[1] UCL, MRC, Clin Trials Unit, London, England
[2] London Sch Hyg & Trop Med, Dept Infect Dis Epidemiol, London, England
[3] Univ Leeds, Clin Trials Res Unit, Leeds, W Yorkshire, England
[4] Univ Calif San Francisco, Ctr TB, San Francisco, CA 94143 USA