Does BCG vaccination protect against infection with M. tuberculosis?

• Published in: The international journal of tuberculosis and lung disease Vol. 26; no. 6; pp. 529 - 536
• Main Authors: Pelzer, P. T., Smit, Y., Tiemersma, E.W., Huong, N. T., Nhung, N. V., Cobelens, F.
• Format: Journal Article
• Language: English
• Published: France International Union Against Tuberculosis and Lung Disease 01.06.2022; International Union against Tuberculosis and Lung Disease (IUATLD)
• Subjects: Bcg; BCG Vaccine; Child; Cicatrix; Genotypes; Humans; Infant, Newborn; Infection; Infections; Mycobacterium tuberculosis; Original; Secondary analysis; Skin tests; Tuberculin; Tuberculin Skin Test; Tuberculosis; Tuberculosis, Lymph Node; Vaccination; Vaccine Efficacy; Vaccines; Vietnam
• ISSN: 1027-3719; 1815-7920; 1815-7920
• DOI: 10.5588/ijtld.21.0607

BACKGROUND: Protection against infection by the bacille Calmette-Guérin vaccine against Mycobacterium tuberculosis remains a subject of controversy. We investigated the association between BCG vaccination at birth and infection by M. tuberculosis.MATERIAL and METHODS: This was a secondary analysis of data from tuberculin skin test (TST) surveys in Vietnamese schoolchildren between 1988 and 2001. We investigated whether a BCG scar was associated with a lower prevalence of TST positivity, adjusting for BCG-induced variation by varying cut-off values for a positive TST.RESULTS: We found a positive association between BCG scar and TST positivity. The strength of the association decreased with increasing TST cut-off values; however, it never inverted significantly, irrespective of geographic region and survey year.CONCLUSION: In Vietnam, BCG vaccination was not associated with reduced M. tuberculosis infection prevalence as measured using TST. This in contrary to a similar study conducted in Tanzania. These contradictory findings may be explained by geographical differences and the relatively high prevalence in Vietnam of the M. tuberculosis Beijing genotype, which is reported to be capable of circumventing BCG-induced immunity.