云南省首例缅甸输入疫苗衍生脊髓灰质炎病毒病例应急处置措施分析

The Epidemiological Investigation and Emergency Response of the First Vaccine-derived Poliovirus Case Imported from Myanmar in Yunnan Province

目的评价云南省1例缅甸输入的Ⅰ型疫苗衍生脊髓灰质炎(脊灰)病毒(Type 1 Vaccine-derived Poliovirus,VDPVⅠ)病例的调查和应急处置效果。方法对病例进行流行病学个案调查,采集病例和密切接触者粪便标本,开展脊灰病毒(Poliovirus,PV)检测;在病例所到过的临沧市临翔区和镇康县,采集健康儿童粪便标本、环境污水标本开展PV检测。在上述两个县(区)及临沧市另外2个与缅甸接壤的耿马县、沧源县,开展口服脊灰减毒活疫苗(Oral Poliomyelitis Attenuated Live Vaccine,OPV)接种率快速评估和急性弛缓性麻痹(Acute Flaccid Paralysis,AFP)病例主动搜索,对输入传播风险进行评估。结果缅甸输入的VDPVⅠ病例标本有21个核苷酸变异,变异率为2.3%。在VDPVⅠ病例密切接触者、健康儿童及外环境中未检测到同类病毒。OPV快速评估接种率为99.5%,≥1岁儿童OPV全程服苗率为93.0%,AFP病例主动搜索未发现漏报。结论云南省AFP病例监测系统运转良好,具备发现输入脊灰疫情的能力。边境地区已经建立较好的免疫屏障,病例输入后未在云南省境内引起二代病例。但由于缅甸曾多次发生VDPV事件,故随时面临输入的风险,要严防输入后引起本地的传播。

Objective To evaluate the result of epidemiological investigation and emergency response of the type one vaccine-derived poliovirus （VDPVI）case which imported from Myanmar in Yunnan province. Method Develop epidemiological investigate to the VDPVt case, Monitor poliovirus by collecting specimens from VDPVI case/intimately contacts/other health children and waste water, conduct a survey in four counties to evaluate OPV （Oral Poliomyelitis Attenuated Live Vaccine）immunization coverage and to assess the sensitivity of AFP（Aeute Flaccid Paralysis）surveillance system, evaluate risk of poliovirus imported again. Result The VDPVI have 21 nucleotides changed and the changing rate was 2.3 %.We did not found the same virus existed in the ＇population and environment. Rapid assessment of OPV immunization coverage rate was 99.55%, and 93.0% of children who 〉 1 year old have immunized 3 doses of OPV. No any case was missed to be reported by AFP active researching. Conclusion AFP surveillance system of Yunnan province is in good status and can monitor poliovirus relative events immediately, OPV immunization coverage of border areas is high. The second generation cases from imported cases have been prevented. But because there were several VDPV cases happened in Myanmar in the past several years, The border area of Yunnan province is still in the risk of infected by the imported cases. It is very important to strengthen comprehensive strategies to prevent poliolocal circulation