Tuberculosis — United States, 2021

Thomas D. Filardo, MD; Pei-Jean Feng, MPH; Robert H. Pratt; Sandy F. Price; Julie L. Self, PhD

Disclosures

Morbidity and Mortality Weekly Report. 2022;71(12):441-446. 

In This Article

Discussion

U.S. TB incidence during 2021 increased by 9.4% following a large decrease during 2020.[2] Although TB cases and incidences have gradually declined in the United States since 1993, with a slowing pace of decline in recent years,[1] larger changes in reported TB have occurred during the COVID-19 pandemic. Similar changes in TB incidence have been reported globally.[3,4] In the United States, the causes for the changes in TB incidence are likely multifactorial. 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. 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.[5]

The reduction in the number of persons with TB disease reported <1 year after arrival in the United States coincides with changes in immigration and travel associated with the pandemic. Immigration to the United States declined by 31% during 2020,††† and similar patterns are suggested during 2021.§§§ However, immigration and travel reductions during 2020–2021 cannot fully account for the reduction in TB, because most TB cases among non–U.S.-born persons occur among those who have lived in the United States for many years and are likely the result of reactivation of latent TB infection (LTBI).[1] Despite overall case count declines, the number of TB cases among non–U.S.-born persons living in the United States for 20 years or longer before diagnosis increased during 2021 compared with average case counts during 2015–2019, highlighting the importance of evaluation and treatment of LTBI to prevent progression to TB disease. CDC is working to raise awareness of TB and LTBI among communities at risk and their health care providers through the new "Think. Test. Treat TB" campaign.¶¶¶

The increased TB incidence observed during 2021 compared with 2020 might be partially explained by delayed detection of cases with symptom onset during 2020 that were not diagnosed until 2021 because of delayed health care–seeking behavior, interruptions in health care access, or disrupted TB services related to the COVID-19 pandemic.[6,7] The small increase in the prevalence of smear positivity at diagnosis, predominantly among non–U.S.-born persons, suggests more advanced pulmonary disease, which might result from delayed diagnosis. Avoiding missed or delayed diagnosis of TB is crucial to preventing transmission. TB should be considered in the differential diagnosis of patients with prolonged cough (>2 weeks) or TB symptoms such as unintentional weight loss or hemoptysis, particularly among persons with epidemiologic risk factors for TB (e.g., birth or former residence in a country with higher TB incidence than that in the United States, history of living in a congregate setting such as a homeless shelter or a correctional facility, or immune suppression).****

The findings in this report are subject to at least two limitations. First, this analysis is limited to provisional 2021 TB surveillance data and case counts might change. Second, calculated rates are based on population estimates that are subject to change.

Ongoing analyses of NTSS data and external data sources, including anti-TB drug dispensing and hospitalization data, will provide more information about the effects of the COVID-19 pandemic on U.S. TB epidemiology, including the extent to which delayed diagnosis has been a factor. Focusing on essential TB activities, including early diagnosis and complete treatment of TB and LTBI, remains critical to achieving TB elimination in the United States.

††† https://www.dhs.gov/immigration-statistics/yearbook/2020
§§§ https://www.census.gov/library/stories/2021/12/net-international-migration-at-lowest-levels-in-decades.html
¶¶¶ https://www.cdc.gov/thinktesttreattb/
****Clinical consultation for potential TB cases is also available through state or local TB programs or the CDC-sponsored TB Centers of Excellence. https://www.cdc.gov/tb/education/professionaltools.htm

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