BCG vaccine may prevent TB infection, not just active disease

BMJ 11/2005:

Researchers studied 979 Turkish children who were living with an adult with active pulmonary tuberculosis. Children with a BCG scar were 24% less likely to test positive for infection than children without a BCG scar. Vaccinated children were also less likely to have active tuberculosis (relative risk reduction 92%).

The difference was detected by a new test, which measures the T cell response to M. tuberculosis antigens and is unaffected by previous vaccination. The traditional PPD, which has been used for the past 100 years, cannot distinguish between past vaccination and recent infection.

The study was published in Lancet but due to the small sample size and the observational design, the results are still inconclusive.

BCG vaccination is highly cost-effective according to another Lancet article. The investigators found the cost of vaccination is $ 200 per year of healthy life gained

Effect of BCG vaccination on childhood tuberculous meningitis and miliary tuberculosis worldwide: a meta-analysis and assessment of cost-effectiveness.
The Lancet 2006; 367:1173-1180
Neonatal BCG vaccination induces IL-10 production by CD4(+) CD25(+) T cells.
Protective effect of BCG vaccination: time to reconsider the vaccination threshold? Thorax
BCG vaccination: 90 years on and still so much to learn - Thorax
Comparing the Tuberculin Skin Test and T-SPOT.TB Blood Test in Children: blood test was better
Image source: CDC

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