西安市1995-2008年检出脊髓灰质炎疫苗病毒的急性弛缓性麻痹病例流行病学分析

分析脊髓灰质炎(脊灰)病毒(PV)的急性弛缓性麻痹(AFP)病例流行病学特征,提高对疫苗衍生脊灰病毒(VDPVs)和循环的疫苗衍生脊灰病毒(cVDPVs)的认识,增加AFP病例监测系统敏感性。对西安市1995-2008年检出的PV阳性AFP病例进行流行病学分析。对疫苗变异PV采用VP1基因核苷酸序列测定方法进行分子生物性状分析。西安市1995-2008年共检出PV13株,检出率4.29%。分离到的PV以II、III型为主,AFP病例散在发生,无聚集性。未全程免疫儿童(全程免疫儿童,年龄以≤1岁儿童为主(84.62%)。麻痹残留率高达84.62%。脊灰相关病例(VAPP)的发生危险性为0.24/100万。型内特征鉴定有1株为疫苗变异PV,经VP1基因核苷酸序列测定未达到VDPV的分类标准。维持无脊灰阶段,存在着VDPV和发生cVDPVs的可能,在保持高水平脊髓灰质炎疫苗(OPV)免疫覆盖率的同时,高质量的AFP病例流行病学监测和病毒学监测工作,具有重要的现实意义。

Epidemiologic analysis on acute flaccid paralysis cases with isolation of poliovirus strains in Xi'an in 1995-2008

The epidemiological characters of AFP cases with poliovirus was analyzed in order to acquire more knowledge of vaccine-derived poliovirus（VDPVs） and circulating vaccine-derived poliovirus（cVDPVs）and increase the sensitivity of AFP surveillance system.XI＇an AFP cases with poliovirus in 1995-2008 were analyzed.The molecular characters of vaccine-derived poliovirus were analyzed by VP1 genomic sequencing technique.13 poliovirus strains were isolated from AFP cases from 1995 to 2008.The isolated rate is 4.29%.Most of them are type Ⅱ and type Ⅲ strains and AFP cases are sporadic.Number of children with full immunization is more than children with no full immunization.Most of them are under 1 year old（84.62%） and the rate of paralysis residue is 84.62%.The incidence risk rate of vaccine-associated paralytic poliomyelitis（VAPP） is 0.24/1000000.One strain has been identified as vaccine-variant poliovirus which variant rate of VP1 sequence did not reach the classified standard of VDPV.VDPV emergence and cVDPVs circulation still possibly occur in course of polio-free.It is important realistic meaning to keep high-level OPV immunization rate,high quality AFP case epidemiologic investingation and virus surveillance.