Tuberculosis

Tuberculosis is caused by a group of mycobacteria of the tuberculosis complex (the most common being mycobacterium tuberculosis or Koch's bacillus). After exposure to the bacteria (known as ‘primary infection’), the immune system manages to contain the disease in most cases. The infection then remains asymptomatic and is said to be ‘latent’. However, in 5 to 10% of cases, it develops into an ‘active’ and symptomatic form, most often affecting the lungs. This usually occurs within 2 years of infection. It can also occur after years of latency, when the immune system is weakened (drugs affecting immunity, co-morbidities, ageing).

Tuberculosis is transmitted by air, mainly when a sick person coughs nearby. Only forms affecting the lungs or, exceptionally, those affecting the ENT tract (such as tuberculous laryngitis) are contagious. Transmission requires close, prolonged contact lasting several hours, so the risk of contamination is limited in everyday situations, such as on public transport. Once treatment has been started, the risk of transmission diminishes rapidly. After a few days of treatment, the patient is no longer contagious.

Factors such as diabetes, alcoholism, smoking, malnutrition and HIV (or other immunosuppressive factors) increase the risk of developing active tuberculosis. Young children and the elderly are also more likely to develop symptoms and complications after infection, or to progress to severe forms (meningitis, disseminated infections).

Most people infected with tuberculosis do not develop symptoms when they are first infected. In the case of active tuberculosis, the most common symptoms include a persistent cough, sometimes accompanied by blood in the sputum, intense fatigue, weight loss, fever, night sweats and shortness of breath. However, there are no typical symptoms, and sometimes there are few or no symptoms at all.

IGRA (Interferon-Gamma Release Assays) blood tests can detect whether a person has been exposed to the tuberculosis bacillus. However, this test cannot differentiate between a latent infection and an active form of the disease. To establish a diagnosis of active tuberculosis, other tests are required, including a clinical examination, a chest X-ray (or CT scan) and biological analysis of sputum (in particular using molecular biology tools - PCR - enabling a diagnosis to be made within a few hours, microscopic examination and culture).

Tuberculosis treatment is based on a combination of specific antibiotics that target the bacteria responsible. The treatment must be taken very regularly over several months (6-12 months depending on the organs affected). Therapeutic compliance (i.e. the fact that the patient takes the prescribed treatment) is crucial: complete cure requires following the treatment through to the end, even though symptoms may disappear more quickly. Failure to do so can lead to relapse or even drug resistance. However, with proper treatment, the vast majority of patients are cured. Patients must be well informed of possible side effects and have clinical and biological monitoring. 

When a person is identified as a carrier of the bacillus but has no symptoms, preventive treatment can be administered to avoid the development of active tuberculosis. If followed correctly, this treatment can reduce the risk of developing the disease by up to 90%. This treatment is recommended in particular for anyone exposed to an infectious case in the preceding 2 years, and for people with a form of acquired immunosuppression (e.g. HIV) or induced by medication.

Multidrug-resistant tuberculosis (MDR-TB) is a form of the disease that does not respond to the two main anti-tuberculosis antibiotics. It is estimated that at least half a million people worldwide are affected each year. Resistance is most often the result of inadequate treatment and/or premature discontinuation of treatment. Multi-resistant tuberculosis is also transmitted from one patient to another, exacerbating the problem. It is rare in Western countries, particularly Switzerland, and occurs mainly in Eastern Europe, Asia, Africa and South America. Treatment for multidrug-resistant tuberculosis is longer, more expensive and associated with more side effects than for antibiotic-sensitive tuberculosis. There are also forms that are resistant to more antibiotics, known as ultra-resistant tuberculosis (XDR-TB), which has a poorer prognosis.

Tuberculosis remains one of the leading causes of infectious death in the world. Children, immunocompromised people and those suffering from other diseases are at increased risk of complications and death. Tuberculosis is the leading cause of death among people living with HIV. In Western countries, however, appropriate treatment and medical follow-up enable the vast majority of sufferers to be cured.

Preventing tuberculosis relies mainly on rapid diagnosis, effective treatment to limit transmission, and identifying and treating people who have been exposed to an infectious case. Preventive treatment of immunosuppressed and infected individuals is also very important. 

The BCG vaccine, used to protect young children from severe forms of the disease, is still widely used in highly endemic countries, but its effectiveness is limited in adults. It is no longer recommended in the majority of Western countries, where childhood tuberculosis is rare and no longer available.

Get medical advice if you develop symptoms such as a persistent cough, fever, shortness of breath, unexplained weight loss, chest pain or bloody sputum.

It's vital to tell your doctor about your history, particularly if you've lived in high-risk areas or been in contact with someone who has tuberculosis.

At Hôpital de La Tour, the Pulmonology Department provides screening, treatment and prevention of tuberculosis. After a screening test, if the result is positive, a pulmonologist assesses whether the disease is latent or active. The expertise of our multidisciplinary team ensures that each patient receives comprehensive, personalised care and appropriate follow-up.

Is tuberculosis contagious?
Tuberculosis is a contagious disease, but only people with pulmonary symptoms can transmit the disease. A patient can infect the people living with him or her, but very rarely the rest of the population, since it takes close contact of several hours with a patient to be contaminated. Transmission is therefore much less widespread than with influenza or COVID-19. 

Can tuberculosis be cured?
In the vast majority of cases, tuberculosis can be cured if appropriate treatment and medical follow-up are provided.

Is there a vaccine against tuberculosis?
There is a vaccine, BCG, but its effectiveness is limited. Although it protects young children against severe forms of the disease, it is not effective in preventing tuberculosis in adults. In Europe, where childhood tuberculosis has become rare, it has been abandoned. However, it is still useful in high-prevalence countries such as Africa, Asia and Eastern Europe, where the risk of contamination for young children is high.

Is tuberculosis a fatal disease?
Tuberculosis can be fatal, but in Switzerland and Western countries, deaths are very rare. If the disease is treated correctly, it is usually cured.

Is it possible to catch tuberculosis in Switzerland?
Tuberculosis has become very rare in Switzerland. Around 20% of cases occur in the native population. In most cases, those affected probably contracted the infection abroad. However, it is possible to become infected if someone close to you is ill.