Tuberculosis Disease and Infection in US-Bound International Adoptees: 2016 to 2023

Abstract

OBJECTIVE:

The objective of this study was to evaluate required culture-based overseas tuberculosis (TB) screening in US-bound international adoptees.

METHODS:

We conducted a cross-sectional analysis of 22 053 international adoptees who underwent TB screening overseas and arrived in the United States during 2016 to 2023.

RESULTS:

Of 22 053 international adoptees (aged younger than 18 years) screened for TB overseas, 12 (54 cases/100 000 persons) were diagnosed with TB disease, and 169 (766 cases/100 000 persons) had suspected TB disease (defined for this analysis as a chest radiograph or clinical signs/symptoms suggestive of TB or known HIV infection but negative sputum culture results overseas). Of 15 386 persons who underwent a tuberculin skin test (TST) or interferon-γ release assay (IGRA) overseas, 390 (2.5%) were diagnosed with latent TB infection (LTBI). Among 12 persons who initiated treatment of TB disease overseas, 10 (83.3%) completed post-arrival evaluation in the United States; of these, none were diagnosed with TB disease after arrival. Among 169 persons diagnosed overseas with suspected TB disease, 108 (63.9%) completed post-arrival evaluation; of these, 2 (1.9%) were diagnosed with TB disease. Among 390 persons diagnosed overseas with LTBI, 220 (56.4%) completed post-arrival evaluation; of these, none were diagnosed with TB disease. Of 150 persons diagnosed with LTBI at post-arrival evaluation, 137 (91.3%) were recommended for treatment; of these, 104 (75.9%) initiated and 79 (57.7%) completed treatment.

CONCLUSIONS:

US-bound international adoptees have a similarly high prevalence of TB disease compared with US-bound immigrant and refugee children, highlighting the importance of TB screening before immigration and ensuring timely recommended post-arrival evaluation.

INTRODUCTION

When children (younger than age 16 years or a sibling younger than age 18 years of a child younger than age of 16 years who has been or will be adopted by the same adoptive parents) are adopted from outside the United States, they must go through the US immigration process.^1,2 All immigrant visa applicants, including international adoptees, must undergo an overseas medical examination by a panel physician who has been designated by US Department of State.^3,4 The purpose of the overseas medical examination is to identify health conditions, such as communicable diseases of public health significance, that make a person inadmissible to the United States.³ International adoptees with these conditions must be treated or obtain a waiver from US Citizenship and Immigration Service before immigrating to the United States.³ Annual arrivals of international adoptees vary, ranging from 5372 in fiscal year 2016 to 1275 in fiscal year 2023.⁵

Communicable disease importation has occurred in the context of international adoption,^6–8 presenting a challenge to the control of communicable diseases in the United States. During 2004 to 2013, 2 measles outbreaks in the United States were reported to be associated with recent adoptees from China,^9,10 and 1 outbreak was reported among adults who traveled with a group of families seeking to adopt children in China.¹¹ Although rare in the United States (incidence rate of just 3.0 cases/100 000 persons in 2024),¹² tuberculosis (TB) is a leading cause of death among adolescents and young adults globally.^13,14 In 2022, 1.3 million TB disease cases were diagnosed among children (aged 0–14 years), and an estimated total of 214 000 children and young adolescents (younger than 15 years) died of TB.¹⁵ Most reported TB cases in the United States are among non–US-born persons. Of 10 347 TB cases that were provisionally reported in the United States in 2024, 7915 (76.5%) were among non–US-born persons, with a corresponding rate of 15.5 cases per 100 000 persons.¹² During 2007 to 2017, non–US-born persons accounted for 32.0% (1655) of 5175 children and adolescents (younger than 18 years) diagnosed with TB disease in the United States.¹⁶

International adoptees are at high risk for acquisition of Mycobacterium tuberculosis infection and progression to TB disease.^8,17 A high prevalence of latent TB infection (LTBI) has been found among international adoptees,^18,19 and TB disease has been reported among international adoptees in the United States.²⁰ To reduce importation of TB into the United States, overseas screening for TB disease is required for US-bound immigrants, including international adoptees, refugees, and follow-to-join asylees.^3,21,22 This screening is effective at finding and facilitating required treatment of TB disease in these groups.^23–25 To assess the epidemiology of TB disease in US-bound international adoptees, we analyzed overseas TB screening data from 2016 to 2023 from US Centers for Disease Control and Prevention’s (CDC) Electronic Disease Notification system (EDN).²⁶

METHODS

Overseas TB Disease Screening

TB disease screening is a major component of the mandatory medical examination for US-bound immigrants, including international adoptees and refugees.^3,21–23 The examination is performed overseas by panel physicians, ie, local physicians who are appointed by US embassies and consulates.⁴ The CDC provides technical instructions, training, and quality oversight for the examination.²² During the analysis period of 2016 to 2023, TB screening instructions required all applicants to be assessed by medical history and physical examination for signs or symptoms of TB disease, all applicants aged at least 15 years to have a chest radiograph, and applicants aged 2 to 14 years in countries with a World Health Organization (WHO)-estimated TB incidence of at least 20 cases/100 000 persons had to undergo a tuberculin skin test (TST) or interferon-γ release assay (IGRA), and, if the result was positive, to have a chest radiograph.²² In 2018, the CDC released the updated TB technical instructions specifying that IGRA must be performed, with TST only accepted in countries where IGRA is not licensed for use.²² This change was driven by evidence showing that TST often yields false-positive results, especially in children who were previously vaccinated with M. bovis bacille Calmette-Guérin or those exposed to nontuberculous mycobacteria. Applicants of any age with a chest radiograph or clinical signs or symptoms suggestive of TB disease, as well as any applicants with a known diagnosis of HIV infection, provided 3 sputum specimens for smear microscopy to identify acid-fast bacilli, culture for mycobacteria, confirmation of Mycobacterium species at least to the M. tuberculosis complex level, and drug susceptibility testing.²² Since October 1, 2024, all sputum testing must include a molecular test, for example, Xpert MTB/RIF or Line Probe Assay, performed on the first sample collected for initial diagnosis to evaluate for drug-resistant TB.²² Completion of directly observed therapy (DOT) is required for those diagnosed with TB disease overseas.²²

Following the TB disease screening process, applicants are classified as having (1) Class A TB, (2) Class B0 TB, pulmonary (ie, those who had Class A TB and successfully completed TB treatment overseas), (3) Class B1 TB, pulmonary, (4) Class B1 TB, extrapulmonary, (5) Class B2 LTBI, (6) Class B3 TB close contact, or (7) no TB classification (Table 1).²² For this analysis, applicants with Class A TB (including anyone granted a waiver) or Class B0 TB are collectively referred to as having TB disease. Additionally, applicants with a Class B1 TB, pulmonary, classification are referred to as having suspected TB disease. LTBI is defined as a state of persistent immune response to stimulation by Mycobacterium TB antigens with no evidence of clinically manifest active TB and without radiographic abnormalities.²⁷ Applicants with Class B2 LTBI classification are referred to as having LTBI. No applicants with a Class B1, extrapulmonary, or Class B3, close contact, classifications were included in this analysis.

TABLE 1.

TB Classifications of Culture-Based Overseas TB Screening

TB Classification	Description
Class ATBa	Applicants who are diagnosed with infectious TB diseaseb (1 or more positive culture results for Mycobacterium tuberculosis complex or diagnosed clinically based on signs and symptoms); This classification also applies to applicants with extrapulmonary tuberculosis who have a chest radiograph suggestive of infectious TB disease, regardless of sputum smear and culture results. Applicants with Class A TB must complete a full course of DOT before travel. A small subset of applicants with Class A TB are granted a waiver and, under these rare circumstances, are allowed to immigrate while still undergoing TB treatment.
Class B0 TB, pulmonarya	Applicants who were diagnosed with Class A TB by the panel physician or presented to the panel physician while on TB treatment and successfully completed DOT under the supervision of a panel physician before immigration.
Class B1 TB, pulmonaryc	Applicants who have chest radiograph or clinical signs/symptoms suggestive of TB disease, or known HIV infection, but negative sputum culture results overseas.
Class B1 TB, extrapulmonary	Applicants who have extrapulmonary TB disease with a normal chest radiograph and negative sputum culture results.
Class B2 LTBId	Applicants who have a positive IGRA or TST result (induration of ≥10 mm, ≥5 mm if applicants are HIV-positive or a known recent contact to a person with TB disease) in the setting of a normal physical examination and chest radiograph.
Class B3 TB, close contact	Applicants who have close contact with a person with known TB disease.
No TB classification	Applicants who have no TB classifications.

Abbreviations: CDC, Centers for Disease Control and Prevention; DOT, directly observed therapy; IGRA, interferon-γ release assay; TB, tuberculosis; TST, tuberculin skin test.

^aIn this analysis, applicants with Class A TB classification (including anyone granted a waiver) or Class B0 TB classification (those who had Class A TB and successfully completed TB treatment overseas) are referred to as having TB disease.

^bUnder CDC’s TB Technical Instructions for Panel Physicians, infectious TB disease includes TB of the lung parenchyma, pleura, larynx, or intrathoracic lymph nodes.

^cIn this analysis, applicants with a Class B1 TB, pulmonary, classification are referred to as having suspected TB disease.

^dIn this analysis, applicants with a Class B2 LTBI classification are referred to as having LTBI.

Analysis Population

The analysis population included international adoptees (aged younger than 18 years) who were screened for TB disease overseas and arrived in the United States during 2016 to 2023. Data of their overseas TB screening, as well as data of post-arrival evaluation for those with an overseas TB classification, were from the CDC’s EDN. The number of yearly adoptee arrivals for 2016 to 2021 were obtained from US Department of Homeland Security and, for 2022 to 2023, were obtained from eMedical, a Web-based system that allows panel physicians to electronically record and submit health information for visa applicants.²⁸ Since 2020, the US Department of States has required panel physicians to use eMedical to record and submit immigration health examination results of US-bound immigrants.

Post-Arrival Evaluation in the United States

The CDC notifies state and local health departments via EDN of arriving persons with an overseas TB classification.^29,30 A post-arrival evaluation and completion of TB treatment at a local or state health department is required for individuals granted a Class A TB waiver. For individuals assigned any other classification, the requirement of a post-arrival evaluation is at the discretion of the local or state health department. Health department physicians use a worksheet developed by the CDC to record findings from recommended post-arrival evaluation of persons with an overseas TB classification.³⁰ Based on individual health department procedures, they may conduct further pulmonary and extrapulmonary TB disease evaluation, and, if needed, provide treatment of TB disease or for LTBI.³⁰ Evaluation results are entered directly into CDC’s EDN database.³⁰ In this analysis, completion of post-arrival evaluation was defined as having an evaluation within 1 year of arrival with assignment of a final TB classification by a health department physician.

Statistical Analysis

We calculated the prevalence of TB disease, suspected TB disease, and LTBI identified at overseas screening among US-bound international adoptees. We calculated the proportion of newly arrived international adoptees who completed a post-arrival evaluation and the proportion of those who were diagnosed with TB disease during this evaluation. For adoptees diagnosed with LTBI at post-arrival evaluation, we calculated the proportion reported as completing treatment of LTBI. We compared the results of overseas TB disease screening and post-arrival evaluation of international adoptees with previous analyses of immigrants and refuggees.^23,30

Ethics Review

This activity was reviewed by the CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy (see, eg, 45 CFR part 46.102 (l)(2), 21 CFR part 56; 42 USC §241(d); 5 USC §552a; 44 USC §3501 et seq.).

RESULTS

Overseas TB Disease Screening in US-Bound International Adoptees

Annual arrivals of international adoptees to the United States decreased from 5253 in 2016 to 1139 in 2023, with the largest decrease among adoptees from China (Figure 1). Of 22 053 international adoptee arrivals during 2016 to 2023, most (55.9%) were from the following 5 countries: China (27.9%), India (7.9%), Colombia (7.5%), Ukraine (6.5%), and South Korea (6.2%) (Table 2). Approximately one-half of these adoptees were female, and 73.4% were aged 2 to 14 years (Table 2).

FIGURE 1.

Arrivals of international adoptees to the United States by year of arrival and country of birth, 2016 to 2023.

TABLE 2.

Results of Overseas TB Screening in International Adoptees Who Arrived in the United States During 2016 to 2023

Variable	Applicants Screened for TB Disease					Applicants Receiving Test for TB Infectiona			WHO-Estimated Country-Specific TB Incidence (Cases/100 000 Persons)
	Applicants Screened, n (%)	TB Diseaseb		Suspected TB Diseasec		Applicants Tested, n (%)	LTBId
		n	Prevalencee	n	Prevalencee		n	%	2016	2023
Year of arrival
2016	5253 (23.8)	6	114	16	305	3704 (24.1)	45	1.2	N/A	N/A
2017	4654 (21.1)	2	43	25	537	3296 (21.4)	69	2.1
2018	3794 (17.2)	1	26	39	1028	2656 (17.3)	66	2.5
2019	2927 (13.3)	0	0	14	478	1991 (12.9)	39	2.0
2020	1384 (6.3)	0	0	12	867	968 (6.3)	34	3.5
2021	1739 (7.9)	0	0	24	1380	1203 (7.8)	62	5.2
2022	1164 (5.3)	1	58	23	1976	802 (5.2)	38	4.7
2023	1139 (5.2)	2	176	16	1405	768 (5.0)	37	4.8
Sex
Male	10 802 (49.0)	9	83	74	685	7561 (49.1)	188	2.5	N/A	N/A
Female	11 251 (51.0)	3	27	95	844	7825 (50.9)	202	2.6
Age
<2 y	3940 (17.9)	1	25	8	203	N/A	N/A	N/A	N/A	N/A
2–14 y	16191 (73.4)	9	56	143	883	15 386 (100)	390	2.5
15–18 y	1923 (8.7)	2	104	18	936	N/A	N/A	N/A
Country of birthf
China	6151 (27.9)	1	16	22	358	5004 (32.5)	47	0.9	63	52
India	1736 (7.9)	1	58	45	2592	1104 (7.2)	35	3.2	225	195
Colombia	1647 (7.5)	1	61	1	61	1301 (8.5)	56	4.3	33	46
Ukraine	1444 (6.5)	3	208	41	2839	871 (5.7)	59	6.8	87	112
South Korea	1357 (6.2)	1	74	0	0	491 (3.2)	1	0.2	76	38
Haiti	1010 (4.6)	0	0	11	1090	914 (5.9)	20	2.2	188	149
Bulgaria	913 (4.1)	0	0	2	219	788 (5.1)	16	2.0	27	16
Nigeria	841 (3.8)	0	0	6	713	591 (3.8)	7	1.2	219	219
The Philippines	683 (3.1)	2	293	6	879	563 (3.7)	64	11.4	554	643
Ethiopia	629 (2.9)	1	159	11	1750	407 (2.6)	6	1.5	177	146
Taiwan	390 (1.8)	0	0	0	0	345 (2.2)	6	1.7	49	28
Democratic Republic of Congo	357 (1.6)	0	0	1	281	344 (2.2)	5	1.5	323	316
Latvia	309 (1.4)	2	647	0	0	235 (1.5)	2	0.9	37	16
Thailand	299 (1.4)	0	0	0	0	242	2	0.8	160	157
Uganda	285 (1.3)	0	0	7	2460	(1.6) 235 (1.5)	5	2.1	201	198
Other	4007 (18.2)	0	0	16	399	1952 (9.9)	59	3.0	N/A	N/A
WHO-estimated TB incidence for country of birth
0–19 cases/100 000 persons	1088 (4.9)	0	0	2	184	N/A	N/A	N/A	N/A	N/A
20–99 cases/100 000 persons	13 127 (59.5)	8	61	69	526	9700 (63.0)	205	2.1
≥100 cases/100 000 persons	7826 (35.5)	4	51	98	1252	5686 37.0)	185	3.3
Unknown	12 (0.1)	0	0	0	0	N/A	N/A	N/A
Total	22 053 (100)	12	54	169	766	15 386 (100)	390	2.5	N/A	N/A

Abbreviations: IGRA, interferon-γ release assay; LTBI, latent TB infection; N/A, not applicable; TB, tuberculosis; TST, tuberculin skin test; WHO, World Health Organization.

^aTest for TB infection was required for international adoptees aged 2 to 14 years in countries with a WHO-estimated TB incidence of at least 20 cases/100 000 persons.

^bApplicants who are diagnosed with TB disease overseas (ie, Class A TB classification, including anyone granted a waiver) or those who successfully completed TB treatment overseas (ie, Class B0 TB classification).

^cApplicants who have chest radiograph or clinical signs/symptoms suggestive of TB disease, or known HIV infection but negative sputum culture results overseas (ie, Class B1 TB, pulmonary classification).

^dApplicants who have a positive IGRA or TST result (induration of ≥10 mm, ≥5 mm if applicants are HIV-positive or a known recent contact to a person with tuberculosis disease) in the setting of a normal physical examination and chest radiograph (ie, Class B2 LTBI classification).

^eNumber of cases per 100 000 persons.

^fTop 15 countries of birth countries for international adoptees who arrived in the United States during 2016 to 2023

Among the 22 053 international adoptees, 12 persons from 8 countries were diagnosed with TB disease overseas for a prevalence of 54 cases/100 000 persons; 1 (8.3%), 9 (75.0%), and 2 (16.7%) were aged 0 to 1, 2 to 14, and 15 to 18 years, respectively (Table 2). A total of 11 of the 12 persons completed overseas TB treatment, and 1 person arrived in the United States under a waiver while still on treatment. None of the M. tuberculosis isolates from these 12 persons were resistant to isoniazid or rifampin.

Among the 22 053 international adoptees, 169 were diagnosed with suspected TB disease overseas for a prevalence of 766 cases/100 000 persons. Of these, 8 (4.7%), 143 (84.6%), and 18 (10.7%) were aged 0 to 1, 2 to 14, and 15 to 18 years old, respectively; 45 (26.6%) were from India, 41 (24.3%) were from Ukraine, and 22 (13.0%) were from China (Table 2). International adoptees from Ukraine had the highest rate (2839 cases/100 000 persons), followed by those from India (2592 cases/100 000 persons), Uganda (2460 cases/100 000 persons), Ethiopia (1750 cases/100 000 persons), Haiti (1090 cases/100 000 persons), and the Philippines (879 cases/100 000 persons) (Table 2).

Among 15 386 international adoptees who underwent a TST or IGRA, 390 met the criteria of LTBI for a prevalence of 2.5%. Prevalence of LTBI ranged from 0.2% among persons from South Korea to 11.4% among those from the Philippines (Table 2). Of these 390 cases of LTBI, 261 (66.9%) were from the following 5 countries: the Philippines (64, 16.4%), Ukraine (59, 15.1%), Colombia (56, 14.4%), China (47, 12.1%), and India (35, 9.0%) (Table 2).

Post-Arrival Evaluation in the United States

Table 3 shows results from the post-arrival evaluation of newly arrived international adoptees. Overall, 338 (59.2%) of 571 international adoptees with an overseas TB classification completed a post-arrival evaluation. Of the 12 persons who were diagnosed with TB disease overseas, 10 (83.3%) completed post-arrival evaluation (9 who completed treatment overseas and 1 who was granted a waiver and immigrated while still on treatment); of these, none were diagnosed with TB disease recurrence or relapse after arrival. Of 169 persons with suspected TB disease overseas, 108 (63.9%) completed a post-arrival evaluation; of these, 2 (1.9%) were diagnosed with TB disease (1 with positive culture results and 1 with unknown culture results). Of 390 persons with LTBI overseas, 220 (56.4%) completed a post-arrival evaluation; of these, none were diagnosed with TB disease.

TABLE 3.

Results of Post-Arrival Evaluation in the United States of Newly Arrived International Adoptees Who Had an Overseas TB Classification, 2016 to 2023

Variable	Total Arrivals	Results of Post-Arrival Evaluation in the United States
		Completion of Post-Arrival Evaluation, n (%)	TB Disease			LTBI, n (%)
			Total Cases, n (%)	Positive Culture Result, n (%)a	Unknown Culture Results, n (%)
Overseas TB classification
TB diseaseb	12	10 (83.3)	0 (0.0)	0 (0.0)	0 (0.0)	N/A
Suspected TB disease	169	108 (63.9)	2 (1.9)	1 (0.9)	1 (0.9)	21 (19.4)
LTBI	390	220 (56.4)	0 (0.0)	0 (0.0)	0 (0.0)	129 (58.6)
Total	571	338 (59.2)	2 (0.6)	1 (0.3)	1 (0.3)	150 (44.4)

Abbreviations: LTBI, latent TB infection; N/A, not applicable; TB, tuberculosis.

^aNone were resistant to first-line drugs for TB.

^bOne person arrived in the United States under a waiver while still on treatment, and eleven completed their overseas TB treatment.

Treatment of LTBI at Post-Arrival Evaluation

Among 328 newly arrived international adoptees identified to have suspected TB disease or LTBI overseas and who had a post-arrival evaluation, 150 (45.7%) were diagnosed with LTBI at post-arrival evaluation; of these, 137 (91.3%) were recommended for LTBI treatment (Table 4). Of 137 persons who were recommended for LTBI treatment, 104 (75.9%) were recorded as having initiated the treatment, and 79 (57.7%) were recorded as having completed it (Table 4).

TABLE 4.

Results of LTBI Treatment in the United States of Newly Arrived International Adoptees Who Were Diagnosed With LTBI at Post-Arrival Evaluation, 2016 to 2023

Variable	Post-Arrival Evaluation in the United States
	Persons Completed Post-Arrival Evaluation	Persons Diagnosed With LTBI at Post-Arrival Evaluation	Persons Recommended for LTBI Treatment		Persons Who Initiated LTBI Treatment		Persons Who Completed LTBI Treatment
			No.	% of Persons Diagnosed With LTBI	No.	% of Persons Recommended for LTBI Treatment	No.	% of Persons Recommended for LTBI Treatment	% of Persons Initiated LTBI Treatment
Overseas TB classification
Suspected TB disease	108	21	18	85.7	15	83.3	12	66.7	80.0
LTBI	220	129	119	92.3	89	74.8	67	56.3	75.3
Total	328	150	137	91.3	104	75.9	79	57.7	76.0

Abbreviations: LTBI, latent TB infection; TB, tuberculosis

Comparison With a Previous Study of Immigrants and Refugees

Compared with immigrant and refugee children aged 0 to 14 years, international adoptees had a similar prevalence of TB disease (P = .7158) but a significantly higher prevalence of suspected TB disease (P < .0001) (Table 5). International adoptees had a significantly lower prevalence of LTBI than immigrant and refugee children (P < .0001) (Table 5).

TABLE 5.

Comparison of Overseas Screening Outcomes for Persons Aged Younger Than 15 years Among US-Bound International Adoptees (2016–2023), Immigrants, and Refugees (2013–2016)

Visa Type	Aged 0–14 y							Aged 2–14 y
		TB Diseasea			Suspected TB Diseaseb			LTBIc
	Persons Screened	Cases	Prevalenced	P Valuee	Cases	Prevalenced	P Valuee	Persons Screened	Cases	Prevalence, %	P Valuee
International adoptee	20 131	10	50	.7158	151	750	<.0001	15 386	390	2.5	<.0001
Immigrant and refugeef	353 619	156	44		956	270		306 084	41 167	13.5

Abbreviations: IGRA, interferon-γ release assay; LTBI, latent TB infection; TB, tuberculosis; WHO, World Health Organization.

^aApplicants who are diagnosed with TB disease overseas (ie, Class A TB classification, including anyone granted a waiver) or those who successfully completed TB treatment overseas (ie, Class B0 TB classification).

^bApplicants who have chest radiograph or clinical signs/symptoms suggestive of TB disease, or known HIV infection, but negative sputum culture results overseas (ie, Class B1 TB, pulmonary classification).

^cApplicants who have a positive IGRA or TST (induration of ≥10 mm, ≥5 mm if applicants are HIV-positive or a known recent contact to a person with TB disease) result in the setting of a normal physical examination and chest radiograph (ie, Class B2 LTBI classification). During the analysis period, screening for TB infection was required for all persons aged 2 to 14 years in countries with a WHO-estimated TB incidence of at least 20 cases/100 000 persons but not routinely required for others.

^dNumber of cases per 100 000 persons.

^eZ test for the difference between 2 proportions.

^fSee Reference 23: During the analysis period (2007–2012) of this previous publication, immigrants and refugees who completed overseas TB treatment were reclassified as having suspected TB disease based on the CDC’s Technical Instructions for Panel Physicians in place at the time. We were able to recalculate prevalence of suspected TB disease (ie, Class B1 TB detected by the culture-based algorithm in Appendix Table 1²³) because the paper reported prevalence of TB disease (ie, persons who completed overseas TB treatment) in Appendix Table 2²³. Among 39 092 persons aged younger than 2 years who were screened by the culture-based algorithm, 66 were classified as having Class B1 TB (Appendix Table 1²³), and 13 completed overseas TB treatment (Appendix Table 2²³); among 314 527 persons aged 2 to 14 years who were screened by the culture-based algorithm, 1046 were classified as having Class B1 TB (Appendix Table 1²³), and 143 completed overseas TB treatment (Appendix Table 2²³). By using these data, we recalculated the prevalence of suspected TB disease for immigrants and refugees aged 0 to 14 years as follows: ([66 − 13] + [1046 − 143])/(39 092 + 314 527) = 270 cases/100 000 persons.

Within 1 year of their arrival, TB disease has been reported in 1.6% of immigrants and refugees (all ages) who had suspected TB disease identified overseas and were examined in the United States during 2013 to 2016.³⁰ In our analysis, TB disease was found in 1.9% of international adoptees who had suspected TB disease overseas and were examined in the United States.

DISCUSSION

During 2016 to 2023, 22 053 international adoptees arrived in the United States. Annual adoptee arrivals varied greatly among countries, but 95.0% of these children were from countries with an elevated WHO-estimated TB incidence of at least 20 cases/100 000 persons compared with a 2024 TB incidence rate of just 3.0 cases/100 000 persons in the United States.¹² Our analysis showed that US-bound international adoptees had a high risk for TB, with 54 cases/100 000 persons having TB disease diagnosed overseas. We also found a prevalence of 766 cases/100 000 persons for suspected TB disease diagnosed overseas among international adoptees and a prevalence of 2.5% for LTBI diagnosed overseas among those aged 2 to 14 years from countries with a WHO-estimated TB incidence of at least 20 cases/100 000 persons.

Our analysis showed that, compared with US-bound immigrant and refugee children aged younger than 15 years,²³ US-bound international adoptees aged younger than 15 years had a similar prevalence of TB disease but a significantly higher prevalence of suspected TB disease on overseas examination. In our analysis, TB disease was diagnosed in 1.9% (2/108) of international adoptees with suspected TB disease overseas who completed a post-arrival evaluation. This result is consistent with previous analyses of TB in immigrants and refugees,^23,30 indicating the similarly high burden of TB among international adoptees. Particularly, international adoptees had a high risk for TB if they were in countries with a high TB incidence. Therefore, the yield of overseas TB screening in US-bound international adoptees depended on their country of origin, a finding that has been observed among other mobile populations.³¹

Our analysis also showed that prevalence of LTBI in international adoptees varied among countries of birth. This result might be caused by factors such as country of origin, age, living conditions, and testing methods. Previous studies have reported 11.9% and 21.0% of international adoptees screened by TST had evidence of LTBI.^18,19 A recent study found that LTBI was diagnosed in 3.3% of children (younger than 15 years) migrating to Australia during 2015 to 2017.³² We found that the prevalence of LTBI in international adoptees was significantly lower than that in immigrant and refugee children. Testing methods could partially contribute to the low prevalence in our analysis. Prior to October 2018, both TST and IGRA were used during overseas TB screening. Since October 2018, overseas TB screening has been required to use IGRA. During 2007 to 2017, only 3.2% of US-bound immigrants and refugees aged 2 to 14 years with LTBI overseas were tested by IGRA, but during 2018 to 2019, 94.8% of those with LTBI overseas were tested by IGRA.³³ Additionally, among 17 996 children with a positive overseas TST result, 73.8% had a negative result when retested by IGRA in the United States; additionally, among 1051 children with a positive overseas IGRA result, 58.0% had a negative result when retested by IGRA in the United States.³³ The large discrepancies in LTBI testing between overseas screening and post-arrival evaluation in the United States indicate that further studies are needed on the diagnosis of LTBI among US-bound immigrants, including international adoptees and refugees.

Completion of recommended post-arrival evaluations for newly arrived international adoptees (59.2%) was more frequent than previously reported for follow-to-join asylees (ie, overseas spouse and unmarried children younger than age 21 years of persons who are granted asylum status in the United States; 45.4%)²⁵ but less frequent than reported for immigrants and refugees (from 62.3% to 64.5%).^21,23,30 Post-arrival evaluation at health departments is encouraged but not required for newly arrived at-risk persons. A previous analysis shows that noncompletion of post-arrival evaluation was associated with country of birth, overseas TB classification, and visa type. International adoptees of US citizen householders have a high insurance rate.³⁴ Some parents might have their adopted children evaluated by private health care providers, and these results were likely not reported to the CDC’s EDN, resulting in a lower proportion of post-arrival evaluation completion. Measures to improve post-arrival evaluation completion are greatly needed because the yield and impact of overseas TB screening also depends on the number of persons at risk who complete a post-arrival evaluation. A previous study has indicated that post-arrival evaluation completion may be improved with intensive outreach efforts from state and local public health departments (eg, “home visits, mailings, or telephone calls to the immigrant’s and refugee’s stated intended residence”).³⁵

Treatment of LTBI is essential for TB elimination in the United States, but it is a challenge to ensure treatment completion.^36,37 Of non–US-born persons who initiated LTBI treatment during 2007 to 2008 in the United States and Canada, only 49.3% completed the treatment.³⁸ In our analysis, 79 of 104 (76.0%) of adoptees who initiated treatment completed it; however, this represented just over one-half (57.7%) of the 137 adoptees recommended for LTBI treatment, demonstrating the need for improved treatment initiation and retention strategies. A study of systematic review and meta-analysis has reported that the shorter treatment regimens for LTBI in migrants are often associated with better outcomes.³⁷ Compared with those treated outside of health departments, refugees treated by health departments are more likely to complete their LTBI treatment.³⁹

Data used in our analysis have several limitations. Misclassification of TB cases might have occurred during overseas screening and post-arrival evaluation. Post-arrival evaluation data were unavailable for 40.7% of newly arrived at-risk international adoptees.

The cascade of care for TB among international adoptees is challenging because of the fragmented nature of care delivery across different service areas. International adoptees with confirmed TB disease are prohibited from traveling to the United States until they have completed TB treatment overseas or are granted a waiver while still undergoing TB treatment. Having to complete TB treatment in the adoptee’s country often delays the adoption process. This delay could create considerable hardship for adopted children and their families. International adoptees are more likely not to have a post-arrival evaluation if their adoptive parents are not familiar with TB disease and do not receive adequate counseling on the importance of follow-up during their adopting process.

CONCLUSIONS

Our analysis shows that international adoptees have a similarly high TB prevalence diagnosed overseas compared with immigrant and refugee children, highlighting, for adoptive parents, health care personnel, and public health departments, the importance of TB screening before immigration, ensuring timely post-arrival evaluation, and completing treatment when indicated.

WHAT’S KNOWN ON THIS SUBJECT:

Previous studies have reported that international adoptees in the United States have a high risk for tuberculosis (TB), but national data sets of overseas TB screening and post-arrival evaluation in the United States of international adoptees have not been assessed.

WHAT THIS STUDY ADDS:

Risk of TB in US-bound international adoptees varied among their countries of origin. Compared with US-bound immigrant and refugee children, international adoptees had a similarly high prevalence of TB disease.

ABBREVIATIONS

CDC

US Centers for Disease Control and Prevention

DOT

directly observed therapy

EDN

Electronic Disease Notification system

IGRA

interferon-γ release assay

LTBI

latent TB infection

TB

tuberculosis

TST

tuberculin skin test

WHO

World Health Organization