Davis X M, Waller L A, Haber M
Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
J Biopharm Stat. 2006;16(4):499-516. doi: 10.1080/10543400600719467.
We develop a Bayesian approach for estimating vaccine efficacy for susceptibility (VEs) and infectiousness (VEI) using outbreak size household data. Our method allows for heterogeneity in transmission probabilities due to factors that are related to individuals' characteristics, such as age, in addition to vaccination status. It also allows for between-household heterogeneity in transmission probabilities due to random effects associated with households, such as genetic or environmental effects. Using age as a potential covariate causing heterogeneity in individuals' transmission probabilities in households consisting of adults and children, we present the results of a simulation study designed to evaluate the performance of the proposed estimators of VEs and VE(I). We found that estimates of VE(I) have larger bias and variance compared to those of VEs. We also use the approach to compare two vaccination designs: one vaccinating both adults and children, the other only children. Simulations reveal that the design that vaccinates both adults and children provides better estimates of VEs. There is no obvious difference between the two designs in the performance of the estimates of VE(I). In regard to random effects between households and the scenarios considered, models that do not account for between-households heterogeneity produce fairly robust estimates even when household-level random effects are present.
我们开发了一种贝叶斯方法，用于使用家庭疫情规模数据估计疫苗对易感性（VEs）和传染性（VEI）的效力。我们的方法考虑了除疫苗接种状态外，因个体特征（如年龄）相关因素导致的传播概率异质性。它还考虑了因与家庭相关的随机效应（如遗传或环境效应）导致的家庭间传播概率异质性。以年龄作为导致由成人和儿童组成的家庭中个体传播概率异质性的潜在协变量，我们展示了一项模拟研究的结果，该研究旨在评估所提出的VEs和VE(I)估计量的性能。我们发现，与VEs的估计值相比，VE(I)的估计值具有更大的偏差和方差。我们还使用该方法比较两种疫苗接种设计：一种为成人和儿童都接种，另一种仅为儿童接种。模拟结果表明，为成人和儿童都接种的设计能更好地估计VEs。在VE(I)的估计性能方面，两种设计之间没有明显差异。对于家庭间的随机效应以及所考虑的情景，即使存在家庭层面的随机效应，未考虑家庭间异质性的模型也能产生相当稳健的估计值。
