Disease Expert: Keep Watch for TB, a Growing Global Concern

If trends in tuberculosis rates continue, more than 10 million people worldwide will be diagnosed with the bacterial disease this year and 1.5 million will die from it. Many will remain "silent" carriers. And despite its world-class medicine and healthcare, Massachusetts won't be immune to the spread. Numbers are rising here, with 254 cases in 2024.

So, as World Tuberculosis Day approaches on March 24, Sampan is spreading the word about this sometimes fatal disease. We recently spoke with Dr. Tine Vindenes, chief of Geographic Medicine and Infectious Diseases at Tufts Medical Center. Dr. Vindenes also co-directs the Tuberculosis Clinic at Tufts. Following is a lightly edited email exchange between Sampan and the doctor.

Sampan: Most people do not think of TB as a problem in the U.S. But what should people be aware of to protect themselves from TB, and where is the risk the greatest?

Vindenes: Tuberculosis, or TB, is an ancient human airborne and contagious bacterial disease that is among the Top 10 causes of death worldwide. It is also the leading cause of death by a single pathogen.

The World Health Organization reported 10.7 million cases of TB in 2024. While TB disease numbers have increased significantly in Massachusetts over the last year – with 254 cases in 2024 – the total numbers are low in a global context. Non-U.S. born and racial/ethnic minority groups are disproportionately affected by TB in Massachusetts. People who have spent one month or longer in a country in Asia should be screened for exposure to tuberculosis bacteria by a blood test, and if positive, a chest X-ray followed by a discussion of treatment to prevent the exposure and inactive infection becoming an active tuberculosis disease. The highest risk of active tuberculosis disease is within two years from an exposure to someone with tuberculosis or when the immune system has been weakened by medications, like immunosuppressives, or by diabetes.

Sampan: Could you explain the difference between inactive and active TB?

Vindenes: Inactive TB, also called latent TB infection, means that bacteria live inside the cells, but the infection is contained and the person feels well without symptoms. A person with inactive TB cannot spread the infection. People who have spent one month or longer in countries with higher risk (this includes any country other than U.S., Canada, New Zealand, Australia, or a country in northern or western Europe) or had a close exposure to someone with active TB disease, should be tested for inactive TB. People who take medications that suppress the immune system, or have diabetes, are at higher risk of developing active TB from those live bacteria inside the cells if not treated. All people with inactive TB should be considered for treatment to avoid it becoming an active disease. Inactive TB can be cured with medications, the most commonly-used of which is called Rifampin.

A person with active TB disease may feel tired, notice weight loss and lack of appetite, and commonly has a cough for several weeks or longer. The person may also have a fever or sweating at night. Tuberculosis mainly attacks the lungs, but can spread to other organs. Testing for active TB includes reviewing samples from coughed up material for the bacteria and review of the lungs by chest X-ray or CT scan. Timely medical treatment is important to avoid complications like extensive infection or even death, as well as avoiding spreading the disease to others. The overwhelming majority of TB cases in U.S are not drug resistant and are treatable with multiple medications by mouth for six months.

'EVERY PATIENT SHOULD BE TREATED: Dr. Tine Vindenes, co-directs the Tuberculosis Clinic at Tufts. Courtsy photo.

Sampan: Why is it, do you believe, that the U.S. does not give the TB vaccine at childhood like in some Asian countries? Attention to the vaccine seemed to spike during Covid, but the faded away. Do you think it would be advantageous to provide it at earlier childhood?

Vindenes: Currently, we do not have an effective vaccine to prevent TB in adults. Most countries give the BCG vaccine in childhood to prevent extensive TB, but the vaccine is less effective against adult lung TB. Also, immunity does not last lifelong and this is why people who have received the BCG vaccine may still get TB as adults. The U.S does not recommend the BCG vaccine in childhood, because it is not seen as being cost effective in countries where the overall disease burden is low.

Sampan: On the flipside, I understand these vaccines can give false positives during routine testing here among immigrants from Asia, who had gotten the vaccine. Does this pose any problems related to screening?

Vindenes: The BCG vaccine may occasionally affect the skin test result, but it does not interfere with or affect the blood test called QuantiFERON.

Sampan: What are some common concerns with the current antibiotic treatments for TB and how to those risks compare with the disease itself?

Vindenes: Treatment for inactive TB/latent TB, or also called TB exposure, is most commonly with one drug called Rifampin. This is a medication where the person takes two pills once a day for 4 months with full cure of the bacteria inside the cells, preventing it from becoming active disease in the future. The most serious, but uncommon, side effects from this medication is the potential for liver injury that can be reviewed by close monitoring by a monthly laboratory test and the medication can be stopped before serious concerns arise. People who already have some liver disease or are taking another medication that may potentially cause liver injury, are most at risk for this adverse effect.

Other potential side effects may include vague gastrointestinal concerns, usually easily mitigated by antinausea medications, and less commonly, a rash. Those with the highest risk of TB disease are people with immune system diseases, those who take medications that may weaken the immune system and those who have diabetes. The risk for a potential side effect rarely outweighs the importance of treatment of the TB exposure. For other people the risk vs. benefit of treatment should be individually discussed with their physician, but the most important thing is to be screened to understand if one has been exposed to the tuberculosis bacteria.

For active TB disease, every patient should be treated to prevent severe and disseminated disease that can lead to death, as well as prevent possible transmission to others. A medication regimen may be complex and not always easy to tolerate, but without treatment the risk death significantly increases.

Sampan: Are there concerns about antibiotic-resistant variants of the bacteria that causes TB in the U.S.?

Vindenes: The overwhelming majority of TB disease in Massachusetts and the U.S is not antibiotic resistant. While we are seeing more concerning drug resistance in the U.S. and around the globe, the resistance is usually limited to only one out of several TB drugs and doctors can safely use an alternative option. TB drug resistance monitoring is a priority for the Massachusetts Department of Public Health.