Meta-analysis can be especially useful for evaluation of vaccine safety, since individual studies often have limited power to detect an increase in safety risk. To gain a perspective on the current state of utilization of the technique of meta-analysis for evaluation of vaccine safety and to assess the methodological characteristics of these meta-analyses, we conducted a systematic review of published meta-analyses. We identified 61 meta-analyses of vaccine safety. Safety outcomes for influenza and human papillomavirus vaccines were most frequently meta-analyzed. The most studied safety outcomes were local and systemic reactions, as well as serious adverse events. Most meta-analyses were literature based. Differences in the definitions of safety outcomes across the different studies and the poor reporting of safety in the published literature were described as challenges when conducting a meta-analysis of vaccine safety. A way to overcome these challenges is through the implementation of standardized safety outcomes definitions and reporting. A prospectively conducted meta-analysis, that is, a meta-analysis planned prior to the conduct of the trials, as well as implementation of subject-level meta-analysis techniques can also reduce or eliminate the impact of these difficulties.

荟萃分析对于评估疫苗的安全性尤其有用，因为个别研究通常检测出安全风险增加的能力有限。为了了解使用荟萃分析技术评估疫苗安全性的现状以及评估这些荟萃分析的方法学特征，我们对已发表的荟萃分析进行了系统综述。我们确定了61项疫苗安全性的荟萃分析。流感和人乳头瘤病毒疫苗的安全性结果最常进行荟萃分析。研究最多的安全性结果是局部和全身反应以及严重不良事件。大多数荟萃分析是基于文献的。在进行疫苗安全性的荟萃分析时，将不同研究的安全性结果定义上的差异以及已发表文献中对安全性的不良报道描述为挑战。克服这些挑战的一种方法是通过实施标准化的安全成果定义和报告。前瞻性进行的荟萃分析，即在进行试验之前计划进行的荟萃分析，以及实施受试者水平的荟萃分析技术，也可以减少或消除这些困难的影响。