Boosting the TB vaccine

The best available vaccine against tuberculosis isn’t foolproof. The so-called bacille Calmette-Guérin (BCG) vaccine is a live but disabled form of the tuberculosis bacterium itself, Mycobacterium tuberculosis. Unfortunately, the vaccine doesn’t carry enough bacterial proteins to prime the immune systems of all recipients for challenges by the real pathogen. The BCG vaccine leaves a fourth of vaccinated children unprotected and protects even fewer adults.