Department of Experimental Oncology, European Institute of Oncology, Milano, Italy.
PLoS One. 2012;7(10):e45653. doi: 10.1371/journal.pone.0045653. Epub 2012 Oct 1.
After a long period of stagnation, traditionally explained by the voluntary nature of the programme, a considerable increase in routine measles vaccine uptake has been recently observed in Italy after a set of public interventions aiming to promote MMR immunization, whilst retaining its voluntary aspect. To account for this take-off in coverage we propose a simple SIR transmission model with vaccination choice, where, unlike similar works, vaccinating behaviour spreads not only through the diffusion of "private" information spontaneously circulating among parents of children to be vaccinated, which we call imitation, but also through public information communicated by the public health authorities. We show that public intervention has a stabilising role which is able to reduce the strength of imitation-induced oscillations, to allow disease elimination, and to even make the disease-free equilibrium where everyone is vaccinated globally attractive. The available Italian data are used to evaluate the main behavioural parameters, showing that the proposed model seems to provide a much more plausible behavioural explanation of the observed take-off of uptake of vaccine against measles than models based on pure imitation alone.
在经历了长期停滞之后，人们通常将其归因于该计划的自愿性质，然而最近在意大利，一系列旨在促进麻疹、腮腺炎、风疹联合疫苗（MMR）免疫接种的公共干预措施出台后，常规麻疹疫苗接种率有了显著提高，同时保留了其自愿性的特点。为了解释这种覆盖率的提升，我们提出了一个简单的 SIR 传播模型，其中包含了疫苗接种选择。与类似的研究不同，接种行为不仅通过在即将接种疫苗的儿童的父母之间自发传播的“私人”信息扩散（我们称之为模仿），而且还通过公共卫生当局传播的公共信息传播。我们表明，公共干预措施具有稳定作用，能够降低模仿引起的波动的强度，从而消除疾病，并使每个人都接种疫苗的无病平衡点具有吸引力。利用意大利现有的数据来评估主要的行为参数，结果表明，与仅基于模仿的模型相比，所提出的模型似乎为观察到的麻疹疫苗接种率的提升提供了一个更合理的行为解释。
