Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.
Army Tuberculosis Prevention and Control Key Laboratory, Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment, Institute for Tuberculosis Research, the 8th Medical Center of Chinese PLA General Hospital, Beijing, China.
Int Rev Immunol. 2022;41(2):283-296. doi: 10.1080/08830185.2021.1922685. Epub 2021 May 7.
Bacillus Calmette-Guérin (BCG) is a live attenuated vaccine that was developed about 100 years ago by Albert Calmette and Camille Guérin. Many countries have been using the vaccine for decades against tuberculosis (TB). The World Health Organization (WHO) recommends a single dose of BCG for infants in TB endemic as well as leprosy high risk countries, and globally almost 130 million infants are vaccinated yearly. The role of BCG is well known in reducing neonatal and childhood death rates. Epidemiological and retrospective cross-sectional studies demonstrated that the BCG vaccination protects the children against respiratory tract infections and lowers the risk of malaria in children. In addition, BCG enhances IFN-γ and IL-10 levels, thus providing immunity against respiratory tract infection even in elderly people. The BCG is also known to provide nonspecific innate immunity against viruses and parasites, through an innate immune mechanism termed 'trained immunity' and is defined as the immunological recall of the innate immune system by epigenetic reprogramming. Based on these studies it is suggested that the BCG has the potential to act as a protective agent against COVID-19. Further proven safety records of BCG in humans, its adjuvant activity and low-cost manufacturing make it an attractive option to stop the pandemic and reduce the COVID-19 related mortality. In this review we discuss the heterologous effects of BCG, induction of trained immunity and its implication in development of a potential vaccine against COVID-19 pandemic.
卡介苗（BCG）是一种减毒活疫苗，由阿尔伯特·卡尔梅特（Albert Calmette）和卡米尔·盖林（Camille Guérin）于 100 多年前开发。许多国家已经使用该疫苗数十年来预防结核病（TB）。世界卫生组织（WHO）建议在结核病流行地区以及麻风病高风险地区为婴儿接种一剂 BCG，并在全球范围内，每年有近 1.3 亿婴儿接种疫苗。BCG 在降低新生儿和儿童死亡率方面的作用是众所周知的。流行病学和回顾性横断面研究表明，BCG 疫苗可保护儿童免受呼吸道感染，并降低儿童疟疾的风险。此外，BCG 可增强 IFN-γ 和 IL-10 水平，从而为呼吸道感染提供免疫力，即使在老年人中也是如此。BCG 还通过一种称为“训练免疫”的先天免疫机制为病毒和寄生虫提供非特异性先天免疫，其定义为通过表观遗传重编程对先天免疫系统的免疫回忆。基于这些研究，有人认为 BCG 有可能成为预防 COVID-19 的保护剂。BCG 在人类中的进一步安全性记录、其佐剂活性和低成本制造使其成为阻止大流行和降低 COVID-19 相关死亡率的有吸引力的选择。在这篇综述中，我们讨论了 BCG 的异源效应、训练免疫的诱导及其在开发针对 COVID-19 大流行的潜在疫苗中的意义。
