Tuberculosis Prevention and Control Key Laboratory/Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment, Senior Department of Tuberculosis, The 8th Medical Center of PLA General Hospital, 100091 Beijing, China.
Department of General Medicine, The 8th Medical Center of PLA General Hospital, 100091 Beijing, China.
Front Biosci (Landmark Ed). 2022 May 13;27(5):157. doi: 10.31083/j.fbl2705157.
Coronavirus disease 2019 (COVID-19), which broke out at the end of 2019, is a global pandemic and seriously threatens human health. Vaccination is the most effective way to prevent and control COVID-19. At present, more than 13 COVID-19 vaccines have been urgently authorized for use, but the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has brought unprecedented challenges to the protective efficiency of these COVID-19 vaccines. In particular, the recent emergence of Delta and Omicron variants, which are rapidly spreading worldwide, may bring many challenges to the medical systems. Interestingly, previous studies have shown that the Bacillus Calmette-Guerin (BCG) vaccine used to prevent tuberculosis can induce non-specific trained immunity, protecting against infectious diseases caused by respiratory viruses. Therefore, there is a hypothesis that BCG plays an essential role in reducing the incidence, severity, hospitalization, and mortality of COVID-19 and enhancing the protection efficiency of the COVID-19 vaccine. To confirm this hypothesis, 56 clinical trials have been conducted globally to assess BCG's protective effectiveness against COVID-19 infection. Herein, this review discussed the trained immunity induced by BCG and its underlying mechanisms and summarised BCG's latest research progress in preventing COVID-19, especially the ongoing clinical trials. We hope this review will provide new strategies for fighting against COVID-19.
2019 年底爆发的 2019 年冠状病毒病（COVID-19）是一种全球性大流行疾病，严重威胁人类健康。接种疫苗是预防和控制 COVID-19 的最有效方法。目前，已有超过 13 种 COVID-19 疫苗被紧急授权使用，但严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）变异株的出现给这些 COVID-19 疫苗的保护效率带来了前所未有的挑战。特别是最近在全球迅速传播的 Delta 和 Omicron 变异株，可能给医疗系统带来许多挑战。有趣的是，先前的研究表明，用于预防结核病的卡介苗（BCG）可以诱导非特异性训练免疫，从而预防由呼吸道病毒引起的传染病。因此，有一个假设认为 BCG 在降低 COVID-19 的发病率、严重程度、住院率和死亡率以及增强 COVID-19 疫苗的保护效率方面发挥着重要作用。为了证实这一假设，全球已经开展了 56 项临床试验，评估 BCG 对 COVID-19 感染的保护效果。在此，本文讨论了 BCG 诱导的训练免疫及其潜在机制，并总结了 BCG 预防 COVID-19 的最新研究进展，特别是正在进行的临床试验。我们希望这篇综述将为抗击 COVID-19 提供新的策略。
