Reported Tuberculosis in the United States, 2020

Executive Commentary

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Introduction

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This 2020 edition of Reported Tuberculosis in the United States  reflects a uniquely challenging year for public health and the TB community. As with past editions, the report describes information on cases of tuberculosis (TB) disease reported to the Centers for Disease Control and Prevention (CDC) since 1993. This year’s report emphasizes cases counted by reporting jurisdictions in 2020 and the effects of the COVID-19 pandemic on TB surveillance.

Information in this report summarizes incident cases of TB reported to CDC’s National Tuberculosis Surveillance System (NTSS) by each of the 50 U.S. states and the District of Columbia (DC) unless otherwise specified. In addition to the 50 U.S. states and DC, five U.S. territories (American Samoa, Commonwealth of the Northern Mariana Islands, Guam, Puerto Rico, and the U.S. Virgin Islands) and three independent countries that are in compacts of free association with the United States (Federated States of Micronesia, Republic of the Marshall Islands, and Republic of Palau) report incident cases of TB to CDC. NTSS has collected information on all newly reported cases of TB since 1953, and cases reported since 1993 are maintained in an electronic database. Small variations in historical data included in this edition, compared with previous editions, are attributable to updated information submitted in the interim by reporting areas.

Six new tables have been added to the report. Tables 2B and 2C and Tables 4B and 4C further examine race/ethnicity by origin of birth and age by origin of birth, respectively. Table 4D examines TB cases by birth cohort (cases born in the same decade of birth). Table 6C looks at TB cases among non-U.S.–born persons diagnosed with TB by years in the United States from 1993–2020. This added table provides insight to changing trends in the proportion of cases diagnosed with TB by length of time in the United States.

Overall Trends

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In 2020, the United States reported 7,174 TB cases and an incidence rate of 2.2 cases per 100,000 persons, representing a 19.4% decline in case count and 19.7% decline in incidence rate compared with 2019. As a result of dedicated efforts to detect, treat, and prevent TB disease in the United States, case counts and incidence rates have steadily decreased since 1992, by 73.1% and 79.1%, respectively. However, the annual rates of decline in case count (19.4%) and incidence rate (19.7%) were substantially greater in 2020 compared with the 2015–2019 annual rates of decline in case count (mean=1.0%; range=3.1% decrease to 1.6% increase) and incidence rate (mean=1.6%; range=3.8% decrease to 0.9% increase) (Table 1), likely as a result of multiple factors associated with the effects of the COVID-19 pandemic.^1,2 In spite of the declines observed in 2020, ongoing concerns about the potential for TB underdiagnosis and public health resource constraints suggest that substantial resources and commitment continue to be necessary to achieve elimination of TB in the United States (defined as <1 case/million annually).^1–4

The National Vital Statistics System reported 526 TB-related deaths (0.2 deaths per 100,000 persons) for 2019, the most recent year for which data are available. This represents a 3.0% decrease in deaths and a 3.4% decrease in mortality rate from 2018. Since 1992, TB-related deaths have declined by 69.1%, and TB-related death rates have declined by 75.9% (Table 1).

As in past years, four states combined reported more than half of all U.S. TB cases in 2020: California (23.8%), Texas (12.3%), New York, including New York City (8.4%), and Florida (5.7%). TB incidence rates (per 100,000 persons) by reporting area were above the national incidence rate in Alaska (7.9), Hawaii (6.5), New York City (5.4), California (4.3), Texas (3.0), New Jersey (2.8), District of Columbia (2.7), and Maryland (2.5). Incidence rates among the U.S. territories ranged from 0.8 (Puerto Rico) to 75.2 (Commonwealth of the Northern Mariana Islands), and among freely associated states ranged from 50.0 (Republic of Palau) to 252.5 (Republic of the Marshall Islands) (Table 28).

Demographics

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Origin of Birth

Because of the substantially greater risk of exposure to TB outside of the United States, origin of birth is the most prominent risk factor for TB in the United States. Between 1993 and 2020, cases of TB have declined by 88.4% (to 2,018 cases) among U.S.-born persons and by 30.8% (to 5,127 cases) among non-U.S.–born persons. Incidence rates have declined since 1993 by 90.3% and 65.7% among U.S.-born and non-U.S.–born persons, respectively. Consistent with previous years, the majority of reported TB cases occurred among non-U.S.–born persons (71.5%) (Table 5).

Among non-U.S.–born persons with TB, the most common countries of birth continue to include Mexico (18.0%), the Philippines (12.5%), India (10.4%), Vietnam (8.2%), and China (5.1%) (Table 6A). These countries of birth also represent substantial proportions of the non-U.S.–born population living in the United States.⁵ Incidence rates per 100,000 persons living in the United States account for the size of the underlying subpopulation by country of birth and give a measure of TB risk in a given subpopulation. Birth countries with the highest U.S. incidence rates (per 100,000 persons) were the Republic of the Marshall Islands (164.2), the Republic of the Congo (120.8), Somalia (81.2), and Myanmar (73.5) (Table 6B).

Among non-U.S.–born persons with TB, the highest percentage of TB diagnoses occurs in the first few years since arrival in the United States. TB risk gradually decreases with time since arrival in the United States, but approximately 1/3 of TB cases among non-U.S.–born persons occur 20 or more years after arrival in the United States.^6,7 In 2020, the percentage of TB cases among non-U.S.–born persons that occurred within one year of arrival in the United States (9.7%) decreased compared with 2019 (13.5%) (Table 6C). Also, in 2020 the percentage of cases by time since arrival in the United States was 17.8% for 1–4 years, 12.6% for 5–9 years, 9.0% for 10–14, 7.4% for 15–19, 8.3% for 20–24, 5.6% for 25–29, 5.9% for 30–34, 4.0% for 35–39, 8.5% for ≥40 years, and 11.4% for an unknown amount of time (Table 19).

Race/Ethnicity

In 2020, non-Hispanic Asian persons continued to represent the largest proportion of persons with TB (35.8%), followed by Hispanic persons (29.7%), non-Hispanic Black persons (19.6%), and non-Hispanic White persons (11.0%) (Table 2). However, the TB incidence rate (per 100,000 persons) remained highest among non-Hispanic Native Hawaiian/Other Pacific Islander persons in 2020 (18.7), and this is the only race/ethnicity group in which the rate did not decrease compared with 2019 (17.5). The second highest incidence rate occurred among non-Hispanic Asian persons (13.3); however, similar to the overall population, the incidence rate for 2020 decreased by 20.2% in this population compared with 2019 (16.6) (Table 2).

Incidence rates (per 100,000 persons) also decreased by 2.9% among non-Hispanic American Indian/Alaska Native persons (3.2 in 2020 compared with 3.3 in 2019), 19.8% among non-Hispanic Black persons (3.4 in 2020 compared with 4.2 in 2019), 21.9% among Hispanic persons (3.5 in 2020 compared with 4.5 in 2019), 22.1% among non-Hispanic White persons (0.4 in 2020 compared with 0.5 in 2019), and 26.1% among persons of more than one race/ethnicity (0.7 in 2020 compared with 0.9 in 2019) (Table 2).

As in past years, the distribution of persons with TB and the incidence rates by race/ethnicity differed markedly in 2020 by origin of birth (Tables 2B, 2C, and 3). Though 35.8% of all U.S. TB cases occurred among non-Hispanic Asian persons, only 4.8% of cases among U.S.-born persons occurred among non-Hispanic Asian persons, and the incidence rates (per 100,000 persons) for non-Hispanic Asian persons were 1.2 among U.S.-born persons compared with 22.1 among non-U.S.–born persons (Tables 2, 2B, and 2C). Among U.S.-born persons, the highest percentage of cases occurred among non-Hispanic Black persons (36.2%), followed by non-Hispanic White persons (28.2%), Hispanic persons (23.7%), and non-Hispanic Asian persons (4.8%) (Table 2B). Approximately half of TB cases reported among non-U.S.–born persons occurred among non-Hispanic Asian persons (48.1%), followed by Hispanic persons (32.0%), non-Hispanic Black persons (13.1%), and non-Hispanic White persons (4.2%) (Table 2C). Since 2003, non-Hispanic Native Hawaiian/Other Pacific Islander persons have experienced a relatively smaller reduction in TB incidence rates compared with other race/ethnicity groups, including a 23.7% decrease (6.5 in 2020 compared with 8.5 in 2003) among U.S.-born persons and a 98.4% increase (33.5 in 2020 compared with 16.9 in 2003) among non-U.S.–born persons (Tables 2B and 2C). Small overall population size estimates among Native Hawaiian/Other Pacific Islander persons often leads to year-to-year variability in incidence rates.

Age

The age distribution among persons with TB has remained relatively steady over time; similar to past years, 95.5% of TB cases in 2020 occurred in persons age ≥15 years (Table 4). Children aged 5–14 years had the lowest TB incidence rate (per 100,000 persons) (0.4) and were the only age group whose incidence rate did not decrease in 2020. Adults aged ≥65 years had the highest TB incidence rate in 2020 (3.4) and experienced the largest percentage decrease (24.3%) compared with 2019 (4.5). Death associated with COVID-19 disproportionately affects older adults;^8,9 increased mortality among older adults in 2020 might have reduced the number of TB cases diagnosed in this age group.

The decreases in incidence rates (per 100,000 persons) for other age groups were 22.5% for 0–4 years (0.9 in 2020 compared with 1.1 in 2019), 18.6% for 15–24 years (1.6 in 2020 compared with 2.0 in 2019), 19.7% for 25–44 years (2.4 in 2020 compared with 3.0 in 2019), and 17.8% for 45–64 years (2.6 in 2020 compared with 3.2 in 2019) (Table 4). Among U.S.-born persons, the highest incidence rates (per 100,000 persons) occurred among those aged ≥65 years (1.0) and 45–64 years (0.9); among non-U.S.–born persons, the highest incidence rates (per 100,000 persons) occurred among those aged ≥65 years (19.4) and 15–24 years (16.2) (Tables 4B and 4C).

Sex and Age

Male persons accounted for 60.6% of TB cases in the United States in 2020 and had a higher incidence rate (2.7 per 100,000) compared with female persons (1.7 per 100,000). Among individuals ≥15 years, male persons accounted for 61.2% of cases; however, among children 0–14 years of age, 46.7% of TB cases occurred in male persons (Table 20). This might indicate that factors associated with increased risk of TB disease (such as homelessness, incarceration, and substance use) disproportionately affect adult men or that migration patterns to the United States differ by sex and age.

Clinical Characteristics

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Primary Reason for Tuberculosis Evaluation

Similar to past years, the majority of U.S. TB cases in 2020 were primarily evaluated for TB because of experiencing TB symptoms (56.7%), followed by abnormal chest radiograph obtained for an indication other than TB symptoms (18.8%), and incidental lab results (9.9%). Active case-finding methods were reported as the primary reason for TB evaluation for 9.5% of TB cases, including investigation of close contacts to an infectious TB case (4.3%), evaluation during targeted testing of groups expected to have elevated prevalence of TB infection (3.5%), immigrant medical examinations (1.1%), administratively required testing for employment (other than health care personnel), school admission or other similar purposes (0.4%), or testing for health care personnel (0.2%) (Table 36). In 2019, CDC updated recommendations for screening and testing of U.S. health care personnel for TB based on recent evidence suggesting that U.S. health care personnel were not at increased risk for TB compared with the general population.^10,11 Routine serial testing of U.S. health care personnel in the absence of TB exposure or ongoing transmission is no longer recommended, but other screening and testing strategies continue to be recommended, including individual baseline (preplacement) risk assessment and symptom evaluation, testing of health care personnel without prior TB or latent TB infection, and annual symptom screening for health care personnel with untreated latent TB infection.

Case Verification Criteria

U.S. TB cases are verified based on the following laboratory testing hierarchy: positive culture, positive nucleic acid amplification test (NAAT) (when culture results are unavailable or negative), or positive acid-fast bacilli (AFB) smear (only when valid culture results are unavailable). For example, cases that were initially verified using nucleic acid amplification testing but subsequently confirmed via positive culture are reported as verified by culture. TB cases may also be verified using prespecified clinical criteria for cases not able to be verified through laboratory testing (Appendix A). Additionally, CDC will accept and count TB case reports based on a health care provider’s diagnosis of TB disease (provider diagnosis), even if the case does not otherwise meet the national surveillance case definition for TB (Appendix B). Since 1993, the large majority of U.S. TB cases have been verified through positive culture (range=75.8%–80.9%); in 2020, 79.3% of cases were verified through positive culture. Cases that are culture-negative but verified by positive NAAT or that are missing valid culture results but have a positive AFB smear continue to account for a small percentage of TB cases in 2020 (2.8% and 0.4%, respectively). In 2020, 13.1% of cases were verified based on the prespecified clinical criteria in the national surveillance case definition, and 4.3% were reported based on provider diagnosis alone (Table 7).

Site of Disease

TB most commonly affects the lungs but can cause disease in any part of the body. Similar to previous years, 78.9% of U.S. TB cases had pulmonary involvement (Table 7). Among the 21.1% of U.S. TB cases with only extrapulmonary involvement, the most common sites affected were the lymphatic system (35.3%), pleura (15.7%), and bones and joints (9.2%) (Tables 7 and 15). TB meningitis, a particularly serious form of the disease, accounted for 4.0% of extrapulmonary only cases (Table 15).

TB Treatment and Drug Resistance

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Effective TB treatment includes providing multiple anti-TB drugs over a sufficient period of time to cure the patient, prevent development of drug resistance, and minimize the risk of transmission to others. The most common initial treatment regimen for drug-susceptible TB, and in situations where drug-susceptibility is unknown, includes isoniazid, H; rifampin, R; pyrazinamide, Z; and ethambutol, E (HRZE).¹²

Among persons alive at diagnosis with initial drug regimen information available in 2020, 83.3% began treatment with HRZE. An additional 10.7% began treatment with a four-drug regimen other than HRZE, 0.9% received no initial drug therapy, and 0.1% were started on one drug (Table 10). Four-drug initial regimens other than HRZE can be clinically appropriate if resistance or one of more of the drugs in the HRZE regimens is known or suspected, or if there are other clinical contraindications to using HRZE. Accordingly, the vast majority (94.0%) of TB patients alive at diagnosis reported in the United States are likely to have received appropriate initial TB therapy.

Anti-TB drug resistance is a concern in the United States and globally. Resistance to isoniazid, one of the most common anti-TB drugs, can be a precursor to multidrug-resistant (MDR) TB, which is defined as resistance to at least isoniazid and rifampin. For the purposes of this report, extensively drug resistant TB is defined as resistance to isoniazid and rifampin, plus any fluoroquinolone and at least one injectable second-line drug. During 2020, isoniazid resistance at initial diagnosis was reported for 456 cases in the United States, including 4.8% of cases among U.S.-born persons and 9.5% of cases among non-U.S.–born persons (Table 8). MDR TB at initial diagnosis was reported for 56 cases, including 0.2% of cases among U.S.-born persons and 1.3% of cases among non-U.S.–born persons (Table 9). Extensively drug-resistant TB continues to be rare in the United States, with only 1 case reported in 2020. Stringent guidelines for TB treatment in the United States, including diligent follow-up efforts by public health personnel, greatly reduce the risk of developing drug-resistant TB.

Directly Observed Therapy and Completion of Treatment

Directly observed therapy (DOT) is a case management strategy that involves direct observation of a patient ingesting anti-TB medications by a trained individual to ensure patients adhere to their prescribed therapy. DOT is a critical component of efforts to avoid development of drug-resistant TB and to achieve completion of TB therapy. For cases reported in 2018, the most recent year for which data are available, anti-TB therapy was administered using exclusively DOT for 61.3% of patients, and 33.7% received anti-TB therapy with a combination of DOT and self-administered therapy (Table 10).

Successful completion of TB therapy is important to prevent TB recurrence and drug resistance, and TB treatment completion remained relatively steady for cases reported in 2018, the most recent year for which data are available. Among all persons diagnosed with TB during 2018 who were alive at diagnosis and taking one or more TB medications, 87.4% completed treatment (Table 12). Reasons for not completing treatment include the patient dying before treatment could be completed (6.6%), loss to follow-up before documenting completion of treatment (1.4%), patient deciding to discontinue treatment prior to completion against medical advice (i.e., refusal) (1.0%), stopping TB treatment because of an adverse treatment event (0.3%), and other or unknown/unreported reasons (3.3%) (Table 12). An uncomplicated course of treatment for drug-susceptible TB takes about 6 months to complete; however, drug resistance or other factors can require treatment for >1 year. Among patients eligible to complete TB treatment within 1 year, 89.1% completed treatment within 1 year and 95.5% ever completed TB treatment (Table 10).

Risk Factors

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Comorbid Conditions

Medical conditions that weaken the immune system can increase the risk for TB. Among all persons with TB in 2020, almost half (44.4%) reported none of the medical risk factors for TB that are collected in NTSS (Table 23). Diabetes mellitus (22.5%) remains the most commonly reported medical risk factor for TB and is proportionately more common among non-U.S.–born persons (25.8%) than U.S.-born persons (14.3%) (Table 23 and Table 35).

Coinfection with human immunodeficiency virus (HIV) is a major risk factor for progression of latent TB infection to TB disease. Among persons with TB in 2020 who were alive at diagnosis, HIV status was known for 89.8%, and 4.8% of persons with known HIV status were coinfected with HIV. Among TB patients with known HIV status, HIV coinfection occurred for 8.0% of persons aged 25–44 years and 5.9% of persons aged 45–64 years (Table 11).

An immunocompromising condition other than HIV was reported for 9.2% of cases, including 9.8% among U.S.-born persons and 9.0% among non-U.S.–born persons. Having been a known contact of a person with infectious TB was reported for 7.4% of cases, including 15.8% among U.S.-born persons and 4.2% among non-U.S.–born persons (Table 23).

Congregate Settings

Living in congregate settings, including homeless shelters, correctional facilities, and long-term–care facilities, is a risk factor for TB because shared airspace can facilitate TB exposure and transmission. Among persons aged ≥15 years with TB in 2020, 290 (4.3%) reported experiencing homelessness within the 12 months preceding TB diagnosis (Table 38). This compares with 383 (4.6%) of TB cases in 2019 among persons aged ≥15 years with reported homelessness in the past year.⁶

Current residents of correctional facilities represented 2.6% of TB cases among persons aged ≥15 years. Among those cases, 10.1% were in residents of federal prisons, 25.1% in residents of state prisons, 22.9% in residents of local jails, and 39.1% in other facilities. Of the TB cases diagnosed in correctional facility residents with information about U.S. Immigration and Customs Enforcement (ICE) custody, including facilities operated by ICE or among persons otherwise in ICE custody, 29.8% occurred among persons who were in ICE custody (Table 37).

During 2020, 1.7% of TB cases were diagnosed among current residents of long-term–care facilities aged ≥15 years (Table 39).

Substance Use

Substance use is also a TB risk factor. The most commonly reported type of substance use during the year preceding diagnosis among persons with TB aged ≥15 years was excess use of alcohol (9.0%), followed by noninjection drug use (6.9%), and injection drug use (1.1%) (Table 40, Table 41, and Table 42).

Case Outcome

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Among all TB cases diagnosed during 2018, a total of 801 (8.9%) patients died, with 281 (35.1%) of those deaths attributed to TB disease or TB treatment. Of the 801 deaths, 197 (24.6%) were dead at the time of TB diagnosis; 33.0% of those deaths were attributed to TB. The remaining 604 (75.4%) deaths occurred after diagnosis, of which 35.8% were attributed to TB (Table 13).

Time required for a patient’s positive sputum culture to convert to negative is an indicator of treatment effectiveness. Among 5,087 cases during 2018 with positive sputum cultures, 4,459 (87.7%) had documented sputum culture conversion to negative. Among the 584 (11.5%) cases for which sputum culture conversion was undocumented, the most common reason was that the patient had died (38.5%) before sputum culture conversion (Table 14).

Molecular Surveillance

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Genotype Clusters

TB genotyping uses laboratory methods to characterize a small portion of the mycobacterial genome, detect strain variations, and designate isolates from culture-positive cases as having particular genotypes. The number of reported TB cases with a genotype declined from 6,966 in 2019 to 5,551 in 2020, a 20.3% reduction mirroring overall case count declines. However, similar to previous years, 97.5% of culture positive cases were associated with a genotype in 2020 (Table 16). Clusters of TB cases with matching genotypes are an indication of possible recent TB transmission. In this report, a TB case is clustered if it had a matching genotype with one or more other cases in the same county or county-equivalent area during the 3-year period of 2018–2020. For this time period, 19.0% of TB cases were clustered. The highest percentages of genotype-clustered cases continue to be observed among American Indian/Alaska Native persons (53.4%) and Native Hawaiian/Other Pacific Islander persons (51.4%) (Table 24). Hispanic or Latino persons (n=1,230) and non-Hispanic Black persons (n=958) represented the highest number of clustered cases. The number of county-based clusters declined from 1,351 in last year’s report⁶ (cases reported nationally during 2017–2019) to 1,280 clusters for the 2018–2020 time period, a 5.3% reduction. Genotype clusters are additionally characterized by alert level (non-alert, medium alert, and high alert), representing the degree of spatial concentration of cases within the same county or county-equivalent area as compared with the concentration of the genotype in the nation overall. For 2018–2020, 38.5% of clustered cases were included in clusters that were classified as either medium or high alert, which are reviewed by DTBE for possible programmatic follow-up (Table 24). American Indian/Alaska Native persons had the highest percentage of genotyped cases in medium or high alert clusters (90%).

Estimates of Recent Transmission

CDC uses genotyping data to estimate the number of TB cases that are attributed to recent transmission. Estimates are based on whether a TB case has a plausible source case with a matching genotype in a TB patient who resides within ≤10 miles and who was diagnosed ≤2 years prior to the case.¹³ The number of cases attributed to recent transmission declined by 10.8%, from 1,712 in 2017–2018 to 1,527 during 2019–2020. However, the 12.5% of genotyped cases attributed to recent transmission during 2019–2020 is comparable to the previous 2-year period 2017–2018 (12.6%). While estimates of recent transmission vary across reporting areas, all but seven reporting areas had at least one case reported in 2019–2020 that was attributed to recent transmission (Table 57).

Cases that are attributed to recent transmission are further assessed for whether they belong to a plausible chain of transmission of ≥6 cases within a 3-year time period. If the case meets these criteria, it is additionally attributed to extensive recent transmission. Nationally, 502 (4.1%) genotyped cases reported in 2019–2020 were attributed to extensive recent transmission, compared with 589 (4.3%) genotyped cases for 2017–2018.

Although 71.5% of reported TB cases were among non-U.S.–born persons during 2019–2020 (Table 5), 54.7% of cases attributed to recent transmission and 59.4% of cases attributed to extensive recent transmission were among U.S.-born persons (Table 59). Notably, the percentage of cases attributed to both recent transmission and extensive recent transmission have increased in 2019–2020 compared with 2017–2018 in some populations at increased risk for TB. Among persons with TB disease who reported injection drug use during 2019–2020, 33.3% and 13.2% were attributed to recent transmission and extensive recent transmission, respectively; in the previous 2-year period the percentages were 20.5% and 6.0%. Among cases in persons incarcerated at the time of TB evaluation during 2019–2020, 21.0% and 14.6% were attributed to recent transmission and extensive recent transmission, respectively, compared with 15.8% and 6.3% in the previous 2-year period.

Disparities in the estimated percentage of cases attributed to recent transmission and extensive recent transmission persist among certain racial/ethnic groups. The percentage of recent transmission is highest among American Indians/Alaska Native persons and was 40.4% in 2017–2018¹⁴ compared with 44.6% in 2019–2020. Among Native Hawaiian/Other Pacific Islander persons, the percentage of cases attributed to recent transmission was 23.9% in 2017–2018¹⁴ compared with 34.2% in 2019–2020, and the percentage of cases attributed to extensive recent transmission was 7.1% in 2017–2018¹⁴ compared with 19.0% in 2019–2020. In contrast, both estimates of recent transmission were lower among non-Hispanic Black persons in 2019–2020 (Table 59).

Conclusion

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In 2020, reported TB cases and incidence rates in the United States declined substantially. Before 2020, TB in the United States had been declining steadily since the early 1990s, but the annual rate of decline was inadequate to achieve TB elimination in this century. The mechanisms for the 20% decline in TB cases in 2020 remain under investigation. The COVID-19 pandemic has likely affected TB incidence in the United States in several ways, including a combination of TB underdiagnosis and a true reduction in incidence.¹

The decline in TB in 2020 was widespread across race/ethnicity, origin of birth, age, and geographic region, and TB continues to disproportionately affect some U.S. populations, particularly people from racial and ethnic minority groups. TB incidence rates remained steady or decreased compared with 2019 for all racial and ethnic groups, but incidence rates are 1.7–46.8 times higher among persons from racial and ethnic minority groups compared with non-Hispanic White persons (Table 2). Racial and ethnic minorities continue to be disproportionately represented in genotype clusters and estimates of recent transmission. The majority of TB cases continue to occur among non-U.S.–born persons, and 9.7% of cases among non-U.S.–born persons occurred within one year of arrival in the United States (Table 6C). The percentage of cases diagnosed within 1 year of arrival decreased from 13.5% in 2019 to 9.7% in 2020, while the percentage of cases diagnosed 20 years or more after arrival in the United States increased from 30.1% in 2019 to 32.2% in 2020 (Table 6C).

Though a steep reduction in disease incidence, as seen in 2020, might initially appear to be a cause for celebration, the decline is unlikely to be sustained over time if it is largely a result of underdiagnosis or reduced migration. Timely TB diagnoses save lives and prevent further community transmission. To accelerate progress towards TB elimination, CDC supports renewed commitments to ensuring timely implementation of fundamental TB control strategies, including cases detection, contact tracing, and targeted testing and treatment.