THINK. TEST. TREAT TUBERCULOSIS

Tuberculosis has been infecting and killing man since the dawn of civilization. Western countries, thanks to concerted Public Health efforts to eliminate TB, have greatly decreased its incidence. The U.S. incidence rate of TB disease, formally known as Active TB, was 52.6 cases per 100,000 population in 1953. The U.S. incidence in 2021, per the current CDC release of “Reported Tuberculosis in the United States, 2021,” is 2.4 per 100,000 population. The Public Health goal of one case per one million population is still a work in progress with the COVID pandemic having slowed the steady progress made in recent years.

In an ever-shrinking world, and in a county that welcomes a significant number of immigrants from countries with high TB incidence, it is useful to review worldwide and State statistics. In 2021, there were 10.6 million cases of TB disease worldwide, with 1.6 million deaths. TB was the 13th leading cause of death worldwide, second only to COVID in infectious causes. Pennsylvania reported 166 cases of TB disease in 2021. The greater Philadelphia metropolitan area, who reports separately, recorded another 160 cases. Non-U.S.-born Pennsylvanian cases were in line with national numbers at 73.5%. Persons 65 and older comprised 30.1% of PA cases. 47% of PA cases were of Asian descent and 10.2% were Hispanic. Healthcare workers made up 8.0% of cases in Pennsylvania.

Activation of Latent TB Infection (LTBI) is responsible for a large percentage of TB disease. It is estimated that up to one third of the world population is infected with TB, with an estimated 13 million infected in the U.S. Activation of LTBI to TB disease occurs in up to 10% of infected but immunocompetent individuals over the course of their lifetime, and increases up to 30% of those infected with concurrent Diabetes. In those living with HIV, the activation rate increases even further to 7-10% per year of their lifetime. With an immature immune system, children 4 years of age and younger have a high risk of TB Infection progressing to TB disease.

THINK TB.

Thinking about the possibility of TB Infection leads to identifying those at risk for LTBI and progression to TB disease. LTBI presents with no symptoms, is not contagious, and is easy to overlook unless we are thinking about TB. It is not recommended to test individuals who have no risk factors or symptoms as it will lead to false positive tests and unnecessary treatment. However, birth, travel, or residence in a country with increased TB prevalence should raise suspicion for LTBI. The only countries with low prevalence of TB are the USA, Canada, Australia, New Zealand, and western and northern Europe. People with HIV, cancer, or any other immune compromise or suppression such as those with a renal transplant should be tested. Evaluation for TB should be performed prior to a patient receiving a biologic agent for treatment of conditions like Rheumatoid Arthritis or Psoriasis. Patients, especially young children, who have close contact to a person with TB disease, and those with suspicious CXR findings, should be tested. Also consider testing patients who have a history of residence in a high risk congregate setting, such as prison or a homeless shelter. High risk healthcare workers should also be considered for testing. Diabetes is the most reported risk factor in 2021, found in 23.9% of TB disease cases in the U.S.

TEST FOR TB.

Testing for TB can be performed by a blood test, commonly referred to as IGRA (interferon gamma releasing assay) or by the Tuberculin Skin Test (TST). There has been universal agreement that the IGRA is the preferred test in the U.S. One of the reasons for the IGRA preference is that unlike the TST, there is no false positive reaction to the BCG vaccination which is performed shortly after birth in many high prevalence countries. The IGRA was previously recommended for patients five years of age and older, but today we use it in patients one year and older. Neither the TST nor the IGRA test can distinguish LTBI from TB disease; therefore, all patients who test positive should be evaluated for TB disease versus LTBI. TB disease is evaluated by detailed history, physical examination and Chest X-Ray. Patients who have a positive IGRA should have a Chest X-Ray and be referred to the Health Department for diagnostic workup and treatment.

TREAT LTBI.

Treating every person with LTBI will significantly lower the cases of TB disease. It is no longer standard of care to assume a person with LTBI will not go on to activation of TB disease. A young healthy person may develop diabetes, be diagnosed with cancer, contract HIV, or simply require a biologic agent for another disease process. Regimens for LTBI have been shortened to 3-4 months and are generally well tolerated. Daily LTBI medication regimens do not require direct observation by the public health department. Shorter course, well tolerated therapy has reduced the pill burden on the patient and improved compliance. By preventing activation of LTBI to TB Disease, we have a large health care cost savings, and significantly reduced morbidity and mortality.

When I think of Chester County, I think of rolling green fields with horses, lush farmland, and quaint towns. I also think of TB, especially with so many newcomers arriving to jump on the ladder of economic success. Think. Test. Treat LTBI will make our county healthier for everyone.