Prevention of TB infection lies primarily in identifying, isolating, and treating those who have it before they pass it on to others.
A vaccine called BCG (bacillus Calmette-Guerin) is often routinely administered in parts of the world where TB is much more common, although studies have shown that this vaccine will not prevent every case of TB. BCG vaccination is being used to selectively target “at-risk” groups and those in areas with a high incidence of TB.
Early detection depends on identifying those at risk and testing them at regular intervals for latent TB infection. It also depends on recognizing, diagnosing, and treating those who progress to active tuberculosis.
The decision to treat latent TB infection is up to you and your doctor. If follow-up testing reveals no indication of active tuberculosis and you are not considered at a high risk for developing active TB, your doctor may decide to simply monitor your health at regular intervals (since about 90% of those with latent infections never develop active tuberculosis).
If, however, your doctor is of the opinion that you are at risk of developing active TB, you may be treated with a six month course of an antibiotic called isoniazid. It is necessary to take it faithfully for the entire treatment period to ensure that all of the latent bacteria have been killed. Your doctor may use lab tests to monitor your liver during this time period, as isoniazid can sometimes affect how the liver functions.
Active tuberculosis must always be treated. Once M. tuberculosis has been positively identified, your doctor will start you on a treatment program that involves taking several drugs for several months. The length of treatment depends on the results of the AFB smears and cultures used to monitor the effectiveness of treatment.
Although your symptoms will often go away after several weeks it is crucial that you continue to take your drugs for the entire time period. There are a large number of mycobacteria to kill and it takes several months to make sure that all of them have been eradicated. If treatment is not continued, the TB can come back, and this time it may be more difficult to treat. It may now be resistant to the first choice drugs, requiring treatment for several more months with drugs that have more side effects.
Those with active tuberculosis may be encouraged to participate in DOT (directly observed therapy). This involves taking your medication each day, or several days a week, under the supervision of medical personnel. This increases patient compliance with treatment and decreases the number of people that have to be treated again because their TB has returned.