The decision to initiate TPT should be individualized and should employ shared decision making between the patient and health care provider. However, in a low TB-burden country like Canada, targeted screening of individuals at increased risk of progression is recommended, with the supposition that treatment will be offered if the screening test is positive (see Chapter 4: Diagnosis of Tuberculosis Infection). The development of active TB disease occurs with greatest frequency in the first 2 years after infection. In fact, 50% of the total lifetime risk of reactivation is estimated to occur in that period.5,6
For all individuals being considered for TPT, it is essential to rule out active TB disease prior to starting any TPT regimen. If TPT is declined, then the patient should be advised of active TB symptoms and told to seek medical attention if these occur. A period of formal observation can be considered for high-risk patients who decline treatment.
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