Zeeman Institute: SBIDER, University of Warwick, Coventry CV4 7AL, UK; Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK; School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
Zeeman Institute: SBIDER, University of Warwick, Coventry CV4 7AL, UK; Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK.
Epidemics. 2017 Dec;21:56-62. doi: 10.1016/j.epidem.2017.06.004. Epub 2017 Jul 8.
When considering a new vaccine programme or modifying an existing one, economic cost-benefit analysis, underpinned by predictive epidemiological modelling, is a key component. This analysis is intimately linked to the willingness to pay for additional QALYs (quality-adjusted life-years) gained; currently in England and Wales a health programme is economically viable if the cost per QALY gained is less than £ 20,000, and models are often used to assess if a vaccine programme is likely to fall below this threshold cost. Before a programme begins, infection levels are generally high and therefore vaccination may be expected to have substantial effects and therefore will often be economically viable. However, once a programme is established, and infection rates are lower, it might be expected that a re-evaluation of the programme (using current incidence information) will show it to be less cost-effective. This is the scenario we examine here with analytical tools and simple ODE models. Surprisingly we show that in most cases the benefits from maintaining an existing vaccination programme are at least equal to those of starting the programme initially, and in the majority of scenarios the differences between the two are minimal. In practical terms, this is an extremely helpful finding, allowing us to assert that the action of immunising individuals does not de-value the vaccination programme.
在考虑新的疫苗接种计划或修改现有的疫苗接种计划时，经济成本效益分析，辅以预测性的流行病学建模，是一个关键组成部分。这种分析与对额外获得的 QALY（质量调整生命年）的支付意愿密切相关；目前在英格兰和威尔士，如果每获得一个 QALY 的成本低于 20000 英镑，那么一个健康计划在经济上就是可行的，而且通常使用模型来评估疫苗接种计划是否有可能低于这一成本门槛。在计划开始之前，感染水平通常较高，因此预计疫苗接种将产生重大影响，因此通常在经济上是可行的。然而，一旦计划建立起来，感染率降低，人们可能会预期对该计划进行重新评估（使用当前的发病率信息）将表明其成本效益较低。这就是我们在这里使用分析工具和简单的 ODE 模型来研究的情况。令人惊讶的是，我们发现，在大多数情况下，维持现有疫苗接种计划的好处至少与最初启动该计划的好处相等，而且在大多数情况下，两者之间的差异微乎其微。实际上，这是一个非常有帮助的发现，使我们能够断言，对个人进行免疫接种的行为并不会降低疫苗接种计划的价值。
