The only available vaccine as of 2011 is Bacillus Calmette-Guérin (BCG).[78] In children it decreases the risk of getting the infection by 20% and the risk of infection turning into disease by nearly 60%.[79]
It is the most widely used vaccine worldwide, with more than 90% of all children being vaccinated.[11] The immunity it induces decreases after about ten years.[11] As tuberculosis is uncommon in most of Canada, the United Kingdom, and the United States, BCG is administered only to those people at high risk.[80][81][82] Part of the reasoning against the use of the vaccine is that it makes the tuberculin skin test falsely positive, reducing the test's use in screening.[82] A number of new vaccines are currently in development