BCG Revaccination Study in Diabetic and Non-Diabetic Adults

Inclusion Criteria: * Healthy adults aged 18-65 years * Resident in or near Oxford for the duration of the study period * Provide written informed consent * Willing to allow the investigators to discuss the volunteer's medical history with their General Practitioner (or review summary care record, if available) * Allow the investigator to register volunteer details with a confidential database (The Over- volunteering Protection Service) to prevent concurrent entry into clinical studies/trials * Agreement to refrain from blood donation during the course of the study * For persons of child-bearing potential (POCBP) only, willingness to practice continuous effective contraception (see below) during the study and a negative pregnancy test on the day(s) of screening, vaccination and bronchoscopy * Able and willing (in the investigator's opinion) to comply with all study requirements * No clinically relevant findings on physical examination * Screening IGRA negative * Willing to be tested for evidence of SARS-CoV-2 infection and to allow public health notification of the results if required * Previously vaccinated with the BCG (at least 12 months prior to enrolment, as evidenced by a visible scar or documentation in medical or occupational health records) * Group C only - Documented diagnosis of T2DM (made at least 12 months prior to enrolment) initiated on a management plan with medication including use of metformin Exclusion Criteria: * Participation in another research study …