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This post was written by Nicole Hartman, NP-C, Parkview Infectious Diseases.
In a recent report, the World Health Organization (WHO) revealed that approximately 8.2 million people were newly diagnosed with tuberculosis (TB) in 2023, the highest number recorded since 1995. This significant increase in transmission has made TB again the leading cause of death among infectious diseases, surpassing COVID-19. In this post, we provide a comprehensive review of this infection, including its progression, the individuals at risk and the importance of timely intervention.
What is TB?
TB is a slow growing bacterial infection with serious health risks. It spreads from person to person through the air when an infected individual coughs or sneezes and others breathe the germs into their lungs.
How is TB diagnosed?
Healthcare providers conduct TB tests to identify individuals exposed to the bacteria. Screening for this disease usually consists of a tuberculin skin test (TST) or a blood test such as QuantiFERON or T-Spot. Individuals who test positive for TB will likely always test positive and require no further testing.
To minimize the number of false positive test results, the Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) recommend targeted screening for individuals at an increased risk of TB exposure or those who have been exposed to and are at an increased risk for progression to an active TB infection.
Who is at risk for TB?
Anyone can be infected with TB. Individuals at a higher risk for exposure include:
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Those who live with or spend time with someone who has TB
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Certain healthcare workers
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Students who are pursuing a degree in a healthcare-related field
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Those who have been incarcerated
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Those who have experienced homelessness
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Those born in countries where TB is endemic
Individuals who have a heightened risk of progressing to active TB if they have been infected include:
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Those who have been exposed within the last two years
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Children younger than 5 years of age
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Those with human immunodeficiency virus (HIV)
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Those who take immunosuppressive medications
How does TB progress?
When a person with a healthy immune system is exposed to someone with active TB and becomes infected, the immune system can "wall off" the bacteria so that it does not multiply and spread throughout the body.
This stage, known as latent tuberculosis, accounts for most people exposed to the bacteria. Latent TB is not contagious and does not cause disease-related symptoms or illness.
However, anyone with latent TB can develop active TB, especially people whose immune systems become compromised. Certain factors, such as immunosuppressive medications or medical conditions that weaken the immune system, may prevent the body from containing the bacteria.
Although the disease typically remains in the lungs, it can travel through the bloodstream to other parts of the body and cause damage to the lymph nodes, bones and joints, the brain and other organ systems.
As the infection spreads, the individual may become ill and develop symptoms such as:
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fever
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cough (sometimes with blood)
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unexplained weight loss
Treatment and prevention
Not everyone exposed to TB bacteria may develop an active infection, but treating the disease in its dormancy is essential for reducing its risk of progression and transmission. Without treatment, healthy individuals with no risk factors face a 5-10% lifetime risk of progressing to active TB, with the highest likelihood occurring within the first 2 years after exposure.
Even if they aren't currently sick, individuals with a weakened immune system are highly prioritized for treatment. For people with diabetes, without intervention, the risk increases to 30% over a lifetime, while those living with untreated HIV and untreated latent TB face a 7-10% annual risk of progression.
Treatment for latent TB involves antibiotics that eliminate the bacteria. Common options include isoniazid, taken daily for six months, and rifampin, taken daily for three months. In 2014, the Federal Drug Administration (FDA) approved a combination of isoniazid and rifapentine as an easier alternative, requiring taking the medications only once per week for 12 weeks. Treatments for latent TB have approximately a 90% success rate in preventing the progression to an active infection.
After completing treatment for latent TB, individuals should receive a letter of completion to share with healthcare providers or others requesting TB testing in the future.
Learn more
If you or someone you know has been exposed to TB or belongs to a high-risk group, speak to a healthcare provider about TB testing and prevention. If you need help scheduling an appointment or establishing care with a provider, our Access Center can help. Call any time, at 877-PPG-TODAY or 877-774-8632 for assistance. Learn more about the team of Infectious Disease providers and the conditions we treat here.
Additional resources
CDC – Clinical Overview of Latent Tuberculosis Infection
