Tuberculosis
Tuberculosis (TB) is the world’s leading infectious disease killer, accounting for 1.5 million deaths worldwide each year.
WHO recommends MSF-led endTB clinical trial treatments
August 22, 2024 — This week, the World Health Organization (WHO) recommended three new regimens for certain drug-resistant forms of tuberculosis (TB) based on the results of Doctors Without Borders/Médecins Sans Frontières' (MSF) endTB clinical trial, a multi-year study aimed at finding more tolerable drug regimens for millions of people living with TB worldwide.
Putting tuberculosis in context
The global tuberculosis (TB) crisis is fueled by several factors, including the alarming rise in drug resistance, reliance on obsolete, harsh drugs that often don’t work, lack of diagnostic tests that are practical for use in low-resource settings, and lackluster political commitment. Doctors Without Borders/Médecins Sans Frontières (MSF) is one of the main non-governmental providers of TB care worldwide, especially for people with drug-resistant TB, and helps lead global efforts to make newer, more effective treatments affordable and available to those who need them.
new TB cases each year
TB is the world's second leading infectious cause of death after COVID-19
people started on tuberculosis treatment in MSF programs in 2023
Facts about tuberculosis
TB is caused by bacteria that spreads by air when infected people cough or sneeze. It most often affects the lungs but can infect other parts of the body, including the bones and nervous system.
Most people who are exposed to TB never develop symptoms, although they can still harbor the infection in an inactive form. But if the immune system weakens, latent TB bacteria may become active and cause disease. About 10 percent of people with latent TB go on to develop active TB and become contagious at some point in their lives.
Globally, TB crisis has grown dramatically since HIV became a widespread epidemic. That’s because people living with HIV/AIDS have weakened immune systems, which increases their risk of contracting and dying from TB—now the leading cause of death among people with HIV. People with other medical conditions that weaken immunity are also at a higher risk of TB infection and death. Children, the elderly, people from regions with high TB rates, and those living in close quarters like prisons, refugee camps, and crowded slums also face greater risk, as do members of households with someone who has active TB.
Many people infected with TB are asymptomatic but can develop an active infection if their immune system becomes weak. Symptoms, which may be mild at first, most often include a prolonged cough and fever. Weakness, chest pain, night sweats, weight loss, and shortness of breath are also common. While lungs are the most common site of infection, TB can affect almost any other body part or organ.
Since TB is airborne it can be easily transmitted in crowded settings, from cramped households and workplaces to health care facilities. For example, people sharing a home with someone who has active TB are at increased risk of developing either a latent (asymptomatic) or an active infection. In these households, sleeping in separate rooms, wearing surgical masks, and using proper cough and respiratory hygiene can limit transmission. Children in these homes, especially those under five years old, are particularly vulnerable. Within health clinics, rapidly attending to patients with TB symptoms and starting treatment quickly for those with active infections lowers the chance they will pass it on to others. Proper ventilation systems within hospitals and the use of face masks that filter out particles in the air can also reduce TB spread.
In recent years the preventive use of TB medications for people at especially high risk of contracting TB—a treatment called Isoniazid Preventive Therapy, or IPT—is gaining ground, although many people who could benefit still do not receive it. It is most often given for defined periods of time (typically 6-36 months) to people living with HIV who do not have active TB, pregnant women in high-TB settings, household contact of TB patients, especially young children, and others with high exposure to TB.
Active Case Finding (ACF) is another preventive approach, based on screening high-risk people (such as household contacts or people with HIV) outside the clinic rather than waiting for them to seek care for their symptoms. ACF can also be used for population-based screening of broader vulnerable groups.
The majority of people infected with TB have not been diagnosed, usually because tests are not available where they live or are not a routine part of primary care. Of the estimated 10 million new cases of TB in 2018, only 7 million cases were reported. Development of simpler, more accurate and cheaper diagnostic tools is, therefore, a critical need.
Until very recently, TB was most commonly diagnosed by examining patient sputum samples (phlegm coughed up from lungs) either under a microscope or by bacterial culture. But both methods require a laboratory and trained technical staff, making them ill-suited for many low-resource settings. And neither test is reliable in children, people with HIV, people with TB outside the lungs, or those infected with drug-resistant TB. In the case of culture, it can take as long as 8 weeks to get a result, which delays patients in starting treatment.
In 2010, a much faster, more accurate diagnostic test called GeneXpert MTB/RIF was introduced and is now used for most patients. It gives results within a few hours and can also distinguish between drug-sensitive and drug-resistant TB. While it represents a big improvement, it still requires a laboratory with stable electric power, trained technicians, and other supplies and infrastructure. And since it relies on sputum, it cannot diagnose TB in patients who cannot cough up sputum or who have TB outside the lungs.
In recent years, MSF and others have tested the usefulness of a urine-based test called TB LAM, which is rapid, inexpensive, and easy-to-perform without electricity or instruments. Due to its lower sensitivity (which means that it misses many positive diagnoses) TB LAM cannot replace other tests, but in combination with GenXpert MTB/RIF, it can help diagnose TB cases in people living with HIV and that would have otherwise gone undetected.
Uncomplicated, drug-sensitive TB is curable, but treatment takes at least six months and relies on a cocktail of the same harsh antibiotics that have been used for decades.
A growing number of people infected with multi-drug resistant TB (MDR-TB) are not cured by the two most powerful first-line antibiotics. As a result, most patients face between nine months and two years of treatment. Over this period they must swallow over 10,000 pills and endure 6-8 months of painful daily drug injections, often along with severe side effects that range from nausea and joint pain to psychosis and partial or total hearing loss. This should begin to improve, though, since new research has found a shorter regimen with these drugs that is no less effective even for MDR-TB. Patients with TB resistant even to the second-line drugs used for MDR-TB are said to have extremely drug-resistant TB (XDR-TB), which is even harder to cure.
In the last few years, much better outcomes have become possible using new, more effective, less harsh medicines. These improved treatments rely on three new drugs--the first new TB medicines in 50 years. For two of them (bedaquiline and delamanid) the best combinations with other TB drugs are still being evaluated, while the third drug, pretomanid, was developed as part of a ready-to-use regimen for treating XDR-TB.
Yet there are still big treatment challenges to solve. Access to the new drugs is extremely limited: fewer than 5 percent of patients who could benefit are receiving them, and they are not available in many countries most affected by TB. Also, most TB drugs are not made in formulations adapted for children, and effective treatment for TB/HIV patients is particularly challenging.
How MSF responds to tuberculosis
We have been involved in TB care for over three decades, often working alongside national health authorities to diagnose and treat patients in contexts ranging from chronic conflict zones and refugee camps to urban slums, prisons, and remote areas. Our programs are designed to provide as many TB services as possible in outpatient community settings rather than in district hospitals. We also work to expand the range of available services by bringing newer, better diagnostic tools and treatments into more widespread use so more patients can access them.