Study shows bacille Calmette-Guérin vaccine can protect mice against lethal SARS-CoV-2 challenge

A recent US study, currently available on bioRxiv preprint server, implies that vaccination with bacille Calmette-Guérin (BCG) can limit the infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by targeting innate immune pathways and could thus be used as a platform for pinpointing early immunologic events affecting the outcome of coronavirus disease (COVID-19). Clinical presentation and pathologic events seen in severe manifestations of COVID-19 are purportedly driven by an overeager and sustained innate immune response. Disease severity positively correlates with high levels of pro-inflammatory proteins known as cytokines, but also myeloid cell activation. BCG represents a live attenuated vaccine that is in wide use for a long time for the prevention of disseminated tuberculosis in infants and young children. However, its non-specific effects linked to epigenetic and metabolic reprogramming of the innate immune system are also well-known. This is why BCG administration has been touted as a potential prophylactic measure in preventing...