Genetic tweaks to TB could speed up discovery of a new vaccine

“OK, smell this,” says Jeff Wagner, a Harvard postdoc of immunology and infectious disease. He’s pointing to the two flasks of bacteria in front of me. I breathe cautiously from the first vial of yellowish broth. Nothing. “Now this one,” he says, with an identical looking sample. And I’m hit with it: a distinct mint aroma like someone melted down a pack of breath mints.