"A Trial of Mass Isoniazid Preventive Therapy for Tuberculosis Control"
NEJM
http://www.nejm.org/doi/full/10.1056/NEJMoa1214289
"CONCLUSIONS

Mass screening and treatment for latent tuberculosis had no significant effect on tuberculosis control in South African gold mines, despite the successful use of isoniazid in preventing tuberculosis during treatment. (Funded by the Consortium to Respond Effectively to the AIDS TB Epidemic and others; Thibela TB Current Controlled Trials number, ISRCTN63327174.)"