TB trial in South Africa did not reduce cases, deaths
Researchers from the London School of Hygiene & Tropical Medicine found while preventative therapy with isoniazid was safe and effective in preventing TB among people who took it, the effect wore off soon after the treatment stopped. The study tested the effectiveness of screening and treatment, examining 78,744 miners in 15 gold mines between 2006 and 2011.
The researchers screened 27,126 miners in eight gold mines for TB. Miners with active TB disease were offered a nine-month course of preventive treatment. Twelve months after the intervention ended, researchers found no difference in the number of TB cases between workers who were mass screened compared to mines continuing standard practice.
"HIV, exposure to silica dust in the mines and close working and living conditions predispose South African gold miners to TB," Alison Grant, the lead investigator of the study, said. "As conventional control methods were not working, we investigated a radical approach to TB control. Our study shows that isoniazid preventive therapy works while people take it, but, in this setting, the effect was not enough to improve overall TB control. The findings highlight the scale of the problem of TB in these mines."
According to the study, the TB epidemic in South Africa's gold mines worsened at the start of the HIV epidemic in the 1990s. In 2008, approximately three percent of gold miners began TB treatment each year.
Grant said the results of the study highlight a need for a combination approach to improve TB control.
"Our data suggests that to control TB in South African gold mines, we need a 'combination prevention' approach with better tests to find TB, prompt treatment for those found to have active TB, increased coverage of HIV treatment and effective TB preventive therapy regimens," Grant said. "Continuous isoniazid preventative therapy should be considered for miners at highest risk of TB infection, such as those with HIV."