In the global fight against tuberculosis, BCG vaccines are the most widely used in the world
(CDC, 2011). However, it has always been surrounded by uncertainty. The main uncertainty stems from
a lack of consistency in clinical trials of the vaccine’s efficacy (i.e. the reduction in the incidence of the
disease among people who have received the vaccine compared to the incidence in unvaccinated people
(Fine, 1995). Another dubious aspect of BCG vaccination is its possible interference with the detection of
latent tuberculosis infection (Menzies, 2000). However, evidence exists that BCG vaccine has proved to
be one of the most effective measures of combating the spread of TB epidemics (Trunz et.al., 2006)