Application of Branching Processes to Measles in California

项目摘要/摘要 麻疹是一种高度传染性的病毒性疾病，2000年在加利福尼亚州宣布消除，原因是 美国成功的疫苗接种计划。然而，麻疹仍然是#年的公共卫生问题。 加利福尼亚州：麻疹暴发继续以小聚集性、传播链或孤立病例的形式出现 来自疫区的引种。每个病例总计约100,000美元的公共卫生资源包括 用于监测疫情和调查病例接触者的其他公共卫生项目。有条理的 反对接种疫苗是控制麻疹的关键组成部分，这仍然是一个重大关切。 与迪士尼主题公园有关的大规模疫情，导致131名加州人感染，使之成为国际性的 2015年初的头条新闻。据推测，这次异常大的疫情是由于疫苗接种量减少所致。 由于反对接种疫苗而导致的死亡率。事实上，目前还不清楚为什么一些疫情比其他疫情更大。 加州公共卫生部的流行病学家观察到，B3麻疹的爆发 菌株往往比其他菌株的菌株大。在传输方面的差异已经被观察到 接种疫苗和未接种疫苗的病例，可能解释了观察到的暴发规模的异质性。此外, 一年中的某些时间可能对传播更为宽松。 这个项目的目标是利用麻疹的数据来确定为什么一些疫情比其他疫情更大。 加州公共卫生部2000至2015年的病例，通过两个 具体目标：我们的目标是确定(目标1)是否有证据表明B3麻疹病毒株更具传播性 以及(目标2)未接种疫苗的个体的聚集性是否解释了为什么 麻疹暴发时有发生。建议的技术包括分支过程理论，该理论可用于 提供对控制程度的直接估计和因果推断，以帮助选择协变量。两者都有 将使用最大似然和模拟技术，以及混合效果建模和参数 自给自足。如果某些菌株更易传播，或者如果未接种疫苗的个体聚集影响 暴发规模、接触者调查策略可以修改，以提高效率。此外，结果显示， 可以用来为全国的疫苗接种政策提供信息。 建议的培训计划包括实践研究经验，以执行建议的目标和实现 申请人的毕业论文要求。培训还将包括加州大学旧金山分校和加州大学的高级课程 加州，伯克利，与赞助商(特拉维斯·波尔科教授)和共同赞助商进行定向阅读 (韦恩·埃纳诺里亚教授)詹妮弗·齐普里奇博士将提供额外的培训和指导， 加州公共卫生部、免疫科和论文委员会的流行病学家 成员包括加州大学洛杉矶分校的玛丽亚·格拉莫教授和加州大学洛杉矶分校的杰米·劳埃德-史密斯教授。

PROJECT SUMMARY/ABSTRACT Measles, a highly contagious viral illness, was declared eliminated in 2000 in California as a result of a successful vaccination program in the United States. However, measles remains a public health problem in California: Measles outbreaks continue to occur as small clusters, transmission chains, or isolated cases due to introductions from endemic areas. Public health resources totaling approximately $100,000 per case are diverted from other public health programs to monitor outbreaks and investigate contacts of cases. Organized opposition to vaccination, the key component of measles control, remains a significant concern. A large outbreak linked to Disneyland theme parks, in which 131 Californians were infected, made international headlines in early 2015. It was speculated that this unusually large outbreak was due to decreased vaccination rates as a result of opposition to vaccination. In fact, it is not clear why some outbreaks are larger than others. Epidemiologists at the California Department of Public Health have observed that outbreaks of the B3 measles strain tend to be larger than those of other strains. Differences in transmission have been observed for vaccinated and unvaccinated cases and may account for observed heterogeneity in outbreak size. In addition, certain times of year may be more permissive for transmission. The goal of this project is to determine why some outbreaks are larger than others using data on measles cases in California from 2000 to 2015 from the California Department of Public Health, achieved through two specific aims: we aim to determine (aim 1) if there is evidence that the B3 measles strain is more transmissible than other strains, and (aim 2) whether clustering of unvaccinated individuals explains why unexpectedly large measles outbreaks occur. Proposed techniques include branching process theory, which can be used to provide direct estimates of the extent of control, and causal inference to aid in covariate selection. Both maximum likelihood and simulation techniques will be used, along with mixed-effects modeling and parametric bootstrapping. If some strains are more transmissible or if clustering of unvaccinated individuals affects outbreak size, contact investigation strategies could be modified for greater efficiency. In addition, the results could be used to inform vaccination policy nationally. The proposed training plan includes hands-on research experience to execute the proposed aims and fulfill the applicant's dissertation requirement. Training will also include advanced coursework at UCSF and University of California, Berkeley and directed readings with the sponsor (Professor Travis Porco) and co-sponsor (Professor Wayne Enanoria). Additional training and mentorship will come from Dr. Jennifer Zipprich, Epidemiologist at the California Department of Public Health, Immunization Branch, and dissertation committee members, Professor Maria Glymour (UCSF) and Professor Jamie Lloyd-Smith (UCLA).