Prevention, Efficacy and Safety of BCG Vaccine in COVID-19 Among Healthcare Workers

In Mexico the total number of confirmed cases of COVID-19 is 232, 000 and 28,510 deaths. Health workers are at high risk of COVID-19 infection. Their absence from work dramatically limits the ability to contain the disease. There is currently no vaccine to prevent the disease. Since the introduction to the vaccination schedule of the Bacillus Calmette-Guerin (BCG) live attenuated vaccine directed towards tuberculosis prevention, a decrease in infant mortality has been reported, not related only to tuberculosis. BCG vaccine has been hypothesized to have a non-specific role towards other unrelated pathogens such as viruses that cause airway disease, with reduced morbidity and mortality. In murine as well as in human models it has been shown to decrease the incidence of acute respiratory influenza infections. Likewise, in countries with a high endemicity for tuberculosis, the BCG vaccine reduces the incidence of respiratory infections by up to 80% . In healthy subjects, the BCG vaccine increases the production of proinflammatory cytokines in monocytes. Likewise, it increases the epigenetic response, causing an increase in the transcription of genes important in the antimicrobial response, as well as an improvement in cellular function. This is the first national clinical trial to evaluate prospectively the effect that the BCG vaccine offers towards the prevention and reduction of severity in cases of COVID-19.