza A and B viruses were detected in 15.1% (112 of 743) of ILI and 6.6% (12 of 181) of SARI patients. Overall, influenza A viruses were largely predominant (81 of 124, 65.3%), with 69.1% of A(H3N2) and 30.9% of A(H1N1)pdm09 strains. Four waves of increased transmission were identified in 2014‐2015, each dominated by different influenza subtypes and clades. Between 2011 and 2016, periods of increased influenza activity varied in their frequency, duration, and timing.

Conclusion

Influenza A and B viruses were detected in a substantial number of ILI and SARI cases in Burkina Faso. Vaccination in September‐October would likely protect the highest number of patients.     

2016-2020年福建省A(H1N1)pdm09流感病毒HA基因特征分析

目的 分析2016-2020年福建省A(H1N1)pdm09亚型流感病毒的血凝素(Hemagglutinin, HA)基因特征,了解与其他省份和全球范围内时间和空间上的分布差异。方法 选取2016-2020年福建省流感监测网络实验室分离A(H1N1)pdm09流感毒株基因序列测定。基因序列用MEGA、Net NGlyc 1.0 Server分析基因特征。结果 2016-2020年福建省A(H1N1)pdm09亚型流感病毒HA基因进化树分析与其他省份及国外大部分一致,但仍有少部分不同。HA分支由6B转化为6B.1并演化至6B.1A5A。HA基因变异主要在抗原性决定簇Sa、Ca、Sb。对于不同地区疫苗株匹配度也会有差异。结论 福建省A(H₁N₁)pdm09病毒流行株具有遗传多样性。     

Serologic evidence of human influenza virus infections in swine populations,Cambodia

Background This study was conducted from 2006 to 2010 and investigated the seroprevalence of influenza A viruses in Cambodian pigs, including human H1N1, H3N2, 2009 pandemic H1N1 (A(H1N1)pdm09), and highly pathogenic avian H5N1 influenza A viruses. Methods A total of 1147 sera obtained from pigs in Cambodia were tested by haemagglutination inhibition (HI) assays for antibody to human influenza A viruses along with both HI and microneutralization (MN) tests to assess immunological responses to H5N1 virus. The results were compared by year, age, and province. Results Antibodies against a human influenza A virus were detected in 14·9% of samples. A(H1N1)pdm09 virus were dominant over the study period (23·1%), followed by those to human H1N1 (17·3%) and H3N2 subtypes (9·9%). No pigs were serologically positive for avian H5 influenza viruses. The seroprevalence of human H1N1 and H3N2 influenza viruses peaked in 2008, while that of A(H1N1)pdm09 reached a peak in 2010. No significant differences in seroprevalence to human influenza subtypes were observed in different age groups. Conclusions Cambodian pigs were exposed to human strains of influenza A viruses either prior to or during this study. The implications of these high prevalence rates imply human‐to‐swine influenza virus transmission in Cambodia. Although pigs are mostly raised in small non‐commercial farms, our preliminary results provide evidence of sustained human influenza virus circulation in pig populations in Cambodia.     

Estimating vaccine effectiveness in preventing laboratory‐confirmed influenza in outpatient settings in South Africa, 2015

Trivalent seasonal influenza vaccine effectiveness during the 2015 season in South Africa was assessed using a test‐negative case control study design. Influenza A(H1N1)pdm09 was the dominant circulating strain. Overall influenza vaccine coverage was 3.2% (29/899). The vaccine effectiveness estimate, against any influenza virus infection, adjusted for age, underlying conditions and timing within season was 46.2% (95% CI: ?23.5 to 76.5), and 53.6% (95% CI: ?62.6 to 80.3) against influenza A(H1N1)pdm09.