ID93/GLA-SE Vaccination + BCG Challenge

The purpose of this study is to: 1. Demonstrate the safety of a novel TB vaccine (ID93/GLA-SE) when given to both BCG-vaccinated and BCG-naïve volunteers. 2. Provide preliminary immunogenicity data of this novel TB vaccine (ID93/GLA-SE). This clinical trial will apply an aerosol BCG challenge model involving 48 participants - 24 historically BCG-vaccinated volunteers and 24 BCG-naïve volunteers. Bronchoscopies will be performed 14 days post-challenge to measure BCG recovered from bronchial samples. Blood tests will be taken to look at potential immunological markers of immunity.

Tuberculosis (TB) remains one of the deadliest infectious diseases worldwide. Key research priorities include the development of an effective vaccine. Currently, the only licensed vaccine against TB is BCG (Bacille Calmette-Guérin). This works well against TB in childhood but is often ineffective in adults. Developing a new TB vaccine is difficult, as it is hard to determine which will be effective. In other diseases, e.g. influenza or malaria, it is possible to experimentally-infect volunteers with the disease to see if the proposed vaccine is effective. This is called a "controlled human challenge or infection model" and is possible in easily treatable or self-limiting diseases. This is not possible with TB, where treatments may be harmful and complex. Using BCG, a live attenuated (weakened) strain of the bacteria that do not cause disease in healthy individuals, the investigators have developed a challenge model to mimic TB infection. Mycobacterium tuberculosis, the bacterium that causes TB, infects people by inhalation into the lungs. Therefore, inhaled BCG more closely imitates TB infection than an injection. Previous studies (TB041 and TB043) and a current study (TB044) in our group used aerosol inhaled BCG in both previously BCG-vaccinated and BCG-naïve volunteers to show that aerosolised BCG could be safely employed, and that BCG could be detected in lung washings two weeks after challenge. A novel TB vaccine (ID93/GLA-SE) has recently undergone clinical trials (phase IIa) to show that it can be given safely to healthy people. Its ability to protect people from TB is currently being investigated. The purpose of this study is to show the safety of this approach and provide preliminary immunogenicity data of this novel TB vaccine (ID93/GLA-SE) in both historically BCG-vaccinated and BCG-naïve volunteers, using an aerosol BCG challenge model. It will involve 48 participants; 12 historically BCG-vaccinated and 12 BCG-naïve participants will initially receive 2 injections of the intramuscular ID93/GLA-SE before challenge with aerosol BCG, while a further 24 participants (12 historically BCG vaccinated) will have aerosol BCG challenge alone. Bronchoscopies will be performed 14 days post aerosol BCG challenge to measure BCG recovered from bronchial samples. Blood samples will be taken to look at potential immunological markers of protection.