THE widely used BCG tuberculosis vaccine will be tested on frontline care workers in Britain for its effectiveness against COVID-19, researchers running the UK arm of a global trial said. Bacillus Calmette-Guérin (BCG) vaccine, used to protect against tuberculosis, induces a broad innate immune-system response and has been shown to protect against infection or severe illness with other respiratory pathogens. "BCG has been shown to boost immunity in a generalised way, which may offer some protection against COVID-19," Professor John Campbell, of the University of Exeter Medical School, said. "We are seeking to establish whether the BCG vaccine could help…