【摘要】 目的对四川省发生的脊髓灰质炎(脊灰)疫苗高变异病毒(VHPV)/脊灰疫苗衍生病毒(VDPV)循环事件及其应急处置情况进行分析,为中国维持无脊灰状态口服脊灰减毒活疫苗(OPV)的使用和在实现无脊灰目标后期,制定脊灰灭活疫苗(IPV)替代OPV的策略提供补充参考依据。方法运用现场流行病学调查、病例个案调查和标本检测、病例所在地及相邻地儿童OPV接种率快速评估、病例所在地及医院急性弛缓性麻痹(AFP)病例主动搜索、病例及密切接触者医学观察、密切接触者和周围健康儿童粪便标本病毒学监测、OPV应急强化免疫等方法进行综合处置。结果 2011-08/2012-02从送检的阿坝县4名AFP病例粪便标本中分离到脊灰病毒(PV),经鉴定为Ⅱ型(PV-Ⅱ),其VP1编码区基因核苷酸序列与Ⅱ型Sabin脊灰疫苗株比较,分别有5、6、8、11个核苷酸变异,变异率分别为0.55%、0.66%、0.89%、1.22%,共享5个突变位点,且高度同源,根据WHO新修订的Ⅱ型VDPV鉴定标准,其中3例标本为VDPV,1例标本为VHPV,表明阿坝县发生了Ⅱ型VHPV/VDPV循环事件。事件发生后,病例所在地及相邻地区开展了现场流行病学调查、OPV强化免疫等多项应急处置措施,成功阻断了VHPV/VDPV循环传播,没有出现新发VHPV/VDPV病例。结论 OPV低免疫覆盖率,是本次VHPV/VDPV循环事件发生的最主要原因。为避免VHPV/VDPV循环的出现和传播,在切实加强常规免疫和提高接种覆盖率的同时,应尽快制定和实施IPV替代OPV方案。更多还原

【Abstract】 Objective To analyze the circulation events caused by vaccine hyperariable polioviruses/vaccine-derived polioviruses(VHPV/VDPV) and corresponding emergency response,and thus to provide reference for OPV application during polio-free status and for formulating OPV/IPV switch strategies in polio eradication endgame.Methods Field epidemiological investigation,case history investigation,laboratory detection and supplementary immunization were comprehensively carried out for joint disposal.Results From August,2012 to February,2013,polioviruses were isolated from stool samples of 4 AFP cases from Aba county.All those polioviruses showed 0.55%-1.22% differences in VP1 complete gene compared with type II Sabin vaccine poliovirus(5,6,8 and 11 nucleotides differences,respectively),and were genetically monophyletic by sharing 5 common mutation sites.According to revised type II VDPV definition,three isolated polioviruses belonged to VDPVs,indicating that VHPV/cVDPVs event occurred in Aba county.Emergency measures after the events,including field epidemiological investigation,supplementary immunization in case-located county and adjacent areas were carried out and successfully interrupted VHPV/cVDPVs transmission,no paralytic case was reported afterward.Conclusion Low OPV coverage is the main risk factor of this event.In order to interrupt VHPV/cVDPVs emergence and transmission,OPV/IPV switch strategy should be formulated and implemented in time.更多还原