At the time of starting the continuation phase there are low numbers of bacilli and hence less chance of selecting drug-resistant mutants. Thus, fewer drugs are necessary, but they are needed for a longer time in order to eliminate the remaining TB bacilli. Killing the persisters prevents relapse after completion of treatment. DOT is the ideal when the patient receives rifampicin in the continuation phase. If local conditions do not allow DOT, the next best option is as close supervision as possible, for example weekly supervision.
The patient usually receives monthly drug supplies for self-administered treatment during a continuation phase that does not include rifampicin.
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