Cost-effectiveness of IGRA/QFT-Plus for TB screening of migrants in Oman

A step forward in tuberculosis elimination: implementing migrant latent tuberculosis screening and treatment in Oman

Objectives

This study aimed to outline the process of implementation of latent tuberculosis (TB) infection (LTBI) screening among migrants using interferon-γ release assay (IGRA), describe the LTBI treatment protocol and cascade of care, and highlight success factors and challenges.

Design

This is a description of the process of implementation of screening of TB infection through a medical fitness program for residency, using primary care treatment module and short regimen.

Results

Before 2018, expatriates seeking residency employment in Oman undergo two-step medical fitness examination process that mainly rely on chest X-ray (CXR) before arrival and physical examination after arrival, with 15% random sample repeated. In 2018, Oman implemented CXR screening for all alongside symptom checks. With further surge of TB cases after COVID-19, screening using IGRA was introduced through a medical fitness program in 2024. Those who are IGRA-positive or indeterminate will proceed to CXR with subsequent referral to primary care for short regimen treatment (3 months of daily rifampicin plus isoniazid and pyridoxine) if eligible.

Conclusions

Oman aims to achieve sustainability through establishing an integrated LTBI screening for migrants within the residency medical fitness program using integrated electronic system, highly sensitive test, public private model (under government regulation), and high throughput testing methods. Treatment using a short regimen (3 months of daily rifampicin plus isoniazid) through primary care will improve treatment adherence, improve outcome, and reduce TB incidence.

Mycobacterium tuberculosis epidemiology in Oman: whole-genome sequencing uncovers transmission pathways

Tuberculosis (TB) originating from expatriates that hail from high TB-burden countries is hypothesized to play a role in continued TB transmission in Oman. Here, we used whole-genome sequencing (WGS) to assess national TB transmission dynamics. The annual incidence per 100,000 population per year was calculated for nationals and expatriates. A convenience sample of Mycobacterium tuberculosis (MTB) isolates from 2018 to 2019 was sequenced and analyzed with publicly available TB sequences from Bangladesh, Tanzania, the Philippines, India, and Pakistan. Relatedness was assessed by generating core-genome single nucleotide polymorphism (SNP) distances. The incidence of TB was five cases per 100,000 persons in 2018 and seven cases per 100,000 persons in 2020 (R2 = 0.34, P = 0.60). Incidence among nationals was 3.9 per 100,000 persons in 2018 and 3.5 per 100,000 persons in 2020 (R2 = 0.20, P = 0.70), and incidence among expatriates was 7.2 per 100,000 persons in 2018 and 12.7 per 100,000 persons in 2020 (R2 = 0.74, P = 0.34). Sixty-eight local MTB isolates were sequenced and analyzed with 393 global isolates. Isolates belonged to nine distinct spoligotypes. Two isolates, originating from an expatriate and an Omani national, were grouped into a WGS-based cluster (SNP distance < 12), which was corroborated by an epidemiological investigation. Relatedness of local and global isolates (SNP distance < 100) was also seen. The relatedness between MTB strains in Oman and those in expatriate countries of origin can aid inform TB control policy. Our results provide evidence that WGS can complement epidemiological analysis to achieve the End TB strategy goal in Oman. IMPORTANCE Tuberculosis (TB) incidence in Oman remains above national program control targets. TB transmission originating from expatriates from high TB-burden countries has been hypothesized to play a role. We used whole-genome sequencing (WGS) to assess TB transmission dynamics between expatriates and Omani nationals to inform TB control efforts. Available Mycobacterium tuberculosis isolates from 2018 to 2019 underwent WGS and analysis with publicly available TB sequences from Bangladesh, the Philippines, India, and Pakistan to assess for genetic relatedness. Our analysis revealed evidence of previously unrecognized transmission between an expatriate and an Omani national, which was corroborated by epidemiological investigation. Analysis of local and global isolates revealed evidence of distant relatedness between local and global isolates. Our results provide evidence that WGS can complement classic public health surveillance to inform targeted interventions to achieve the End TB strategy goal in Oman.

The Global Expansion of LTBI Screening and Treatment Programs: Exploring Gaps in the Supporting Economic Evidence

The global burden of latent TB infection (LTBI) and the progression of LTBI to active TB disease are important drivers of ongoing TB incidence. Addressing LTBI through screening and TB preventive treatment (TPT) is critical in order to end the TB epidemic by 2035. Given the limited resources available to health ministries around the world in the fight against TB, we must consider economic evidence for LTBI screening and treatment strategies to ensure that limited resources are used to achieve the biggest health impact. In this narrative review, we explore key economic evidence around LTBI screening and TPT strategies in different populations to summarize our current understanding and highlight gaps in existing knowledge. When considering economic evidence supporting LTBI screening or evaluating different testing approaches, a disproportionate number of economic studies have been conducted in high-income countries (HICs), despite the vast majority of TB burden being borne in low- and middle-income countries (LMICs). Recent years have seen a temporal shift, with increasing data from low- and middle-income countries (LMICs), particularly with regard to targeting high-risk groups for TB prevention. While LTBI screening and prevention programs can come with extensive costs, targeting LTBI screening among high-risk populations, such as people living with HIV (PLHIV), children, household contacts (HHC) and immigrants from high-TB-burden countries, has been shown to consistently improve the cost effectiveness of screening programs. Further, the cost effectiveness of different LTBI screening algorithms and diagnostic approaches varies widely across settings, leading to different national TB screening policies. Novel shortened regimens for TPT have also consistently been shown to be cost effective across a range of settings. These economic evaluations highlight key implementation considerations such as the critical nature of ensuring high rates of adherence and completion, despite the costs associated with adherence programs not being routinely assessed and included. Digital and other adherence support approaches are now being assessed for their utility and cost effectiveness in conjunction with novel shortened TPT regimens, but more economic evidence is needed to understand the potential cost savings, particularly in settings where directly observed preventive therapy (DOPT) is routinely conducted. Despite the growth of the economic evidence base for LTBI screening and TPT recently, there are still significant gaps in the economic evidence around the scale-up and implementation of expanded LTBI screening and treatment programs, particularly among traditionally hard-to-reach populations.

First evaluation of the performance of portable IGRA, QIAreach® QuantiFERON®-TB in intermediate TB incidence setting

Diagnosis and treatment of tuberculosis infection (TBI) are the core elements of tuberculosis elimination. Interferon gamma release assays have advantages over the tuberculin skin test, although their implementation in low-resource settings is challenging. The performance of a novel digital lateral flow assay QIAreach® QuantiFERON®-TB (QIAreach QFT) against the QuantiFERON®-TB Gold Plus (QFT-Plus) assay was evaluated in an intermediate incidence setting (Malaysia) according to the manufacturer's instructions. Individuals aged 4-82 years, who were candidates for TB infection screening for contact investigation were prospectively recruited. On 196 samples, the QIAreach-QFT showed a positive percent agreement (sensitivity) was 96.5% (CI 87.9-99.6%), a negative percent agreement (specificity) 94.2% (CI 88.4% to 97.6%) and an overall percentage of agreement was 94.9% (95% CI 90.6-97.6%) with a Cohen's κ of 0,88. Out of 196, 5.6% (11/196) samples gave an error result on QIAreach-QFT and 4.1% (8/196) samples gave indeterminate result on QFT-plus. The TTR for QIAreach QFT positive samples varied from 210-1200 seconds (20 min) and significantly correlated with IFN-γ level of QFT-Plus. QIAreach QFT could be considered an accurate and reliable point-of-need test to diagnose TB infection helping to achieve the WHO End TB programme goals even in decentralised settings where laboratory expertise and infrastructure may be limited.

Assessing Oman's knowledge, attitude and practice regarding tuberculosis: a cross-sectional study that calls for action

BACKGROUND

Tuberculosis (TB) remains a major public health issue. Elimination mandates collaboration between decision makers, practitioners and the community. Few studies address the knowledge, attitude and practice (KAP) from countries with low incidence.

AIM

Assess KAP regarding TB in Oman.

METHOD

A cross-sectional survey based on validated questionnaire conducted via phone on randomly selected participants.

RESULTS

A total of 1048 participants completed the questionnaire. Males accounted for 63% (n=664) of respondents, Omanis 76% (n=796) and 18-39-year-olds 50% (n=527). The overall knowledge was fair (53%), overall attitude scored good and fair (46%) equally and a good score (78%) for overall practice. While female gender associated with higher knowledge (53.9%, n=201), males showed higher attitude and practice, (48.5%, n=322) and (80.3%, n=533) respectively. Omani nationality correlated with higher knowledge (49.1%, n= 391) and attitude (46.9%, n=373) whereas non-Omani nationality correlated with higher practice (85.3%, n=214). Literacy was associated with higher knowledge (73.3%, n=11) and attitude (60%, n=9).

CONCLUSION

Despite efforts by the Ministry of Health, more must be done to raise TB knowledge to encourage preferable attitudes and practice. Interventions to improve KAP are required to speed up disease reduction rate. Utilization of different resources, especially digital platforms, for knowledge dissemination should consider community diversity, including the presence of expatriates.

A systematic review of cost-utility analyses of screening methods in latent tuberculosis infection in high-risk populations

Background

The World Health Organisation (WHO) recommends that testing and treatment for latent tuberculosis infection (LTBI) should be undertaken in high-risk groups using either interferon gamma release assays (IGRAs) or a tuberculin skin test (TST). As IGRAs are more expensive than TST, an assessment of the cost-effectiveness of IGRAs can guide decision makers on the most appropriate choice of test for different high-risk populations. This current review aimed to provide the most up to date evidence on the cost-effectiveness evidence on LTBI testing in high-risk groups—specifically evidence reporting the costs per QALY of different testing strategies.

Methods

A comprehensive search of databases including MEDLINE, EMBASE and NHS-EED was undertaken from 2011 up to March 2021. Studies were screened and extracted by two independent reviewers. The study quality was assessed using the Bias in Economic Evaluation Checklist (ECOBIAS). A narrative synthesis of the included studies was undertaken.

Results

Thirty-two studies reported in thirty-three documents were included in this review. Quality of included studies was generally high, although there was a weakness across all studies referencing sources correctly and/or justifying choices of parameter values chosen or assumptions where parameter values were not available. Inclusions of IGRAs in testing strategies was consistently found across studies to be cost-effective but this result was sensitive to underlying LTBI prevalence rates.

Conclusion

While some concerns remain about uncertainty in parameter values used across included studies, the evidence base since 2010 has grown with modelling approaches addressing the weakness pointed out in previous reviews but still reaching the same conclusion that IGRAs are likely to be cost-effective in high-income countries for high-risk populations. Evidence is also required on the cost-effectiveness of different strategies in low to middle income countries and countries with high TB burden.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02149-x.

Drug resistant Mycobacterium tuberculosis in Oman: resistance-conferring mutations and lineage diversity

Background

The Sultanate of Oman is country a low TB-incidence, with less than seven cases per 10⁵ population detected in 2020. Recent years have witnessed a persistence in TB cases, with sustained incidence rate among expatriates and limited reduction among Omanis. This pattern suggests transmission from the migrant population. The present study examined the genetic profile and drug resistance-conferring mutations in Mycobacterium tuberculosis collected from Omanis and expatriates to recognise possible causes of disease transmission.

Methods

We examined M. tuberculosis cultured positive samples, collected from Omanis (n = 1,344) and expatriates (n = 1,203) between 2009 and 2018. These isolates had a known in vitro susceptibility profile to first line anti-TB, Streptomycin (SM), Isoniazid (INH), Rifampicin (RIF), Ethambutol (EMB) and Pyrazinamide (PZA). The diversity of the isolates was assessed by spacer oligo-typing (spoligotyping). Drug resistance-conferring mutations resulted from full-length sequence of nine genes (katG, inhA, ahpc, rpoB, rpsL, rrs, embB, embC, pncA) and their phenotypic relationship were analysed.

Results

In total, 341/2192 (13.4%), M. tuberculosis strains showed resistance to any drug, comprising mono-resistance (MR) (242, 71%), poly-resistance (PR) (40, 11.7%) and multi-drug resistance (MDR) (59, 17.3%). The overall rate of resistance among Omanis and expatriates was similar; however, MDR and PZA^R were significantly higher among Omanis, while INH^R was greater among expatriates. Mutations rpsL K43R and rpoB S450L were linked to Streptomycin (SM^R) and Rifampicin resistance (RIF^R) respectively. Whereas, katG S315T and inhA -C15T/G-17T were associated with Isoniazid resistance (INH^R). The resistance patterns (mono-resistant, poly-resistant and MDR) and drug resistance-conferring mutations were found in different spoligo-lineages. rpsL K43R, katG S315T and rpoB S450L mutations were significantly higher in Beijing strains.

Conclusions

Diverse drug resistant M. tuberculosis strains exist in Oman, with drug resistance-conferring mutations widespread in multiple spoligo-lineages, indicative of a large resistance reservoir. Beijing's M. tuberculosis lineage was associated with MDR, and multiple drug resistance-conferring mutations, favouring the hypothesis of migration as a possible source of resistant lineages in Oman.

Does health economics research align with the disease burden in the Middle East and North Africa region? A systematic review of economic evaluation studies on public health interventions

INTRODUCTION

Economic evaluation studies demonstrate the value of money in health interventions and enhance the efficiency of the healthcare system. Therefore, this study reviews published economic evaluation studies of public health interventions from 26 Middle East and North Africa (MENA) countries and examines whether they addressed the region's major health problems.

METHODS

PubMed and Scopus were utilized to search for relevant articles published up to June 26, 2021. The reviewers independently selected studies, extracted data, and assessed the quality of studies using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist.

RESULTS

The search identified 61 studies. Approximately half (28 studies; 46%) were conducted in Israel and Iran. The main areas of interest for economic evaluation studies were infectious diseases (21 studies; 34%), cancers (13 studies; 21%), and genetic disorders (nine studies; 15%). Five (8%), 39 (64%), 16 (26%), and one (2%) studies were classified as excellent, high, average, and poor quality, respectively. The mean of CHEERS checklist items reported was 80.8% (SD 14%). Reporting the structure and justification of the selected model was missed in 21 studies (37%), while price and conversion rates and the analytical methods were missed in 21 studies (34%).

CONCLUSIONS

The quantity of economic evaluation studies on public health interventions in the MENA region remains low; however, the overall quality is high to excellent. There were obvious geographic gaps across countries regarding the number and quality of studies and gaps within countries concerning disease prioritization. The observed research output, however, did not reflect current and upcoming disease burden and risk factors trends in the MENA region.

Importance of Tuberculosis Screening of Resident Visa Applicants in Low TB Incidence Settings: Experience from Oman

Introduction

For Oman, a country targeting tuberculosis (TB) elimination, TB among expatriates is a major challenge. Thus, screening for active TB using chest X-ray was made mandatory for expatriates’ residency renewals.

Objective

To estimate the incidence of bacteriologically confirmed TB and assess impact of chest X-ray based TB screening among expatriates in Muscat Governorate.

Methods

Applicants for residency and renewals were mandated for chest X-ray-based TB screening in 2018. We collected data of screened subjects with radiological suspicion of TB who were subjected to further bacteriological evaluation.

Results

Of 501,290 applicants screened during the study period, 436 (0.09%) had X-ray findings suggestive of TB. Among the 436, TB was confirmed in 53 (12.2%; 95% CI 9.2–15.6), giving an overall prevalence of 10.6 (95% CI 8–13.9) per 100,000 applicants (number needed to be screened 9458). Among renewals, the point prevalence of TB was 10.5 per 100,000 expatriates screened (95% CI 6.9–14.04 per 100,000), with a mean follow-up period of 11.8 years.

Conclusion

Our findings are consistent with the recommendation for utilization of chest X-ray as a preferred tool for active case finding in the setting of expatriate screening. Our findings are also suggestive of the need for latent TB screening and ruling out TB prior to latent TB treatment.

COVID-19 and Pulmonary Mycobacterium Tuberculosis Coinfection

The Coronavirus disease-2019 (COVID-19) outbreak was classified as a global pandemic by the World Health Organization on 11 March 2020. It is caused by the novel severe acute respiratory syndrome coronavirus 2. The virus affects mainly the human respiratory system. Mycobacterium tuberculosis (TB) is another respiratory infection known to affect humans and may share joint clinical presentations and risk factors with COVID-19 infection. Therefore, clinicians must have a high index of suspicion that the two infections might coexist so that there is no delay in diagnosis and starting the appropriate treatment. There are few case reports about TB and COVID-19 coinfection. The first case report ever was from China and there have been a few others around the world. Here, we report two cases of coexisting COVID-19 and newly diagnosed pulmonary TB infection in Oman.

First clinical evaluation of the QIAreachTM QuantiFERON-TB for tuberculosis infection and active pulmonary disease

OBJECTIVE

1) to compare the QIAreach^TM QuantiFERON-TB (QIAreach QFT) vs. QuantiFERON®-TB Gold Plus assay (QFT-Plus) to detect tuberculosis (TB) infection; 2) to evaluate diagnostic sensitivity of QIAreach QFT using active TB as surrogate for TB infection; 3) to preliminarily evaluate QIAreach QFT in immunocompromised individuals.

METHODS

QIAreach QFT measures the level of interferon-γ (IFN-γ) in plasma specimens from blood stimulated by ESAT-6 and CFP-10 peptides in one blood collection tube (equivalent to the TB2 tube of the QFT-Plus). QIAreach QFT was applied to plasma samples from 41 patients with pulmonary TB and from 42 healthy or low-TB-risk individuals.

RESULTS

Sensitivity and specificity of QIAreach QFT vs. QFT-Plus were 100% (41/41) and 97.6% (41/42), respectively; overall concordance was 98.8% (82/83). All samples were measured within 20 min. The time to result of each sample was significantly correlated with IFN-γ level with a natural logarithmic scale (r = -0.913, p < 0.001). Seven cases in the active TB group were immunocompromised (CD4 <200/μL) and tested positive by QIAreach QFT.

CONCLUSIONS

QIAreach QFT provides an objective readout with a minimum blood sample volume (1 mL/subject), potentially being a useful point-of-care screening test for TB infection in high-TB-burden, low-resource countries and for immunocompromised patients.