Vaccinating in disease-free regions:: a vaccine model with application to yellow fever
Vaccinating in disease-free regions:: a vaccine model with application to yellow fever
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DOI：
10.1098/rsif.2007.0234
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发表时间：
2007-12-22
影响因子：
3.9
通讯作者：
Struchiner, Claudio
中科院分区：
文献类型：
--
作者：
Codeco, Claudia T.;Luz, Paula M.;Struchiner, Claudio
对自然或诱发的传染病出现的关切引发了一场关于对处于不确定风险下的人群进行先发制人的疫苗接种的利弊的辩论。在没有直接风险的情况下，就会出现伦理问题，因为与疫苗相关的更小风险也大于直接的疾病风险（即零风险）。本文提出的模型旨在从易感个体的角度将疫苗接种决策过程正式化，结果显示在巴西城市出现黄热病的背景下。该模型将个体对是否接种疫苗的选择分解为不确定成分。选择建模为以下因素的函数：(i)疫苗不良事件的风险；（ii）疫情爆发的风险；（iii）在疫情爆发的情况下接种疫苗或避免严重疾病的概率。此外，我们探讨了这种决策如何随着不同效率的大规模疫苗接种策略而变化。如果疾病被认为是可能发生的，但不太可能发生（爆发的风险小于0.1），如果预期开展合理有效的运动，延迟接种疫苗是一个很好的策略。等待的好处随着传播率的降低而增加（低R-0），这表明病媒控制规划和紧急疫苗接种准备共同努力，有利于这一战略。如果黄热病城市化的可能性很高，或者如果预期的R-0很高，并且预计紧急行动缓慢，则倾向于采取相反的策略，即先发制人地接种疫苗。总之，我们的模型强调了个人最佳策略对应对黄热病暴发或其他突发传染病的准备的非线性依赖。
Concerns regarding natural or induced emergence of infectious diseases have raised a debate on the pros and cons of pre-emptive vaccination of populations under uncertain risk. In the absence of immediate risk, ethical issues arise because even smaller risks associated with the vaccine are greater than the immediate disease risk (which is zero). The model proposed here seeks to formalize the vaccination decision process looking from the perspective of the susceptible individual, and results are shown in the context of the emergence of urban yellow fever in Brazil. The model decomposes the individual's choice about vaccinating or not into uncertain components. The choice is modelled as a function of (i) the risk of a vaccine adverse event, (ii) the risk of an outbreak and (iii) the probability of receiving the vaccine or escaping serious disease given an outbreak. Additionally, we explore how this decision varies as a function of mass vaccination strategies of varying efficiency. If disease is considered possible but unlikely (risk of outbreak less than 0.1), delay vaccination is a good strategy if a reasonably effcient campaign is expected. The advantage of waiting increases as the rate of transmission is reduced (low R-0) suggesting that vector control programmes and emergency vaccination preparedness work together to favour this strategy. The opposing strategy, vaccinating pre-emptively, is favoured if the probability of yellow fever urbanization is high or if expected R-0 is high and emergency action is expected to be slow. In summary, our model highlights the nonlinear dependence of an individual's best strategy on the preparedness of a response to a yellow fever outbreak or other emergent infectious disease.