The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the most formidable challenge to humanity in a century. It is widely believed that prepandemic normalcy will never return until a safe and effective vaccine strategy becomes available and a global vaccination programme is implemented successfully. Here, we discuss the immunological principles that need to be taken into consideration in the development of COVID-19 vaccine strategies. On the basis of these principles, we examine the current COVID-19 vaccine candidates, their strengths and potential shortfalls, and make inferences about their chances of success. Finally, we discuss the scientific and practical challenges that will be faced in the process of developing a successful vaccine and the ways in which COVID-19 vaccine strategies may evolve over the next few years.

由严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 引起的 2019 年冠状病毒病 (COVID-19) 大流行是一个世纪以来人类面临的最严峻的挑战。人们普遍认为，除非制定出安全有效的疫苗策略并成功实施全球疫苗接种计划，否则大流行前的正常状态将永远不会恢复。在这里，我们讨论在制定 COVID-19 疫苗策略时需要考虑的免疫学原理。根据这些原则，我们研究了当前的 COVID-19 候选疫苗、它们的优势和潜在的不足，并推断它们的成功机会。最后，我们讨论了在开发成功疫苗的过程中将面临的科学和实践挑战，以及未来几年 COVID-19 疫苗策略可能发展的方式。