Guest blogger Jonathan Smith from Yale University School of Public Health discusses the challenges of tackling South Africa’s “TB factories.”
TB in the South African mining industry has recently seen unprecedented political will and international attention. Notably, the Declaration on Tuberculosis in the Mining Industry spearheaded by the Swazi, Sotho, and South African Ministers of Health should be commended with the highest regard.
With regret I should mention this ambition is tempered with the hard truth that, even at full capacity, the current infrastructure is inherently set up to fail. The infection pressure at the mine is simply too powerful to address the epidemic with the tools and policies we have today. Mining is one of the only settings in the world where tertiary care exceeding the WHO target of 85% for TB cure rates remains insufficient for interrupting TB transmission. A setting where, despite treatment adherence of 95-98%, multi-and extensively drug resistant strains continue to emerge.
This remarkably high infection pressure is because shafts up to four kilometers underground make ventilation and reducing exposure to silica dust a logistical and engineering problem of considerable dimension, and high-density single-sex housing and other social conditions have led to one out of every three men contracting HIV. Independently, silica dust exposure and HIV are incredibly dangerous, but when combined they exhibit multiplicative risks of TB infection 15 times the risk of someone unexposed to these factors. Whereas the gold mining companies AngloGold Ashanti and Goldfields are at the very least attempting to improve, the industry as a whole rarely meets the occupational standards – so rarely in fact that the industry is deemed to have ‘a pervasive culture of non-compliance to legislative requirements.’ Even if Occupational Exposure Levels (OELs) for silica dust were met, there remains a 35% TB prevalence of past or present TB infection for miners working at or below the OEL level of 0.1 mg/m3 – and this is despite the fact that sicker workers are removed from the workforce. Other studies show that even dust levels reduced to half OEL standards (0.05 mg/m3) are not protective to the development of silicosis. The infection pressure is so incredibly high at the mine that isoniazid preventative therapy (IPT) for miners – a typically effective prevention measure against TB for high-risk groups – failed to have any effect on population level infection rates as demonstrated in the world’s largest preventative TB study.
Unfortunately, these extreme infection rates reflect the innovations seen during the past two decades. And despite the incredible considerations leading to TB infection at the mine itself, the battle is far from over once the miner returns home. The lung parenchyma is unable to rid itself of the silica dust particle and continues to act as a predisposition to TB for the duration of one’s life – even if exposure ceases and with or without the development of clinical silicosis. Thus, TB susceptibility for ex-miners continues to increase long after they leave the mine. When the miner returns home, either by choice or by medical termination, he enters a health system that is characterized by excellent policies but plagued with inadequate emphasis on implementation, monitoring, research and development, and assessment. At home, starved by economic conditions such as extreme unemployment and poverty, the men are driven back to the mineshaft. This cycle of poverty creates a short-term, circular migration pattern that increases the annual odds of mortality for miner up to double the general population. It is far from surprising that mining remains responsible for 760,000 cases of TB each year in the general population; a literal “TB factory.” However, miners themselves are 3.6 times more likely to die from TB compared to their non-miner contemporaries, hence the colloquial phrase, “being sent home to die.”
“Welcome to the Mines” by Clint Smith from the film They Go to Die
We are facing an extraordinary hyper-epidemic that simply cannot be defeated with orthodox thinking. For over a century, addressing TB in mining has been deemed an “urgent necessity” or “a matter of grave concern.” Given the Ministers’ personal dedication, this issue is becoming less about complicity and more about fighting a battle we can’t win using the inadequate tools and policies we have today. The research community must work to aggressively design, validate, and implement novel, industry-specific interventions and programs for miners and ex-miners. Innovation beyond the industry’s traditional purview is also necessary – one is correct to question the feasibility of achieving zero TB deaths in the mines this decade without a vaccine or novel drug therapies. The government and industry have their own role to play in overcoming the epidemic, but they only follow the path our data take them. If we lead with ingenuity, they will follow.
Jonathan Smith is a lecturer in Epidemiology of Microbial Diseases and Global Health at Yale University School of Public Health, where he researches TB and HIV in the context of mining in sub-Saharan Africa. He is an affiliate of the Yale Global Health Leadership Institute and Founding Director of Visual Epidemiology, a non-profit organization seeking to combine academic data and discourse with personal narratives through film making.