Vaccination status of children exempted from school-entry immunization mandates

描述（由申请人提供）：常规儿童免疫计划被广泛认为是上个世纪最成功的公共卫生干预措施。尽管取得了这一成功，但父母对疫苗的犹豫仍很普遍。疫苗犹豫可能导致家长以非医疗或“个人信仰”为由豁免入学免疫规定。在加州，这项研究的重点，个人信仰豁免（PBEs）从1996年到2010年翻了两番。疫苗可预防儿童疾病（VPCDs）的发病率也在上升。虽然较高的豁免率已被证明与VPCDs爆发风险增加有关，但这种关联的强度及其影响在很大程度上取决于豁免儿童的真实疫苗接种状况。然而，关于豁免儿童的疫苗接种状况的证据不足，使豁免流行率成为爆发风险的一个嘈杂信号。目前使用豁免流行率评估疫情风险的方法可能错误估计了这一风险。与此同时，人们对学校层面的做法知之甚少，这些做法可能会促进不受家长偏好影响的豁免。本研究的目的是改进与豁免相关的疾病爆发风险的估计。中心假设是，豁免儿童的疫苗接种状况因学校一级的豁免率和学校一级与跟踪豁免有关的做法而异。两个具体目的将检验这一假设：(1)估计加州幼儿园的疫苗接种状况与个人信仰豁免。(2)确定与高豁免率和低豁免率相关的学校实践。该研究将使用加州公共卫生部例行收集的儿童免疫数据和学校免疫跟踪实践，对豁免儿童的疫苗接种状况和学校程序与PBE率的关系进行二次分析。有界估计和拉丁超立方采样技术将用于解决缺失的数据。本研究的预期结果包括首次在大州对豁免幼儿园儿童的疫苗接种状况进行人口水平估计。这些估计值可用于评估与PBEs相关的实际疾病爆发风险，并降低与学校社区内聚集性疫苗拒绝相关的VPCDs风险。这项研究还将确定学校层面的做法，这些做法可能是减少豁免的干预措施的良好候选者。这个研究项目的长期目标是保持群体对VPCDs的免疫力。

DESCRIPTION (provided by applicant): The routine child immunization schedule is widely claimed to be the most successful public health intervention of the past century. Despite this success, parental vaccine hesitancy is widespread. Vaccine hesitancy may lead parents to obtain a non-medical or "personal beliefs" exemptions from school-entry immunization mandates. In California, the focus of this study, personal beliefs exemptions (PBEs) quadrupled from 1996 to 2010. Incidence of vaccine- preventable childhood diseases (VPCDs) is also on the rise. While higher rates of exemptions have been shown to be associated with increased outbreak risk of outbreak of VPCDs, the strength of this association and its implications depend critically on the true vaccination status of children with exemptions. However, there is scant evidence on the vaccination status of exempted children, making exemption prevalence a noisy signal for outbreak risk. Current approaches to assessing outbreak risk using exemption prevalence likely misestimate that risk. At the same time, little is known about school-level practices that may promote exemptions independent of parental preferences. The goal of this study is to improve estimates of the disease outbreak risk associated with exemptions. The central hypothesis is that the vaccination status of exempted children varies by school-level exemption rates and by school-level practices related to tracking exemptions. Two specific aims will test this hypothesis: (1) Estimate the vaccination status of California kindergarteners with personal beliefs exemptions. (2) Identify school practices associated with higher vs. lower exemption rates. The study will use child-level immunization data and school-level immunization tracking practices routinely collected by the California Department of Public Health to conduct secondary analyses of the vaccination status of exempted children and the association of school procedures with PBE rates. Bounded estimates and Latin Hypercube Sampling techniques will be used to address missing data. The expected outcomes of this study include the first population-level estimates of the vaccination status of exempted kindergarteners in a large state. These estimates can be used to assess the actual disease outbreak risk associated with PBEs, and to reduce the risk of VPCDs associated with the clustering of vaccine refusal within school communities. The study will also identify school-level practices that may be good candidates for interventions to reduce exemptions. The long-term goal of this program of research is to preserve herd immunity against VPCDs.