An Effective Health System Approach to End TB: Implementing the Double X Strategy in Vietnam

Anh L. Innes; Victoria Lebrun; Gia Linh Hoang; Andres Martinez; Nhi Dinh; Thi Thuy Ha Nguyen; Tan Phat Huynh; Van Luong Quach; Thanh Binh Nguyen; Van Chinh Trieu; Nghi Do Bao Tran; Huy Minh Pham; Van Luong Dinh; Binh Hoa Nguyen; Thi Thanh Huyen Truong; Van Cu Nguyen; Viet Nhung Nguyen; Thu Hien Mai

doi:10.9745/GHSP-D-24-00024

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FIGURE 1
The 2X Health System Strategy to Screen and Diagnose TB Disease,^a Vietnam
Abbreviations: 2X, Double X; ACF, active case-finding; CXR, chest radiography; ICF, intensified case-finding; Xpert, GeneXpert; ±, with or without.
^a Facility-based ICF and community ACF reached a range of vulnerable populations, who were evaluated (with or without symptoms) followed by CXRs, and, if TB-presumptive, Xpert testing.
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FIGURE 2
Algorithms for TB Disease and TB Infection Among Household Contacts, Vietnam
Abbreviations: CXR, chest radiography, MTB, Mycobacterium TB; TST, tuberculin skin test; QFT, QuantiFERON-TB Gold Plus; Xpert, GeneXpert; (+), positive diagnostic test result.
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A man scans the quick-response code to complete a TB screening questionnaire in Tay Ninh province, 2022. © 2022 Vu Ngoc Dung/FHI 360
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FIGURE 3
Rates for TB-Presumptive CXR and Xpert Positivity From 2X ACF Before CAD, After CAD Piloting, and CAD Standardization^a
Abbreviations: 2X, Double X; ACF, active case-finding; CAD, computer-aided diagnosis; CXR, chest radiography; Xpert, GeneXpert.
^a Number of CXRs interpreted for each year: 2020, N=52,868; 2021, N=19,275; and 2022, N=28,437.
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FIGURE 4
Xpert Testing for Project Provinces Directly Implementing 2X^a Compared to Non-Project Provinces Receiving TA on 2X
Abbreviations: 2X, Double X; TA, technical assistance; Xpert, GeneXpert.
^a For 2X project sites, data were analyzed from 6 provinces that implemented for the full duration from 2020 through 2022, excluding 3 provinces that phased in or out of direct implementation. Data before project implementation (2017–2019) are shown for comparison with project results (2020–2022).

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TABLE 1.

TB Cascade for 2X ACF and ICF Implementation, March 2020–December 2022, Vietnam

Model	Screened With CXRs, No.	TB-Presumptive CXRs, No. (%)	Tested With Xpert, No.	Xpert Positive, No. (%)	TB Diagnosed (All Forms), No.	All Forms TB Yield per 100,000 CXR, No.	NNS With CXR	Cost to Detect 1 Person With TB Disease, US$	Initiated on TB Treatment, No. (%)
2X ACF community campaigns	100,580	16,197 (16.1)	16,033	1,393 (8.7)	1,448	1,440	69		1,193 (82.4)
Household contacts	21,529	2,120 (9.8)	2,217	138 (6.2)	140	650	154	739	121 (86.4)
Other TB vulnerable populations	79,051	14,077 (17.8)	13,816	1,255 (9.1)	1,308	1,655	60	739	1,072 (82.0)
2X ICF in health facilities	573,944	30,688 (5.3)	28,676	6,375 (22.2)	6,465	1,126	89	83	5,818 (90.0)
Diabetes outpatients	73,025	5,324 (7.3)	5,027	724 (14.4)	730	1,000	100	446	667 (91.4)
Smokers, alcohol use disorders, elderly^a	6,539	1,703 (26.0)	1,605	328 (20.4)	338	5,169	19	116	304 (89.9)
Inpatients and outpatients	494,380	23,661 (4.8)	22,044	5,323 (24.1)	5,397	1,092	92	31^b	4,847 (89.8)

Abbreviations: 2X, Double X; ACF, active case-finding; CXR, chest radiography; ICF, intensified case-finding; NNS, number needed to screen; Xpert, GeneXpert.
^a ICF smokers, those with alcohol use disorders, and those aged 60 years and older were evaluated in Dong Thap and Thai Binh provinces in 2021, and in An Giang province in 2022.
^b CXR costs were covered by the project for ACF and all ICF populations except inpatients and outpatients with clinical indications for TB whose CXRs were covered by social health insurance. Supplement Table S2 lists full cost details for all models.

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TABLE 2.

CXR and Xpert Results by Demographic Characteristics for 2X ACF and ICF Participants, March 2020–December 2022, Vietnam

	CXRs, No.	TB-Presumptive CXRs, No. (%)	Tested With Xpert, No.	Xpert Positive, No. (%)	TB Diagnosed (All forms), No.	All Forms TB Yield per 100,000 CXR, No.	NNS With CXR
ACF	100,580	16,197 (16.1)	16,033	1,393 (8.7)	1,448	1,440	69
Age, years
<5	693	94 (13.6)	181	3 (1.7)	3	433	231
5–14	4,481	263 (5.9)	288	4 (1.4)	4	89	1,120
15–24	2,968	221 (7.4)	213	18 (8.5)	18	606	165
25–34	5,346	499 (9.3)	491	47 (9.6)	47	879	114
35–44	10,367	1,109 (10.7)	1,073	99 (9.2)	101	974	103
45–54	17,173	2,419 (14.1)	2,391	227 (9.5)	234	1,363	73
55–64	26,546	4,521 (17)	4,453	393 (8.8)	421	1,586	63
≥65	30,880	7,004 (22.7)	6,918	515 (7.4)	533	1,726	58
Sex
Female	56,208	5,292 (9.4)	5,284	269 (5.1)	282	502	199
Male	44,372	10,905 (24.6)	10,749	1,124 (10.5)	1,166	2,628	38
ICF	573,944	30,688 (5.3)	28,676	6,375 (22.2)	6,465	1,126	89
Age, years^a
<5	NA	NA	495	13 (2.6)	15	NA	NA
5–14	NA	NA	269	35 (13.0)	40	NA	NA
15–24	NA	NA	536	225 (42.0)	227	NA	NA
25–34	NA	NA	1,249	461 (36.9)	464	NA	NA
35–44	NA	NA	2,359	838 (35.5)	844	NA	NA
45–54	NA	NA	4,346	1,317 (30.3)	1,331	NA	NA
55–64	NA	NA	7,262	1,571 (21.6)	1,593	NA	NA
≥65	NA	NA	11,003	1,658 (15.1)	1,694	NA	NA
Age NA	NA	NA	1,157	257 (22.2)	257	NA	NA
Sex
Female	279,292	11,000 (3.9)	10,272	1,450 (14.1)	1,475	528	189
Male	294,652	19,688 (6.7)	18,404	4,925 (26.8)	4,990	1,694	59

Abbreviations: ACF, active case-finding; CXR, chest radiography; ICF, intensified case-finding; NA, not available; NNS, number needed to screen; Xpert, GeneXpert.
^a CXRs disaggregated by age groups were not available for ICF implementation.

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TABLE 3.

TB Cascade for the 2X Strategy Adapted During the COVID-19 Pandemic, March 2021–December 2022, Vietnam

2X Model	Screened With CXRs, No.	TB-Presumptive CXRs, No. (%)	Tested With Xpert, No.	Xpert Positive, No. (%)	TB Diagnosed (All Forms), No.	All Forms TB Yield per 100,000 CXR, No.	NNS With CXR	Cost to Detect 1 Person With TB Disease, US$	Initiated on TB Treatment, No. (%)
Hybrid ACF/ICF from March 2021	8,674	1,463 (16.9)	1,575	91 (5.8)	96	1,107	90	718	84 (87.5)
Single X from October 2021	N/A	N/A	8,822	954 (10.8)	962	N/A	N/A	72	830 (86.3)
QR code self-screen from April 2022	2,554	1,062 (41.6)	1,048	217 (20.7)	228	8,927	11	225	213 (93.4)

Abbreviations: 2X, Double X; ACF, active case-finding; CXR, chest radiography; ICF, intensified case-finding; N/A, not applicable; NNS, number needed to screen; QR, quick response; Single X, GeneXpert-only algorithm.

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TABLE 4.

TB Infection Cascade Results Before and After Changing the TST Induration Threshold, Vietnam

	TB Infection^aDiagnostic Tests, No.	TB Infection Test Results, No. (%)	Positive TB Infection Test Results, No. (%)	Eligible for TPT After Excluding TB Disease, No.	Initiated on TPT, No. (%)
March 2020–October 2021: TST threshold ≥10 mm
ACF community campaigns	25,378	25,320 (99.8)	3,190 (12.6)	3,101	1,674 (54.0)
November 2021–December 2022: TST threshold ≥5 mm
ACF community campaigns	7,334	7,174 (97.8)	1,936 (26.4)	1,885	1,497 (79.4)

Abbreviations: ACF, active case-finding; QFT, QuantiFERON-TB Gold Plus; TPT, TB preventive treatment; TST, tuberculin skin testing.
↵^a TB infection was diagnosed using TST; in a subset of individuals (2,887 [8.8%]) who received both TST and QFT for quality assurance, a positive TST or QFT result yielded a diagnosis of TB infection. COVID-19 pandemic restrictions decreased the number undergoing TB infection evaluation in 2022.

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TABLE 5.

TB Cascade Before and After CAD Integration Into 2X ICF Facility Implementation, Vietnam

	Evaluated With CXRs, No.	TB-Presumptive CXRs, No. (%)	Tested With Xpert, No. (%)	TB Diagnosed (All Forms), No. (%)	All Forms TB Yield/ 100,000 CXR, No.	Initiated on TB Treatment, No. (%)
Before CAD: April–December 2021
CAD facilities (n=7)	12,351	1,322 (10.7)	1,320 (99.8)	437 (33.1)	3,538	424 (97.0)
After CAD: April–December 2022
CAD facilities (n=7)	19,289	3,884 (19.9)	3,352 (85.9)	896 (26.7)	4,645	816 (91.1)
Non-CAD facilities (n=23)	81,245	7,269 (8.9)	7,029 (96.4)	1,915 (27.2)	2,357	1,729 (90.3)

Abbreviations: CAD, computer-aided diagnosis; CXR, chest radiograph; ICF, intensified case-finding; Xpert, GeneXpert.

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TABLE 6.
All Forms TB Notifications per Year in 2X Provinces,^a Vietnam, 2017–2022
All Forms TB Notified, No. Rate of All Forms TB Notified per 100,000 Population
2017 14,854 127.24
2018 14,755 125.88
2019 14,753 125.38
2020 14,688 124.39
2021 10,690 90.25
2022 15,207 128.04
Abbreviation: 2X, Double X.
↵^a Annual TB notifications at the provincial level from the National TB Program’s Vietnam TB Information Management Electronic System were used to calculate notification rates per 100,000 population, using the total TB notifications for each province by year among the provinces’ total annual populations. Estimates of subnational populations in Vietnam for 2015–2030 were obtained from the U.S. President’s Emergency Plan for AIDS Relief’s U.S. Census Bureau.⁴³ Data were analyzed for the 6 2X provinces that implemented for the full duration from 2020–2022; data from pre-project implementation (2017–2019) are shown to compare trends.