Bacillus Calmette–Guérin (BCG) is the most widely used vaccine worldwide and has been used to prevent tuberculosis for a century. BCG also stimulates an anti-tumour immune response, which urologists have harnessed for the treatment of non-muscle-invasive bladder cancer. A growing body of evidence indicates that BCG offers protection against various non-mycobacterial and viral infections. The non-specific effects of BCG occur via the induction of trained immunity and form the basis for the hypothesis that BCG vaccination could be used to protect against the severity of coronavirus disease 2019 (COVID-19). This Perspective article highlights key milestones in the 100-year history of BCG and projects its potential role in the COVID-19 pandemic.

卡介苗 (BCG) 是全世界使用最广泛的疫苗，一个世纪以来一直用于预防结核病。卡介苗还能刺激抗肿瘤免疫反应，泌尿科医生已利用这种免疫反应来治疗非肌层浸润性膀胱癌。越来越多的证据表明卡介苗可以预防各种非分枝杆菌和病毒感染。 BCG 的非特异性作用是通过诱导训练有素的免疫力而产生的，并构成了 BCG 疫苗接种可用于预防 2019 年冠状病毒病 (COVID-19) 严重程度的假设的基础。这篇观点文章重点介绍了 BCG 100 年历史中的关键里程碑，并预测了它在 COVID-19 大流行中的潜在作用。