湖南省1例免疫缺陷疫苗衍生脊髓灰质炎病毒病例的流行病学调查和处置

Epidemiological Survey and Handling of an Immunodeficiency-associated Vaccine-derived Poliovirus Case in Hunan Province

目的分析湖南省首例患原发性免疫缺陷的疫苗衍生脊髓灰质炎(脊灰)病毒(Immunodeficiency-associated Vaccine-derived Poliovirus,i VDPV)病例,探讨控制策略。方法对该i VDPV病例进行流行病学调查,检测脊灰抗体,测定免疫功能,并定期采集粪便标本分离病毒,对病例所在地及医院进行急性弛缓性麻痹病例主动搜索,对病例所在地进行接种率调查和人群抗体水平检测,开展风险评估。结果病例最终分类诊断为i VDPV病例,当地适龄儿童常规免疫接种率较高,人群具有较高的脊灰抗体水平,粪便标本未分离到疫苗衍生脊灰病毒(VDPV)。在病例所在地及相邻地区开展脊灰疫苗查漏补种。结论病毒未在当地造成循环,高水平的免疫屏障、高效率的监测系统、及时有效的应急处置是防范野病毒输入和VDPV传播的保障。但随着全球消灭脊灰的进展,应对患免疫缺陷的儿童采取针对性的策略和研究。

Objective To analyze and discuss the strategy to control a first case of immunodeficiency- associated vaccine-derived poliovirus （iVDPV） case in Hunan province. Method Epidemiological survey for the iVDPV case was conducted, antibody against poliovirus was detected, and immunological function of the case was tested. Stool specimen was collected at a regular period of interval for enterovirus isola- tion. Active search for cases of acute flaccid paralysis （AFP） was implemented in areas and hospitals a- round the case. A survey for vaccination rate and antibody level in population, as well as risk assess- ment, was conducted. Result The case was finally categorized as an iVDPV case. The routine immuni- zation rate and antibody level against polio were fairly high in local eligible children living around the case. No VDPV was isolated from collected stool specimen. Catch-up vaccination against polio was con- ducted in areas where the case lived and his neighborhood. Conclusion The iVDPV case did not circu- late in local areas, which can be attributed to the high level of immunological barrier and efficient surveil- lance system, along with immediate effective response and handling. The interruption of transmission of imported wild poliovirus and VDPV were ensured. However, it is suggested that with the advancement of global polio eradication campaign, focused research and strategy related to children with immunodeficieney should be considered.