Integration of Electrochemical Sensing and Machine Learning to Detect Tuberculosis via Methyl Nicotinate in Patient Breath.

Tuberculosis (TB) remains a significant global health issue; making early, accurate, and inexpensive point-of-care detection critical for effective treatment. This paper presents a clinical demonstration of an electrochemical sensor that detects methyl-nicotinate (MN), a volatile organic biomarker associated with active pulmonary tuberculosis. The sensor was initially tested on a patient cohort comprised of 57 adults in Kampala, Uganda, of whom 42 were microbiologically confirmed TB-positive and 15 TB-negative. The sensor employed a copper(II) liquid metal salt solution with a square wave voltammetry method tailored for MN detection using commercially available screen-printed electrodes. An exploratory machine learning analysis was performed using XGBOOST. Utilizing this approach, the sensor was 78% accurate with 71% sensitivity and 100% specificity. These initial results suggest the sensing methodology is effective in identifying TB from complex breath samples, providing a promising tool for non-invasive and rapid TB detection in clinical settings.

Circulating cell-free RNA in blood as a host response biomarker for detection of tuberculosis.

Tuberculosis (TB) remains a leading cause of death from an infectious disease worldwide, partly due to a lack of effective strategies to screen and triage individuals with potential TB. Whole blood RNA signatures have been tested as biomarkers for TB, but have failed to meet the World Health Organization's (WHO) optimal target product profiles (TPP). Here, we use RNA sequencing and machine-learning to investigate the utility of plasma cell-free RNA (cfRNA) as a host-response biomarker for TB in cohorts from Uganda, Vietnam and Philippines. We report a 6-gene cfRNA signature, which differentiates TB-positive and TB-negative individuals with AUC = 0.95, 0.92, and 0.95 in test, training and validation, respectively. This signature meets WHO TPPs (sensitivity: 97.1% [95% CI: 80.9-100%], specificity: 85.2% [95% CI: 72.4-100%]) regardless of geographic location, sample collection method and HIV status. Overall, our results identify plasma cfRNA as a promising host response biomarker to diagnose TB.

C-reactive protein-based tuberculosis triage testing: a multi-country diagnostic accuracy study.

Rationale: C-reactive protein (CRP)-based tuberculosis (TB) screening is recommended for people with HIV (PWH). However, its performance among people without HIV and in diverse settings is unknown. Objectives: In a multi-country study, we aimed to determine whether CRP meets the minimum accuracy targets (sensitivity ≥90%, specificity ≥70%) for an effective TB triage test. Methods/Measurements: Consecutive outpatient adults with cough ≥2 weeks from five TB endemic countries in Africa and Asia had baseline blood collected for point-of-care CRP testing and HIV and diabetes screening. Sputum samples were collected for Xpert MTB/RIF Ultra (Xpert) testing and culture. CRP sensitivity and specificity (5 mg/L cut-point) was determined in reference to sputum test results and compared by country, sex, and HIV and diabetes status. Variables affecting CRP performance were identified using a multivariate receiver operating characteristic (ROC) regression model. Results: Among 2904 participants, of whom 613 (21%) had microbiologically-confirmed TB, CRP sensitivity was 84% (95% CI: 81-87%) and specificity was 61% (95% CI: 59-63%). CRP accuracy varied geographically, with higher sensitivity in African countries (≥91%) than Asian countries (64-82%). Sensitivity was higher among men than women (87% vs. 79%, difference +8%, 95% CI: 1-15%) and specificity was higher among people without HIV than PWH (64% vs. 45%, difference +19%, 95% CI: 13-25%). ROC regression identified country and measures of TB disease severity as predictors of CRP performance. Conclusions: Overall, CRP did not achieve the minimum accuracy targets and its performance varied by setting and in some sub-groups, likely reflecting population differences in mycobacterial load.

Solicited Cough Sound Analysis for Tuberculosis Triage Testing: The CODA TB DREAM Challenge Dataset.

Cough is a common and commonly ignored symptom of lung disease. Cough is often perceived as difficult to quantify, frequently self-limiting, and non-specific. However, cough has a central role in the clinical detection of many lung diseases including tuberculosis (TB), which remains the leading infectious disease killer worldwide. TB screening currently relies on self-reported cough which fails to meet the World Health Organization (WHO) accuracy targets for a TB triage test. Artificial intelligence (AI) models based on cough sound have been developed for several respiratory conditions, with limited work being done in TB. To support the development of an accurate, point-of-care cough-based triage tool for TB, we have compiled a large multi-country database of cough sounds from individuals being evaluated for TB. The dataset includes more than 700,000 cough sounds from 2,143 individuals with detailed demographic, clinical and microbiologic diagnostic information. We aim to empower researchers in the development of cough sound analysis models to improve TB diagnosis, where innovative approaches are critically needed to end this long-standing pandemic.

Negative effects of undernutrition on sputum smear conversion and treatment success among retreatment cases in Uganda: A quasi-experimental study.

Rationale: The causal relationship between undernutrition and response to anti-tuberculosis (TB) treatment and TB treatment outcomes among people with retreatment TB is understudied. Objective: To evaluate the effect of undernutrition on treatment success and sputum smear conversion among people with retreatment drug-susceptible TB in Kampala, Uganda. Methods: We conducted a quasi-experimental study utilizing propensity score weighting among people with retreatment drug-susceptible TB aged ≥ 15 years treated between 2012 and 2022 in Kampala. The primary exposure was undernutrition assessed using the mid-upper arm circumference at the time of TB diagnosis. The primary outcome was treatment success defined as cure or treatment completion at month 6. Sputum smear conversion was the secondary outcome and was measured as a change in sputum smear status from positive to negative at months 2, 5, and 6. We estimated the causal effect of undernutrition on the outcomes using a propensity-score weighted modified Poisson regression model with robust error variance. Measurements and main results: Of the 605 participants, 432 (71.4 %) were male, 215 (35.5 %) were aged 25-34 years, 427 (70.6 %) had bacteriologically confirmed pulmonary TB, 133 (22.0 %) were undernourished and 398 (65.8 %) achieved treatment success. Of participants with bacteriologically confirmed pulmonary TB, 232 (59.0 %), 327 (59.3 %), and 360 (97.6 %) achieved sputum smear conversion at months 2, 5, and 6, respectively. Undernutrition reduced treatment success (RR 0.42, 95 % CI 0.32-0.55) as well as sputum smear conversion at months 2 (RR 0.45, 95 % CI 0.42-0.49) and 5 (RR 0.46, 95 % CI 0.43-0.51) but not month 6 (RR 0.99, 95 % CI 0.97-1.02). Conclusion: Undernutrition negatively impacts treatment outcomes. Therefore, nutritional assessment should be an integral component of TB care, with nutritional counseling and support offered to those undernourished to optimize their TB treatment response and outcomes.

New Manual Quantitative Polymerase Chain Reaction Assay Validated on Tongue Swabs Collected and Processed in Uganda Shows Sensitivity That Rivals Sputum-based Molecular Tuberculosis Diagnostics.

BACKGROUND: Sputum-based testing is a barrier to increasing access to molecular diagnostics for tuberculosis (TB). Many people with TB are unable to produce sputum, and sputum processing increases assay complexity and cost. Tongue swabs are emerging as an alternative to sputum, but performance limits are uncertain. METHODS: From June 2022 to July 2023, we enrolled 397 consecutive adults with cough >2 weeks at 2 health centers in Kampala, Uganda. We collected demographic and clinical information, sputum for TB testing (Xpert MTB/RIF Ultra and 2 liquid cultures), and tongue swabs for same-day quantitative polymerase chain reaction (qPCR) testing. We evaluated tongue swab qPCR diagnostic accuracy versus sputum TB test results, quantified TB targets per swab, assessed the impact of serial swabbing, and compared 2 swab types (Copan FLOQSWAB and Steripack spun polyester). RESULTS: Among 397 participants, 43.1% were female, median age was 33 years, 23.5% were diagnosed with human immunodeficiency virus, and 32.0% had confirmed TB. Sputum Xpert Ultra and tongue swab qPCR results were concordant for 98.2% (95% confidence interval [CI]: 96.2-99.1) of participants. Tongue swab qPCR sensitivity was 92.6% (95% CI: 86.5 to 96.0) and specificity was 99.1% (95% CI: 96.9 to 99.8) versus microbiological reference standard. A single tongue swab recovered a 7-log range of TB copies, with a decreasing recovery trend among 4 serial swabs. Swab types performed equivalently. CONCLUSIONS: Tongue swabs are a promising alternative to sputum for molecular diagnosis of TB, with sensitivity approaching sputum-based molecular tests. Our results provide valuable insights for developing successful tongue swab-based TB diagnostics.

Comparison of 3 optimized delivery strategies for completion of isoniazid-rifapentine (3HP) for tuberculosis prevention among people living with HIV in Uganda: A single-center randomized trial.

BACKGROUND: Expanding access to shorter regimens for tuberculosis (TB) prevention, such as once-weekly isoniazid and rifapentine taken for 3 months (3HP), is critical for reducing global TB burden among people living with HIV (PLHIV). Our coprimary hypotheses were that high levels of acceptance and completion of 3HP could be achieved with delivery strategies optimized to overcome well-contextualized barriers and that 3HP acceptance and completion would be highest when PLHIV were provided an informed choice between delivery strategies. METHODS AND FINDINGS: In a pragmatic, single-center, 3-arm, parallel-group randomized trial, PLHIV receiving care at a large urban HIV clinic in Kampala, Uganda, were randomly assigned (1:1:1) to receive 3HP by facilitated directly observed therapy (DOT), facilitated self-administered therapy (SAT), or informed choice between facilitated DOT and facilitated SAT using a shared decision-making aid. We assessed the primary outcome of acceptance and completion (≥11 of 12 doses of 3HP) within 16 weeks of treatment initiation using proportions with exact binomial confidence intervals (CIs). We compared proportions between arms using Fisher's exact test (two-sided α = 0.025). Trial investigators were blinded to primary and secondary outcomes by study arm. Between July 13, 2020, and July 8, 2022, 1,656 PLHIV underwent randomization, with equal numbers allocated to each study arm. One participant was erroneously enrolled a second time and was excluded in the primary intention-to-treat analysis. Among the remaining 1,655 participants, the proportion who accepted and completed 3HP exceeded the prespecified 80% target in the DOT (0.94; 97.5% CI [0.91, 0.96] p < 0.001), SAT (0.92; 97.5% CI [0.89, 0.94] p < 0.001), and Choice (0.93; 97.5% CI [0.91, 0.96] p < 0.001) arms. There was no difference in acceptance and completion between any 2 arms overall or in prespecified subgroup analyses based on sex, age, time on antiretroviral therapy, and history of prior treatment for TB or TB infection. Only 14 (0.8%) participants experienced an adverse event prompting discontinuation of 3HP. The main limitation of the study is that it was conducted in a single center. Multicenter studies are now needed to confirm the feasibility and generalizability of the facilitated 3HP delivery strategies in other settings. CONCLUSIONS: Short-course TB preventive treatment was widely accepted by PLHIV in Uganda, and very high levels of treatment completion were achieved in a programmatic setting with delivery strategies tailored to address known barriers. TRIAL REGISTRATION: ClinicalTrials.gov NCT03934931.

Evaluation of the Xpert MTB Host Response assay for the triage of patients with presumed pulmonary tuberculosis: a prospective diagnostic accuracy study in Viet Nam, India, the Philippines, Uganda, and South Africa.

BACKGROUND: Non-sputum-based triage tests for tuberculosis are a priority for ending tuberculosis. We aimed to evaluate the diagnostic accuracy of the late-prototype Xpert MTB Host Response (Xpert HR) blood-based assay. METHODS: We conducted a prospective diagnostic accuracy study among outpatients with presumed tuberculosis in outpatient clinics in Viet Nam, India, the Philippines, Uganda, and South Africa. Eligible participants were aged 18 years or older and reported cough lasting at least 2 weeks. We excluded those receiving tuberculosis treatment in the preceding 12 months and those who were unwilling to consent. Xpert HR was performed on capillary or venous blood. Reference standard testing included sputum Xpert MTB/RIF Ultra and mycobacterial culture. We performed receiver operating characteristic (ROC) analysis to identify the optimal cutoff value for the Xpert HR to achieve the target sensitivity of 90% or more while maximising specificity, then calculated diagnostic accuracy using this cutoff value. This study was prospectively registered with ClinicalTrials.gov, NCT04923958. FINDINGS: Between July 13, 2021, and Aug 15, 2022, 2046 adults with at least 2 weeks of cough were identified, of whom 1499 adults (686 [45·8%] females and 813 [54·2%] males) had valid Xpert HR and reference standard results. 329 (21·9%) had microbiologically confirmed tuberculosis. Xpert HR had an area under the ROC curve of 0·89 (95% CI 0·86-0·91). The optimal cutoff value was less than or equal to -1·25, giving a sensitivity of 90·3% (95% CI 86·5-93·3; 297 of 329) and a specificity of 62·6% (95% CI 59·7-65·3; 732 of 1170). Sensitivity was similar across countries, by sex, and by subgroups, although specificity was lower in people living with HIV (45·1%, 95% CI 37·8-52·6) than in those not living with HIV (65·9%, 62·8-68·8; difference of 20·8%, 95% CI 13·0-28·6; p<0·0001). Xpert HR had high negative predictive value (95·8%, 95% CI 94·1-97·1), but positive predictive value was only 40·1% (95% CI 36·8-44·1). Using the Xpert HR as a triage test would have reduced confirmatory sputum testing by 57·3% (95% CI 54·2-60·4). INTERPRETATION: Xpert HR did not meet WHO minimum specificity targets for a non-sputum-based triage test for pulmonary tuberculosis. Despite promise as a rule-out test that could reduce confirmatory sputum testing, further cost-effectiveness modelling and data on acceptability and usability are needed to inform policy recommendations. FUNDING: National Institute of Allergy and Infectious Diseases of the US National Institutes of Health. TRANSLATIONS: For the Vietnamese and Tagalog translations of the abstract see Supplementary Materials section.

Barriers and facilitators to viral load suppression among people living with HIV following intensive adherence counseling in Kampala, Uganda: A qualitative study.

We explored the barriers and facilitators to viral load (VL) suppression after three or more intensive adherence counseling (IAC) sessions among adolescents and adults living with human immunodeficiency virus (HIV) on a first-line anti-retroviral therapy (ART) with initially unsuppressed VL in Kampala, Uganda. Using a qualitative study, data were collected through in-depth interviews with people living with HIV (PLHIV) with unsuppressed and suppressed VL and caregivers of younger adolescents living with HIV after three or more IAC sessions. We held key informant interviews with health workers involved in IAC implementation, namely ART/HIV focal persons, IAC Team Leaders, and linkage facilitators. Guided by the socioecological model, we performed content analysis and reported the findings using themes along with the participants' quotes. We studied 24 participants and found the individual-level barriers as forgetting to take HIV medications, high pill burden, medication side effects, a lack of food, and HIV-related psychological distress. Undisclosed HIV status and broken families were the barriers at the interpersonal level. Institutional-level barriers included insufficient HIV and ART counseling. Stigma was considered a community-level barrier while nonadherence to HIV treatment guidelines was a policy-level barrier. Facilitators included personal reminders, knowing the importance of taking treatment, and the ability to deal with side effects of HIV medications at the personal level; treatment support, peer support clubs, and incentivized treatment at the interpersonal level; and mental health support club and explaining during counseling that HIV is a chronic disease at the institutional level. We found an unsuppressed VL after completing IAC was due to several barriers at the personal, interpersonal, health systems, community, and policy levels. Achieving ≥95% VL suppression necessitates tackling the barriers to VL suppression and scaling up the facilitators by HIV control programs.

Tuberculin test using Indian indigenous purified-protein derivative (PPD) shows only moderate agreement with international standard PPD.

Background: In India, the prevalence of Latent TB infection (LTBI) is estimated to be around 40%. Various formulations of PPD(Purified protein derivative) are available, for diagnosis of LTBI, which may give variable responses. The commercially available PPD in India is by Arkray Healthcare (TST-Arkray). It is unclear if this product may have a similar sensitivity compared to other internationally accepted tuberculins (TST-Tubersol). Objectives: To assess the performance of the two TSTs compared to Quantiferon-Gold Plus (QFT-Plus). Methodology: A blood sample was collected for the QFT-Plus test. Both the TSTs were placed in the right and the left volar aspect of the forearms and 48 hrs later, the subjects came back to the study site for reading. Results: Among the 512 participants who were recruited, 326 subjects were healthcare professionals and 186 subjects were household contacts of patients with tuberculosis. They were tested with both TST-Tubersol and TST-Arkray, 139(27 %) participants tested positive for TST-Tubersol (≥10 mm), whereas 203 participants (40.1 %)tested positive for TST-Arkray. There was moderate agreement between the two tests with k = 0.58. Also, there was only poor agreement between both the TSTs with QFT Plus(kappa = 0.19 for Tubersol and 0.17 for Arkray). With QFT-Plus as gold standard, the sensitivity, specificity, PPV and NPV of TST-Tubersol, ast an induration cut-off of 10 mm was 46.8 %,76.3 %,31.8 % and 85.8 %. respectively and TST- Arkray; 60.6 %, 64 %, 28.5 % and 87.2 % respectively. Conclusion: The Indian TST (Arkray Diagnostics) has shown moderate agreement with the internationally accepted Tubersol. Additionally, there was poor agreement between the TSTs and QFT plus test.

Cost-effectiveness of Low-complexity Screening Tests in Community-based Case-finding for Tuberculosis.

INTRODUCTION: In high-burden settings, low-complexity screening tests for tuberculosis (TB) could expand the reach of community-based case-finding efforts. The potential costs and cost-effectiveness of approaches incorporating these tests are poorly understood. METHODS: We developed a microsimulation model assessing 3 approaches to community-based case-finding in hypothetical populations (India-, South Africa-, The Philippines-, Uganda-, and Vietnam-like settings) with TB prevalence 4 times that of national estimates: (1) screening with a point-of-care C-reactive protein (CRP) test, (2) screening with a more sensitive "Hypothetical Screening test" (95% sensitive for Xpert Ultra-positive TB, 70% specificity; equipment/labor costs similar to Xpert Ultra, but using a $2 cartridge) followed by sputum Xpert Ultra if positive, or (3) testing all individuals with sputum Xpert Ultra. Costs are expressed in 2023 US dollars and include treatment costs. RESULTS: Universal Xpert Ultra was estimated to cost a mean $4.0 million (95% uncertainty range: $3.5 to $4.6 million) and avert 3200 (2600 to 3900) TB-related disability-adjusted life years (DALYs) per 100 000 people screened ($670 [The Philippines] to $2000 [Vietnam] per DALY averted). CRP was projected to cost $550 (The Philippines) to $1500 (Vietnam) per DALY averted but with 44% fewer DALYs averted. The Hypothetical Screening test showed minimal benefit compared to universal Xpert Ultra, but if specificity were improved to 95% and per-test cost to $4.5 (all-inclusive), this strategy could cost $390 (The Philippines) to $940 (Vietnam) per DALY averted. CONCLUSIONS: Screening tests can meaningfully improve the cost-effectiveness of community-based case-finding for TB but only if they are sensitive, specific, and inexpensive.

Decline in prevalence of tuberculosis following an intensive case finding campaign and the COVID-19 pandemic in an urban Ugandan community.

BACKGROUND: Systematic screening is a potential tool for reducing the prevalence of tuberculosis (TB) and counteracting COVID-19-related disruptions in care. Repeated community-wide screening can also measure changes in the prevalence of TB over time. METHODS: We conducted serial, cross-sectional TB case finding campaigns in one community in Kampala, Uganda, in 2019 and 2021. Both campaigns sought sputum for TB testing (Xpert MTB/RIF Ultra) from all adolescents and adults. We estimated the prevalence of TB among screening participants in each campaign and compared characteristics of people with TB across campaigns. We simultaneously enrolled and characterised community residents who were diagnosed with TB through routine care and assessed trends in facility-based diagnosis. RESULTS: We successfully screened 12 033 community residents (35% of the estimated adult/adolescent population) in 2019 and 11 595 (33%) in 2021. In 2019, 0.94% (95% CI: 0.77% to 1.13%) of participants tested Xpert positive (including trace). This proportion fell to 0.52% (95% CI: 0.40% to 0.67%) in 2021; the prevalence ratio was 0.55 (95% CI: 0.40 to 0.75)). There was no change in the age (median 26 vs 26), sex (56% vs 59% female) or prevalence of chronic cough (49% vs 54%) among those testing positive. By contrast, the rate of routine facility-based diagnosis remained steady in the 8 months before each campaign (210 (95% CI: 155 to 279) vs 240 (95% CI: 181 to 312) per 100 000 per year). CONCLUSIONS: Following an intensive initial case finding campaign in an urban Ugandan community in 2019, the burden of prevalent TB as measured by systematic screening had decreased by 45% in 2021, despite the intervening COVID-19 pandemic.

Blazing the trail for innovative tuberculosis diagnostics.

The COVID-19 pandemic brought diagnostics into the spotlight in an unprecedented way not only for case management but also for population health, surveillance, and monitoring. The industry saw notable levels of investment and accelerated research which sparked a wave of innovation. Simple non-invasive sampling methods such as nasal swabs have become widely used in settings ranging from tertiary hospitals to the community. Self-testing has also been adopted as standard practice using not only conventional lateral flow tests but novel and affordable point-of-care molecular diagnostics. The use of new technologies, including artificial intelligence-based diagnostics, have rapidly expanded in the clinical setting. The capacity for next-generation sequencing and acceptance of digital health has significantly increased. However, 4 years after the pandemic started, the market for SARS-CoV-2 tests is saturated, and developers may benefit from leveraging their innovations for other diseases; tuberculosis (TB) is a worthwhile portfolio expansion for diagnostics developers given the extremely high disease burden, supportive environment from not-for-profit initiatives and governments, and the urgent need to overcome the long-standing dearth of innovation in the TB diagnostics field. In exchange, the current challenges in TB detection may be resolved by adopting enhanced swab-based molecular methods, instrument-based, higher sensitivity antigen detection technologies, and/or artificial intelligence-based digital health technologies developed for COVID-19. The aim of this article is to review how such innovative approaches for COVID-19 diagnosis can be applied to TB to have a comparable impact.

Feasibility of a social protection linkage program for individuals at-risk for tuberculosis in Uganda.

Social protection interventions have the potential to accelerate progress towards global tuberculosis (TB) targets. We piloted a screening and linkage program at four community health centers (HC) to enroll adults seeking TB diagnostic evaluation services into existing government-supported social protection programs in Uganda. From May-December 2021, health center staff were asked to screen adults being evaluated for TB for eligibility for government-supported social protection programs, and to refer eligible people to a sub-county community development office (CDO) responsible for enrolling community members into government-supported social protection programs. Linkage was facilitated with a transportation reimbursement via mobile money and referral documentation confirming program eligibility. We assessed feasibility using programmatic data and conducted post-intervention surveys to understand experiences with the linkage program. Of 855 people undergoing TB evaluation, 655 (76%) adults met criteria for at least one government-supported social protection program. 25 (4%) of those were not interested in referral; the rest were referred to their local CDO. While 386 (61%) of the 630 participants reported to the CDO seeking social protection enrolment, only 122 (32%) of those were ultimately enrolled into a social protection scheme, representing only 19% (n = 655) of those eligible. In surveys conducted among 97 participants, 46 of the 60 (77%) people who reported that they sought enrollment at the CDO were not enrolled into a social protection program. Reasons provided for non-enrollment among these 46 participants were either unknown (n = 25, 54%) or due to operational challenges at the CDO including a lack of human resources or available groups to join in the social protection program (n = 20, 43%). 61 survey participants (63%) indicated that they would not have sought social protection enrollment without the referral program. Overall, we found that most adults seeking TB diagnostic evaluation are eligible for and interested in obtaining government-supported social protection. We found facilitated linkage from HCs to CDOs offering social protection services to be feasible, however ultimate enrollment into programs was limited. Additional research is needed to identify strategies to improve access to existing social protection programs for eligible TB-affected individuals. Trial Registration: Pan African Clinical Trials Registry (PACTR201906852160014).

Risk factors for unsuppressed viral load after intensive adherence counseling among HIV infected persons in Kampala, Uganda: a nested case-control study.

BACKGROUND: Intensive adherence counseling (IAC) is the global standard of care for people living with human immunodeficiency virus (PLHIV) who have unsuppressed VL after ≥ 6 months of first-line anti-retroviral therapy (ART). We investigated whether the number of IAC sessions is associated with suppressed VL among PLHIV in Kampala, Uganda. METHODS: We conducted a nested case-control study among PLHIV with unsuppressed VL after ≥ 3 IAC sessions (cases) and a 2:1 random sample of PLHIV with suppressed VL after ≥ 3 IAC sessions (controls). Unsuppressed VL was defined as VL ≥ 1000 copies/ml. We performed multivariable logistic regression to identify factors that differed significantly between cases and controls. RESULTS: Demographic and clinical characteristics were similar among the 16 cases and 32 controls including mean age, sex, baseline CD4 count, VL before IAC, and WHO clinical stage. Only the number of IAC sessions differed significantly between cases and controls in unadjusted (p = 0.012) and adjusted (p = 0.016) analyses. Each unit increase in IAC session was associated with unsuppressed VL (Adjusted odds ratio 5.09; 95% CI 1.35-19.10). CONCLUSIONS: VL remained unsuppressed despite increasing IAC frequency. The fidelity to standardized IAC protocol besides drug resistance testing among PLHIV with unsuppressed VL before IAC commencement should be examined.

The socioeconomic burden of pediatric tuberculosis and role of child-sensitive social protection.

BACKGROUND: Households of children with tuberculosis (TB) experience financial and social hardships, but TB-specific social protection initiatives primarily focus on adults. METHODS: We conducted a single-arm, pilot study of multi-component supportive benefits for children with pulmonary TB in Kampala, Uganda. At diagnosis, participants received in-kind coverage of direct medical costs, a cash transfer, and patient navigation. Caregivers were surveyed before diagnosis and 2 months into TB treatment on social and financial challenges related to their child's illness, including estimated costs, loss of income and dissaving practices. RESULTS: We included 368 children from 321 households. Pre-diagnosis, 80.1% of caregivers reported that their child's illness negatively impacted household finances, 44.1% of caregivers missed work, and 24% engaged in dissaving practices. Catastrophic costs (> 20% annual income) were experienced by 18.4% (95% CI 13.7-24.0) of households. School disruption was common (25.6%), and 28% of caregivers were concerned their child was falling behind in development. Two months post-diagnosis, 12 households (4.8%) reported being negatively affected by their child's TB disease (difference -75.2%, 95% CI -81.2 to -69.2, p < 0.001), with limited ongoing loss of income (1.6%) or dissavings practices (0.8%). Catastrophic costs occurred in one household (0.4%) at 2 months post-diagnosis. CONCLUSIONS: Households face financial and social challenges prior to a child's TB diagnosis, and child-sensitive social protection support may mitigate ongoing burden.

Preferences of people living with HIV for features of tuberculosis preventive treatment regimens - a discrete choice experiment.

Background: Tuberculosis (TB) preventive treatment (TPT) is recommended for people living with HIV (PLHIV) in high TB burden settings. While 6 months of daily isoniazid remains widely used, shorter regimens are now available. However, little is known about preferences of PLHIV for key features of TPT regimens. Methods: We conducted a discrete choice experiment among adult PLHIV engaged in care at an urban HIV clinic in Kampala, Uganda. In nine random choice tasks, participants chose between two hypothetical TPT regimens with different features (pills per dose, frequency, duration, need for adjusted antiretroviral therapy [ART] dosage and side effects). We analyzed preferences using hierarchical Bayesian estimation, latent class analysis, and willingness-to-trade simulations. Results: Of 400 PLHIV, 392 (median age 44, 72% female, 91% TPT-experienced) had high quality choice task responses. Pills per dose was the most important attribute (relative importance 32.4%, 95% confidence interval [CI] 31.6 - 33.2), followed by frequency (20.5% [95% CI 19.7 - 21.3]), duration (19.5% [95% CI 18.6 - 20.5]), and need for ART dosage adjustment (18.2% [95% CI 17.2 - 19.2]). Latent class analysis identified three preference groups: one prioritized less frequent, weekly dosing (N=222; 57%); another was averse to ART dosage adjustment (N=107; 27%); and the last prioritized short and tolerable regimens (N=63; 16%). All groups highly valued fewer pills per dose. Participants were willing to accept a regimen of 2.8 months' additional duration [95% CI: 2.4 - 3.2] to reduce pills per dose from five to one, 3.6 [95% CI 2.4 - 4.8] months for weekly rather than daily dosing, and 2.2 [95% CI 1.3 - 3.0] months to avoid ART dosage adjustment. Conclusions: To align with preferences of PLHIV, decision-makers should prioritize the development and implementation of TPT regimens with fewer pills, less frequent dosing, and no need for ART dosage adjustment, rather than focus primarily on duration of treatment.

New manual qPCR assay validated on tongue swabs collected and processed in Uganda shows sensitivity that rivals sputum-based molecular TB diagnostics.

Background: Reliance on sputum-based testing is a key barrier to increasing access to molecular diagnostics for tuberculosis (TB). Many people with TB are unable to produce and sputum processing increases the complexity and cost of molecular assays. Tongue swabs are emerging as an alternative to sputum, but performance limits are uncertain. Methods: From June 2022 to July 2023, we enrolled 397 consecutive adults with cough >2 weeks at two health centers in Kampala, Uganda. We collected routine demographic and clinical information, sputum for routine TB testing (one Xpert MTB/RIF Ultra® and two liquid cultures), and up to four tongue swabs for same-day qPCR. We evaluated tongue swab qPCR diagnostic accuracy in reference to sputum TB test results, quantified TB targets per swab, assessed the impact of serial swabbing, and compared two swab types (Copan FLOQSWAB® and Steripack® spun polyester swabs). Results: Among 397 participants, 43.1% were female, median age was 33 years, 23.5% were living with HIV (PLHIV) and 32.3% had confirmed TB. Sputum Xpert Ultra and tongue swab qPCR results were concordant for 98.2% [96.2-99.1] of participants. Tongue swab qPCR sensitivity was 91.0% [84.6-94.9] and specificity 98.9% [96.2-99.8] vs. microbiological reference standard (MRS). A single tongue swab recovered a seven-log range of TB copies, with a decreasing recovery trend among four serial swabs. We found no difference between swab types. Conclusions: Tongue swabs show promise as an alternative to sputum for TB diagnosis, with sensitivity approaching sputum-based molecular tests. Our results provide valuable insights for developing successful tongue swab-based TB diagnostics.

Impact of intensive adherence counseling on viral load suppression and mortality among people living with HIV in Kampala, Uganda: A regression discontinuity design.

Intensive adherence counseling (IAC) is recommended for people living with HIV (PLHIV) with viral load (VL) ≥1,000 copies/ml after ≥6 months of anti-retroviral therapy (ART). We evaluated the effect of IAC on VL suppression and all-cause mortality among PLHIV on first-line ART with VL ≥1,000 copies/ml after ≥6 months of ART in Kampala, Uganda using regression discontinuity design, a quasi-experimental method for effect estimation when interventions depend on a cut-off. PLHIV just above VL ≥1,000 copies/ml cut-off who received ≥3 IAC sessions formed the intervention group while those just below the cut-off who received routine psychosocial support constituted the control group. Primary outcome was repeat VL suppression defined as VL <1,000 copies/ml approximately 9-12 months following initial VL assessment. Secondary outcome was all-cause mortality. We used logistic regression for causal-effect analysis, reported as odds ratio (OR) with a 95% confidence interval (CI). We performed sensitivity analyses to assess the robustness of findings to varying bandwidths at the cut-off. We found 3,735 PLHIV were started on ART between Nov 2020 and Nov 2021 of whom 3,199 were included in the analysis (3,085 control, 114 intervention). Within an optimal bandwidth, there were 236 participants (222 control, 14 intervention) with similar demographic and clinical characteristics. Repeat VL suppression was lower in the intervention than in the control group (85.7% versus 98.6%, p = 0.021) while all-cause mortality was similar (0% versus 0.5%, p = 1.000). In multivariable analysis, the odds of repeat VL suppression were 91% lower in the intervention than control group (OR = 0.09; 95% CI, 0.01-0.66). Findings are robust to varying bandwidths around the cut-off. We concluded IAC is ineffective in suppressing VL among PLHIV on first-line ART in Kampala, Uganda. Findings suggest a need to investigate the IAC implementation fidelity for successful translation in practice and the reasons for VL persistence beyond the suppression threshold.