Tuberculosis (TB) is one of the most deadly infectious diseases in the world. In 2015, 10.4 million people became ill with TB and 1.8 million people died from the disease, mainly in developing countries. Today, TB is the leading killer infectious disease, followed by malaria and HIV/AIDS.
TB is often thought of as a disease of the past, but a recent resurgence and alarming rise in cases of drug-resistant (DR-TB) and multidrug-resistant TB (MDR-TB) make it very much an issue of the present day and age. Drug resistance – when TB does not respond to the customary first-line drugs – can result from inappropriate or incorrect use of antimicrobial drugs, premature treatment interruption and, increasingly, from person-to-person transmission.
One-third of the world’s population is currently infected with the TB bacillus – but, with a latent form of the disease, have no symptoms and cannot transmit it. In some people, the latent TB infection progresses to acute TB, often due to a weak immune system. Of the 10.4 million new cases of TB in 2015, 5.9 million (56%) were men, 3.5 million (34%) were women and 1.0 million (10%) were children.Every year, about nine million people develop active TB and 1.5 million die from it.
Transmission: TB is caused by bacteria (Mycobacterium tuberculosis) that are spread through the air when infected people cough or sneeze. While anyone can be infected with TB, people with weakened immune systems are at particular risk of developing active TB. People living with HIV are more likely to develop active TB and accounted for 1.2 million (11%) of all new TB cases in 2015.
Signs and symptoms: Most people exposed to TB never develop symptoms, since the bacteria can live in an inactive form in the body. The disease most often affects the lungs. Symptoms include a persistent cough, fever, weight loss, chest pain and breathlessness in the lead-up to death.
Diagnosis: In countries where TB is most prevalent, diagnosis depends largely on the microscopic examination of sputum, or lung fluid, for the TB bacilli. The test is only accurate half of the time, even less so for patients who also have HIV.
Treatment: A course of treatment for uncomplicated TB takes six months. Treatment for multidrug-resistant TB (MDR-TB) is especially arduous, taking up to two years and causing many side effects. When patients show resistance to MDR-TB drugs, they are considered to have extensively drug-resistant TB (XDR-TB) and have even fewer treatment options.
A Global Fund to fight HIV, TB and malaria together: MSF Canada's Stephen Cornish on tackling the world's biggest killers
Doctors Without Borders/Médecins Sans Frontières (MSF) Canada's executive director called upon world leaders, including Canada, to renew their commitment to the fight against AIDS, TB and malaria through the replenishment of the Global Fund last September.
MSF has been fighting TB for over 30 years. We provide treatment for the disease in many different contexts, from chronic conflict situations, such as Sudan, to vulnerable patients in stable settings such as Uzbekistan, southern Africa and the Russian Federation.
MSF has TB treatment projects in 24 countries around the world, and in 2015 supported more than 20,000 TB patients on treatment, including 2,000 patients with DR-TB. Two new drugs – bedaquiline and delamanid – have recently become available to some patients who have no other treatment options left. MSF and other treatment providers are showing that stronger TB regimens containing one of the new TB drugs along with ‘repurposed’ drugs (not specifically developed for TB but that have shown efficacy in treating it) can significantly improve the health of people with MDR-TB.
As of October 2016, MSF has initiated more than 1,000 patients on bedaquiline and/or delamanid in 12 countries. Programmatic data has shown promising early results on the effectiveness of these regimens, while patients report that the toxic side effects of treatment are reduced. It is also hoped that using the two new drugs in combination will be particularly effective in treating patients with the most severe forms of drug-resistant TB. In MSF projects in Armenia, Belarus, India, Mozambique, South Africa, and Swaziland, medical teams are already piloting the combination of the two new drugs as part of the regimen for patients with very limited treatment options.
MSF is involved in two TB clinical trials – TB PRACTECAL and as part of the endTB partnership – to find new, shorter, more effective combination treatments for multi-drug resistant TB that include the new drugs. Patients’ needs are at the heart of both trials, which aim to find treatments that contain no injectable drugs and have manageable side effects. Both trials are expected to enrol the first patients by the end of 2016.
Globally, there is still an unacceptable gap between those who would benefit from these new drugs and those who are able to access them. As of October 2016, only 5,738 patients have been able to access bedaquiline globally through programmatic use (i.e. outside clinical trials) or compassionate use, the majority of them in South Africa. There is an urgent need to increase people’s access to these more effective treatments by making them affordable and available.
Access to appropriate diagnostic tools for detecting TB must also be prioritised, including developing affordable rapid tests that deliver results on the spot. The most widely-used test for diagnosing active TB in developing countries relies on examining a patient’s phlegm under a microscope, known as microscopy. This method, developed nearly 140 years ago, detects less than half of all active TB cases and largely fails to detect the disease in children, people co-infected with HIV and those with drug-resistant forms of TB. Other diagnostic methods exist, but most require laboratories, a steady power supply and, like microscopy, skilled staff to deliver results – all of which are mainly unavailable in remote and rural settings. Diagnostic tests that can determine if patients are resistant to standard TB treatments are also needed.