/ 19 October 2012

TB slowly succumbs to teamwork

Research suggests that multidrug-resistant TB is spreading much faster than initially thought.
Research suggests that multidrug-resistant TB is spreading much faster than initially thought.

It is a document that deserves close reading here in South Africa, which bears one of the world's highest burdens of TB.

The WHO's report offered South Africans some welcome news. However, it also highlighted the continued challenges we face in turning the tide on a disease that remains a leading cause of death in this country, especially among people who are living with HIV.

On the positive side, South Africa has made significant gains in reducing TB mortality and the prevalence of the disease in the general population – the first sizable reductions since the late 1990s. Our health system also shows gains in the treatment success rate among new TB patients diagnosed by smear micro-scopy. This suggests that South Africa is doing a better job identifying and diagnosing TB patients when they come to clinics and referring them for treatment.

But such encouraging news is ­offset by cases of ­multidrug-resistant (MDR) TB that continue to rise and the treatment success rate for patients who are resistant to first-line drugs that remains dangerously low. First-line drugs are physicians' first choice for treatment. Second-line drugs are an alternate treatment if the first-line treatment is not an option or is ineffective.

Why should we be worried about drug-resistant TB? Research recently published in the Lancet confirmed that resistance to second-line TB drugs was much more prevalent than we believed. And an article published in the New England Journal of Medicine earlier this year showed that more than 5% of first-time TB cases had strains of MDR-TB.

These findings suggest that MDR-TB is spreading much faster than we thought and they show that anyone can contract MDR-TB, not just patients who do not complete their treatment.

Drug-sensitive TB
The challenge for South Africa's health system is that drug-resistant TB can be hundreds of times more costly to treat and contain than drug-sensitive TB. In addition, MDR-TB patients must go through two years of therapy, including daily injections for the first six months, a painful regimen that causes many patients simply to stop treatment. One of the results is that the global cure rate for MDR-TB is just 53%.

But amid these challenges we are starting to make progress against TB on many fronts. Global partners are taking action and the pipeline for the discovery and development of tools such as vaccines, drugs and new diagnostics for TB has never been stronger. More affordable innovations in TB diagnosis and treatment have begun to reach middle- and low-income countries, in which 95% of all TB deaths occur. And new public-private collaborations – many of which involve South Africa's health department and its research institutions – are accelerating the identification of new drug and vaccine candidates at a rapid pace.

South Africa has adopted GeneXpert, a revolutionary new molecular diagnostic system that can detect TB and drug-resistant TB in less than two hours. GeneXpert is also significantly more effective at diagnosing TB in HIV-positive people. Until the system was introduced, most laboratories used smear microscopy, a technique that is not effective in diagnosing TB in those who are HIV positive and incapable of determining whether someone has MDR-TB.

Before GeneXpert was introduced, many patients were "lost to follow-up" before their results were ready. Now, clinics in poor and rural settings can deliver rapid results and immediately start patients on the most appropriate treatment, including second-line drugs for individuals infected with MDR-TB.

It is also encouraging to see the South African government and industrial sector coming together to ensure that TB prevention, diagnosis and treatment get to those who live at highest risk of infection. According to the WHO, mine workers in South Africa have the highest TB rate in the world, with an estimated 3% becoming ill each year.

Migratory workers
This issue has massive implications for the health and economic growth of the entire region, because South Africa's mines are heavily dependent on migratory workers from neighbouring territories.

Every worker who goes home with active TB may spread the disease to 15 people; a third of all TB infections in sub-Saharan Africa is believed to be linked to mining. Moreover, if miners are diagnosed and treated for TB timeously, it can eliminate an estimated R7.74-billion in health costs a year while increasing economic productivity by R6.74-billion because of averted illness.

That is why Health Minister Aaron Motsoaledi recently joined Mphu Ramatlapeng, vice-chair of the Global Fund to Fight Aids, Tuberculosis and Malaria, and Swaziland Health Minister Benedict Xaba to spearhead the adoption of a declaration on TB in the mining sector by Southern African Development Community heads of state. The declaration's objectives include detecting and treating TB among miners, eliminating mine conditions that cause high rates of TB, improving standards of treatment, checking former miners for TB and creating a legal and regulatory framework that compensates miners for occupational disease.

But although policy change is critical to enhancing TB diagnosis, detection and treatment, we still need biomedical breakthroughs and strong community involvement to get ahead of the epidemic. That is why I am excited by the leadership South Africa has shown in supporting clinical research. Our nation has faced seemingly insurmountable challenges before and I believe we can overcome TB by committing to work together in partnership.

Gavin Churchyard, MD, PhD, is a TB expert and chief executive of the independent, not-for-profit Aurum Institute for Health Research. He is also a member of the World Health Organisation's strategic technical advisory group for TB