The international community will need an expanded, cooperative, and holistic response to tuberculosis if it is to eliminate the ancient disease, James Trauer writes.
Tuberculosis (TB) is arguably the world’s leading infectious threat, being responsible for more deaths each year than any other organism. Despite this, it is often forgotten in low-burden settings, where its profile is considerably lower than that of several other major infectious diseases.
For many years, TB was thought to be in decline and official statistics still report a declining burden of disease. However, paradoxically, each of the last three annual estimates for the total global burden of TB has been greater than that for the preceding year. Admittedly, this may relate to improved diagnostics, surveillance and techniques for estimating case numbers, but the sense that this ancient disease is resurgent is hard to escape.
Factors such as rising drug resistance, urbanisation and the rise of HIV could all contribute to a resurgence, while the steady increase in the number of refugees and displaced persons globally means that the disease cannot continue to be paid so little attention by developed countries.
Just as the total burden of TB may be underestimated, the prevalence of drug-resistant strains may also be under-recognised. Although only a relatively small proportion of all TB cases worldwide are reported to be highly drug-resistant (“multidrug-resistant” or “MDR-TB”), testing is typically targeted towards patients most likely to harbour such resistant strains. While reported rates of MDR-TB are considerably lower in patients who have never previously been treated for TB, failure to test such patients at their first presentation for care could artificially lower these rates.
Despite the extent of the drug resistance problem, the World Health Organization’s (WHO) recent list of 12 global priority antibiotic-resistant bacteria failed to include the TB bacterium. The justification was that TB was already a top priority. For such an important pathogen struggling with recognition, this missed opportunity caused understandable frustration across organisations engaged with fighting TB.
Given the huge burden of the disease and additional challenges facing those fighting it, such as insufficient funding and drug resistance, a markedly expanded response would be a welcome development.
In this context, WHO’s End TB Strategy calls for dramatic reductions in TB burden and an end to catastrophic costs suffered by affected families. Such a strategy is an ambitious call to arms and exactly what is needed if the vision of a TB-free world is to be realised.
However, while control of the big three infectious diseases (HIV, malaria and TB) was one of eight pre-2015 Millennium Development Goals, health and well-being as a whole constitutes only one of 17 post-2015 Sustainable Development Goals. Meanwhile, low-income countries are increasingly battling dual epidemics of both communicable and non-communicable diseases.
Even as these ambitious new targets have been adopted, TB’s profile relative to other health and development priorities appears to have fallen. Fortunately, this is not a zero-sum game, as the TB epidemic has always been inextricably linked to poverty and marginalisation, while broad strengthening of health systems complements TB-specific interventions.
In addition to achieving broader socioeconomic development, a key determinant of our success in attaining the post-2015 goals for TB will be the extent of international cooperation. As case rates vary more than 200-fold between the lowest (e.g. the USA) and the highest (e.g. South Africa) burden countries, global control will only be achieved through dramatic reductions in disease in low-income, high-burden countries.
Wealthy, low-burden countries may choose to address TB as either a migration or as a human rights issue. This balance may be difficult to strike.
Given that the large majority of cases in wealthy countries occur in those born overseas, detecting and treating inactive infections in immigrants may achieve the marked reductions called for, but only for specific individual countries.
It is also possible to make economic arguments for improved control by pointing to the huge economic toll that TB takes through its high rates of death among previously well and productive young adults. However, TB currently takes at least six months to treat, requiring consistent support from robust health services, while drug-resistant forms will require tailored care and increasingly expensive medications.
In short, neither an exclusive focus on migration screening nor an appeal to hard-nosed economic calculations will achieve the goal of TB elimination.
Instead, universal adoption of Universal Health Coverage – which incorporates both preventive and curative approaches, along with protection against catastrophic financial costs – will be the only route to achieving the bold vision of the End TB Strategy. This approach must be underpinned by dialogue that recognises safe and effective TB care as a fundamental human right, even for the hardest to reach patients.