1 Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC H3A 1A2, Canada; McGill International TB Centre, Montreal, QC, Canada.
2 Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC H3A 1A2, Canada; McGill International TB Centre, Montreal, QC, Canada; Montreal Chest Institute, Montreal, QC, Canada. Electronic address: dick.menzies@mcgill.ca.