Convergence between global BCG vaccination and COVID-19 pandemic.

The novel coronavirus SARS-CoV-2 has kept the whole world in tenterhooks due to its severe life-threatening infectious disease, COVID-19. The virus is distinct its cousins, SARS-CoV and MERS-CoV in term of severity of the infection. The obligated killing properties of the SARS-CoV-2 virus is mediated by its unique structure. Efforts for developing vaccines for COVID-19 are ongoing, but it is unlikely to be available in the immediate future. Due to the absence of precise treatment, the investigators are discovering other effective, protective and healing choices. However, the lower than predictable number of SARS-CoV-2 cases in countries with fragile health systems is mystifying. Recently, there has been a buzz about the protective effect of BCG vaccine in COVID-19 through long-term boosting of trained immunity. Based on epidemiological correlations, we link up that BCG vaccination adopted by different countries might influence the SARS-CoV-2 transmission patterns and/or COVID-19 associated mortality through the vaccine's capacity to confer heterologous protection. A number of clinical studies are underway to investigate this possibility but -even if they prove effective-many questions will remain. Moreover, responsible stewardship of the BCG vaccine in the context of the COVID-19 epidemic is directly needed. This article is protected by copyright. All rights reserved.