23 January 2014 - Johannesburg, South Africa - A combination of preventative approaches, rather than one single intervention, is the most likely solution to controlling tuberculosis (TB) in South Africa’s mines, according to the final results of the Thibela TB study, published in the New England Journal of Medicine this week.
Mining communities in South Africa have some of the highest rates of TB in the world, with estimated 2% to 8% of miners becoming ill with the disease each year.
The Thibela TB Study, a cluster randomised study, which was carried out by Aurum Institute and the London School of Hygiene and Tropical Medicine, offered isoniazid preventive treatment (IPT) treatment to gold miners at eight ‘shaft clusters’ operated by three mining companies in South Africa over a five year period. A further seven clusters were enrolled as control groups.
The study showed that offering IPT on a broad basis to the whole mining cluster did not result in a decrease in the number of TB cases. However, as the study was conducted on a voluntary basis, not all miners in the community agreed to take IPT and, of those that did, not all miners took their daily treatment for the full nine months. For the miners who did start IPT, TB incidence was reduced by 58% during the first nine months. This effect wore off rapidly after they stopped taking IPT after nine months.
Modelling carried out the investigators suggests that while IPT is not the ‘magic bullet’ hoped for, success is most likely with a ‘combination prevention’ approach, combining better diagnostic tests to screen for TB, reducing time from diagnosis to treatment, maximising coverage of antiretroviral therapy for people with HIV and using effective TB preventive therapies, including IPT.