Vaccines remain the main prospect for an exit strategy from the COVID-19 pandemic, and may, depending on efficacy, duration of protection and uptake, make herd immunity feasible. If herd immunity is not achievable, SARS-COV-2 will circulate long-term. There are many vaccine candidates in development and choices between vaccines that will vary in efficacy and safety. The efficacy of available vaccines is compared and ranges from 62–95% against symptomatic infection with the G614 variant. Efficacy is reduced against new variants of concern and is uncertain against asymptomatic infection. Some vaccines show a better protective immune response than natural infection. The principles of herd immunity and prerequisites for achieving it, such as vaccine efficacy, duration of protection and coverage, are discussed. The alternative vaccine strategies including mass vaccination, targeted risk or age-based vaccination and ring vaccination, as well as speed of vaccination are reviewed. Finally, the impact of variants of concern on vaccine programs and the logistics of mass vaccination are discussed.

疫苗仍然是从COVID-19大流行中退出的主要策略，并且可能根据功效，保护时间和摄取时间而定，使畜群免疫变得可行。如果无法获得畜群免疫力，SARS-COV-2将长期传播。在开发中有许多候选疫苗，在疫苗之间的选择和选择将在功效和安全性方面有所不同。比较了可用疫苗的功效，其针对G614变体有症状感染的范围为62–95％。对新的关注变体的功效降低，并且对无症状感染的不确定性。一些疫苗显示出比自然感染更好的保护性免疫反应。讨论了牛群免疫的原理以及达到牛群免疫的先决条件，例如疫苗效力，保护期和覆盖范围。审查了替代疫苗策略，包括大规模疫苗接种，针对性风险或基于年龄的疫苗接种和环形疫苗接种以及疫苗接种速度。最后，讨论了关注变量对疫苗计划和大规模疫苗接种后勤的影响。