If a TB epidemic were to occur, the impact could far outweigh the risks more publicized infections such as HIV and meningitis. The current treatments could leave many patients uncured, and there is little in the pipeline to replace them. Governments should consider subsidizing research into more effective drugs, or risk facing the consequences.
On Monday, the UK government launched its national "TB - Be Aware" campaign, aiming to improve diagnosis rates for tuberculosis. Most people in western countries would not see tuberculosis as a personal health risk alongside HIV and meningitis. But although its incidence declined in the early 1990s, there is evidence that an epidemic may be on the cards.
It's hard to determine the cause of this rise in epidemiology, as tuberculosis remains latent for a considerable length of time following exposure. But it is real - and awareness is not just low among the public. Physician perception of tuberculosis prevalence is minimal, and NHS management is little more knowledgeable.
The drugs currently used to treat the disease - isoniazid, rifampin and rifabutin - could leave many patients without the possibility of an immediate cure in the event of an epidemic. All are prone to emerging resistance, require long treatment regimens and are subject to poor compliance. A CDC survey in the US has also identified a risk of severe liver disease and possible mortality following long-term rifampin usage.
Drug discovery technologies including the sequencing of the Mycobacterium tuberculosis genome have made higher efficacy drugs possible. However, because TB is currently only prevalent in emerging markets, therapeutic research is not seen as economically worthwhile. Current research is aimed more at replacing the inefficient BCG vaccine, with GlaxoSmithKline the only major company investigating a new treatment.
Drug development is highly dependent on apparent unmet need and government interest. Until governments accept the risk of a tuberculosis outbreak, and assess the health economic impact of the inefficient therapies that currently exist, tuberculosis will remain a secondary priority in pharmaceutical R&D.
Unless patient potential is realized, the scale of the patient group made apparent, and pharmaceutical companies ascertain that a definitive market for new drugs does exist, they will not place the substantial investment required (up to $500 million) in TB drug development. At present, responsibility lies with politicians, not the pharmaceutical laboratories.