Tuberculosis — United States, 2020

Molly Deutsch-Feldman, PhD; Robert H. Pratt; Sandy F. Price; Clarisse A. Tsang, MPH; Julie L. Self, PhD


Morbidity and Mortality Weekly Report. 2021;70(12):409-414. 

In This Article


TB cases and incidence have decreased gradually since the peak of resurgence in 1992,[1] highlighting the impact of nationwide TB control efforts. Although steep decreases have been reported previously, most notably after the 2008 economic recession,[3] the annual decrease reported during 2020 is far larger than any reported during the last decade.[1] Similar trends in TB have been reported globally[4] and for other diseases domestically.[5,6] Multiple factors have likely led to both a true decrease in TB incidence and underascertainment of cases.

The reduction in the number of persons with TB disease reported ≤1 year after arrival in the United States indicates that changes in immigration and travel patterns during 2020 might have contributed to a decrease in TB incidence. However, given the large proportion of cases that occur each year among persons who have been in the United States >1 year, particularly those who have been in the United States >10 years,[7] and the broad decreases reported among both non–U.S.-born and U.S.-born populations, immigration and travel changes cannot fully explain the decrease in the number of reported TB cases during 2020. Another possible cause of this decrease is that mitigation strategies implemented for slowing the spread of COVID-19 (e.g., mask-wearing and social distancing) might have also reduced TB transmission.

The unexpectedly steep and widespread reduction in the number of reported TB cases causes concern regarding underdiagnosis. CDC has received anecdotal reports of persons who repeatedly sought medical attention for persistent TB signs and symptoms, received a negative test result for SARS-CoV-2 multiple times, and received a TB diagnosis much later (in certain cases on autopsy), demonstrating that other TB cases might have been missed during 2020. TB should be considered in the differential diagnosis of patients with prolonged (>2 weeks) cough or TB symptoms such as unintentional weight loss, particularly in the context of negative tests for SARS-CoV-2 and epidemiologic risk factors for TB (e.g., birth or former residence in a country with high TB incidence, a history of living in a congregate setting such as a homeless shelter or a correctional facility, or immune suppression). In such cases, health care providers should consider ordering rapid TB diagnostic tests (e.g., sputum microscopy or nucleic acid amplification tests) to quickly identify patients with TB disease. Clinical consultation for potential TB cases is also available through TB programs or the CDC-sponsored TB Centers of Excellence.***

Limited access to and reluctance to seek medical care during the COVID-19 pandemic have been reported[8] and might also contribute to underdiagnosis. Persons with persistent respiratory symptoms should be encouraged to seek medical attention and return to a health care provider if symptoms persist or return despite initial treatment.[8,9] Timely TB diagnoses save lives and prevent further community transmission.

The findings in this report are subject to at least two limitations. First, this analysis is limited to provisional TB surveillance data reported for 2020. In previous years, final case counts have not differed substantially from provisional data. However, although anecdotal information from reporting areas demonstrates that underreporting is not a major contributor to the reported decrease in TB incidence during 2020, underreporting from providers and underdiagnosis are possible. Second, denominators used to calculate incidence are based on estimated population numbers and might change slightly if population estimates are adjusted.

Further work is in progress to examine the causes of the steep decrease in reported TB cases. The extent of underdiagnosis will be explored by using external data sources of mortality, TB hospitalization, and anti-TB drug dispensation. Further analysis of laboratory data and conversations with clinical infection preventionists will help determine the extent of underreporting. In addition, changes in recent transmission will be examined by using isolate genotyping data. Identifying reversible causes of underdiagnosis or actual causes of an actual reduction in TB cases during 2020 will help identify effective public health responses. Supporting public health infrastructure for performing fundamental principles of TB control (e.g., case detection, contact tracing, and targeted testing and treatment for latent TB infection) is important. CDC remains committed to working with its public health partners to eliminate TB in the United States.