Non-specific effects of BCG vaccine on viral infections

BackgroundSome strains of Bacillus Calmette–Guérin (BCG) vaccine not only confer protection against disseminated forms of tuberculosis, but also reduce all-cause mortality by the induction of protection against infections with non-related pathogens.ObjectivesWe review evidence for non-specific protection induced by BCG vaccination against viral infections, discuss possible mechanisms of action, and summarize implications for vaccination policies...