Technical Notes

Introduction

Information in the 2023 edition of Reported Tuberculosis in the United States summarizes incident cases of tuberculosis (TB) reported to Centers for Disease Control and Prevention's (CDC) National Tuberculosis Surveillance System (NTSS) by each of the 50 U.S. states and the District of Columbia (D.C.) unless otherwise specified. In addition to the 50 U.S. states and D.C., 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. Some jurisdictions require reporting of latent TB infection, a related condition in which TB bacteria live in the body without making a person sick. However, latent TB infection is not required to be reported to CDC, so this report focuses exclusively on cases of TB disease reported to NTSS.

About the data

National Tuberculosis Surveillance System

Reporting areas (i.e., the 50 U.S. states, D.C., New York City, Puerto Rico, and other U.S. jurisdictions in the Pacific Ocean and Caribbean Sea) provide information about TB cases to the NTSS by using a standard case report format, the Report of Verified Case of TB (RVCT).

All reporting jurisdictions implemented a revised RVCT for the first time in 2023. CDC expects minor fluctuations in data quality and completeness while reporting jurisdictions are adjusting to the revised RVCT. A known issue reflected in this year's annual report is a potentially higher number and percentage of persons identifying as "multiple race" in 2023 as a result of changes in data transmission for race and ethnicity data.

TB cases are verified according to the TB case definition for public health surveillance (Appendix A). TB cases are reported and counted according to the recommendations for reporting and counting TB cases (Appendix B).

TB case definition

The current TB surveillance case definition was adopted by the Council of State and Territorial Epidemiologists in 2009. TB cases are verified according to the following specified laboratory and clinical criteria (Appendix A).

Laboratory criteria for diagnosis

A TB case may be verified by the laboratory case definition with ≥1 of the following criteria: (1) isolation of Mycobacterium tuberculosis complex from a clinical specimen; or (2) demonstration of M. tuberculosis complex from a clinical specimen by nucleic acid amplification (NAA) test; or (3) demonstration of acid-fast bacilli (AFB) in a clinical specimen when a culture has not been or cannot be obtained or is falsely negative or contaminated.

Clinical case criteria

A TB case may be verified by the clinical case definition in the presence of all of the following clinical criteria: (1) a positive tuberculin skin test (TST) result or positive interferon-gamma release assay (IGRA) result for M. tuberculosis complex; and (2) other signs and symptoms compatible with TB (e.g., abnormal chest radiograph, abnormal chest computerized tomography [CT] scan, or other chest imaging study or clinical evidence of current disease); and (3) treatment with ≥2 anti-TB drugs; and (4) a completed diagnostic evaluation.

Provider diagnosis

Provider diagnosis is not a component of the case definition for TB as described in Appendix A. However, when cases of TB are diagnosed but do not meet either the clinical or laboratory case definition, reporting areas have the option of verifying TB cases on the basis of provider diagnosis as described in Appendix B.

TB case verification criteria calculation

The software for TB surveillance developed by CDC includes a calculated variable for TB case verification called "VERCRIT."

VERCRIT is calculated by using the following criteria in hierarchical order (beginning with the most preferred method of verification):

1. Positive culture,
2. Positive NAA test,
3. Positive AFB,
4. Clinical case confirmation, or
5. Provider diagnosis.

Reporting and counting of TB cases

TB cases that are verified but not countable for morbidity statistics should still be reported to CDC as a measure of programmatic and case management burden. However, data for noncountable TB cases are not included in this report.

Immigrant and refugee populations, and non-U.S.–born visitors examined after arriving in the United States and receiving a diagnosis of TB disease requiring TB treatment should be reported and counted by the locality of their residence at the time the diagnostic evaluation for TB began. Persons residing in the United States ≥90 consecutive days (inclusive of report date) who are medically evaluated or treated for TB while in the United States should be reported and counted by the locality where the diagnostic evaluation for TB began.

RVCT versions

In 2020, CDC published updates to the RVCT. This updated version, known as the “2020 RVCT,” includes items that are either new or revised from the previous RVCT that was published in 2009, known as the “2009 RVCT.” Since 2020, reporting areas have been gradually implementing the 2020 RVCT; in 2023, all reporting jurisdictions fully implemented the 2020 RVCT for the first time.

The instructions for completing the 2020 RVCT are available in the 2020 RVCT instruction manual.1

Tabulation and presentation of TB data

This report presents summary data for TB cases counted by reporting areas through the end of 2023. TB cases are tabulated by year in which a reporting area verified a TB case and included it in its official annual TB case count. Since 2004, the published report has reflected updated information about the numbers of confirmed TB cases for each year from 1993 onward. U.S. totals include data from the 50 U.S. states and D.C.

Trend data are presented in Tables 1–22. Age-group tabulations are based on a person's age during the month and year reported to the health department as having a presumptive TB case. State tabulations are based on a person's reported residence. Percentages and rates are calculated using unrounded numbers.

Origin of birth

CDC uses U.S. Census Bureau definitions for national origin. Persons are U.S.-born if they were entitled to U.S. citizenship at birth, i.e., they were born in the United States, certain U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, and Commonwealth of the Northern Mariana Islands) or elsewhere to at least one U.S. citizen parent (with certain minor exceptions). All other persons are categorized as non-U.S.–born.2

Rates

Rates are expressed as the number of cases reported each calendar year per 100,000 persons. Percentage change in all TB rates is calculated with unrounded figures. Percentage change results are reported to one decimal. Population denominators used in calculating TB rates are based on official census and midyear postcensal estimates from the U.S. Census Bureau. In Table 1, the U.S. total populations for 1990–1999 are taken from the Bridged-Race Intercensal Population Estimates for July 1, 1990–July 1, 1999: Single-year of age State estimates;3 populations for 2000–2009 are taken from the U.S. Census Intercensal Estimates of the Resident Population for the United States, Regions, States, and Puerto Rico for April 1, 2000–July 1, 2010;4 populations for 2010–2019 are taken from the U.S. Census Annual Estimates of the Resident Population for the United States, Regions, States, and Puerto Rico: April 1, 2010 to July 1, 2020;5 and populations for 2020 through 2023 are taken from the U.S. Census Annual Estimates of the Resident Population for the United States, Regions, States, and Puerto Rico for April 1, 2020 to July 1, 2023.6

During 2003, two modifications were made to the RVCT form: (1) multiple race entries (≥2 races reported for a person) were allowed, and (2) the previous category of "Asian or Pacific Islander" was divided into "Asian" and "Native Hawaiian or Other Pacific Islander." In 2023, "Other" race entries were allowed as a selection in the 2020 RVCT.

To calculate rates for Table 3 and Table 6, denominators for 1993–1999 were obtained from the U.S. Census Monthly Postcensal Resident Population, by single year of age, sex, race, and Hispanic origin.7 For 2000–2009, denominators for Table 3 were obtained from U.S. Census Intercensal Estimates of the Resident Population by Sex, Race, and Hispanic Origin for the United States: April 1, 2000–July 1, 2010,8 and denominators for Table 6 were obtained from Intercensal Estimates of the Resident Population by Single Year of Age and Sex for States and the United States: April 1, 2000–July 1, 2010.8 For 2010–2019, denominators for Table 3 were obtained from the U.S. Census Monthly National Population Estimates by Age, Sex, Race, Hispanic Origin, and Population Universe for the United States: April 1, 2010 to December 1, 2020,9 and denominators for Table 6 were obtained from U.S. Census Annual Estimates of the Resident Population by Single Year of Age and Sex for the United States: April 1, 2010 to July 1, 2020.9 For 2020–2023, denominators for Table 3 were obtained from the U.S. Census Annual Estimate of the Resident Population by Sex, Race, and Hispanic Origin for the United States: April 1, 2020 to July 1, 2023,10 and denominators for Table 6 were obtained from the U.S. Census Annual Estimates of the Resident Population by Single Year of Age and Sex for the United States: April 1, 2020 to July 1, 2023.10

The population source for nativity is the Current Population Survey,11 which is used to calculate case rates for U.S.-born and non-U.S.–born persons with diagnosed TB. U.S.-born populations include persons born in the 50 states and D.C., those born abroad to U.S. parents, and those born in U.S. certain territories. To compute rates for Table 9, the population denominators for U.S.-born and non-U.S.–born persons for 1993 were obtained from Quarterly Estimates of the United States Foreign-Born and Native Resident Populations: April 1, 1990–July 1, 1999,12 and for 1994–2023 were obtained from U.S. Census Bureau's MDAT tool.13 Denominators for computing 2023 rates in Table 23 were obtained from the U.S. Census Bureau's MDAT tool.13

Four trend tables with case rates were originally created for the 2020 Annual TB Report using data from 1994 and onward. Tables 4 and 5 report the trends of race-ethnicity among U.S.-born persons (Table 4) and non-U.S.–born persons (Table 5). Tables 7 and 8 report trends for different age groups among U.S.-born persons (Table 7) and non-U.S.–born persons (Table 8). Denominators for these tables were obtained from the U.S. Census Bureau's MDAT tool.13

Mortality data

The annual mortality rate is calculated as the number of deaths caused by TB in that year, divided by the estimated population for the year, multiplied by 100,000 (Table 1). The number of deaths was obtained from CDC's National Center for Health Statistics, Multiple Cause of Death Files, 1999–2022,14 available from CDC's WONDER online database. Finalized 2023 TB-related death data were unavailable at the time of publication.

Initial reason evaluated for TB

Table 34 reflects the 2020 RVCT variable, Initial Reason Evaluated for TB, which modified the Primary Reason Evaluated for TB Disease in the 2009 RVCT. During 2020–2022, TB cases were submitted in either the 2009 or 2020 RVCT versions. In 2023, all cases were submitted in the 2020 RVCT version. The 2009 RVCT responses Targeted Testing, Health Care Worker, Employment/Administrative Testing, and Immigration Medical Exam were combined into the 2020 RVCT Screening response. Initial reasons for evaluation related to an Incidental Lab Result or Abnormal Chest Radiograph were combined into the Other category.

Isoniazid (INH) drug-resistant and multidrug-resistant (MDR) TB disease

Organisms resistant to one of the most common anti-TB drugs, isoniazid (INH), cause INH-resistant TB disease. Multidrug-resistant (MDR) TB disease is caused by an organism that is resistant to at least isoniazid and rifampin. In Tables 12–14, INH-resistant and MDR cases are displayed by year and stratified by a patient’s history of previous TB disease.

Starting in 2023, information on drug resistance included results of molecular drug susceptibility testing in addition to growth-based susceptibility testing for isoniazid and rifampin. An isolate was considered resistant to isoniazid or rifampin if either the growth-based test or molecular test detected resistance.

Persons who are current or former smokers

The numbers and percentages of reported cases of persons who are current or former smokers are displayed in Table 35. The variable "current or former smokers" includes persons with TB who currently use tobacco every day, use tobacco some days (but not every day), were smokers (or tobacco users) but current status is unknown, or have smoked tobacco (or nicotine) at least 100 times in their lifetime and have quit. The data exclude persons with TB who have not smoked at least 100 times in their lifetime or whose tobacco history is not known. Smoking includes consumption of tobacco (or nicotine) through combustible tobacco product or electronic nicotine delivery systems. It does not include chewing tobacco or smoking of substances other than tobacco.

TB therapy

The percentages of reported cases for persons with initial drug regimen information and who are alive at diagnosis are displayed in Table 15. The method of administration for drug therapies are displayed in Table 16 for persons on an initial drug therapy with at least one drug.

Extensively drug-resistant (XDR) and pre-XDR TB disease

In 2021, CDC adopted new definitions of extensively drug-resistant (XDR) and pre-XDR TB disease. Pre-XDR TB disease is caused by an organism that is resistant to isoniazid, rifampin, and a fluoroquinolone or by an organism that is resistant to isoniazid, rifampin, and a second-line injectable drug (amikacin, capreomycin, and kanamycin). XDR TB disease is caused by an organism that is resistant to isoniazid, rifampin, a fluoroquinolone, and a second-line injectable drug (amikacin, capreomycin, and kanamycin) or by an organism that is resistant to isoniazid, rifampin, a fluoroquinolone, and bedaquiline or linezolid.15

Completion of therapy (COT)

Date and reason therapy was stopped (e.g., the person with TB completed therapy, or the person died) are collected in the RVCT with a 2-year lag and were used to calculate COT percentages. Cases were stratified by the indicated length of therapy, based on American Thoracic Society, CDC, and Infectious Diseases Society of America treatment guidelines in effect during the period covered and the person's initial drug-susceptibility test results, age, and disease site.16

In Table 17, the first column lists the total number of cases eligible to complete treatment within one year reported by year and the remaining columns are grouped under two headings: persons reported as having completed therapy and persons who did not complete therapy. Persons eligible to complete therapy in ≤1 year were alive at time of diagnosis and were initiated on therapy with ≥1 drug. Eligible persons did not have rifampin resistance; did not die in ≤1 year after initiating therapy; did not move out of the country in ≤1 year after initiating therapy; and did not have meningeal TB, bone or joint TB, or TB of the central nervous system, regardless of age. Additionally, persons aged 0–14 years old with TB were ineligible to complete therapy in ≤1 year if they had disseminated disease (defined for this report as miliary TB, a positive TB blood culture, or a positive NAA test on a blood specimen). Persons with culture-negative disease, those with an unknown culture status, and those with culture-positive disease but unknown initial drug-susceptibility test results were included under the category of therapy of ≤1 year indicated. COT percentages, regardless of duration, were calculated by dividing the number of persons reported as having completed therapy by the number of total eligible persons.

For the group that completed therapy, the percentage of cases are displayed for COT regardless of duration (i.e., duration of therapy ≤1 year or >1 year or duration unknown). For COT ≤1 year, the numerator included only those persons completing therapy in ≤366 days based on the dates therapy was started and stopped. Persons with missing dates were classified as "duration unknown" for this calculation.

For the group that did not complete therapy, the percentage of cases are displayed for all persons with an outcome other than completed therapy (i.e., moved, lost to follow-up, refused treatment, or other). Persons with an unknown outcome were also classified as "did not complete therapy."

Miliary disease

Miliary disease should be reported as a pulmonary form of TB (Table 20). Beginning in 2009, miliary disease was classified as a TB disease site because of the understanding that it is a clinical or a radiologic finding. As such, it should be recorded under Initial Chest Radiograph, Initial Chest CT Scan, or Other Chest Imaging Study as noted in the 2020 RVCT Instruction Manual.

National Tuberculosis Molecular Surveillance Center

In 2018, National Tuberculosis Molecular Surveillance Center (NTMSC) began whole-genome sequencing (WGS)-based genotyping, which assigns Mycobacterium tuberculosis complex (MTBC) isolates a whole-genome multilocus sequence type (wgMLST). Effective June 30, 2022, WGS-based genotyping superseded earlier methods reported for TB surveillance.

Genotype clustering

For this report, a genotype cluster comprises ≥2 cases that have M. tuberculosis complex isolates with matching genotype in a single county or county-like jurisdiction within a 3-year period. Cases that are part of the same genotype cluster are likely to be related by TB transmission in some way; however, the cases might not be directly related (i.e., one person did not necessarily transmit M. tuberculosis to another person in the cluster) or recently related (i.e., both persons might have contracted TB from the same person, but the exposure might have happened years ago).

Mycobacterium bovis

For culture-confirmed TB cases that have been genotyped, Mycobacterium bovis has been defined for this report on the basis of spoligotyping results or WGS. Since 2018, M. bovis has been defined using WGS-based lineage. During 2004–2017, the spoligotype-based definition for M. bovis required either (1) the absence of spoligotyping spacers 3, 9, 16, and 39–43; the presence of ≥1 of the spacers 29–32; and the presence of ≥1 of the spacers 33–36; (2) the absence of spacers 3, 9, 16, and 39–43 and ≥2 copies of the repeated sequence at MIRU-VNTR locus 24 (i.e., loci 2687);17 or (3) determination based on microbiologic expertise (Table 21). Data reported since 2004 exclude cases of bacillus Calmette-Guérin M. bovis, defined as spoligotype 676773777777600 with x, y, or z in the second MIRU-VNTR position or WGS-based lineage.

Recent transmission

In this report, recent transmission estimates are not available pending validation of the recent transmission algorithm using the WGS-based wgMLSType genotyping methods. During 2011–2021, CDC used data from conventional genotyping to estimate the number and percentage of TB cases that were attributed to recent transmission.

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