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  Gauteng, North West and Free State Provinces, South Africa

Thibela TB, which means Prevent TB in Sotho, a predominant language among South African gold miners, is a large workplace-based  study among gold miners in Gauteng, Free State and North West provinces in South Africa. Gold miners have a very high prevalence of both TB and HIV.  The aim of the study is to examine whether isoniazid preventive  therapy (IPT) given to gold-miners on a community-wide basis reduces the incidence of TB.

It is a cluster randomized trial, meaning that entire workforces (rather than individuals) were selected at random to receive either the study intervention in addition to the usual TB control programme, or to continue with the usual TB control programme activities. The study intervention consisted of, first, screening for active TB, using symptoms and a chest X-ray; anyone suspected of having active TB was referred for TB treatment; then, individuals without active TB were offered nine months of IPT. 

In this study, the intervention was designed to find as many people with active TB as possible and make sure they started TB treatment, and to give isoniazid preventive therapy to as many people as possible who did not have active TB, to try and stop the transmission of TB from one person to another. We would expect this intervention to work better in stopping TB transmission if as many people as possible within the cluster take part.
15 "clusters", each made up of all employees at a mine shaft, took part in the study. There were about 80,000 employees in total in these 15 mine shafts.

Inclusion in the study

Since the primary endpoint was to decrease the incidence of TB in the mining workforce , all mine employees were given the option of joining the study.

Exclusion Criteria

There were no exclusion criteria for taking part in the first component of the Thibela TB intervention, which was to be screened for active tuberculosis. Individuals who were suspected of having active TB were referred for further investigation and treatment. Those with no evidence of active TB were eligible for IPT, unless they were potentially at higher risk of side effects from IPT, if for example they had a past history of liver disease.

Community Mobilization and Education Strategies

The recruitment of study participants involved a community mobilization and education campaign that began several weeks before study enrollment started.  The campaign involved training peer educators, distributing educational materials , conducting dramas using well-known actors, and broadcasting information into the mines through a radio campaign.  The communication strategy particularly used the spoken word and pictures to support written information.

Screening for active TB

A symptom questionnaire and chest x-ray was used to screen miners for active TB prior to starting IPT.   Symptoms were cough, night sweats and weight loss.  If miners had symptoms suggesting active TB or abnormal chest x-ray, they were investigated further for TB with sputum microscopy and culture, and referred for further investigation and treatment for TB where necessary.

Experience with IPT

The primary study outcome (decreased community TB incidence) is expected in 2012, but we have learned from experience in implementing IPT on a large scale. Over 27,000 mine employees enrolled in the study; 88% were eligible for IPT and 98% started IPT.  Among over 24,000 participants who started IPT, 130 people experienced adverse events (0.5%); 95% of these adverse events were graded mild or moderate. In a substudy in which we asked participants how IPT affected their health, almost two-thirds reported feeling in better health since they started taking IPT.
Screening for TB before implementing IPT is an effective method of conducting intensified case finding for TB among a high risk community.  We found that doing chest X-rays helped to increase the number of people with TB who were picked up at screening. Overall, screening done before IPT as part of Thibela TB picked up a substantial number of people with active TB who were unaware of it.

Working within an occupational structure

The involvement of constituent’s stakeholders has been key to the success of the program. The study team met with the South Africa Department of Heath, organized labor, unions and mineworkers health and safety committees.  They engaged with them long before implementing the study and continued to meet with them throughout the study. They identified leaders among the miners and developed advisory boards to assist them and to serve as the “ear piece” for clarifying and dispelling rumors and for educating participants.

*FAST Screening Tool: http://alcoholism.about.com/od/tests/a/fast.htm
** Defined as sensory alteration or paresthesia causing greater than minimal interference with usual social and functional activities

Below you can see abstracts and publications from the Thibela Study.

Thibela