Treatment of latent tuberculosis infection in HIV: shorter or longer?

Nine months of daily isoniazid is efficacious in treating latent M. tuberculosis infection, but completion rates are low, limiting treatment effectiveness. In 2011, three important studies were published involving novel regimens for the treatment of latent M. tuberculosis infection. At least 36 months of isoniazid was more effective than 6 months of isoniazid in one study, but not in another-both of which were conducted among tuberculin skin test positive HIV-infected adults living in high tuberculosis incidence settings. Three months of once-weekly isoniazid plus rifapentine or twice-weekly isoniazid plus rifampin (both given under direct observation) resulted in tuberculosis rates similar to those seen with 6 months of isoniazid among HIV-infected persons in high tuberculosis incidence settings. Three months of once-weekly, directly-observed isoniazid plus rifapentine was at least as effective as 9 months of daily isoniazid among predominantly HIV-uninfected persons living in low and medium tuberculosis incidence countries. The 3-month once-weekly isoniazid plus rifapentine regimen demonstrates promise for treatment of latent M. tuberculosis infection in HIV-infected persons.