流感大流行与国境口岸流感监测

目的应对甲型H1N1流感大流行。方法对流感监测的意义以及当前全球和中国流感监测发展的现况进行总结分析,对国境口岸如何加强流感监测进行了探讨。结果流感监测是应对流感大流行的基础,国境口岸可从加强国际合作、延伸监测网络、建设口岸实验室网络和流感监测专业队伍等措施加强流感监测,实现早期预警。结论在流感大流行的早期,出入境检验检疫机构必须重视加强国境口岸的流感监测和早期预警,及时掌握第一手资料,积极应对流感大流行,控制传染源入境。     

防范流感大流行

冬季来临,又到流感的多发季节。善变的流感病毒常常搅得我们不能安宁,特别是我国距上次流感大爆发已有30多年。专家认为,下一次全球流感的流行是不可避免的,传染力强、传播速度快且具有新抗原性的亚型会出现,引发流感大流行。那么,我们应该如何做好准备,严阵以待呢?     

全球流感大流行概述

在过去的100年里,共暴发过4次全球范围内的流感大流行,极大地危害和影响了全球人类健康和社会秩序。本文对历史上4次流感大流行的特征及当时采取的防控措施进行回顾和总结,期望从中获得一些经验或吸取教训,用于提升我国现阶段流感大流行应对准备能力,以从容应对可能到来的下一次流感大流行。     

新型流感病毒出现和流感大流行

20世纪出现了3次流感大流行,分别由A型流感病毒H1N1、H2N2和H3N2三种不同的抗原亚型引起,其中1957年和1968年的两次流行发生在现代病毒学时代,流感病毒的特征得到了系统的研究。流感流行事件表明流感大流行在时间和形式上是不可预测的。有证据显示流感大流行主要是由人流感病毒与动物A型流感病毒的基因重排而产生新血凝素亚型的病毒引起。     

中国应对流感大流行的对策分析

上世纪全球发生了3次世界流感大流行：1918西班牙型流感（H1N1亚型）；1957亚洲型流感（H2N2亚型）；1968香港型流感（H3N2亚型）；其中第一次流感大流行，在6～9个月的时间内席卷了全球，全世界有20％的人口——4亿人感染，死亡4000万～5000万，对全世界的经济、社会活动造成了毁灭性的影响，成为人类传染病史上最大的灾难。美国对该次流行的危害做了进一步统计，短短的3个星期传遍全国，     

厦门市医疗机构流感大流行应对能力的评估

目的评估厦门市二级以上医疗机构流感大流行应对能力。方法通过对医疗救治资源的调查,用模型Flu surge估算出流感大流行期间可能的住院患者人数、死亡人数,以及呼吸机、ICU、病床等医疗设备的负担能力,进而评估流感大流行对医疗机构的冲击。结果发生流感大流行时门诊病例、住院病例及死亡病例将超过医院的承载能力,尤其是ICU重症监护病床数将不能满足救治病人的需要。结论 Flu surge模型估计的结果提示,厦门市二级以上医疗机构应继续加强医疗救治能力建设,同时应采取压低流感流行高峰,推迟流行时间等防控策略减轻医疗机构负荷。     

流感大流行对医疗机构的威胁及应对策略

流感是由流感病毒引起的急性呼吸道传染病.流感病毒分为甲、乙、丙3型,其中甲型流感病毒易发生变异,包括亚型内的变异和新亚型的出现或旧亚型的重现.     

世界卫生组织和中国在流感大流行应对准备计划方面的发展及现状

历史上流感的每次大流行都给人类带来灾难,其中以1918年"西班牙流感"大流行最为严重。近100年来,随着对流感病毒了解的不断深入,以及检测技术的长足发展和监测手段的逐步丰富,人类面对流感大流行并非如前般无所适从。为努力延缓和降低其危害,人们希望通过不断完善应对准备工作,以期实现早期预警或尽早发现具备大流行潜能的流感病毒,以及在大流行期间,通过实施应对准备计划中相应的防控措施,延缓高峰出现和控制疫情流行,从而达到降低影响的目的。本文回顾了百年来WHO和中国的流感大流行应对准备工作的策略、重点及其随时间的演变与发展进程,以温故而知新,为今后不断完善流感大流行应对准备工作提供参考。     

风险沟通在防控流感大流行中的应用

甲型H1N1流感发生后,风险沟通成为我国公共卫生管理领域内备受关注的热点问题。本文介绍了风险沟通的概念及其重要性,针对我国卫生系统风险沟通的现状,设计和提出了卫生系统应对流感大流行的风险沟通流程,即风险认知、风险评估、风险决策和风险传播等。     

中国、世界卫生组织、美国流感大流行准备计划比较分析

迄今为止，各国针对可能发生的流感大流行开展的主要防备活动集中于制定和演习应对计划，研制应对大流行的疫苗，以及确保抗病毒药物的供应。现在较多的国家已有大流行防备计划：全世界大约五分之一的国家有某种形式的应对计划，但是这些计划在广泛性和完成阶段方面差异极大。     

Source for influenza pandemics

There are three ways how influenza A viruses can escape the immune response in the human population: (1) By antigenic drift. This means by mutation and selection of variants under the selection pressure of the immune system. These variants have amino acid replacements mainly in the epitopes of the hemagglutinin. (2) By antigenic shift. This means replacement of at least the hemagglutinin gene of the prevailing human strain by the allelic gene of an avian influenza virus by reassortment. (3) As a rare event, direct or indirect introduction of an avian influenza virus in toto into the human population. A prior introduction of an avian virus into pigs and an adaptation to the new host might be a presupposition for its final passage to humans. In this sense the nowadays situation is reminiscent to that of about 100 years ago, when an avian virus was presumably first introduced into pigs, and from there into humans. Immediately or some time thereafter the disastrous Spanish Flu in 1918/19 had killed at least 20,000,000 people in one winter. Pandemic strains can be created by all three means, however the most common way is by reassortment. In order to recognize a pandemic strain as soon as possible a worldwide surveillance system and collaborating laboratories equipped with corresponding modern technologies are required.     

Influenza pandemics of the 20th century

Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968. The latter 2 were in the era of modern virology and most thoroughly characterized. All 3 have been informally identified by their presumed sites of origin as Spanish, Asian, and Hong Kong influenza, respectively. They are now known to represent 3 different antigenic subtypes of influenza A virus: H1N1, H2N2, and H3N2, respectively. Not classified as true pandemics are 3 notable epidemics: a pseudopandemic in 1947 with low death rates, an epidemic in 1977 that was a pandemic in children, and an abortive epidemic of swine influenza in 1976 that was feared to have pandemic potential. Major influenza epidemics show no predictable periodicity or pattern, and all differ from one another. Evidence suggests that true pandemics with changes in hemagglutinin subtypes arise from genetic reassortment with animal influenza A viruses.     

Differential mortality rates by ethnicity in 3 influenza pandemics over a century, New Zealand

Evidence suggests that indigenous populations have suffered disproportionately from past influenza pandemics. To examine any such patterns for Māori in New Zealand, we searched the literature and performed new analyses by using additional datasets. The Māori death rate in the 1918 pandemic (4,230/100,000 population) was 7.3× the European rate. In the 1957 pandemic, the Māori death rate (40/100,000) was 6.2× the European rate. In the 2009 pandemic, the Māori rate was higher than the European rate (rate ratio 2.6, 95% confidence interval 1.3-5.3). These findings suggest some decline in pandemic-related ethnic inequalities in death rates over the past century. Nevertheless, the persistent excess in adverse outcomes for Māori, and for Pacific persons residing in New Zealand, highlights the need for improved public health responses.     

The effectiveness of influenza vaccination among nursery school children in China during the 2016/17 influenza season

BackgroundThe effectiveness of influenza vaccine among nursery school children has not been systematically studied. We conducted a cohort study of children from 13 nursery schools in Suzhou, China, to estimate the effectiveness of influenza vaccine against laboratory-confirmed influenza during 2016–17.MethodsChildren aged 36–72 months were chosen from 13 nursery schools from 3 District in Suzhou. The surveillance started 2 weeks after vaccination during October 2016–February 2017. Class teachers reported the names of students with ILI (influenza-like illness) to study clinicians on each school day. Further, local physicians collected the student’s nasopharyngeal swab or throat swab, either at a study clinic or at the child’s home. The swabs were sent to the National Influenza Network Laboratory in Suzhou Center for Disease Control and Prevention for influenza testing by RT-PCR.ResultA total of 4614 children were enrolled, of which 15 children (vaccinated: 2; unvaccinated: 13) were lost to follow-up. Of the remaining 4599 children, 558 swabs were collected. Among these swabs, 70 samples tested positive for influenza virus; 17 in the vaccinated group (B Victoria: 2; H3N2: 15) and 53 in the unvaccinated group (B Victoria: 14; A(H1N1)pdm09: 1; H3N2: 38). The overall influenza vaccine effectiveness (VE) during the influenza season of 2016–2017 was 20.6%. The incidence of developing ILI symptoms and healthcare seeking behavior through clinical visits was significantly lower in vaccinated children than in the unvaccinated group.ConclusionInfluenza vaccine protection in vaccinated and unvaccinated children showed no statistical difference and the VE percentage varied for different virus subtypes. However, the incidence rate of developing ILI and healthcare seeking behavior was significant lower in the vaccinated group than in the unvaccinated children. Larger studies are required to estimate the VE according to the influenza type, subtype, and lineage during influenza seasons in China in the future.     

陕西省咸阳市2016—2020监测年度流感流行病学特征分析

目的 分析陕西省咸阳市近4个监测年度流感型别分布和流行特征,为防控措施制定提供科学参考。方法 对《中国流感监测信息系统》中咸阳市2016—2020监测年度国家级流感监测哨点医院报告的流感样病例（ILI）和流感监测网络实验室的病原学检测结果进行描述性分析。结果 4个监测年度共报告ILI 26 822例,总流感样病例比例（ILI%）为3.66%,ILI%流行趋势呈明显的冬春季流行高峰;流感监测网络实验室共检测ILI标本6 045例,检出阳性标本835例（阳性率为13.81%）,阳性标本以A(H3N2)最多,共计362例(43.35%);各监测年度的优势流行株在A(H3N2)、A(H1N1)pdm09与B(Yamagata)之间交替出现,其中2016—2017和2019—2020监测年度优势流行株为A(H3N2)亚型,占比分别为78.32%和88.50%,2017—2018监测年度以B(Yamagata)（45.98%）和A(H1N1)pdm09（32.59%）为主,2018—2019监测年度优势流行株为A(H1N1)pdm09（62.69%）;4个监测年度流感流行高峰均以冬春季（10月—次年4月）为主;流感阳性病例在性别、年龄和职业分布上的差异均有统计学意义(均有P＜0.001)。结论 咸阳市流感流行具有明显季节性和特定人群高发,流行期主要分布在冬春季（10月—次年4月）,0～14岁儿童和学生为重点防控对象,且男性占比高于女性。今后的防控工作中应继续加强流感监测,密切关注优势流行株的变化趋势。高发季节,应针对高发人群,采取积极有效的干预措施,加强防控工作。     

2015-2017年柳州市流感病原学监测分析

目的 分析2015年1月-2017年12月柳州市流感病原学流行特征,为本地区流感防控工作提供科学依据。方法 采集柳州市流感哨点监测医院流感样病例以及流感样病例聚集性疫情病例咽拭子样本,采用用RT-PCR对流感病毒基因分型进行检测,对结果进行描述性分析。结果 3个年度共采集流感样病例咽拭子标本3387份,流感病毒检出率为11.43%。2015-2017年阳性率分别为8.46%、14.71%、10.93%,不同年度阳性率有统计学意义(x2=21.886,P<0.05)。H3N2亚型阳性率高峰在2015年和2017年夏季、2016年冬季,新甲型H1N1阳性率的高峰在2016年春季,乙型流感病毒全年均有分布,2014-2017年流行趋势逐渐增强,并在2017年冬季形成流行高峰。不同年龄组的流感病毒核酸阳性率差异有统计学意义(x2=8.786,P<0.05),以15岁年龄组阳性率最高(12.88%)。3个年度共报告聚集性疫情91起,其中2015跟2017年以乙型为主,2016年以H3N2亚型为主,不同年度阳性率有统计学意义(x2=20.807,P<0.001)。结论 2015-2017年度乙型、甲型H1N1与H3N2流感病毒呈交替流行趋势,应加强本地区流感监测网络建设,提高流感监测及预警能力,为本地区流感疫情防控措施的制定及干预提供依据。     

Influenza pandemics in Singapore, a tropical, globally connected city

Tropical cities such as Singapore do not have well-defined influenza seasons but have not been spared from influenza pandemics. The 1918 epidemic in Singapore, which was then already a major global trading hub, occurred in 2 waves, June-July, and October-November, and resulted in > or = 2,870 deaths. The excess mortality rate was higher than that for industrialized nations in the Northern Hemisphere but lower than that for less industrialized countries in Asia and Africa. The 1957 epidemic occurred in May and resulted in widespread illness. The 1968 epidemic occurred in August and lasted a few weeks, again with widespread illness. Tropical cities may be affected early in a pandemic and have higher mortality rates. With the increase in travel and trade, a future pandemic may reach a globally connected city early and spread worldwide. Preparedness and surveillance plans must be developed to include the megacities of the tropical world.     

Prevalence and factors of influenza vaccination during the COVID-19 pandemic among university students in China

BackgroundPrevious outbreaks of emerging infectious diseases (e.g., SARS) had increased the uptake of influenza vaccination (IV). It is uncertain whether such was also true for COVID-19. This study hence investigated prevalence of IV behavior/intention prior to and during the COVID-19 pandemic and associated cognitive factors.MethodsA self-administered, online, and anonymous cross-sectional survey was conducted among 6,922 university students of five provinces in China during November 1–28, 2020 (response rate: 72.3%).ResultsOf all the participants, 35.1% self-reported behavioral intention of IV (next 12 months), while 62.9% reported an increased intention of IV due to COVID-19. However, only 4.7% and 2.9% had taken up IV during the 12-month period prior to the outbreak (1/2019–12/2019) and during the COVID-19 outbreak (1–11/2020), respectively. Adjusted for the background factors, the multivariable logistic regression analysis showed that in general the COVID-19 related perceptions (perceived susceptibility, perceived severity, and perceived chance of having another wave of COVID-19 outbreak) were significantly and positively associated the IV behavior (during the COVID-19 outbreak) and intention of IV uptake in the next 12 months.ConclusionsThe COVID-19 pandemic may have influenced actual behavior and intention of IV uptake among university students during the pandemic. Efforts are warranted to reduce the intention-behavior gap of IV uptake; modification of perceived susceptibility and perceived severity regarding COVID-19 may help. Future longitudinal and intervention studies are needed to confirm the findings of this study and explore other factors affecting IV uptake during the COVID-19 period.