Department of Mathematics and Statistics, University of Strathclyde, Glasgow G1 1XH, UK.
LIM01-Hospital de Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil; Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
Math Biosci. 2017 Dec;294:15-32. doi: 10.1016/j.mbs.2017.09.004. Epub 2017 Sep 19.
In this paper we study a mathematical model to analyse the optimal vaccination age against Dengue in Brazil. Data from Brazil are used to estimate the basic reproduction numbers for each of the four Dengue serotypes and then the optimal vaccination age is calculated using a method due to Hethcote [1]. The vaccine has different efficacies against each serotype. Vaccination that is too early is ineffective as individuals are protected by maternal antibodies but leaving vaccination until later may allow the disease to spread. First of all the optimal vaccination ages are calculated where there is just one serotype in circulation and then when there are multiple serotypes. The calculations are done using data both assuming constant vaccine efficacy and age-dependent vaccine efficacy against a given serotype. The multiple serotype calculations are repeated assuming that the first infection is a risky infection and that it is not (to model Dengue Antibody Enhancement). The calculations are then repeated when any third or fourth Dengue infections are asymptomatic, so that two Dengue infections with different serotypes provide effective permanent immunity. The calculations are also repeated when the age-dependent risk function (fitted to Brazilian data) is hospitalisation from Dengue and when it is mortality due to Dengue. We find a wide variety of optimal vaccination ages depending on both the serotypes in circulation and the assumptions of the model.
本文研究了一个数学模型，以分析巴西针对登革热的最佳疫苗接种年龄。使用来自巴西的数据估计了四种登革热血清型的基本繁殖数，然后使用 Hethcote [1] 的方法计算最佳疫苗接种年龄。该疫苗对每种血清型的效果不同。接种过早是无效的，因为个体受到母体抗体的保护，但等到晚些时候接种可能会使疾病传播。首先，在只有一种血清型传播的情况下计算最佳疫苗接种年龄，然后在有多种血清型传播的情况下计算。使用数据进行计算，同时假设针对给定血清型的疫苗效力和年龄依赖性疫苗效力保持不变。在假设首次感染是危险感染且不是感染的情况下（模拟登革热抗体增强）重复多血清型计算。当任何第三次或第四次登革热感染无症状时，再次进行计算，以便两种不同血清型的登革热感染提供有效的永久免疫力。当年龄相关的风险函数（拟合巴西数据）是登革热住院或登革热死亡时，也会进行计算。我们发现，最佳疫苗接种年龄因循环中的血清型和模型的假设而多种多样。
