Pulmonary Medicine
Volume 2021 (2021), Article ID 6680651, 12 pages
https://doi.org/10.1155/2021/6680651

Review Article

Prevalence of Latent Tuberculosis Infection in the Middle East and North Africa: A Systematic Review

Mazin Barry

Department of Internal Medicine, Division of Infectious Diseases, College of Medicine, King Saud University, Riyadh, Saudi Arabia

Correspondence should be addressed to Mazin Barry; mbarry@ksu.edu.sa

Received 21 October 2020; Revised 8 January 2021; Accepted 12 January 2021; Published 29 January 2021

Academic Editor: Stefano Centanni

Copyright © 2021 Mazin Barry. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Objective. Data on the prevalence of latent tuberculosis infection (LTBI) in Middle Eastern and North African countries are scarce. We aimed to review all relevant published data in countries belonging to this region to determine the overall prevalence of LTBI in the Middle East and North Africa (MENA) region. Methods. In this systematic review PubMed and Google Scholar databases were searched for observational, prospective, retrospective, cross-sectional, and cohort studies providing prevalence data of LTBI in any MENA country. Studies fulfilling the search criteria were incorporated in the review. Overall prevalence of LTBI with 95% confidence intervals (CI) was calculated using the random-effects model; heterogeneity was assessed using statistics. Gender and age group-based subgroup analyses were performed to evaluate the basis of heterogeneity. Results. The total number of overall LTBI studies identified was 956, of which 31 studies from ten countries within the MENA region were included that represented 12,439 subjects. The overall prevalence was 41.78% (95% CI 31.18% to 52.78%, ). By gender-based subgroup analysis, the prevalence of LTBI was 33.12% (95% CI 18.97% to 49.04%, ) and 32.65% (95% CI 19.79% to 47%, ) in males and females, respectively, while in the age-based subgroup analysis, the prevalence of LTBI was 0.44% (95% CI -0.05% to 0.9%), 3.37% (95% CI 2.23% to 4.74%, ), and 43.81% (95% CI 33.09% to 54.82%, ) for children, adolescents, and adults, respectively. Conclusion. This systematic review reveals a high prevalence of LTBI in the MENA region; enhanced LTBI surveillance and prompt infection prevention steps are urgently needed to prevent active tuberculosis, this would help achieve the World Health Organization End TB Strategy 2035, and the United Nations Sustainable Development Goals 2030 target in the MENA region.

1. Introduction

Tuberculosis (TB) is a major health problem, with an estimated 10 million people (range 9 to 11.1 million) developing TB disease in 2018, of which 5.8 million, 3.2 million, and 1 million were men, women, and children, respectively. Two-thirds of cases were from eight countries, India (27%), China (9%), Indonesia (8%), Philippines (6%), Pakistan (5%), Nigeria (4%), Bangladesh (4%), and South Africa (3%) [1]. Latent tuberculosis infection (LTBI) does not induce infectious expression of the disease, although it causes continuous immune response generated towards TB antigens. LTBI has a 10% probability of progressing into active TB disease, 5% during the first two years of acquiring the infection, and 5% during the rest of the individual’s lifetime. The detection of LTBI and prevention before it becomes infectious is a crucial component of the WHO-End TB strategy. It has been reported from mathematical models that approximately 30% of the population worldwide are LTBI carriers [2]. Previous studies have documented the rates of LTBI to be 31.2% in Ethiopia [3], 49% in Uganda [4], 55.2% in South Africa [5], 11.2% in Spain [6], 50% in India [7], 51% in Korea [8], and 7.6% in England [9];however, very few studies have been undertaken to estimate the prevalence of LTBI in the Middle East and North Africa (MENA) region.

In previous studies, it has been observed that patients belonging to lower socioeconomic groups, refugees, and migrants [10], patients with abnormal immune responses (post-organ transplant, hemodialysis patients, people living with HIV, etc.), and chronic inflammatory conditions have an increased risk of acquiring TB and its progression to active disease [11–13];further, LTBI in people living with HIV has a 10% probability of progressing into active TB, when left untreated, annually; furthermore, it has been shown that a significant geographical variation in TB infection rates persists across the world, implying that health care workers (HCW) in various countries encounter different risks of acquiring TB [14]. In 2018, 87% of new TB cases occurred in the top thirty high TB burden countries, of which eight countries accounted for two-thirds of all new TB cases, they include India, China, Indonesia, Philippines, Pakistan, Nigeria, Bangladesh, and South Africa, while the occurrence was extremely low in the MENA regions [1], it has also been reported that HCW are at particular risk of LTBI, and hence, annual screening is performed in most standardized health care facilities. In addition, the prevalence of LTBI in HCW has been reported to be higher than that of other community groups around the world [15, 16].

Currently, the direct diagnosis of LTBI is not fully possible [17]. The diagnosis of memory T-cell response against LTBI is performed by either the tuberculin skin test (TST) or interferon-gamma release assays (IGRA) [18]. At present, no gold standard test has been developed to measure LTBI; however, there are increasing advancements in this field looking into tumor necrosis factor, chemokines, interleukin growth factors, and other factors that could enhance LTBI diagnosis [19]. With TST, TB-purified protein derivative (PPD) stimulates a type IV hypersensitivity-delayed type reaction [20–22], its advantage is that it is inexpensive and generally accepted especially in low economic countries including Africa [3], but has several disadvantages, as it has demonstrated poor response in individuals with reduced immunity and those with active TB, requires two-step verification, is operative dependent, and exhibits low specificity in determining reactivation of TB in Bacillus Calmette-Guérin (BCG) vaccinated individuals, it can also cause false-positive results in patients sensitized to naturally existing nontuberculous mycobacteria [18, 23].

On the other hand, IGRA has greater specificity compared to TST [17], it involves only one blood test after incubation with Mycobacteria tuberculosis-specific antigens, following which T-cell mediated immune response and interferon- (IFN-) gamma release are measured. The QuantiFERON®-TB-Gold-in-Tube (QFT-GIT) and T-SPOT.TB assay tests are the two commercially available IGRA, in which the former is based on ELISA (enzyme-linked immunosorbent assay) and comprises of peptides from the ESAT-6, CFP-10, and TB7.7 antigens of TB. T-SPOT.TB assay is preferred in immunocompromised patients [24–26]. IGRA provides more conclusive results that would help in decision-making, with only a single visit required for the test, it also eliminates false-positive results in people vaccinated with BCG or sensitized with nontuberculous mycobacteria.

Several previous studies have documented the prevalence of LTBI in many countries of the Middle East and North Africa, in a wide range of population, including HCW, household contacts, people living with HIV, prisoners, refugees, and in patients with varied health problems; however, to our knowledge, there are no published studies that have assessed the overall prevalence within the whole MENA region; hence, we performed a systematic review to evaluate the prevalence of LTBI in the MENA region in different population groups belonging to various age groups.

2. Methods

2.1. Criteria for Considering Studies

2.1.1. Inclusion Criteria

Studies based on the incidence or prevalence of LTBI among people of all ages, origin, socioeconomic, and educational backgrounds, in countries located in the Middle East and North Africa, that are cross-sectional, observational, cohort, prospective, and retrospective studies, with LTBI detection performed with either TST or IGRA or both.

2.1.2. Exclusion Criteria

Systematic reviews, case reports, case series, editorials, letters to the editors, and randomized controlled trials.

2.2. Search Strategy

The author searched PubMed and Google Scholar databases for articles published between January 1, 2000 and November 30, 2018, in the English language. The use of medical subject heading (MeSH) terms for LTBI was employed in the database search combined with the following search terms: (latent tuberculosis OR TB OR LTBI OR Mycobacterium tuberculosis) AND (Prevalence OR Epidemiology OR “Country name”). The Middle East countries included were Iran, Iraq, Saudi Arabia, Yemen, Syria, Jordan, United Arab Emirates, Israel, Lebanon, Oman, Kuwait, Qatar, Bahrain, Palestine, Cyprus, and Turkey. North African countries included were Egypt, Libya, Algeria, Morocco, Tunisia, Sudan, Western Sahara, and Mauritania. A broad search strategy was used to ensure that all relevant studies were identified, with no filters included in the searches. Following this, the author independently analyzed the title of the study and its abstract and keywords outlining the record, based on which studies were either included or excluded. No minimal sample size was required to be included in the analysis; however, a sample size of ≥200 was considered as adequate, and a sample size of <200 was considered as inadequate.

2.3. Data Extraction

2.3.1. Study Selection and Data Extraction

A detailed search of PubMed and Google Scholar databases by employing various search terms was performed. The duplicate citations were removed, and the studies for inclusion in the review were selected. The initial screening was based on the citation titles and abstracts, following which, the articles were selected and picked up and their complete text obtained, reviewed, and assessed for their eligibility for inclusion. The bibliographic information of the included studies was also screened to identify additional relevant articles for inclusion; furthermore, the data from relevant studies were abstracted using a data extraction form, and the applicable items for the review were reported in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist. The following key information has been presented in the data extraction template: first author, period of study and year of publication, country where the research was conducted, study design, number of participants, age at assessment, tools used for assessment, and key findings.

2.3.2. Quality (Risk of Bias) Assessment

The Mirza and Jenkins [27] checklist were referred to for investigating the quality of included studies. The assessment was based on the following nine criteria: clear study aims, adequate sample size, representative sample, inclusion and exclusion criteria, adequate assessment of outcome, response rate reported, adequate description of data, appropriate statistical analysis, and appropriate informed consent obtained. A final total score was calculated for each of the criteria, scored 0 if absent and 1 if present. Thus, the minimum and maximum obtainable scores would be 0 and 9, respectively.

2.4. Statistical Analysis

Analysis was performed using STATA software. The effect sizes were reported as proportions with 95% confidence intervals. The heterogeneity of effects was assessed and quantified by the . The values greater than 50% were considered to represent substantial heterogeneity. The random-effects model was subjected in cases exhibiting substantial heterogeneity. Subgroup analysis based on sex (male and female), by age strata, and by quality score of the studies (<5 and ≥5) was also performed. A value less than 0.05 was considered statistically significant for all the analyses undertaken.

3. Results

3.1. Search Results and Study Selection

The database search resulted in a total of 956 citations, of which 384 citations were eliminated due to their duplication, and the rest of the 572 citations were examined. After screening, examination of titles and abstracts resulted in the elimination of 362 citations from the study. Following this, 210 full-text citations were retrieved, and after subjecting them to inclusion and exclusion criteria, a total of 31 studies were identified (Figure 1).

Figure 1: Flowchart for study selection.

3.2. Study Characteristics

Thirty-one studies representing 12,439 subjects from ten countries within the MENA region were included: thirteen from Turkey, five from both Iran and Saudi Arabia, two from Egypt, and one each from Syria, Israel, Oman, Qatar, Tunisia, and United Arab Emirates. These studies were conducted between 2005 till 2018. The sample size ranged from 34 to 2,650 (Table 1).

Table 1: Study characteristics.

Study/reference number
Duration of study
Year
Country
Study population
TST and/or QFT
Study design
Sample size
Age ()
Tools
LTBI
Prevalence (95% CI)
Outcome

Nasehi et al. [31]
October to December 2013
2016
Iran
TB laboratory staff and low-risk healthcare workers
TST
Cross-sectional
1006
and
ANOVA, logistic regression
791
78.62% (75.96, 81.12)
TB laboratory staff the OR of developing LTBI

Mamani et al. [32]
March 2013, 6 months
2016
Iran
Prisoners
TST
Cross-sectional
1208
18-60 years
Wilson procedure with continuity correction
756
62.58% (59.78, 65.32)
High prevalence of LTBI

Bukhary et al. [33]
December 2015
2018
Saudi Arabia
Healthcare workers working in hajj pilgrimage
TST QFT-GIT
Cross-sectional
520
22-62 years
Standardized questionnaire, chi-square test, Fisher exact test
56
10.76% (8.23, 13.75)
Low prevalence of LTBI

Balkhy et al. [34]
July 2010 to March 2013
2017
Saudi Arabia
Primary healthcare workers
TST QFT-GIT
Cross-sectional
1369
<15 to ≥65 years
Chi-square test, McNemar test
146
10.66% (9.07, 12.42)
Low prevalence of LTBI

El-Helaly et al. [35]
August 2009 to May 2011
2014
Saudi Arabia
Preemployment screening of tertiary healthcare workers
TST QFT-GIT
Cross-sectional
1372
18-60 years
Kappa coefficient, chi-square test
421
30.68% (28.25, 33.20)
Fair agreement between TST and QFT-G tests

Hassan and Diab et al. [36]
January to June 2012
2014
Saudi Arabia
Laboratory personnel at a university hospital
QFT-GIT
Cross-sectional
134
21-60 years ()
Standardized questionnaire, chi-square test, Fisher’s exact test
26
19.4% (13.08, 27.12)
Assessed risk factors involved with LTBI

Abbas et al. [37]
January 2008 to December 2009
2010
Saudi Arabia
Healthcare workers in tertiary care hospital
TST
Cross-sectional
2650
10 to >50 years
ANOVA
291
10.98% (9.81,12.23)
Highest LTBI rates in physicians and nurses

Warrington et al. [38]
January 2016
2018
Syria
Syrian refugees entering Canada
QFT-GIT
Cross-sectional
99
5 to <50 years
Two-tailed independent -tests
9
9.09% (4.24, 16.55)
Low prevalence of LTBI. No active TB

Mekaini et al. [39]
April to October 2013
2014
UAE
Pediatric population
QFT-GIT
Cross-sectional
669
1-19 years
Kruskal-Wallis one-way ANOVA, chi-square test, Fisher’s exact test
3
0.44% (0.09, 1.30)
Low prevalence of LTBI

Shitrit et al. [28]
September and December 2002
2005
Israel
High school students and adults
TST
Cross-sectional
84
years
Pearson correlation coefficient, Student’s -test
57
67.85% (56.77, 77.63)
High prevalence of LTBI

Khamis et al. [40]
January to June 2012
2016
Oman
Healthcare workers exposed to active TB in tertiary care hospital
TST QFT-GIT
Cross-sectional
291
20 to 65 years
Descriptive statistics
123
42.26% (36.52, 48.17)
High prevalence of LTBI among healthcare workers

Garcell et al. [41]
August 2012 to May 2013
2014
Qatar
Healthcare workers in community hospital
TST QFT-GIT
Cross-sectional
202
 years
Test of independence, Student’s -test, and Wilcoxon Mann–Whitney
14
6.93% (3.84, 11.35)
Low prevalence of LTBI

Gunluoglu et al. [42]
September to November 2011
2015
Turkey
Chronic renal failure patients undergoing regular hemodialysis
TST QFT-GIT
Cross-sectional
44 (TST); 50 (QFT-GIT)
62.2 years (mean age)
Kappa statistic, Mann–Whitney -test, chi-square, Fisher’s exact test, Wilks’ lambda test
16 (TST+); 27 (QFT-GIT+)
50% (37.23, 62.76)
High prevalence of LTBI

Duman et al. [43]
Not available
2014
Turkey
Psoriasis patients
TST QFT-GIT
Cross-sectional
61 (psoriasis); 40 (psoriatic arthritis)
 years
Kolmogorov–Smirnov test, -test, Mann–Whitney -test, chi-square test, multivariable logistic regression, multiple linear regression
52 (psoriasis); 29 (psoriatic arthritis)
80.19% (71.08, 87.46)
High prevalence of LTBI

Babayigit et al. [44]
Not available
2014
Turkey
BCG vaccinated healthcare workers
TST QFT-GIT
Cross-sectional
64
21 to 51 years ()
Kolmogorov-Smirnov test, Shapiro Wilk test, Mann–Whitney -test, Fisher exact test, Pearson chi-square test, logistic regression analysis
32
50% (37.23, 62.76)
High prevalence of LTBI

Yilmaz et al. [29]
Not available
2012
Turkey
Patients with systemic lupus erythematosus
TST
QFT-GIT
Cross-sectional
78
13 to 67 years
Cohen’s kappa analysis, chi-square test, Mann–Whitney -test
41
52.56% (40.93, 63.99)
High prevalence of LTBI

Hanta et al. [45]
Not available
2012
Turkey
Patients with rheumatologic diseases
TST QFT-GIT
Cross-sectional
90
 years
Chi-square test or Fisher’s exact test
66
73.33% (62.96, 82.10)
High prevalence of LTBI

Soysal et al. [46]
May 2006 to May 2007
2012
Turkey
Hemodialysis patients
TST T-SPOT.TB
Cross-sectional
411
19 to 84 years
Student’s -test, chi-square test or Fisher’s exact test, logistic regression analysis
61
14.84% (11.54, 18.65)
Use of T-SPOT.TB in patients with negative TST for diagnosis of LTBI

Caglayan et al. [47]
August 2005
2011
Turkey
Healthcare workers of tertiary care hospital
TST QFT-GIT
Cross-sectional
78
years
ANOVA
59
75.64% (64.60, 84.65)
High prevalence of LTBI

Karadag et al. [48]
Not available
2010
Turkey
Patients with Takayasu arteritis
TST
QFT-GIT
Cross-sectional
94
 years
Student’s -test, Wilcoxon rank-sum test, chi-square test, Fisher’s exact test
55
58.51% (47.88, 68.58)
High prevalence of LTBI

Inanc et al. [49]
March 2007 to June 2008
2009
Turkey
Patients with rheumatoid arthritis and Ankylosing spondylitis
TST QFT-GIT
Cross-sectional
140
 years
Chen’s kappa analysis, Mann–Whitney -test, chi-square test
85
60.71% (52.11, 68.85)
High prevalence of LTBI

Seyhan et al. [50]
Not available
2010
Turkey
Hemodialysis patients
TST QFT-GIT
Cross-sectional
100
years
Student -test, Mann–Whitney -test, chi-square test
56
56% (45.71, 65.91)
High prevalence of LTBI

Hanta et al. [51]
April 2005 to January 2008
2008
Turkey
Patient with rheumatoid arthritis, ankylosing arthritis, and psoriatic arthritis
TST
Cross-sectional
192
 years
Fisher’s exact test
129
67.18% (60.05, 73.77)
TST can be used for diagnosis of LTBI in rheumatologic disease before anti-TNF therapy.

Ozdemir et al. [52]
June to August 2005
2007
Turkey
Healthcare workers in Duzce University hospital
TST QFT-GIT
Cross-sectional
76
18 to 50 years ()
Cohen’s kappa, chi-square test, Student’s -test
67
88.15% (78.70, 94.44)
High prevalence of LTBI

Bozkanat et al. [53]
March 2008
2016
Turkey
Healthcare workers in specialist tuberculosis hospital
TST QFT-GIT
Cross-sectional
34
years
Kappa test
23
67.64% (49.47, 82.61)
High prevalence of LTBI

Hasanain et al. [54]
December 2015 to January 2017
2018
Egypt
Patients with erectile dysfunction
TST QFT-GIT
Cross-sectional
97
years
Chi-square test, Fisher’s exact test
29
29.89% (21.02, 40.04)
Prevalence of LTBI was high in patients with high-grade ED

El-Sokkary et al. [55]
August 2012 to January 2013
2015
Egypt
Healthcare providers
TST QFT-GIT
Cross-sectional
132
years
Chi-square test, Fisher’s exact test
78
59.09% (50.19, 67.56)
High prevalence of LTBI

Slouma et al. [56]
2007 to 2014
2017
Tunisia
Patients with chronic inflammatory diseases receiving biologic agents since at least 6 months
TST QFT-GIT
Cohort
113
 years
Student’s -test, ANOVA
23
20.35% (13.36, 28.95)
Low prevalence of LTBI

Khazraiyan et al. [57]
January to May 2013
2016
Iran
HIV positive patients
TST QFT-GIT
Cross-sectional
130
19 to 71 years ()
Chi-square test, Fisher’s exact test
38
29.23% (21.58, 37.84)
Low prevalence of LTBI

Jam et al. [30]
January 2006 to February 2007
2010
Iran
Patients with HIV/AIDS
TST
Cross-sectional
262
1 month to >60 years
Chi-square test
63
24.04% (19, 29.68)
Medium prevalence of LTBI

Amiri et al. [58]
June to August 2012
2014
Iran
Homeless people of Tehran
QFT-GIT
Cross-sectional
593
Not available
Logistic regression and chi-square test
277
46.71% (42.63,50.81)
High prevalence of LTBI

[Overall prevalence 41.78% (31.18, 52.78)]

QFT-GIT: QuantiFERON-TB Gold In-Tube; TST: tuberculin skin test; LTBI: latent tuberculosis infection; OR: odds ratio; ANOVA: analysis of variance; HIV: human immunodeficiency virus; AIDS: acquired immunodeficiency syndrome; TNF: tumor necrosis factor.

3.3. Publication Bias

From the 31 studies, the minimal checklist score was 5 in two studies, while the highest was 9. Details of all included studies clarity, adequacy of sample size, and other details are outlined in Table 2.

Table 2: Quality assessment of the studies included in the review.

Study
Clear study aims
Adequate sample size
Representative sample
Inclusion and exclusion criteria
Adequate assessment of outcome
Response rate reported
Adequate description of data
Appropriate statistical analysis
Appropriate informed consent obtained
Total score

Nasehi et al., 2016 [31]
1
1
1
1
1
1
1
1
1
9

Mamani et al., 2016 [32]
1
1
1
1
1
1
1
1
1
9

Bukhary et al., 2018 [33]
1
1
1
1
1
0
1
1
1
8

Balkhy et al., 2017 [34]
1
1
1
1
1
0
1
1
1
8

El-Helaly et al., 2014 [35]
1
1
1
1
1
0
1
1
0
7

Hassan and Diab, 2014 [36]
1
0
1
1
0
0
1
1
1
6

Abbas et al., 2010 [37]
1
1
1
1
1
0
1
1
0
7

Warrington et al., 2018 [38]
1
0
1
1
0
0
1
1
0
5

Mekaini et al., 2014 [39]
1
1
1
1
1
0
1
1
1
8

Shitrit et al., 2005 [28]
1
0
1
1
0
1
1
1
1
7

Khamis et al., 2016 [40]
1
1
1
1
1
0
1
1
0
7

Garcell et al., 2014 [41]
1
1
1
1
1
0
1
1
0
7

Gunluoglu et al., 2015 [42]
1
0
1
1
0
1
1
1
1
7

Duman et al., 2014 [43]
1
0
1
1
0
1
1
1
1
7

Babayigit et al., 2014 [44]
1
0
1
1
0
1
1
1
1
7

Yilmaz et al., 2012 [29]
1
0
1
1
0
1
1
1
1
7

Hanta et al., 2012 [45]
1
0
1
1
0
1
1
1
0
6

Soysal et al., 2012 [46]
1
0
1
1
0
0
1
1
0
5

Caglayan et al., 2011 [47]
1
0
1
1
0
1
1
1
0
6

Karadag et al., 2010 [48]
1
0
1
1
0
1
1
1
0
6

Inanc et al., 2009 [49]
1
1
1
1
1
1
1
1
1
9

Seyhan et al., 2010 [50]
1
0
1
1
0
1
1
1
1
7

Hanta et al., 2008 [51]
1
0
1
1
0
1
1
1
0
6

Ozdemir et al., 2007 [52]
1
0
1
1
0
1
1
1
1
7

Bozkanat et al., 2016 [53]
1
0
1
1
0
1
1
1
0
6

Hasanain et al., 2018 [54]
1
0
1
1
0
0
1
1
1
6

El-Sokkary et al., 2015 [55]
1
0
1
1
0
1
1
1
1
7

Slouma et al., 2017 [56]
1
0
1
1
0
0
1
1
0
5

Khazraiyan et al., 2016 [57]
1
0
1
1
0
0
1
1
1
6

Jam et al., 2010 [30]
1
1
1
1
1
0
1
1
1
8

Amiri et al., 2014 [58]
1
1
1
1
1
0
1
1
0
7

A sample size of ≥200 was considered as adequate and a sample size of <200 was considered as inadequate. †A response rate of <50% was considered as , and>50% was considered as .

3.4. Prevalence of LTBI

The prevalence of LTBI was assessed in 31 studies using random-effects model. A total of 3,981 events were observed among the 12,439 subjects. The proportion of LTBI ranged from 0.44% to 88.15%. The overall prevalence was observed to be 41.78% (95% CI 31.18% to 52.78%, ).

The subgroup analyses revealed the existence of heterogeneity. In the gender-based subgroup analysis, some of the studies failed to mention the gender-based prevalence of LTBI, and hence 14 and 15 studies were excluded from the subgroup analysis of males and females, respectively; hence, the subgroup analysis of males was performed with 17 studies, and that of females with 16 studies. The analysis revealed that the proportion of LTBI ranged from 0.32% to 86.04% and from 0.54% to 90.90% in males and females, respectively. The overall prevalence was estimated to be 33.12% (95% CI 18.97% to 49.04%, ) and 32.65% (95% CI 19.79% to 47%, ) in males and females, respectively.

For the evaluation of age-based prevalence, the WHO classification for age groups was utilized, and the age range for children, adolescents, and adults was taken as <10 years, between 10 and 19 years, and >19 years, respectively; further, three studies, Shitrit et al. [28], Yilmaz et al. [29], and Jam et al. [30], were excluded from this subgroup analysis as the age of subjects in those studies overlapped the age range for children, adolescents, and adults, i.e., 12 years and above, 13 to 67 years, and 1 month to above 60 years, respectively. Moreover, there was no differentiation in the age range for the prevalence of LTBI in these studies; hence, the subgroup analysis of children, adolescents, and adults was performed with 1, 2, and 27 studies, respectively. The prevalence of LTBI in children was observed to be 0.44% (95% CI -0.05% to 0.9%); the prevalence of LTBI in adolescents and adults ranged from 2.46% to 3.55% and 6.93% to 88.15%, respectively. The overall prevalence was observed to be 3.37% (95% CI 2.23% to 4.74%, ) and 43.81% (95% CI 33.09% to 54.82%, ) for adolescents and adults, respectively.

4. Discussion

After screening 956 studies, a total of 31 scientific papers from ten countries within the MENA region were included in this systematic review [28–58]. The subjects included in these studies were healthcare workers, laboratory staff, medical school students, people living with HIV, and patients with chronic inflammatory diseases. The detection of LTBI in these studies was performed by TST or IGRA or both; furthermore, the studies covered the incidence of LTBI among populations belonging to varying age groups, including children, adolescents, and adults.

In the present study, LTBI prevalence was evaluated by employing the random effects model since high heterogeneity was encountered among studies. The existence of high heterogeneity may have possibly been due to variations in study settings, subjects or participants, methodologies involved, exposure to TB patients, and the control measures taken across the studies.

The overall prevalence of LTBI in the MENA region was found to be 41.78%. In the gender-based subgroup analyses, the prevalence of LTBI was found to be 33.12% and 32.65% in males and females, respectively. As for the age-based prevalence, it was assessed to be 0.44%, 3.37%, and 43.81% in children, adolescents, and adults, respectively; therefore, this systematic review implies a high prevalence of LTBI in the MENA region irrespective of gender, and in order to achieve the WHO End TB 2035 objective, there is an immediate need to scale up measures to stop TB disease and enhance LTBI detection within the MENA region.

There are some strengths and limitations within this study that needs to be highlighted; first, as per our findings, this is the first systematic review on the epidemiology and prevalence of LTBI in the MENA region. As for limitations, studies published in English alone have been included, therefore, other reports from countries with high TB incidence that are published in native or other languages other than English, in national or local journals, have not been included; additionally, studies published in journals indexed in PubMed and Google Scholar were included, while other studies may exist that were published in other indexing databases.

To conclude, this review indicates a high prevalence of LTBI in the MENA region despite the high heterogeneity observed. Future studies should aim towards more rigorous assessment of LTBI prevalence within the MENA region to reach exact estimates as the first important step to hamper TB disease diffusion in these countries.

Data Availability

All data are included in the manuscript.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

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