1. Known active Mycobacterium tuberculosis disease 2. Fever (greater than or equal to 38 ºC) or any other respiratory symptoms/illnesses within the past 14 days 3. BCG vaccination in the previous 12 months 4. Has any BCG vaccine contraindication/s 5. Confirmed existing or past COVID-19 infection by PCR or serology testing methods with or without symptoms 6. Pregnant or breastfeeding women 7. Women of child-bearing potential not agreeing to use adequate contraception 8. Current active viral or bacterial infection 9. Expected vaccination during the study period, independently of the type of vaccination 10. Severely immunocompromised participants. This exclusion category comprises a) participants with known infection by the HIV, b) participants with solid organ transplantation, c) participants with bone marrow transplantation, d) participants under chemotherapy/radiotherapy, e) participants with primary immunodeficiency, f) treatment with any anticytokine therapies. g) treatment with oral or intravenous steroids defined as daily doses of 10mg prednisolone or equivalent for longer than 3 months from the time of screening, or probable use of oral or intravenous steroids in the following four weeks 11. Active solid or non-solid malignancy or lymphoma within the prior two years 12. Individuals known to be hypersensitive to any component of the vaccine 13. Eczema or other significant skin lesion or infection at the site/s of injection. 14. Any other medical condition which in the opinion of the investigator may affect the participant’s safety or study participation and conduct.

1. Known active Mycobacterium tuberculosis disease 2. Fever (greater than or equal to 38 ºC) or any other respiratory symptoms/illnesses within the past 14 days 3. BCG vaccination in the previous 12 months 4. Has any BCG vaccine contraindication/s 5. Confirmed existing or past COVID-19 infection by PCR or serology testing methods with or without symptoms 6. Pregnant or breastfeeding women 7. Women of child-bearing potential not agreeing to use adequate contraception 8. Current active viral or bacterial infection 9. Expected vaccination during the study period, independently of the type of vaccination 10. Severely immunocompromised participants. This exclusion category comprises a) participants with known infection by the HIV, b) participants with solid organ transplantation, c) participants with bone marrow transplantation, d) participants under chemotherapy/radiotherapy, e) participants with primary immunodeficiency, f) treatment with any anticytokine therapies. g) treatment with oral or intravenous steroids defined as daily doses of 10mg prednisolone or equivalent for longer than 3 months from the time of screening, or probable use of oral or intravenous steroids in the following four weeks 11. Active solid or non-solid malignancy or lymphoma within the prior two years 12. Individuals known to be hypersensitive to any component of the vaccine 13. Eczema or other significant skin lesion or infection at the site/s of injection. 14. Any other medical condition which in the opinion of the investigator may affect the participant’s safety or study participation and conduct.