Introduction: Bacille Calmette-Guérin (BCG) is the only live attenuated vaccine to protect against tuberculosis, derived from Mycobacterium bovis, it provides around 80% protection against Miliary and Meningeal tuberculosis.1 The WHO recommends routine neonatal BCG vaccination In endemic countries, local (BCGeitis) or disseminated (BCGosis) infections can occur, In patients with SCID, these reactions are often severe or fatal.1,2,4
Clinical case: 6-month-old male, product of 2nd pregnancy, by cesarean, at 38 weeks, without complications. Consanguineous parents (cousins), healthy sister. Incomplete vaccinations (BCG, 1 dose of Pentavalent). He has pulmonary infections since he was 2 months old, requires hospital treatment with broad-spectrum antibiotics, on 3 occasions in PICU due to Pneumonia (H. Influenzae, SARS-COV2; at 5 months, crusted, ulcerative lesion in the BCG vaccine area, right axillary lymph node of +/- 2 cm in diameter, lungs with rales, hepatomegaly 2 cm from the right costal margin; Gene Xpert MTB Detected is requested, Immunoglobulins: IgA 0.2 gr/L, IgM 0.5 gr/L, IgG 3.6 gr/L, Ig E: 1127, Lymphocyte population count: Lymphocytes 1640, LT CD3 1377, LT CD4 110, LT CD8 1019, LB 229.6, LNK 32.8. Diagnosis of severe combined immunodeficiency (SCID) T-B-NK-, BCGosis. Replacement treatment with human immunoglobulin is started every 21 days, specific treatment for Tuberculosis. Currently a patient in fair general condition undergoing SARS-COV2 infection. He is in the HSCT protocol, after remission of infections.
Discussion: BCG-related complications are rare in immunocompetent people, in the case of patients with IEI they can be severe and fatal, especially in SCID. Undiagnosed PIDs predispose to a high risk of serious BCG vaccine infections; there is a need for early detection and diagnosis. The occurrence of severe BCG complications in a patient strongly suggests an underlying primary or secondary immunodeficiency.3