Statistics, Modelling, and Economics Department, National Infection Service, Public Health England, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.
Immunisation and Countermeasures Department, National Infection Service, Public Health England, London, UK.
Value Health. 2021 Oct;24(10):1391-1399. doi: 10.1016/j.jval.2021.03.022. Epub 2021 Jul 30.
Incremental cost-effectiveness analyses may inform the optimal choice of healthcare interventions. Nevertheless, for many vaccines, benefits fluctuate with incidence levels over time. Reevaluating a vaccine after it has successfully decreased incidences may eventually cause a disease resurgence if switching to a vaccine with lower indirect benefits. Decisions may successively alternate between vaccines alongside repeated rises and falls in incidence and when indirect effects from historic use are ignored. Our suggested proposal aims to prevent suboptimal decision making.
We used a conceptual model of demand to illustrate alternating decisions between vaccines because of time-varying levels of indirect effects. Similar to the concept of subsidies, we propose internalizing the indirect effects achievable with vaccines. In a case study over 60 years, we simulated a hypothetical 10-year reevaluation of 2 oncogenic human papillomavirus vaccines, of which only 1 protects additionally against anogenital warts.
Our case study showed that the vaccine with additional warts protection is initially valued higher than the vaccine without additional warts protection. After 10 years, this differential decreases because of declines in warts incidence, which supports switching to the nonwarts vaccine that causes a warts resurgence eventually. Instead, pricing the indirect effects separately supports continuing with the warts vaccine.
Ignoring how the observed incidences depend on the indirect effects achieved with a particular vaccine may lead to repeated changes in vaccines at successive reevaluations, with unintended resurgences, economic inefficiencies, and eroding vaccine confidence. We propose internalizing indirect effects to prevent vaccines falling victim to their own success.
增量成本效益分析可用于为医疗干预措施提供最佳选择。然而，对于许多疫苗而言，其效益会随时间推移而随发病率的变化而波动。如果转而使用间接效益较低的疫苗，成功降低发病率后对疫苗进行重新评估最终可能导致疾病再次流行。如果忽略历史使用的间接影响，决策可能会随着发病率的反复上升和下降而在疫苗之间交替，并且会不断交替。我们建议的方案旨在防止做出次优决策。
我们使用需求概念模型来说明由于间接效应随时间变化而导致疫苗之间的交替决策。类似于补贴的概念，我们建议将可通过疫苗实现的间接效应内在化。在一项为期 60 多年的案例研究中，我们模拟了对 2 种致癌型人乳头瘤病毒疫苗进行为期 10 年的重新评估，其中只有 1 种疫苗可额外预防生殖器疣。
我们的案例研究表明，具有额外疣保护作用的疫苗最初比没有额外疣保护作用的疫苗更具价值。10 年后，由于疣发病率下降，这种差异会减小，这支持转而使用最终会导致疣再次流行的非疣疫苗。相反，单独为间接效应定价可支持继续使用疣疫苗。
忽略观察到的发病率如何取决于特定疫苗所实现的间接效应，可能会导致在连续重新评估中反复更换疫苗，从而导致意外的再次流行、经济效率低下和疫苗信心的削弱。我们建议将间接效应内在化，以防止疫苗成为自身成功的受害者。
