Q+A: Tuberculosis as an Ongoing Threat

A patient receiving a skin test for tuberculosis.

For many people in the United States, tuberculosis is a disease that seems dated, more likely to be associated with Ellis Island than a present day trip to the doctor’s office.

However, the United States Preventive Services Task Force still keeps tuberculosis (or TB, as it’s known in shorthand) in its sights. And although tuberculosis has continued to decline year-by-year for more than two decades, the United States did experience an outbreak as recently as 1992.

A potentially deadly bacterial infection spread mostly through coughing, tuberculosis continues to spread relatively unimpeded in developing nations where health systems are not as robust. Globally, deaths due to tuberculosis have now eclipsed those due to HIV. As such, with international travel becoming near ubiquitous, the concern of a new outbreak in the United States remains.

With that in mind, the Preventive Services Task Force has issued an updated recommendation for screening for the disease. The guideline encourages screening in those who are not showing symptoms of tuberculosis, but still considered at-risk.
Esther Chernak, MD, associate research professor in the Dornsife School of Public Health and director of the Center for Public Health Readiness and Communication, explains what that means and why it is so important to stay vigilant.

  • Why would the recommendation call for the screening of people who aren’t even showing symptoms of tuberculosis?

There are two forms of tuberculosis. There is active tuberculosis, when individuals are symptomatic and may be contagious, especially when the infection involves the lungs. Then there is latent tuberculosis infection, which refers to the period when people who are infected are asymptomatic and not contagious.

People with latent tuberculosis infection are at risk of developing active tuberculosis, so treating people during this latent, asymptomatic phase considerably reduces the risk of developing an active form of the disease.

Treatment with antibiotics for a period of four to nine months is very effective in reducing the risk of developing the active disease. Treating latent disease is far simpler and easier to tolerate than the active form, which often requires taking four or more medicines for six to nine months and, occasionally, longer.

  • So who exactly des the task force recommend screening?

It recommends testing people who were born in, or who are former residents of, countries with an increased prevalence of TB, such as Asian and sub-Saharan Africa. Most cases of tuberculosis in the United States, 66 percent, can be tied to individuals not born in the country.

The task force also recommended testing people who live in, or have lived in, “high risk” congregate settings such as homeless shelters or correctional facilities. TB is more common among residents of these facilities as people may be living in close quarters and can spread the germs easily.

  • Why is tuberculosis more prevalent in developing countries?

Ultimately, the control of tuberculosis relies on strong health systems and investments in public health programs that identify and treat people who have active disease. There also needs to be programs that prevent people with latent infection from developing an active, contagious infection.

Many countries just don’t have the health care and/or public health systems to manage the large number of cases they see.

  • Do you agree with the recommendation made by the task force? Do you think it should be expanded — or relaxed?

The recommendation leaves out other high-risk groups, such as people with HIV infection or other causes of immune suppression. This might be under the presumption that TB screening occurs in those populations as part of their routine care, though that might not always be the case.

More importantly, the recommendations don’t address the high risk of tuberculosis in the U.S.-born populations of people of color, such as Latinos, blacks and Asian-Americans. Their risks vary from state to state, but among the reasons for their increased risk are socio-economic issues that often result in a lack of access to health care.

Additionally, stigma related to the disease and language or cultural barriers stand as impediments to access for screening in many of these communities.

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