Verani Jennifer R, Baqui Abdullah H, Broome Claire V, Cherian Thomas, Cohen Cheryl, Farrar Jennifer L, Feikin Daniel R, Groome Michelle J, Hajjeh Rana A, Johnson Hope L, Madhi Shabir A, Mulholland Kim, O'Brien Katherine L, Parashar Umesh D, Patel Manish M, Rodrigues Laura C, Santosham Mathuram, Scott J Anthony, Smith Peter G, Sommerfelt Halvor, Tate Jacqueline E, Victor J Chris, Whitney Cynthia G, Zaidi Anita K, Zell Elizabeth R
National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA, USA.
International Center for Maternal and Newborn Health, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD, USA.
Vaccine. 2017 Jun 5;35(25):3295-3302. doi: 10.1016/j.vaccine.2017.04.037. Epub 2017 Apr 22.
Case-control studies are commonly used to evaluate effectiveness of licensed vaccines after deployment in public health programs. Such studies can provide policy-relevant data on vaccine performance under 'real world' conditions, contributing to the evidence base to support and sustain introduction of new vaccines. However, case-control studies do not measure the impact of vaccine introduction on disease at a population level, and are subject to bias and confounding, which may lead to inaccurate results that can misinform policy decisions. In 2012, a group of experts met to review recent experience with case-control studies evaluating the effectiveness of several vaccines; here we summarize the recommendations of that group regarding best practices for planning, design and enrollment of cases and controls. Rigorous planning and preparation should focus on understanding the study context including healthcare-seeking and vaccination practices. Case-control vaccine effectiveness studies are best carried out soon after vaccine introduction because high coverage creates strong potential for confounding. Endpoints specific to the vaccine target are preferable to non-specific clinical syndromes since the proportion of non-specific outcomes preventable through vaccination may vary over time and place, leading to potentially confusing results. Controls should be representative of the source population from which cases arise, and are generally recruited from the community or health facilities where cases are enrolled. Matching of controls to cases for potential confounding factors is commonly used, although should be reserved for a limited number of key variables believed to be linked to both vaccination and disease. Case-control vaccine effectiveness studies can provide information useful to guide policy decisions and vaccine development, however rigorous preparation and design is essential.
病例对照研究常用于评估已获许可的疫苗在公共卫生项目中推广后的效果。此类研究能够提供“现实世界”条件下与疫苗性能相关的政策数据，为支持和维持新疫苗的引入提供证据基础。然而，病例对照研究无法衡量疫苗引入对人群层面疾病的影响，且容易受到偏倚和混杂因素的影响，这可能导致结果不准确，从而误导政策决策。2012年，一组专家会面回顾了评估几种疫苗效果的病例对照研究的近期经验；在此我们总结该小组关于病例和对照的规划、设计及纳入的最佳实践建议。严谨的规划和准备应聚焦于了解研究背景，包括就医和疫苗接种情况。病例对照疫苗效果研究最好在疫苗引入后不久开展，因为高覆盖率会产生很强的混杂可能性。针对疫苗目标的特定终点优于非特定临床综合征，因为通过接种疫苗可预防的非特定结果的比例可能随时间和地点而变化，从而导致可能令人困惑的结果。对照应代表病例所来自的源人群，通常从病例纳入的社区或医疗机构招募。虽然通常会将对照与病例就潜在混杂因素进行匹配，但应仅用于少数被认为与疫苗接种和疾病均相关的关键变量。病例对照疫苗效果研究可为指导政策决策和疫苗研发提供有用信息，然而严谨的准备和设计至关重要。
