According to the results of a concurrent study, the BCG vaccine has a protective effect against tuberculosis in adults for decades after vaccination. The data published by Thorax was devoted to World Tuberculosis Day and has important implications for national BCG vaccination policies.

The BCG vaccine has a proven protective effect against tuberculous meningitis and widespread tuberculosis in children and is used as an additional method in the tuberculosis control strategy. According to scientists in Taiwan, more than 80% of newborns and infants have received the BCG vaccine in countries where the vaccine is part of the national childhood immunization program. However, the protective effect of BCG against pulmonary tuberculosis according to previous studies remains a controversial issue.

To determine if the effect of BCG vaccination against tuberculosis will continue into adulthood, in a prison in northern Taiwan with more than 3,000 HIV-negative male inmates, a simultaneous study of the prevalence of Latent TB infection (ITL) was conducted using the QuantiFERON-TB Gold In-tube (QFT-OH) test system. A QFT-IT score greater than 0.35 IU / ml was considered to be the presence of LTI. A QFT-IT greater than 0.7 IU / ml has been assessed as the current LTI. The relationship between the number of scars after BCG and LTI stratified by age was analyzed.

Among 2385 participants, 25% had a QFT-IT greater than 0.35 IU / ml. An increase in LTI (14%, 32% and 50%) was observed with an increase in age (18-34 years, 35-54 years and over 55 years) (p less than 0.001 according to the criterion of Cochrane-Armitage trend). The number of scars after BCG was inversely correlated with the result of the QFT-IT analysis for LTI and current LTI in the three age groups (p less than 0.001 according to the Cochrane-Mantel-Hanzel criterion).

Limitations of this study included a one-step design, the use of scar numbers after BCG as confirmation of BCG vaccination, and the possible effect of age cohorts.

Thus, a study carried out by Taiwanese scientists shows the protective effect of the BCG vaccine in adults for decades after vaccination according to the number of “fresh” infections (QFT-IT is greater than 0.7 IU / ml ). This fact is of great importance for the national BCG vaccination policy. The need for additional prospective cohort studies on the protective effect of the BCG vaccine against tuberculosis in adults is justified.