Think Tuberculosis

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Alice Lehman, MD, FAAP, CTropMed

For the first time in decades the world is witnessing an increase in the number o For the first time in decades the world is witnessing an increase in the number of people dying from Mycobacterium tuberculosis as known as tuberculosis (TB) disease. This increase in morbidity is witnessed across all levels – globally, regionally, and by country, which parallels the drop in new cases of TB in 2020 (Figure 1). During 2020 in the United States, we witnessed a similar drop in new TB cases whilst 2021 brought an increase (Figure 2). The drop in new cases is multifactorial representing reductions in access to TB screening, decreased international migration, and pandemic mitigation efforts. The increase in TB deaths correlates with reduced accessibility to latent tuberculosis infection (LTBI) preventive treatment, active TB disease treatment, and missed diagnoses. Pandemic public health mitigation policies including quarantining, school closures, work from home measures, and supply chain disruption predispose historically high-risk populations to increased TB transmission and disease. f people dying from Mycobacterium tuberculosis as known as tuberculosis (TB) disease. This increase in morbidity is witnessed across all levels – globally, regionally, and by country, which parallels the drop in new cases of TB in 2020 (Figure 1). During 2020 in the United States, we witnessed a similar drop in new TB cases whilst 2021 brought an increase (Figure 2). The drop in new cases is multifactorial representing reductions in access to TB screening, decreased international migration, and pandemic mitigation efforts. The increase in TB deaths correlates with reduced accessibility to latent tuberculosis infection (LTBI) preventive treatment, active TB disease treatment, and missed diagnoses. Pandemic public health mitigation policies including quarantining, school closures, work from home measures, and supply chain disruption predispose historically high-risk populations to increased TB transmission and disease.

Figure 1  Global trends in the estimated number of TB death (WHO Global Tuberculosis Report 2021)

Figure 2 United States TB case counts and incidence, characterized by patient birth origin (MMWR Tuberculosis United States 2021, March 2022)

In Minnesota, cases of TB increased by 15 percent in 2021 as compared to 2020 (Figure 3). Minnesota pediatric TB cases increased by 30 percent, from 25 to 33 cases in children and young adults (< 24 years), with the 8 additional cases occurring in school aged children < 15 years. Focusing on young children <5 years, incidence has more than double from 3 to 8 cases, including a neonatal death. This contrasted national pediatric TB data from 2021 suggesting small reductions in TB cases for children < 15 years of age; however, this data is limited by provisional surveillance data and the rate may be higher than reported.

Figure 3 2021 Number of cases of tuberculosis by age in Minnesota (MDH Tuberculosis Quarterly Surveillance Report 2022)

Transmission of TB is mediated by the infectiousness of the source case and the degree and duration of contact with the source. For instance, a child has a higher risk of infection if the source case is the primary caregiver or sleeps in the same room. Downstream effects of pandemic mitigation policies led to increased overcrowding, housing instability, and unemployment which disproportionally affected populations historically at higher risk for TB, including people born outside of the United States, people living below the poverty line or unemployed, and people living in congregate settings. In conjunction with the decreased accessibility and utilization of the medical system during the pandemic, this led to environments that promoted increased TB transmission.

Children <5 years and post-pubertal adolescents years carry an increased risk of progression to TB disease after initial exposure/infection. The lifetime risk of progression from infection to active TB disease is lowest for elementary school-aged children (<5 percent), intermediate for adolescents and preschool-aged children (10–20 percent), and highest for infants (40–50 percent).

Knowing these trends in TB both globally and locally, pediatric TB disease cases may rise in the coming year. Multiple factors contribute to this prediction including 1) risk of progression to TB disease is highest in first two years after initial exposure/infection, 2) increased international travel with known decreased TB screening and preventive treatment globally in last 2 years, and 3) decreased access to preferred LTBI treatment due to a national shortage of rifampin (4).

Pediatricians should have a decreased threshold to screen children for TB infection. Updated screening guidelines recommend using an interferon-gamma release assay (IGRA) for LTBI or TB exposure in children >2 years and in children who have received a BCG vaccine. A Tuberculin skin test should be used in children <2 years, as IGRAs have a lower sensitivity and perform inconsistently in this age group.

In the era of the COVID-19, pediatricians should maintain an index of suspicion for TB disease in children who present with fever, cough, weight loss and nonspecific radiograph findings such as hilar adenopathy or mediastinal thickening. A careful tuberculosis exposure history can be helpful in characterizing epidemiologic risk, such as screening for close contact to a person with infectious TB disease, living with persons who have immigrated from endemic areas of the world, or living in high transmission environments such as shelters and homeless encampments.

Your infectious diseases colleagues are always eager to help therefore please reach out with concerns or questions you have so we can all better serve our patients and communities we care about.

 

Resources:

Center for Disease Control. Think, Test, Treat Tuberculosis. https://www.cdc.gov/tb/default.htm

Minnesota Department of Health. Tuberculosis Information for Health Professionals. https://www.health.state.mn.us/diseases/tb/hcp/index.html

WHO Global Tuberculosis Report 2021

Tuberculosis – United States 2021. MMWR, March 2022. Filardo TD, Feng P, Pratt RH, Price SF, Self JL.

Tuberculosis Infection in Children and Adolescents: Testing and Treatment Pediatrics December 2021; 148 (6): e2021054663. 10.1542/peds.2021-054663

FDA Drug Shortage List. USA Food and Drug Administration. https://www.accessdata.fda.gov/scripts/drugshortages/


About the Author

Alice Lehman MD, FAAP, CTropMed, is a pediatric and adult infectious diseases fellow at University of Minnesota. She works to better understand and intervene on the intersectionality of infectious diseases and health disparities.

 

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