英国伦敦卫生与热带医学院G. R. Macklin小组的研究发现了停用2型口服脊髓灰质炎疫苗（POV2）后2型脊灰病毒血清型的流行病学进化史。该研究于2020年3月20日发表在《科学》杂志上。

使用统计模型，研究人员预估了2016年5月至2019年11月之间检测到2型脊髓灰质炎疫苗衍生脊髓灰质炎病毒（VDPV2）的出现日期和来源。单纯OPV2使用造成的暴发是诱导免疫力预防传播的唯一有效途径。然而，研究人员的分析表明，单纯使用OPV2会产生更多麻痹性VDPV2爆发，并有可能建立地方性传播。如果这种疫苗未能如期实现或发挥预期作用，则迫切需要新型OPV2和应急策略。

据悉，尽管20多年来没有发生2型野生脊髓灰质炎病毒病例，但在几大洲传播的VDPV2和相关的麻痹病例对其根除构成威胁。2型口服脊髓灰质炎病毒疫苗已于2016年4月停用，以阻止VDPV2出现并确保根除所有2型脊髓灰质炎病毒。在全球范围内，此日期之后出生的儿童具有对其传播有限的免疫力。

附：英文原文

Title: Evolving epidemiology of poliovirus serotype 2 following withdrawal of the type 2 oral poliovirus vaccine

Author: G. R. Macklin, K. M. O’Reilly, N. C. Grassly, W. J. Edmunds, O. Mach, R. Santhana Gopala Krishnan, A. Voorman, J. F. Vertefeuille, J. Abdelwahab, N. Gumede, A. Goel, S. Sosler, J. Sever, A. S. Bandyopadhyay, M. A. Pallansch, R. Nandy, P. Mkanda, O. M. Diop, R. W. Sutter

Issue&Volume: 2020/03/19

Abstract: AbstractWhile there have been no cases of type-2 wild poliovirus for over 20 years, transmission of type-2 vaccine-derived poliovirus (VDPV2) and associated paralytic cases in several continents represent a threat to eradication. The withdrawal of the type-2 component of oral poliovirus vaccine (OPV2) was implemented in April 2016 to stop VDPV2 emergence and secure eradication of all poliovirus type 2. Globally, children born after this date have limited immunity to prevent transmission. Using a statistical model, we estimate the emergence date and source of VDPV2s detected between May 2016 and November 2019. Outbreak response campaigns with monovalent OPV2 are the only available method to induce immunity to prevent transmission. Yet, our analysis shows that using monovalent OPV2 is generating more paralytic VDPV2 outbreaks with the potential for establishing endemic transmission. The novel OPV2 is urgently required, alongside a contingency strategy if this vaccine does not materialize or perform as anticipated.

DOI: 10.1126/science.aba1238

Source: https://science.sciencemag.org/content/early/2020/03/18/science.aba1238