LONDON : Scientists in the UK will begin recruiting frontline healthcare workers to test if an old vaccine used to combat tuberculosis (TB), the Bacillus Calmette-Guerin or BCG jab, can be repurposed to help boost immunity against the novel coronavirus as well.The University of Exeter in south-west England said on Sunday that it is leading the UK arm of the worldwide research called the BCG vaccination to Reduce the impact of COVID-19 in healthcare workers (BRACE) trial.Participants will be given either the BCG vaccine, currently given to more than 100 million babies worldwide each year, including in India, to protect against TB, or a placebo injection.The BCG vaccine boosts immunity by “training" the immune system to respond to other.