Infectious Tuberculosis among Newly Arrived Refugees in the United States
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《新英格兰医药杂志》
To the Editor: In 2002, 51 percent of persons with tuberculosis in the United States were foreign-born; 19 percent of them had been in the United States for less than one year.1 To prevent persons with potentially infectious tuberculosis from entering the United States and to detect possible noninfectious tuberculosis, immigrants and refugees undergo tuberculosis screening overseas with the use of chest radiography. If radiographs suggest active tuberculosis, sputum smears are examined for acid-fast bacilli. Travel to the United States is deferred if smears are positive. For those with radiologic findings compatible with inactive tuberculosis, examination of smears for acid-fast bacilli is not required.2 The ability to detect infectious tuberculosis accurately and to deter it is affected by the sensitivity and specificity of screening tools and the possibility that a new infection or progression of existing disease may occur between the overseas screening evaluation and the evaluation after arrival.
To evaluate the effectiveness of overseas screening in detecting infectious tuberculosis, we reviewed tuberculosis and refugee health registries for 2000 in four states, which together accounted for 17,446 of the 75,854 refugees (23 percent) who arrived in the United States that year.3 Each foreign-born person with tuberculosis was cross-matched against the national Information on Migrating Populations database4 to confirm his or her refugee status.
Of 712 foreign-born persons with tuberculosis, 91 (13 percent) were newly arrived refugees. Using the states' total refugee arrivals as the denominator, the rate of tuberculosis disease among newly arrived refugees was 504 per 100,000 persons — a rate approximately 80 times the 2000 U.S. national rate (Table 1). 1 Tuberculosis case rates were highest among refugees with active-tuberculosis classifications overseas, but rates of sputum-smear positivity for acid-fast bacilli were highest among refugees with a classification of inactive tuberculosis. Most refugees (82 percent) with smear-positive tuberculosis were screened within 6 months before departure to the United States, and 50 percent were given a diagnosis within 30 days after arrival in the United States.
Table 1. Cases of Tuberculosis and Estimated Incidence Rates among Newly Arrived Refugees in Minnesota, New York, Virginia, and Washington, October 1999 to September 2000.
Although only four states were included in the study, we believe that the incidence estimates are representative of those in the United States. The distribution of the geographic origin of the refugees studied was similar to that seen in the United States as a whole, as was the distribution of classifications on overseas tuberculosis screening (Table 1).
Currently, only refugees with a classification of active tuberculosis undergo examinations of sputum for acid-fast bacilli overseas. The high rate of smear positivity among those classified as having inactive tuberculosis suggests that radiographs alone have a low negative predictive value for identifying infectious tuberculosis. Examining smears from refugees classified as having inactive tuberculosis may improve the effectiveness of screening. Current policies recommend tuberculosis evaluations for all refugees on arrival in the United States; the high rates of tuberculosis documented in this study emphasize this need.
Lorna E. Thorpe, Ph.D.
New York City Department of Health and Mental Hygiene
New York, NY 10013
lthorpe@health.nyc.gov
Kayla Laserson, Sc.D.
Susan Cookson, M.D.
Centers for Disease Control and Prevention
Atlanta, GA 30333
Wendy Mills, M.P.H.
Minnesota Department of Health
Minneapolis, MN 55414
Kim Field, R.N.
Washington State Department of Health
Olympia, WA 98504
Venkatarama R. Koppaka, M.D., Ph.D.
Virginia Department of Health
Richmond, VA 23218
Margaret Oxtoby, M.D.
New York State Department of Health
Albany, NY 12237
Susan Maloney, M.D.
Charles Wells, M.D.
Centers for Disease Control and Prevention
Atlanta, GA 30333
References
Reported tuberculosis in the United States, 2002. Atlanta: Centers for Disease Control and Prevention, September 2003.
Centers for Disease Control and Prevention, Division of Global Migration and Quarantine. Instructions to panel physicians for completing new U.S. Department of State medical examination for immigrant or refugee applicant. (Accessed April 22, 2004, at http://www.cdc.gov/ncidod/dq/dsforms/index.htm.)
Immigration and Naturalization Service. Statistical yearbook of the Immigration and Naturalization Service, 1999. Washington, D.C.: Government Printing Office, 2002.
Banerji S, Cochran J, Cookson S. Update of the electronic TB class A/B notification project. TB Notes No. 2. 2001:17-23. (Atlanta: Centers for Disease Control and Prevention.)
To evaluate the effectiveness of overseas screening in detecting infectious tuberculosis, we reviewed tuberculosis and refugee health registries for 2000 in four states, which together accounted for 17,446 of the 75,854 refugees (23 percent) who arrived in the United States that year.3 Each foreign-born person with tuberculosis was cross-matched against the national Information on Migrating Populations database4 to confirm his or her refugee status.
Of 712 foreign-born persons with tuberculosis, 91 (13 percent) were newly arrived refugees. Using the states' total refugee arrivals as the denominator, the rate of tuberculosis disease among newly arrived refugees was 504 per 100,000 persons — a rate approximately 80 times the 2000 U.S. national rate (Table 1). 1 Tuberculosis case rates were highest among refugees with active-tuberculosis classifications overseas, but rates of sputum-smear positivity for acid-fast bacilli were highest among refugees with a classification of inactive tuberculosis. Most refugees (82 percent) with smear-positive tuberculosis were screened within 6 months before departure to the United States, and 50 percent were given a diagnosis within 30 days after arrival in the United States.
Table 1. Cases of Tuberculosis and Estimated Incidence Rates among Newly Arrived Refugees in Minnesota, New York, Virginia, and Washington, October 1999 to September 2000.
Although only four states were included in the study, we believe that the incidence estimates are representative of those in the United States. The distribution of the geographic origin of the refugees studied was similar to that seen in the United States as a whole, as was the distribution of classifications on overseas tuberculosis screening (Table 1).
Currently, only refugees with a classification of active tuberculosis undergo examinations of sputum for acid-fast bacilli overseas. The high rate of smear positivity among those classified as having inactive tuberculosis suggests that radiographs alone have a low negative predictive value for identifying infectious tuberculosis. Examining smears from refugees classified as having inactive tuberculosis may improve the effectiveness of screening. Current policies recommend tuberculosis evaluations for all refugees on arrival in the United States; the high rates of tuberculosis documented in this study emphasize this need.
Lorna E. Thorpe, Ph.D.
New York City Department of Health and Mental Hygiene
New York, NY 10013
lthorpe@health.nyc.gov
Kayla Laserson, Sc.D.
Susan Cookson, M.D.
Centers for Disease Control and Prevention
Atlanta, GA 30333
Wendy Mills, M.P.H.
Minnesota Department of Health
Minneapolis, MN 55414
Kim Field, R.N.
Washington State Department of Health
Olympia, WA 98504
Venkatarama R. Koppaka, M.D., Ph.D.
Virginia Department of Health
Richmond, VA 23218
Margaret Oxtoby, M.D.
New York State Department of Health
Albany, NY 12237
Susan Maloney, M.D.
Charles Wells, M.D.
Centers for Disease Control and Prevention
Atlanta, GA 30333
References
Reported tuberculosis in the United States, 2002. Atlanta: Centers for Disease Control and Prevention, September 2003.
Centers for Disease Control and Prevention, Division of Global Migration and Quarantine. Instructions to panel physicians for completing new U.S. Department of State medical examination for immigrant or refugee applicant. (Accessed April 22, 2004, at http://www.cdc.gov/ncidod/dq/dsforms/index.htm.)
Immigration and Naturalization Service. Statistical yearbook of the Immigration and Naturalization Service, 1999. Washington, D.C.: Government Printing Office, 2002.
Banerji S, Cochran J, Cookson S. Update of the electronic TB class A/B notification project. TB Notes No. 2. 2001:17-23. (Atlanta: Centers for Disease Control and Prevention.)