The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused considerable morbidity and mortality worldwide. The protection provided by vaccines and booster doses offered a method of mitigating severe clinical outcomes and mortality. However, by the end of 2021, the global distribution of vaccines was highly heterogeneous, with some countries gaining over 90% coverage in adults, whereas others reached less than 2%. In this study, we used an age-structured model of SARS-CoV-2 dynamics, matched to national data from 152 countries in 2021, to investigate the global impact of different potential vaccine sharing protocols that attempted to address this inequity. We quantified the effects of implemented vaccine rollout strategies on the spread of SARS-CoV-2, the subsequent global burden of disease and the emergence of novel variants. We found that greater vaccine sharing would have lowered the total global burden of disease, and any associated increases in infections in previously vaccine-rich countries could have been mitigated by reduced relaxation of non-pharmaceutical interventions. Our results reinforce the health message, pertinent to future pandemics, that vaccine distribution proportional to wealth, rather than to need, may be detrimental to all.

严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 大流行已在全球范围内造成相当大的发病率和死亡率。疫苗和加强剂量提供的保护提供了一种减轻严重临床结果和死亡率的方法。然而，到 2021 年底，疫苗的全球分布存在高度异质性，一些国家的成人覆盖率超过 90%，而其他国家的覆盖率不到 2%。在这项研究中，我们使用了 SARS-CoV-2 动态的年龄结构模型，与 2021 年来自 152 个国家/地区的国家数据相匹配，以调查试图解决这种不公平现象的不同潜在疫苗共享协议的全球影响。我们量化了已实施的疫苗推广策略对 SARS-CoV-2 传播的影响，随后的全球疾病负担和新变种的出现。我们发现，更多的疫苗共享会降低全球疾病的总负担，并且可以通过减少非药物干预措施的放松来减轻以前疫苗丰富的国家中任何相关的感染增加。我们的结果强化了与未来流行病相关的健康信息，即疫苗分配与财富成正比，而不是与需求成正比，可能对所有人都有害。