* fever (\>38 ºc) within the past 24 hours * suspicion of current active viral or bacterial infection * expected vaccination during the first three months of the study period * severely immunocompromised subjects. this exclusion category comprises: a) subjects with known infection by the human immunodeficiency virus (hiv-1); b) neutropenic subjects with less than 500 neutrophils/mm3; c) subjects with solid organ transplantation; d) subjects with bone marrow transplantation; e) subjects under chemotherapy; f) subjects with primary immunodeficiency; g) severe lymphopenia with less than 400 lymphocytes/mm3; h) treatment with any immunosuppressant drugs such as anti-cytokine therapies, and treatment with oral or intravenous steroids defined as daily doses of 10mg prednisone or equivalent for longer than 3 months, or probable use of oral or intravenous steroids in the following four weeks. * active solid or non-solid malignancy or lymphoma within the prior two years * active participation in another research study that involves bcg administration

* fever (\>38 ºc) within the past 24 hours * suspicion of current active viral or bacterial infection * expected vaccination during the first three months of the study period * severely immunocompromised subjects. this exclusion category comprises: a) subjects with known infection by the human immunodeficiency virus (hiv-1); b) neutropenic subjects with less than 500 neutrophils/mm3; c) subjects with solid organ transplantation; d) subjects with bone marrow transplantation; e) subjects under chemotherapy; f) subjects with primary immunodeficiency; g) severe lymphopenia with less than 400 lymphocytes/mm3; h) treatment with any immunosuppressant drugs such as anti-cytokine therapies, and treatment with oral or intravenous steroids defined as daily doses of 10mg prednisone or equivalent for longer than 3 months, or probable use of oral or intravenous steroids in the following four weeks. * active solid or non-solid malignancy or lymphoma within the prior two years * active participation in another research study that involves bcg administration

- fever (>38 ºc) within the past 24 hours - suspicion of current active viral or bacterial infection - expected vaccination during the first three months of the study period - severely immunocompromised subjects. this exclusion category comprises: a) subjects with known infection by the human immunodeficiency virus (hiv-1); b) neutropenic subjects with less than 500 neutrophils/mm3; c) subjects with solid organ transplantation; d) subjects with bone marrow transplantation; e) subjects under chemotherapy; f) subjects with primary immunodeficiency; g) severe lymphopenia with less than 400 lymphocytes/mm3; h) treatment with any immunosuppressant drugs such as anti-cytokine therapies, and treatment with oral or intravenous steroids defined as daily doses of 10mg prednisone or equivalent for longer than 3 months, or probable use of oral or intravenous steroids in the following four weeks. - active solid or non-solid malignancy or lymphoma within the prior two years - active participation in another research study that involves bcg administration

- fever (>38 ºc) within the past 24 hours - suspicion of current active viral or bacterial infection - expected vaccination during the first three months of the study period - severely immunocompromised subjects. this exclusion category comprises: a) subjects with known infection by the human immunodeficiency virus (hiv-1); b) neutropenic subjects with less than 500 neutrophils/mm3; c) subjects with solid organ transplantation; d) subjects with bone marrow transplantation; e) subjects under chemotherapy; f) subjects with primary immunodeficiency; g) severe lymphopenia with less than 400 lymphocytes/mm3; h) treatment with any immunosuppressant drugs such as anti-cytokine therapies, and treatment with oral or intravenous steroids defined as daily doses of 10mg prednisone or equivalent for longer than 3 months, or probable use of oral or intravenous steroids in the following four weeks. - active solid or non-solid malignancy or lymphoma within the prior two years - active participation in another research study that involves bcg administration