Reported Tuberculosis in the United States, 2011
Reported Tuberculosis in the United States, 2011
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Since 1953, in cooperation with state and local health departments, the United States national tuberculosis program has collected information on each newly reported case of tuberculosis (TB) disease in the United States. Currently, each individual TB case report (Report of Verified Case of Tuberculosis, or RVCT) is submitted electronically. Following are the highlights of the 2011 report.
- Updated case counts for each year from 1993 through 2010.
- Case counts: 10,528 TB cases were reported to CDC from the 50 states and the District of Columbia (DC) for 2011, representing a 5.8% decrease from 2010 (Table 1).
- Eighteen states reported increased case counts from 2010 (Table 20).
- California, Texas, New York, and Florida accounted for 50% of the national case total (Table 19).
- For the first time, Asians exceeded all other racial or ethnic groups with the largest percentage of total cases (30%) (Table 2).
- Hispanics, who since 2004 had the largest percentage of total cases, now comprise the second largest racial or ethnic group (29%) (Table 2).
- Blacks or African Americans born in the United States represented 39% of TB cases in U.S.-born persons (Table 16) and accounted for approximately 15% of the national case total.
- Asians born outside the United States represented 46% of TB cases in foreign-born persons (Table 17) and accounted for 29% of the national case total.
- Case rates: In 2011, the TB case rate declined from 3.6 to 3.4 per 100,000 persons, representing a 6.4% decrease from 2010.
- Burden among the foreign-born: In 2011, the percentage of cases occurring in foreign-born persons increased to 62% of the national case total. This percentage has risen steadily since 1993.
- Foreign-born Hispanics and Asians together represented 80% of TB cases in foreign-born persons, • and accounted for 50% of the national case total (Table 17).
- In 34 states, ≥ 50% of TB cases occurred among foreign-born persons (Table 23).
- In 17 states, ≥ 70% of TB cases occurred among foreign-born persons (Table 23).
- In 10 states, ≥ 75% of TB cases occurred among foreign-born persons (Table 23).
- The top five countries of origin of foreign-born persons with TB were Mexico, the Philippines, Vietnam, India, and China (Table 6).
- Drug resistance: 1.3% of reported cases had primary multidrug resistance, which is defined as no previous history of TB disease and resistance to at least isoniazid and rifampin (Table 10).
- HIV status: In 2011, 82% of persons with TB reported HIV test results.
- Among persons of all ages, the percentage with HIV test results increased from 67% in 2010 to 82% in 2011; among persons 25–44 years of age, reporting of HIV test results increased from 75% to 90% (Table 12).
- The percentage of persons with TB who reported HIV-positive results has remained the same (6%) since 2008 for persons of all ages. Among persons 25–44 years of age, 10% of persons with TB reported HIV-positive results; this percentage has remained between 9%-10% since 2008(Table 12). The percentages have declined since 1993, when 15% of persons with TB reported HIV-positive results among persons of all ages, and 29% for persons between 25−44 years of age.
In 2011, the reported number of TB cases (10,528) and case rate (3.4 cases per 100,000) both decreased; these represented declines of 5.8% and 6.4%, respectively, compared to 2010. Since the 1992 TB resurgence peak in the United States, the number of TB cases reported annually has decreased by 61% (Table 1).
TB case rates vary by well-known factors such as age, race and ethnicity, and country of origin. The proportion of total cases occurring in foreign-born persons has been increasing since 1993. In 2011, 62% of TB cases occurred in foreign-born persons. Foreign-born persons have accounted for the majority of TB cases in the United States every year since 2001. Moreover, the case rate among foreign-born persons in 2011 was approximately 11 times higher than among U.S.-born persons (Table 5).
Tuberculosis deaths decreased by 10%, from 590 deaths in 2008 to 529 deaths in 2009. The number of TB deaths reported annually has decreased by 69% since 1992 (Table 1).
Since 1993, TB case rates have declined annually for almost all age groups. In 2011, TB case rates continued the trend with declines in all age groups. The highest burden of disease continues to be among older adults. In 2011, adults aged 65 years and older had a case rate of 5.4 cases per 100,000, while children aged ≤ 14 years had the lowest rate at 0.9 cases per 100,000 (Table 4).
In 2003, the race and ethnicity category “non-Hispanic, Asian or Pacific Islander” was split into “non-Hispanic Asian” and “non-Hispanic Native Hawaiian or Other Pacific Islander.” In 2011, Asians had the highest TB case rate at 20.9 cases per 100,000, which was a slight decrease from 21.5 in 2010. Native Hawaiians or Other Pacific Islanders had the second-highest TB case rate at 15.9 cases per 100,000, which is a decrease compared to 19.0 cases per 100,000 reported in 2010. Owing to low case numbers among Native Hawaiians or other Pacific Islanders, case rates fluctuate and must be interpreted with caution (Table 2).
Since 1993, TB case rates have declined between 60% and 78% in the following racial and ethnic groups: among Hispanic or Latinos, from 19.9 to 5.8 cases per 100,000; among non-Hispanic blacks or African Americans, from 28.5 to 6.3 cases per 100,000; among American Indian or Alaska Natives, from 14.0 to 5.6 cases per 100, 000; and among non-Hispanic whites, from 3.6 to 0.8 cases per 100,000. In 2011, the TB case rate for Asians remained approximately three times higher than that for Hispanics or blacks or African Americans (Table 2).
Since 1993, the TB case rate among U.S.-born persons has declined annually. In 2011, the TB case rate for U.S.-born persons was 1.5 cases per 100,000, representing a 80% decrease from 7.4 cases per 100,000 in 1993. The TB case rate among foreign-born persons also declined during the same interval, though the decline was less substantial. In 2011, the TB case rate among foreign-born persons was 17.2 cases per 100,000, representing a 49% decrease from 34.0 cases per 100,000 in 1993 (Table 5).
The proportion of TB cases among persons born in the United States has also declined annually since 1993. In 2011, 38% of TB cases were among U.S-born persons compared to 69% in 1993 (Table 5). In 34 states, ≥ 50% of TB cases occurred among foreign-born persons. In 17 states (California, Colorado, Connecticut, Delaware, Hawaii, Iowa, Maryland, Massachusetts, Minnesota, Nevada, New Jersey, New York, North Dakota, Rhode Island, Utah, Washington, Wyoming), ≥ 70% of TB cases occurred among foreign-born persons (Table 23)
From 2007 through 2011, the top five countries of origin of foreign-born persons with TB were Mexico, the Philippines, India, Vietnam and China (Table 6). The distribution of TB cases by world region of origin reflects immigration patterns among persons settling in the United States.1 Of the 6,510 TB cases reported among foreign-born persons in 2011, 38% occurred among persons born in the Americas region, and 31% occurred among persons born in the Western Pacific region (Table 18). From 1993 through 2011, the proportion of cases increased among persons born in the Eastern Mediterranean region (3% in 1993 to 4% in 2011), the Southeast Asia region (6% in 1993 to 14% in 2011), and the Africa region (2% in 1993 and 8% in 2011) (Table 18).
From 1993, when the RVCT was expanded to include drug-susceptibility results, the proportion of patients with primary multidrug-resistant (MDR) TB, which is defined as no previous history of TB disease and resistance to at least isoniazid and rifampin, decreased from 2.5% to 1.0% by 1998. However, there has been a slight increase in the percentage of primary MDR TB cases, from 0.9% of the total number of reported TB cases in 2008 (88 cases), to 1.1% percent in 2009 (86 cases), to 1.2% in 2010 (89 cases), to 1.3% in 2011 (98 cases). Since 1997, the percentage of U.S.-born patients with primary MDR TB has remained below 1.0%. However, of the total number of reported primary MDR TB cases, the proportion occurring in foreign-born persons increased from 25.3% (103 of 407) in 1993 to 82.7% (81 of 98) in 2011 (Table 10).
CDC has included an updated case count of extensively drug-resistant (XDR) TB cases from 1993 to 2011 in the slide set that accompanies this report. XDR TB is defined as resistance to isoniazid and rifampin, plus resistance to any fluoroquinolone and at least one of three injectable second-line anti-TB drugs (i.e., amikacin, kanamycin, or capreomycin).2,3 Six cases were reported as XDR TB in 2011, compared with 1 case in 2010, 0 cases in 2009, and 5 in 2008. Of the 12 XDR TB cases reported since 2008, 11 were among foreign-born persons.
The proportion of TB patients prescribed an initial treatment regimen including at least isoniazid, rifampin, and pyrazinamide increased from 72% in 1993 to 88% in 2011. The proportion of patients who completed therapy within 1 year increased from 64% in 1993 to 88% in 2009 (the latest year for which complete outcome data are available). The proportion of persons receiving directly observed therapy for at least a portion of the treatment duration also increased from 36% in 1993 to 90% in 2009, the latest year for which complete outcome data are available (Table 11).
Between 2010 and 2011, the proportion of persons with TB who reported HIV test results increased by 20% for all ages and 22% for persons aged 25–44. This increase is attributed to new reporting by states that were not previously reporting HIV test results. The American Thoracic Society and the Infectious Diseases Society of America recommend that all TB patients be counseled and tested for HIV.4
Both the absolute number of TB cases and the TB case rate in the United States continued to decrease in 2011. With 10,528 total cases, representing a case rate of 3.4 cases per 100,000 persons, 2011 had the lowest number of reported TB cases since reporting began in 1953. Furthermore, the number of TB cases reported in 2011 and the corresponding case rate decreased by approximately 6% from the previous year. However, despite successful declines in TB cases and case rates over the past 60 years, it is unlikely that current TB control and prevention efforts will result in TB elimination (<1 case per 1,000,000 population)5 in this century.6
Racial and ethnic minorities and foreign-born persons continue to be disproportionately affected by TB. In 2011, 84% of all TB cases occurred among persons who were Asian, black or African American, Hispanic, American Indian or Alaskan Native, or Native Hawaiian. The TB case rate among Asians is 25 times higher than the TB case rate among non-Hispanic whites. Asians accounted for 30% of all TB cases reported in 2011, the highest percentage of any racial or ethnic group, and 96% of Asian TB patients were foreign-born.
Since 2002, more than half of all TB cases reported in the U.S. have occurred among foreign-born persons. The gap between the proportion of TB cases among foreign-born and U.S.-born persons continued to widen in 2011, with 62% of all TB cases occurring among foreign-born persons. TB control strategies that have been successful in reducing transmission among U.S.-born TB cases have had less success in controlling TB among foreign-born persons.7 Focusing on LTBI testing and treatment of foreign-born persons would likely be more successful in decreasing TB among this group.7 Additionally, a new LTBI regimen that reduces treatment time may lead to better LTBI treatment completion among foreign-born persons.8
Continuing the decline in TB cases in the United States will require sustained focus on domestic TB control activities and further support of global TB control initiatives.9 Improving TB control among racial/ethnic minorities and foreign-born persons is imperative as the United States strives to prevent TB transmission and meet TB elimination goals.10
1 United States Department of Homeland Security. 2010 Yearbook of Immigration Statistics. In: U.S. Department of Homeland Security, Office of Immigration Statistics; 2011.
2 Centers for Disease Control and Prevention. Revised Definition of Extensively Drug-Resistant Tuberculosis. MMWR Morb Mortal Wkly Rep 2006;55:1176.
3 Extensively drug-resistant tuberculosis (XDR-TB): recommendations for prevention and control. Wkly Epidemiol Rec 2006;81:430-2.
4 CDC. Treatment of tuberculosis. American Thoracic Society, CDC, and Infectious Diseases Society of America. MMWR 2003;52(No. RR-11).
5 Ending Neglect: The Elimination of Tuberculosis in the United States. Washington, DC: National Academy Press; 2000.
6 Hill AN, Becerra JE, Castro KG. Modelling tuberculosis trends in the USA. Epidemiol Infect 2012;140(10):1862-72.
7 Cain KP, Benoit SR, Winston CA, MacKenzie WR. Tuberculosis among foreign-born persons in the United States. JAMA. 2008;300(4):405-12.
8 Jereb JA, Goldberg SV, Powell K, Villarino E, LoBue P. Recommendations for use of an Isoniazid-Rifapentine regimen with direct observation to treat latent Mycobacterium tuberculosis Infection. MMWR Morb Mortal Wkly Rep. 2011;60(48):1650-3.
9 Centers for Disease Control and Prevention. Trends in tuberculosis – United States 2011. MMWR Morb Mortal Wkly Rep 2012;61(11):181-5.
10 Centers for Disease Control and Prevention. CDC’s response to ending neglect: the elimination of tuberculosis in the United States 2002.