The remarkable success of messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has propelled the rapid development of this vaccination technology in recent years. Over the last three decades, numerous studies have shown the considerable potential of mRNA vaccines that elicit protective immune responses against pathogens or cancers in preclinical studies or clinical trials. These effective mRNA vaccines usually contain specific adjuvants to obtain the desired immune effect. Vaccine adjuvants traditionally are immunopotentiators that bind to pattern recognition receptors (PRRs) of innate immune cells to increase the magnitude or achieve qualitative alteration of immune responses, finally enhancing the efficacy of vaccines. Generally, adjuvants are necessary parts of competent vaccines. According to the existing literature, adjuvants in mRNA vaccines can be broadly classified into three categories: 1) RNA with self-adjuvant characteristics, 2) components of the delivery system, and 3) exogenous immunostimulants. This review summarizes the three types of adjuvants used in mRNA vaccines and provides a comprehensive understanding of molecular mechanisms by which adjuvants exert their functions in mRNA vaccines.

针对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的信使RNA（mRNA）疫苗取得了巨大成功，推动了该疫苗接种技术近年来的快速发展。在过去的三十年里，大量研究表明，mRNA 疫苗在临床前研究或临床试验中具有巨大的潜力，可以引发针对病原体或癌症的保护性免疫反应。这些有效的mRNA疫苗通常含有特定的佐剂以获得所需的免疫效果。传统上，疫苗佐剂是免疫增强剂，它与先天免疫细胞的模式识别受体（PRR）结合，以增加免疫反应的强度或实现免疫反应的质变，最终增强疫苗的功效。一般来说，佐剂是有效疫苗的必要组成部分。根据现有文献，mRNA疫苗中的佐剂大致可分为三类：1）具有自身佐剂特性的RNA，2）递送系统的成分，3）外源性免疫刺激剂。本综述总结了mRNA疫苗中使用的三种佐剂，并全面了解佐剂在mRNA疫苗中发挥作用的分子机制。