HIV-infected patients at high risk for TB but without confirmed TB infection do not benefit from preventive treatment with a frontline TB drug, warns a study supported by the National Institute of Allergy and Infectious Diseases (NIAID), US, and published in the latest issue of The New England Journal of Medicine. "Clinicians who care for people with HIV/AIDS should take note of this important finding," says NIAID director Anthony S. Fauci. "This study suggests that we can make more efficient use of TB prevention resources by focusing on HIV-infected persons with known TB infection or who have close contact with another person with active TB."