Strengths and weaknesses of current polio vaccines--a view from industry.
Strengths and weaknesses of current polio vaccines--a view from industry.
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当前脊髓灰质炎疫苗的优点和缺点——来自行业的观点。
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
F. André
中科院分区：
文献类型：
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作者：
F. André
消灭脊髓灰质炎是我们力所能及的事情，除非发生严重错误和意外的事情，否则三种野生脊髓灰质炎病毒将在未来几年内停止在人群中传播。这一成就将是合理使用 OPV 的结果。届时必须做出一项重大的全球决定——停止接种疫苗。影响该决定的最重要的不确定性是，在“根除”定义为“完全中断野生脊髓灰质炎病毒传播”后，野生脊髓灰质炎病毒是否会重新出现。重要的是要认识到“根除”并不意味着“灭绝”，即渡渡鸟已经灭绝。根除后，野生脊髓灰质炎病毒仍潜伏在实验室标本和受保护的环境场所（如冰川）中，甚至可能通过回复突变或萨宾衍生毒株的重组而“重新出现”，即使在停止使用 OPV 后，这些毒株也可能继续传播。理论上，如果使用 IPV 多年来对停止使用 OPV 后出生的所有儿童进行免疫，野生脊髓灰质炎病毒重新出现的风险就会降低。但问题是“多少？”。 IPV 疫苗接种将降低持久性 OPV 衍生菌株（例如免疫缺陷患者）在完全停止疫苗接种后有机会建立永久传播的风险。然而，重新出现的风险不会改变，因为这将由意外重新引入的风险决定。在全球范围内从 OPV 完全转向 IPV 的费用是否合理，将取决于野生脊髓灰质炎病毒从 OPV 衍生来源或其他环境来源重新出现的相对风险，包括从 IPV 生产设施中“逃逸”的剧毒种子病毒。这种可能性和风险的平衡将很难确定。无论如何，将 IPV 生产扩大到所需水平的决定可能已经推迟太久，因此发达国家和欠发达国家将通过使用 OPV 来根除脊髓灰质炎，而欠发达国家则无力以足够高的疫苗覆盖率使用 IPV 以确保其安全。在西半球，野生脊髓灰质炎病毒的传播已被 OPV 阻断。世界其他地方没有理由不能这样做。在有能力支付费用且疫苗覆盖率足以防止野生病毒传播的工业化国家，将越来越多地使用联合疫苗中的 IPV。让我们希望发展中国家的政治家和发达国家热心的伦理学家能够理解为什么在当前和可预见的未来情况下，OPV 比贫穷国家的 IPV 更好，并且不会以健康公平的名义要求完全转向 IPV。对于根除来说，IPV 不能而且希望也不需要取代 OPV。在这个阶段不应该。
Polio eradication is within our grasp and, unless something terribly wrong and unexpected happens, the three types of wild polioviruses will cease to circulate in human populations within the next few years. This achievement will be a result of the rational use of OPV. A momentous global decision--discontinuation of vaccination--will then have to be taken. The most important uncertainty that will weigh upon that decision is whether wild polioviruses can re-emerge after "eradication" defined as "complete interruption of wild polioviruses transmission", has been obtained. It is important to realise that "eradication" does not mean "extinction" in the sense that the dodo is extinct. After eradication, wild polioviruses will still lurk in laboratory specimens and in protected environmental sites (like glaciers) and may even "re-emerge" by back mutation or recombination of Sabin-derived strains that may continue to circulate even after OPV use is discontinued. Theoretically, the risk of re-emergence of wild polioviruses would be lessened if IPV was used for a number of years to immunise all those born after cessation of OPV usage. But the question is "by how much?". Vaccination with IPV will reduce the risk that persistent OPV-derived strains (e.g. in immunodeficient patients) will have the chance to establish permanent transmission after vaccination is totally discontinued. However, the risk of re-emergence will not be changed since this will be determined by the risk of accidental re-introduction. Whether the expense of switching completely from OPV to IPV globally can be justified will depend upon the relative risks of wild poliovirus re-emergence from either OPV-derived sources or other environmental sources including "escape" of virulent seed viruses from IPV production facilities. This balance of probabilities and risks will be very difficult to determine. In any case, it is likely that the decision to upscale IPV production to required levels has already been delayed too long so that polio eradication will be achieved by the use of OPV in developed as well as in less developed countries that cannot afford to use IPV at a high enough vaccine coverage rate to make it safe. Wild poLiovirus transmission has been interrupted with OPV in the Western Hemisphere. There is no reason why this cannot be done in the rest of the world. In industrialized countries that can afford it and where vaccine coverage is sufficient to prevent wild virus circulation, IPV, in combined vaccines, will be increasingly used. Let us hope that politicians in developing countries and zealous ethicists in the developed world will understand why, in the present and foreseeable future circumstances, OPV is better than IPV in the poorer countries and will not demand, in the name of equity in health, a total switch to IPV. For eradication, IPV cannot, and hopefully need not, replace OPV. At this stage it should not.