Kid Risk, Inc., Orlando, FL, USA.
National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Vaccine. 2023 Apr 6;41 Suppl 1(Suppl 1):A136-A141. doi: 10.1016/j.vaccine.2021.04.061. Epub 2021 May 14.
The Global Polio Eradication Initiative (GPEI) faces substantial challenges with managing outbreaks of serotype 2 circulating vaccine-derived polioviruses (cVDPV2s) in 2021. A full five years after the globally coordinated removal of serotype 2 oral poliovirus vaccine (OPV2) from trivalent oral poliovirus vaccine (tOPV) for use in national immunization programs, cVDPV2s did not die out. Since OPV2 cessation, responses to outbreaks caused by cVDPV2s mainly used serotype 2 monovalent OPV (mOPV2) from a stockpile. A novel vaccine developed from a genetically stabilized OPV2 strain (nOPV2) promises to potentially facilitate outbreak response with lower prospective risks, although its availability and properties in the field remain uncertain. Using an established global poliovirus transmission model and building on a related analysis that characterized the impacts of disruptions in GPEI activities caused by the COVID-19 pandemic, we explore the implications of trade-offs associated with delaying outbreak response to avoid using mOPV2 by waiting for nOPV2 availability (or equivalently, delayed responses waiting for national validation of meeting the criteria for nOPV2 initial use). Consistent with prior modeling, responding as quickly as possible with available mOPV2 promises to reduce the expected burden of disease in the outbreak population and to reduce the chances for the outbreak virus to spread to other areas. Delaying cVDPV2 outbreak response (e.g., modeled as no response January-June 2021) to wait for nOPV2 can considerably increase the total expected cases (e.g., by as many as 1,300 cVDPV2 cases in the African region during 2021-2023) and increases the likelihood of triggering the need to restart widescale preventive use of an OPV2-containing vaccine in national immunization programs that use OPV. Countries should respond to any cVDPV2 outbreaks quickly with rounds that achieve high coverage using any available OPV2, and plan to use nOPV2, if needed, once it becomes widely available based on evidence that it is as effective but safer in populations than mOPV2.
全球消灭脊灰行动（GPEI）在 2021 年管理 2 型循环疫苗衍生脊灰病毒（cVDPV2）疫情方面面临重大挑战。在全球协调停用用于国家免疫规划的三价口服脊灰病毒疫苗（tOPV）中的 2 型口服脊灰病毒疫苗（OPV2）整整五年后，cVDPV2 并未消失。自 OPV2 停止使用以来，针对由 cVDPV2 引起的疫情的应对措施主要使用了库存的 2 型单价口服脊灰病毒疫苗（mOPV2）。一种由遗传稳定的 OPV2 株开发的新型疫苗（nOPV2）有望以较低的预期风险促进疫情应对，但它在现场的供应情况和特性仍不确定。本研究使用已建立的全球脊灰病毒传播模型，并借鉴了一项相关分析，该分析描述了 GPEI 活动因 COVID-19 大流行而中断的影响，我们探讨了与延迟疫情应对相关的权衡取舍的影响，这些权衡取舍是为了避免使用 mOPV2，等待 nOPV2 的供应（或者说，等待国家验证符合使用 nOPV2 初始标准的延迟应对）。与之前的建模一致，尽快使用可用的 mOPV2 做出应对，有望减轻疫情人群的疾病负担，并降低疫情病毒传播到其他地区的机会。延迟 cVDPV2 疫情应对（例如，模拟 2021 年 1 月至 6 月无应对）以等待 nOPV2 可能会大大增加预期的总病例数（例如，2021-2023 年期间，非洲区域可能会增加多达 1300 例 cVDPV2 病例），并增加触发在使用 OPV 的国家免疫规划中重新广泛使用含 OPV2 疫苗的预防性使用的必要性。各国应迅速应对任何 cVDPV2 疫情，使用任何可用的 OPV2 进行高覆盖率的轮次接种，并在 nOPV2 广泛供应后，根据其在人群中比 mOPV2 更有效但更安全的证据，计划按需使用 nOPV2。
