Incidence of TB increased 9.4 percent in U.S. during 2021

The incidence of tuberculosis (TB) in the United States increased 9.4 percent during 2021, according to research published in the March 25 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

Noting that the steadily decreasing incidence of TB during 1993 to 2019 slowed in the later years, followed by a sharp decrease in 2020, Thomas D. Filardo, M.D., from the CDC in Atlanta, and colleagues describe the incidence of TB in 2021, as reported to the CDC National Tuberculosis Surveillance System by the 50 U.S. states and the District of Columbia.

The researchers note that 7,860 TB cases were provisionally reported during 2021. The national incidence of reported TB increased 9.4 percent during 2021 compared with during 2020 (2.37 versus 2.16 cases per 100,000), but remained lower than the rate during 2019 (2.71 cases per 100,000). The incidence of TB increased among U.S.-born and non-U.S.-born persons during 2021. The increased incidence may be partly due to delayed diagnosis among persons with symptom onset during 2020.

"Probable explanations include a true reduction in TB disease resulting from reduced TB transmission because of pandemic mitigation efforts and fewer new arrivals from countries with higher TB incidence than the United States," the authors write. "In addition, delayed or missed TB diagnoses because of disruptions in health care access or assumptions that patients with respiratory symptoms had COVID-19 might contribute to the observed changes."