Application of Branching Processes to Measles in California

分支过程在加利福尼亚州麻疹中的应用

• 批准号: 9192435
• 负责人: Sarah Frances Ackley
• 金额: $ 3.82万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9192435
• 关键词: Accounting; Affect; Age; Area; California; Chronic Disease; Committee Members; Coronavirus; Crowding; Data; Disease; Disease Outbreaks; Ebola virus; Epidemiologist; Epidemiology; Ethnic Origin; Ethnic group; Goals; Graph; Health Resources; Heterogeneity; Immunization; Individual; International; Investigation; Letters; Link; Measles; Measures; Mentorship; Methods; Modeling; Monitor; Mumps; Outcome; Play; Policies; Process; Public Health; Race; Reading; Reproduction; Research; Role; Seasonal Variations; Seasons; Stochastic Processes; Techniques; Time; Training; Tuberculosis; United States; Universities; Vaccinated; Vaccination; Vaccines; Viral; Visit; Vulnerable Populations; Work; disease transmission; disorder control; evidence base; experience; improved; interest; prevent; professor; programs; racial and ethnic; simulation; theories; tool; transmission process; vaccine efficacy

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).

项目概要/摘要 麻疹是一种高度传染性的病毒性疾病，2000 年加利福尼亚州宣布消灭麻疹，原因是 美国的疫苗接种计划取得了成功。然而，麻疹仍然是一个公共卫生问题 加州：麻疹疫情持续发生，呈小规模聚集性、传播链或孤立病例 从流行地区引进。每个病例总计约 100,000 美元的公共卫生资源 从其他公共卫生项目中转移来监测疫情并调查病例接触者。有组织 反对接种疫苗是麻疹控制的关键组成部分，仍然是一个重大问题。 与迪士尼乐园主题公园相关的大规模疫情导致 131 名加州人感染，这一事件引起了国际关注 2015 年初的头条新闻。据推测，这次异常大规模的疫情是由于疫苗接种减少所致 反对疫苗接种的结果。事实上，目前尚不清楚为什么有些疫情比其他疫情规模更大。 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大。已观察到传输差异 接种疫苗和未接种疫苗的病例，可能是观察到的暴发规模的异质性的原因。此外， 一年中的某些时间可能更容易传播。 该项目的目标是利用麻疹数据确定为什么某些疫情比其他疫情规模更大 加州公共卫生部 2000 年至 2015 年在加州的病例，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 麻疹病毒株更具传染性 比其他菌株，以及（目标 2）未接种疫苗的个体的聚集是否可以解释为什么意外地大 出现麻疹疫情。提出的技术包括分支过程理论，可用于 提供控制程度的直接估计和因果推断以帮助协变量选择。两个都 将使用最大似然和模拟技术，以及混合效应建模和参数化 引导。如果某些菌株更具传染性，或者未接种疫苗的个体聚集会影响 可以修改疫情规模、接触者调查策略以提高效率。此外，结果 可用于为全国疫苗接种政策提供信息。 拟议的培训计划包括实践研究经验，以执行拟议的目标并实现 申请人的论文要求。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 加利福尼亚州伯克利分校，与赞助商（Travis Porco 教授）和共同赞助商进行定向阅读 （韦恩·埃纳诺里亚教授）。 Jennifer Zipprich 博士将提供额外的培训和指导， 加州公共卫生部免疫部门和论文委员会的流行病学家 成员包括 Maria Glymour 教授（加州大学旧金山分校）和 Jamie Lloyd-Smith 教授（加州大学洛杉矶分校）。