Tuberculosis (TB) is the 13th leading cause of death in the world, and it is rising together with the increased prevalence of drug-resistant TB in many countries. The Bacille Calmette-Guerin (BCG) vaccine is the only available TB vaccine, and it has been given to more people than any other vaccine. While the BCG vaccine has saved tens of millions of lives, it confers suboptimal protection against pulmonary TB as it is limited to providing protection only until early childhood. Significantly, the BCG vaccine is administered intradermally to confer exceptional mucosal immunity as compared to most other vaccines, which are more commonly administered intramuscularly. Novel strategies to improve the duration of TB mucosal immunity are urgently needed.