Tuberculosis — United States, 2017

Rebekah J. Stewart, MSN, MPH; Clarisse A. Tsang, MPH; Robert H. Pratt; Sandy F. Price; Adam J. Langer, DVM

Disclosures

Morbidity and Mortality Weekly Report. 2018;67(11):317-323. 

In This Article

Abstract and Introduction

Introduction

In 2017, a total of 9,093 new cases of tuberculosis (TB) were provisionally* reported in the United States, representing an incidence rate of 2.8 cases per 100,000 population. The case count decreased by 1.8% from 2016 to 2017, and the rate declined by 2.5% over the same period. These decreases are consistent with the slight decline in TB seen over the past several years.[1] This report summarizes provisional TB surveillance data reported to CDC's National Tuberculosis Surveillance System for 2017 and in the last decade. The rate of TB among non–U.S.-born persons in 2017 was 15 times the rate among U.S.-born persons. Among non–U.S.-born persons, the highest TB rate among all racial/ethnic groups was among Asians (27.0 per 100,000 persons), followed by non-Hispanic blacks (blacks; 22.0). Among U.S.-born persons, most TB cases were reported among blacks (37.1%), followed by non-Hispanic whites (whites; 29.5%). Previous studies have shown that the majority of TB cases in the United States are attributed to reactivation of latent TB infection (LTBI).[2] Ongoing efforts to prevent TB transmission and disease in the United States remain important to continued progress toward TB elimination. Testing and treatment of populations most at risk for TB disease and LTBI, including persons born in countries with high TB prevalence and persons in high-risk congregate settings,[3] are major components of this effort.

Health departments in the 50 states and the District of Columbia electronically report to CDC verified TB cases that meet the CDC and Council of State and Territorial Epidemiologists' surveillance case definition. Reported data include the patient's country of birth, self-identified race and ethnicity (i.e., Hispanic or non-Hispanic), human immunodeficiency virus (HIV) status, drug-susceptibility test results, and information on risk factors, including homelessness§ and residence in a congregate setting (i.e., long-term care or correctional facility). Persons of Hispanic ethnicity might be of any race; non-Hispanic persons are categorized as Asian, black, white, American Indian/Alaska Native, Native Hawaiian or other Pacific Islander, or of multiple races. A U.S.-born person is defined as a person who was eligible for U.S. citizenship at birth, regardless of the actual place of birth. CDC calculates overall national and state TB rates using U.S. Census Bureau population estimates and by racial/ethnic group and national origin using population denominators from the bureau's Current Population Survey. Yearly case counts and rates were compared overall and by origin of birth and race/ethnicity. Annual percent changes between years were calculated to compare differences in case counts and rates over time. Drug-susceptibility testing results were reported from culture-confirmed cases in 2016, the most recent year for which complete TB drug-susceptibility data were available.

State-specific TB rates (cases per 100,000 persons) ranged from 0.3 in Montana to 8.1 in Hawaii (Table 1) with a median state TB rate of 1.8. As has been the case for the past decade, four states (California, Florida, New York, and Texas) reported half of the total TB cases in the United States in 2017. The annual percent change in rate in recent years has slowed from an average decline of 5.3% during 2010–2013 to an average decline of 2.0% during 2014–2017. In 2017, a total of 6,346 (69.8%) of U.S. TB cases occurred among non–U.S.-born persons, 2,698 (29.7%) cases occurred among U.S.-born persons, and 49 (0.5%) occurred among persons with no reported national origin. The TB rate among non–U.S.-born persons (14.6) was 15 times the rate among U.S.-born persons (1.0) (Figure). Although these rates represent decreases among both groups in 2017 compared with 2016, the rate among U.S.-born persons declined 7.0%, whereas that among non–U.S.-born persons declined 0.9%.

Figure.

Number of tuberculosis (TB) cases and rate, by national origin — United States, 2008–2017

Among non–U.S.-born persons, the highest TB rate among all racial/ethnic groups occurred among Asians (27.0 per 100,000 persons), followed by blacks (22.0) (Table 2). As in previous years, in 2017, the top five countries of birth of non–U.S.-born persons with TB were Mexico (1,204; 19.0% of all non–U.S.-born persons with TB), Philippines (783; 12.3%), India (595; 9.4%), Vietnam (526; 8.3%), and China (400; 6.3%). Persons who received a diagnosis of TB ≥10 years after arriving in the United States accounted for 2,854 (45.0%) of all TB cases among non–U.S.-born persons.

Among U.S.-born persons in 2017, a total of 1,001 (37.1%) TB cases were reported among blacks, and 797 (29.5%) among whites, representing a 55% decrease in case count for each group in the past decade. The highest TB rate among U.S.-born persons was reported among Native Hawaiians and other Pacific Islanders (6.5), followed by American Indians and Alaska Natives (3.7), blacks (2.8), Asians (2.0), Hispanics (1.5), and whites (0.4).

In 2017, 388 (4.3%) TB cases were reported among persons experiencing homelessness in the year preceding diagnosis, 148 (1.6%) among persons residing in a long-term care facility at the time of diagnosis, and 266 (3.0%) among persons confined in a correctional facility at the time of diagnosis. Although cases among U.S.-born persons accounted for <30% of total TB cases in the United States, they accounted for 61.1% among those reporting homelessness, 44.6% among those in long-term care facilities, and 39.5% among persons incarcerated at the time of diagnosis. HIV status was known for 86.3% of TB cases reported in 2017; among those cases, 5.6% had coinfection with HIV.

Drug susceptibility testing results were reported for 98.3% of culture-confirmed cases in 2016. Among all 9,256 cases reported in 2016, 97 (1.0%) were multidrug-resistant (MDR) TB, including 78 (80.4%) cases with primary MDR TB,** 18 (18.6%) with a prior history of TB, and one (1.0%) with an unknown history of previous TB diagnosis. Among the 97 MDR TB cases in 2016, 89 (91.8%) occurred among 6,355 non–U.S.-born persons, accounting for 1.4% of all TB cases among non–U.S.-born persons. One case of extensively drug-resistant†† TB was reported in a non–U.S.-born person.

*This report is limited to National Tuberculosis Surveillance System case reports verified as of February 12, 2018. Updated data will be available in CDC's annual TB surveillance report later this year.
Appendix A, page 137, Report of Verified Case of Tuberculosis (RVCT) Instruction Manual. https://www.cdc.gov/tb/programs/rvct/instructionmanual.pdf.
§Homelessness is defined as a lack of fixed, regular, and adequate nighttime residence at any time during the 12 months preceding TB diagnostic evaluation and a primary nighttime residence that is either a shelter, an institution that provides temporary residence for persons intended to be institutionalized, or a public place not designated for, or ordinarily used as, a regular sleeping accommodation for human beings. A homeless person may also be defined as a person without a home or in an unstable housing situation. Pages 85–86, Report of Verified Case of Tuberculosis (RVCT) Instruction Manual. https://www.cdc.gov/tb/programs/rvct/instructionmanual.pdf.
U.S. Census Bureau Population and Housing Unit Estimates Tables; https://www.census.gov/programs-surveys/popest/data/tables.html and Current Population Survey; https://www.census.gov/programs-surveys/cps.html.
**Primary multidrug-resistant tuberculosis (TB) is defined as a case of TB in a person with a Mycobacterium tuberculosis isolate with resistance to at least isoniazid and rifampin and who was not previously diagnosed with or treated for drug-susceptible TB disease.
††Defined by the World Health Organization as a case of TB in a person with a Mycobacterium tuberculosis isolate with resistance to at least isoniazid and rifampin among first-line anti-TB drugs, resistance to any fluoroquinolone (e.g., ciprofloxacin or ofloxacin), and resistance to at least one second-line injectable drug (i.e., amikacin, capreomycin, or kanamycin).

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