Lopalco P L
Department of Translational Research and New Technologies in Medicine and Surgery University of Pisa,Italy.
Epidemiol Infect. 2017 Feb;145(3):413-419. doi: 10.1017/S0950268816002569. Epub 2016 Nov 21.
Polio cases due to wild virus are reported by only three countries in the world. Poliovirus type 2 has been globally eradicated and the last detection of poliovirus type 3 dates to November 2012. Poliovirus type 1 remains the only circulating wild strain; between January and September 2016 it caused 26 cases (nine in Afghanistan, 14 in Pakistan, three in Nigeria). The use of oral polio vaccine (OPV) has been the key to success in the eradication effort. However, paradoxically, moving towards global polio eradication, the burden caused by vaccine-derived polioviruses (VDPVs) becomes increasingly important. In this paper circulation of both wild virus and VDPVs is reviewed and implications for the polio eradication endgame are discussed. Between April and May 2016 OPV2 cessation has been implemented globally, in a coordinated switch from trivalent OPV to bivalent OPV. In order to decrease the risk for cVDPV2 re-emergence inactivated polio vaccine (IPV) has been introduced in the routine vaccine schedule of all countries. The likelihood of re-emergence of cVDPVs should markedly decrease with time after OPV cessation, but silent circulation of polioviruses cannot be ruled out even a long time after cessation. For this reason, immunity levels against polioviruses should be kept as high as possible in the population by the use of IPV, and both clinical and environmental surveillance should be maintained at a high level.
全球仅三个国家报告了野生病毒导致的脊髓灰质炎病例。脊髓灰质炎2型已在全球范围内根除,最后一次检测到脊髓灰质炎3型的时间可追溯到2012年11月。脊髓灰质炎1型仍然是唯一传播的野生毒株;在2016年1月至9月期间,它导致了26例病例(阿富汗9例,巴基斯坦14例,尼日利亚3例)。口服脊髓灰质炎疫苗(OPV)的使用一直是根除工作取得成功的关键。然而,矛盾的是,在迈向全球根除脊髓灰质炎的进程中,疫苗衍生脊髓灰质炎病毒(VDPV)造成的负担变得越来越重要。本文回顾了野生病毒和VDPV的传播情况,并讨论了对脊髓灰质炎根除最后阶段的影响。2016年4月至5月期间,全球已实施停用OPV2,从三价OPV协调转换为二价OPV。为了降低cVDPV2再次出现的风险,所有国家的常规疫苗接种计划中都引入了灭活脊髓灰质炎疫苗(IPV)。随着停用OPV时间的推移,cVDPV再次出现的可能性应会显著降低,但即使在停用很长时间后也不能排除脊髓灰质炎病毒的隐匿传播。因此,应通过使用IPV使人群中针对脊髓灰质炎病毒的免疫水平尽可能高,并应保持高水平的临床和环境监测。