An estimated 10 million people develop tuberculosis every year. It’s most common in low to middle income countries but can be found in countries around the globe, including the United States.

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Tuberculosis (TB) is a serious bacterial infection and one of the leading causes of death worldwide. According to the World Health Organization (WHO), 1.6 million people died from TB in 2021.

Since the 19th century, when the bacteria that causes TB was first discovered, the disease has become far less common. It can be treated and prevented with antibiotic therapy.

Despite efforts to stamp out the disease, TB is widespread in several parts of the world, particularly in Asia and Africa. And multidrug-resistant TB remains a major public health risk in these areas.

Although it’s rare, TB is still present in the United States.

TB is the second most deadly infectious disease in the world, after coronavirus disease 2019 (COVID-19).

TB bacteria are extremely common. Estimates suggest that one-quarter of the world’s population is already infected with the bacteria that causes TB (Mycobacterium tuberculosis). But only 5–10% of those infected with TB bacteria will develop symptoms of the disease and become contagious.

According to the WHO’s Global TB Report, an estimated 10.6 million people became ill with TB in 2021.

TB affects both adults and children. People with compromised immune systems, like those living with HIV, malnutrition, and diabetes, are the most at risk.

TB is much less common in the United States than it once was. In 2022, there were only about 8,300 people reported to have TB.

Decades of testing and treatment have helped control the spread of TB.

But about 13 million people in the United States do have what’s known as a latent TB infection. Latent TB infections happen when you have TB bacteria in your body, but you aren’t sick or contagious.

Certain groups might be more vulnerable to TB infections. These include people who:

  • have weakened immune systems
  • are very young
  • reside in close quarters with others, such as in homeless shelters or hospitals
  • have certain chronic conditions, such as diabetes
  • are undergoing treatment for cancer or autoimmune diseases
  • live with HIV

TB is most common in the following regions:

  • Africa
  • Asia
  • Caribbean
  • Eastern Europe
  • Latin America

A lack of access to treatment and testing facilities contributes to high TB rates in many countries. Other factors that play a role include malnutrition and other co-occurring conditions that may weaken your immune system.

About 80% of all TB-related deaths occur in low to middle income countries.

TB is an airborne disease that spreads from person to person. When someone with active TB disease coughs, speaks, or sings, they release bacteria into the air. These tiny bacteria can then be inhaled by somebody nearby.

Most people briefly exposed to TB bacteria don’t develop an infection. Their immune systems can fight off the bacteria before they take root.

Transmission is most common among groups of people who spend a lot of time together regularly. This includes families, school children, and co-workers.

Most people who do become infected with TB develop what’s known as latent TB. This happens when your immune system keeps the bacteria in check and prevents them from growing. If you have a latent TB infection, you won’t have any symptoms and you won’t be contagious.

People with latent TB can only spread the disease to others if their infection progresses into active TB disease.

About 10% of all people with latent TB develop active TB disease.

There’s a vaccine for TB, but it’s rarely used in the United States. The bacillus Calmette-Guérin (BCG) vaccine, which was developed in 1921, is commonly used in countries where TB and meningitis are common. It’s typically given to infants as part of their standard vaccination protocol.

This vaccine doesn’t always work though, and people still get sick. The BCG vaccine can also lose effectiveness over time, so people vaccinated as babies may need booster shots to stay protected.

Some people in the United States who are at higher risk of developing a TB infection may be considered for the BCG vaccine. This includes international healthcare workers who will regularly be exposed to high risk populations. Other people who may be considered for the vaccine include people with compromised immune systems.

TB is curable for many people. But latent TB infections are much easier to treat than active TB disease. Treating TB may involve taking antitubercular medications every day or every week for 4–6 months.

These antibiotics include:

  • isoniazid
  • ethambutol
  • pyrazinamide
  • rifampin
  • rifapentine
  • moxifloxacin

It’s important to take your prescriptions as directed and to finish the entire course. Stopping your medications too soon can cause the TB infection to come back. When TB comes back, it can be resistant to multiple drugs.

Multidrug-resistant TB is more difficult to treat than TB disease. Because the standard treatments don’t help, doctors have to prescribe more toxic treatments to kill the bacteria.

TB is considered an airborne disease, which means it can spread when someone with an active TB infection coughs, talks, or sings.

Unlike other types of infections, TB doesn’t spread in droplets. This means that you can’t get infected by sharing food, kissing, or touching surfaces.

If you’re contagious, you’re most likely to spread the disease to people you spend a lot of time with, like your family and friends.

In the 1800s, TB was often called “consumption.” The term was based on the appearance of people with the disease. Symptoms like weight loss, paler skin tone, and cough made it seem like the person was wasting away or being consumed by the disease.

TB was responsible for more deaths in the 19th and earlier 20th centuries than any other disease.

The name “tuberculosis” was coined by Johann Schonlein in 1834 based on the appearance of infectious tissue in the lungs.

Earlier, TB was known by different names, including “the white plague” in the 1700s.

TB was once common in the United States, but awareness, testing, and medications have reduced the number of people who contract and develop active TB in recent decades. Still, millions of people living in the United States may have latent TB infections. Worldwide, TB is still very common.

But with a prompt diagnosis, the infection is considered curable. You might also consider asking a doctor or other healthcare professional about TB testing if you have been exposed.