Treatment to prevent active TB from developing in a person with a latent tuberculosis infection (LTBI) aims to kill walled-up germs that are doing no damage right now but could break out (activate) years from now.
If you should be treated to prevent sickness, your doctor usually prescribes a daily dose of isoniazid (also called INH), an inexpensive TB medicine.
You will take INH for up to a year, with periodic checkups to make sure you are taking it as prescribed and that it is not causing undesirable side effects. In some cases, intolerance or allergic response can mandate an alternative treatment that may go on for 18 months.
Treatment also can stop the spread of TB in large populations.
The tuberculosis vaccine, known as bacille Calmette-Guérin (BCG) may prevent the spread of tuberculosis and tuberculous meningitis in children, but the vaccine does not necessarily protect against pulmonary tuberculosis. It can, however, result in a false-positive tuberculin skin test that in many cases can be differentiated by the use of the QuantiFERON-TB Gold test mentioned above.
Health officials generally recommend the vaccine in countries or communities where the rate of new infection is greater than 1% per year. BCG is not generally recommended for use in the United States because there is a very low risk of tuberculosis infection. It may be considered for very select patients at high risk for tuberculosis and who meet special criteria.