Tuberculosis (TB) is an infectious disease that usually affects the lungs. It is sometimes fatal. Symptoms include coughing, phlegm, and more. Doctors may prescribe antibiotics for TB.

In the past, tuberculosis (TB), or “consumption,” was a major cause of death worldwide. Following improvements in living conditions and the development of antibiotics, the prevalence of TB fell dramatically in industrialized countries.

However, numbers started to rise again in the 1980s. The World Health Organization (WHO) describes it as an “epidemic”. It reports that it is 13th leading cause of death globally and “the second leading infectious killer after COVID-19”.

The WHO estimates that in 2020, nearly 10 million people worldwide developed TB and 1.5 million people died from the disease, including 214,000 people who also had HIV.

A majority of the people affected were in Asia. However, TB remains a matter of concern in many other areas, including the United States. The same year, doctors reported 7,174 cases of TB in the U.S., according to the Centers for Disease Control and Prevention (CDC).

Currently, antibiotic resistance is causing renewed concerns about TB among experts. Some strains of the disease are not responding to the most effective treatment options. In this case, TB is difficult to treat. Keep reading to learn more.

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Packing ampoules of the BCG (Bacillus Calmette-GuŽrin) vaccine for tuberculosis developed by the Pasteur Institute in Paris, France in 1931. FPG/Getty Images

A person may develop TB after inhaling Mycobacterium tuberculosis (M. tuberculosis) bacteria, primarily from person to person.

When TB affects the lungs, the disease is the most contagious, but a person will usually only become sick after close contact with someone who has this type of TB.

TB infection (latent TB)

An individual can have TB bacteria in their body and never develop symptoms. In most people, the immune system can contain the bacteria so that they do not replicate and cause disease. In this case, a person will have TB infection but not active disease.

Doctors refer to this as latent TB. An individual may never experience symptoms and be unaware that they have the infection. There is also no risk of passing on a latent infection to someone else. However, a person with latent TB still requires treatment.

The CDC estimates that as many as 13 million people in the U.S. have latent TB.

TB disease (active TB)

The body may be unable to contain TB bacteria. This is more common when the immune system is weakened due to illness or the use of certain medications.

When this happens, the bacteria can replicate and cause symptoms, resulting in active TB. People with active TB can spread the infection.

Without medical intervention, TB becomes active in 5–10% of people with the infection. According to the CDC, progression occurs within 2–5 years in about 50% of these people.

The risk of developing active TB is higher in:

  • anyone with a weakened immune system
  • anyone who first developed the infection in the past 2–5 years
  • older adults and young children
  • people who inject recreational drugs
  • people who have not previously received appropriate treatment for TB

Learn more about pulmonary TB, which primarily affects the lungs, here.

Latent TB: A person with latent TB will have no symptoms, and no damage will show on a chest X-ray. However, a blood test or skin prick test will indicate that they have TB infection.

Active TB: An individual with TB disease may experience a cough that produces phlegm, fatigue, a fever, chills, and a loss of appetite and weight. Symptoms typically worsen over time, but they can also spontaneously go away and return.

Early warning signs

A person should see a doctor if they experience:

  • a persistent cough, lasting at least 3 weeks
  • phlegm, which may have blood in it, when they cough
  • a loss of appetite and weight
  • a general feeling of fatigue and being unwell
  • swelling in the neck
  • a fever
  • night sweats
  • chest pain

Beyond the lungs

TB usually affects the lungs, though symptoms can develop in other parts of the body. This is more common in people with weakened immune systems.

TB can cause:

  • persistently swollen lymph nodes, or “swollen glands”
  • abdominal pain
  • joint or bone pain
  • confusion
  • a persistent headache
  • seizures

A person with latent TB will have no symptoms, but the infection can show up on tests. People should ask for a TB test if they:

  • have spent time with someone who has or is at risk of TB
  • have spent time in a country with high rates of TB
  • work in an environment where TB may be present

A doctor will ask about any symptoms and the person’s medical history. They will also perform a physical examination, which involves listening to the lungs and checking for swelling in the lymph nodes.

Two tests can show whether TB bacteria are present:

  • the TB skin test
  • the TB blood test

However, these cannot indicate whether TB is active or latent. To test for active TB disease, the doctor may recommend a sputum test and a chest X-ray.

Everyone with TB needs treatment, regardless of whether the infection is active or latent.

Find out what to expect from a tuberculosis skin test here.

Learn more about how to read TB skin test results here.

With early detection and appropriate antibiotics, TB is treatable.

The right type of antibiotic and length of treatment will depend on:

  • the person’s age and overall health
  • whether they have latent or active TB
  • the location of the infection
  • whether the strain of TB is drug resistant

Treatment for latent TB can vary. It may involve someone taking an antibiotic once a week for 12 weeks or every day for 9 months.

Treatment for active TB may involve taking several drugs for 6–9 months. When a person has a drug-resistant strain of TB, the treatment will be more complex.

It is essential for people to complete the full course of treatment, even if symptoms go away. If a person stops taking their medication early, some bacteria can survive and become resistant to antibiotics. In this case, the person may go on to develop drug-resistant TB.

Depending on the parts of the body that TB affects, a doctor may also prescribe corticosteroids.

M. tuberculosis bacteria cause TB. They can spread through the air in droplets when a person with pulmonary TB coughs, sneezes, spits, laughs, or talks.

Only people with active TB can transmit the infection. However, most individuals with the disease can no longer transmit the bacteria after receiving appropriate treatment for at least 2 weeks.

Ways of preventing TB from infecting others include:

  • getting a diagnosis and treatment early
  • staying away from other people until there is no longer a risk of infection
  • wearing a mask, covering the mouth, and ventilating rooms

In some countries, children receive an anti-TB vaccination — the bacillus Calmette–Guérin (BCG) vaccine — as part of a regular immunization program.

However, experts in the U.S. do not recommend BCG vaccination for most people unless they have a high risk of TB. Some of the reasons include a low risk of infection in the country and a high likelihood that the vaccine will interfere with any future TB skin tests.

People with weakened immune systems are most likely to develop active TB. The following are some issues that can weaken the immune system.


For people with HIV, doctors consider TB to be an opportunistic infection. This means that a person with HIV has a higher risk of developing TB and experiencing more severe symptoms than someone with a healthy immune system.

Treatment for TB can be complex in a person with HIV, but a doctor can develop a comprehensive treatment plan that addresses both issues.

TB can become a complication of HIV. Learn about other HIV complications here.


Tobacco use and secondhand smoke increase the risk of developing TB. These factors also make the disease harder to treat and more likely to return after treatment.

Quitting smoking and avoiding contact with smoke can reduce the risk of developing TB.

Other conditions

Some other health issues that weaken a person’s immune system and can increase the risk of developing TB include:

Some medical treatments, such as an organ transplant, can also impede the functioning of the immune system.

Spending time in a country where TB is common can also increase the risk of a person developing it. For information about the prevalence of TB in various countries, people can use this tool from the WHO.

Without treatment, TB can be fatal.

If it spreads throughout a person’s body, the infection can cause problems with the cardiovascular system and metabolic function, among other issues.

TB can also lead to sepsis, a potentially life threatening form of infection.

An active TB infection is contagious and potentially life threatening if a person does not receive appropriate treatment. However, most cases are treatable, especially when doctors detect them early.

Anyone with a high risk of developing TB or any symptoms of the disease should consult a doctor as soon as possible.

TB is a reportable disease to each state’s department of health. State sanctioned regulations and treatment plans can provide care for patients regardless of immigration status, insurance coverage, or socioeconomic status.

Read the article in Spanish.