Noval Rivas Magali, Rosser Charles J, Arditi Moshe
Department of Pediatrics, Division of Infectious Diseases and Immunology, Infectious and Immunologic Diseases Research Center (IIDRC) and Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
Bladder Cancer. 2021 May 25;7(2):121-131. doi: 10.3233/BLC-201529. eCollection 2021.
Despite the implementation of mitigation measures, Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still spreading worldwide, and has caused more than 1 million deaths so far. Although recent reports indicate that three vaccine candidates are effective against SARS-CoV-2, more time is needed to generate enough doses for the general population. Meanwhile, frontline healthcare workers are at high risk of SARS-CoV-2 exposure. To avoid collapse of the medical care system, there is a need to develop novel approaches to limit SARS-CoV-2 spread. Through a process called trained immunity, the Bacillus Calmette-Guerin (BCG) vaccine boosts the action of innate immune cells, resulting in a nonspecific reduction in the incidence of viral infections. Due to this immunomodulatory action, the BCG vaccine is currently used as a therapeutic in bladder cancer. Data collected from epidemiological and observational studies indicate that BCG vaccination might provide protection against COVID-19. While these observations do not provide evidence of causality and are limited by cofounding and intrinsic biases, it is crucial to explore the hypothesis that BCG vaccination may provide a nonspecific innate immune boost and therefore protect against COVID-19 in randomized controlled clinical trials, particularly for people at higher risk of developing COVID-19, such as frontline healthcare workers.
尽管实施了缓解措施，但由严重急性呼吸综合征冠状病毒2（SARS-CoV-2）引起的2019冠状病毒病（COVID-19）仍在全球范围内传播，迄今为止已导致100多万人死亡。尽管最近的报告表明，三种候选疫苗对SARS-CoV-2有效，但仍需要更多时间来为普通人群生产足够剂量的疫苗。与此同时，一线医护人员面临着较高的SARS-CoV-2暴露风险。为避免医疗系统崩溃，有必要开发新方法来限制SARS-CoV-2的传播。卡介苗（BCG）疫苗通过一种称为训练免疫的过程增强先天免疫细胞的作用，从而非特异性地降低病毒感染的发生率。由于这种免疫调节作用，卡介苗目前被用作膀胱癌的一种治疗方法。从流行病学和观察性研究中收集的数据表明，卡介苗接种可能对COVID-19有保护作用。虽然这些观察结果没有提供因果关系的证据，并且受到混杂因素和内在偏差的限制，但在随机对照临床试验中探索卡介苗接种可能提供非特异性先天免疫增强作用并因此预防COVID-19这一假设至关重要，特别是对于感染COVID-19风险较高的人群，如一线医护人员。
