What is a common regimen to reduce reactivation risk in latent TB infection?

• A. Isoniazid for 6–9 months
• B. Rifampin for 2 weeks
• C. Rifapentine/Isoniazid weekly for 3 months
• D. Ethambutol daily for 9 months

Answer: (A)

Treating latent TB infection to prevent progression to active disease is the goal. Isoniazid given daily for 6–9 months has long been the standard regimen because, when taken as prescribed, it significantly lowers the risk of reactivation. The duration matters for effectiveness and adherence, with the 9-month course historically providing strong protection. Other options exist, such as shorter regimens with rifapentine/isoniazid or rifampin alone, but those are not the classic, most widely taught approach. Ethambutol is not used for latent infection.