The Thibela TB study provided clear evidence that community-wide TB preventive therapy did not improve TB control at a population level even though it was effective in reducing the risk of TB among individuals taking the prophylaxis isoniazid.
The study targeted over 27 000 miners in a study which was based on finding, treating and preventing TB across an entire workforce of eight gold mines.
TB remains the principle cause of death among the mining workforce and the incidence is between three and six times higher than in the general population.
The programme provided community-wide isoniazid preventive therapy (IPT) in eight gold mines, but was found to not improve TB control.
However, evidence showed that there were 63 per cent fewer TB cases among individuals in the programme during the first nine months of the programme, providing reassurance that IPT works for people who take it. The benefit was reduced and disappeared once they stopped taking the IPT after nine months.
The Thibela TB project, was carried out by the South Africa-based Aurum Institute and London School of Hygiene and Tropical Medicine, and was launched in response to the need to introduce a radical method of TB control in South African gold mines.
The initial results of the Thibela TB study were announced last Friday at the 19th Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle. Final results are expected to be announced at the South African TB Conference in June.
Professor Gavin Churchyard, principal investigator and CEO of the Aurum Insitute was due to present the findings to Bill Gates in a private forum. The Bill and Melinda Gates Foundation funded the study.
An upbeat Churchyard said despite the disapppointment, “Thibela has been a roaring success”.
“We asked an important question and we have a clear result. We needed to evaluate a strategy to control TB and we will now be able to save money and time,” said Churchyard.
He said they would be able to use the huge amount of rich data for modeling to explore other strategies that may work.
The study was the largest ever carried out in South Africa and one of the biggest in the world.