Lung Innate Immunity and Microbiome After Tuberculosis Exposure

Inclusion Criteria: 1. Adults aged 18-65 years 2. Resident in or near London or Oxford for the duration of the study period 3. Provide written informed consent 4. Willing to allow the investigators to review the volunteer's review NHS care record, medical history, blood results and radiographs. 5. Able and willing (in the investigator's opinion) to comply with all study requirements Group A and B Specific Inclusion Criteria 6. Have undergone screening for TB through NHS services (including IGRA testing +/- CXR where indicated) 7. Close contact with a sputum smear positive TB case within the last 12 weeks Exclusion Criteria: 1. Participation in another research study involving receipt of an investigational product in the 30 days preceding enrolment or during the trial follow up period. 2. History of anaphylaxis or any allergy likely to be exacerbated by any essential study procedure 3. History of currently poorly controlled of airways disease (including asthma), current cancer (except BCC of the skin or CIS of the cervix), bleeding disorder, or drug or alcohol abuse 4. Any significant autoimmune conditions or immunodeficiency (including HIV) 5. Previous diagnosis or treatment for TB disease or latent TB infection 6. Clinical, radiological, or laboratory evidence of current active TB disease 7. Previous receipt of any investigational TB vaccines or aerosolised BCG. 8. Clinically Significant abnormalities in spirometry. 9. Concurrent use of oral, inhaled or systemic steroid medication or use for more than 14 days within the last 6 months (steroids used as a cream or ointment are permissible), or the use of other immunosuppressive agents concurrently or for more than 14 days within the last 6 months 10. Use of antibiotics in the past 4 weeks. 11. Administration of immunoglobulins and/or any blood products within the three months preceding the planned study 12. Administration of a live vaccine within the preceding 28 days prior to enrolment. 13. Administration of any other non-live vaccine within the preceding 14 days prior to enrolment. 14. Pregnancy or intention to become pregnant during study period 15. Any other significant disease, disorder, or finding, which, in the opinion of the investigator, may either put the volunteer at risk, affect the volunteer's ability to participate in the study or impair interpretation of the study data Group C Specific Exclusion Criteria 16. History of close contact with case of TB, or previous contact tracing by TB services.