Clinical outcomes in children living with HIV treated for non-severe tuberculosis in the SHINE Trial.

BACKGROUND: Children living with HIV(CLWH) are at high risk of tuberculosis(TB) and face poor outcomes, despite antiretroviral treatment(ART). We evaluated outcomes in CLWH and HIV-uninfected children treated for non-severe TB in the SHINE trial. METHODS: SHINE was a randomized trial that enrolled children aged <16 years with smear-negative, non-severe TB who were randomized to receive 4 vs 6 months of TB treatment and followed for 72 weeks. We assessed TB relapse/recurrence, mortality, hospitalizations, grade ≥3 adverse events by HIV status, and HIV virological suppression in CLWH. RESULTS: Of 1204 enrolled, 127(11%) were CLWH, of similar age (median(IQR) 3.6(1.2, 10.3) vs. 3.5(1.5, 6.9)years, p= 0.07), but more underweight (WAZ; -2.3(-3.3, -0.8) vs -1.0(-1.8, -0.2), p<0.01) and anemic (hemoglobin 9.5(8.7, 10.9) vs 11.5(10.4, 12.3)g/dl, p<0.01) compared to HIV-uninfected children. 68(54%) CLWH were ART-naïve; baseline median CD4 count 719(241-1134) cells/mm3, CD4% 16(10-26)%). CLWH were more likely to be hospitalized (aOR=2.4(1.3-4.6)) and die (aHR(95%CI) 2.6(1.2,5.8)). HIV status, age <3 years (aHR 6.3(1.5,27.3)), malnutrition (aHR 6.2(2.4,15.9)) and hemoglobin <7g/dl(aHR 3.8(1.3,11.5) independently predicted mortality. Among children with available VL, 45% and 61% CLWH had VL<1000copies/ml at weeks 24 and 48, respectively. There was no difference in the effect of randomized treatment duration (4 vs 6 months) on TB treatment outcomes by HIV status (p for interaction=0.42). CONCLUSIONS: We found no evidence of a difference in TB outcomes between 4 and 6 months of treatment for CLWH treated for non-severe TB. Irrespective of TB treatment duration, CLWH had higher rates of mortality and hospitalization than HIV-uninfected counterparts.

We compared outcomes between children with and without HIV treated for non-severe TB. Regardless of treatment duration (4 or 6 months), children with HIV had similar TB outcomes but had higher mortality and hospitalization rates than their HIV-uninfected counterparts.

Correction: Early mortality in tuberculosis patients initially lost to follow up following diagnosis in provincial hospitals and primary health care facilities in Western Cape, South Africa.

[This corrects the article DOI: 10.1371/journal.pone.0252084.].

Pharmacokinetics and Optimal Dosing of Levofloxacin in Children for Drug-Resistant Tuberculosis: An Individual Patient Data Meta-Analysis.

BACKGROUND: Each year 25 000-32 000 children develop rifampicin- or multidrug-resistant tuberculosis (RR/MDR-TB), and many more require preventive treatment. Levofloxacin is a key component of RR/MDR-TB treatment and prevention, but the existing pharmacokinetic data in children have not yet been comprehensively summarized. We aimed to characterize levofloxacin pharmacokinetics through an individual patient data meta-analysis of available studies and to determine optimal dosing in children. METHODS: Levofloxacin concentration and demographic data were pooled from 5 studies and analyzed using nonlinear mixed effects modeling. Simulations were performed using current World Health Organization (WHO)-recommended and model-informed optimized doses. Optimal levofloxacin doses were identified to target median adult area under the time-concentration curve (AUC)24 of 101 mg·h/L given current standard adult doses. RESULTS: Data from 242 children (2.8 years [0.2-16.8] was used). Apparent clearance was 3.16 L/h for a 13-kg child. Age affected clearance, reaching 50% maturation at birth and 90% maturation at 8 months. Nondispersible tablets had 29% lower apparent oral bioavailability compared to dispersible tablets. Median exposures at current WHO-recommended doses were below the AUC target for children weighing <24 kg and under <10 years, resulting in approximately half of the exposure in adults. Model-informed doses of 16-33 mg/kg for dispersible tablets or 16-50 mg/kg for nondispersible tablets were required to meet the AUC target without significantly exceeding the median adult Cmax. CONCLUSIONS: Revised weight-band dosing guidelines with doses of >20 mg/kg are required to ensure adequate exposure. Further studies are needed to determine safety and tolerability of these higher doses.

Association between tuberculosis and pregnancy outcomes: a retrospective cohort study of women in Cape Town, South Africa.

BACKGROUND: Tuberculosis (TB) remains a leading cause of mortality among women of childbearing age and a significant contributor to maternal mortality. Pregnant women with TB are at high risk of adverse pregnancy outcomes. This study aimed to determine risk factors for an adverse pregnancy outcome among pregnant women diagnosed with TB. METHODS: Using TB programmatic data, this retrospective cohort analysis included all women who were routinely diagnosed with TB in the public sector between October 2018 and March 2020 in two health subdistricts of Cape Town, and who were documented to be pregnant during their TB episode. Adverse pregnancy outcome was defined as either a live birth of an infant weighing <2500 g and/or with a gestation period <37 weeks or as stillbirth, miscarriage, termination of pregnancy, maternal or early neonatal death. Demographics, TB and pregnancy characteristics were described by HIV status. Logistic regression was used to determine risk factors for adverse pregnancy outcome. RESULTS: Of 248 pregnant women, half (52%) were living with HIV; all were on antiretroviral therapy at the time of their TB diagnosis. Pregnancy outcomes were documented in 215 (87%) women, of whom 74 (34%) had an adverse pregnancy outcome. Being older (35-44 years vs 25-34 years (adjusted OR (aOR): 3.99; 95% CI: 1.37 to 11.57), living with HIV (aOR: 2.72; 95% CI: 0.99 to 4.63), having an unfavourable TB outcome (aOR: 2.29; 95% CI: 1.03 to 5.08) and having presented to antenatal services ≤1 month prior to delivery (aOR: 10.57; 95% CI: 4.01 to 27.89) were associated with higher odds of an adverse pregnancy outcome. CONCLUSIONS: Pregnancy outcomes among women with TB were poor, irrespective of HIV status. Pregnant women with TB are a complex population who need additional support prior to, during and after TB treatment to improve TB treatment and pregnancy outcomes. Pregnancy status should be considered for inclusion in TB registries.

Reducing Initial Loss to Follow-up Among People With Bacteriologically Confirmed Tuberculosis: LINKEDin, a Quasi-experimental Study in South Africa.

Every person diagnosed with tuberculosis (TB) needs to initiate treatment. The World Health Organization estimated that 61% of people who developed TB in 2021 were included in a TB treatment registration system. Initial loss to follow-up (ILTFU) is the loss of persons to care between diagnosis and treatment initiation/registration. LINKEDin, a quasi-experimental study, evaluated the effect of 2 interventions (hospital recording and an alert-and-response patient management intervention) in 6 subdistricts across 3 high-TB burden provinces of South Africa. Using integrated electronic reports, we identified all persons diagnosed with TB (Xpert MTB/RIF positive) in the hospital and at primary health care facilities. We prospectively determined linkage to care at 30 days after TB diagnosis. We calculated the risk of ILTFU during the baseline and intervention periods and the relative risk reduction in ILTFU between these periods. We found a relative reduction in ILTFU of 42.4% (95% CI, 28.5%-53.7%) in KwaZulu Natal (KZN) and 22.3% (95% CI, 13.3%-30.4%) in the Western Cape (WC), with no significant change in Gauteng. In KZN and the WC, the relative reduction in ILTFU appeared greater in subdistricts where the alert-and-response patient management intervention was implemented (KZN: 49.3%; 95% CI, 32.4%-62%; vs 32.2%; 95% CI, 5.4%-51.4%; and WC: 34.2%; 95% CI, 20.9%-45.3%; vs 13.4%; 95% CI, 0.7%-24.4%). We reported a notable reduction in ILTFU in 2 provinces using existing routine health service data and applying a simple intervention to trace and recall those not linked to care. TB programs need to consider ILTFU a priority and develop interventions specific to their context to ensure improved linkage to care.

Impaired lung function in adolescents with pulmonary tuberculosis during treatment and following treatment completion.

Background: Little is known about post-tuberculosis lung disease in adolescents. We prospectively assessed lung function in adolescents with microbiologically confirmed pulmonary tuberculosis during treatment and after treatment completion. Methods: In a prospective study, we enrolled adolescents diagnosed with microbiologically confirmed tuberculosis and healthy tuberculosis-exposed household controls, between October 2020 and July 2021 in Cape Town, South Africa. Spirometry, plethysmography, diffusion capacity lung function tests and 6-min walking test (6MWT) were completed according to international guidelines 2 months into treatment and following treatment completion. Abnormal lung function was defined as abnormal spirometry (z-score < -1.64 for forced expiratory volume in 1 s (FEV1) and/or forced vital capacity (FVC) and/or FEV1/FVC), plethysmography (total lung capacity (TLC) < 80% of predicted, residual volume over TLC of >45%) and/or diffusion capacity (DLCO z-score < -1.64). Findings: One-hundred adolescents were enrolled; 50 (50%) with tuberculosis and 50 (50%) healthy tuberculosis-exposed controls. Of the 50 adolescents with tuberculosis, ten had multidrug-resistant tuberculosis. Mean age of the group was 14.9 years (SD 2.7), 6 (6.0%) were living with HIV and 9 (9.0%) were previously treated for tuberculosis. Lung function improved over time; during treatment abnormal lung function was found in 76% of adolescents with tuberculosis, compared to 65% after treatment completion. Spirometry indices were lower in adolescents with tuberculosis compared to controls, both at 2 months and after treatment completion. Plethysmography in adolescents with tuberculosis showed that air-trapping was more common during treatment than in controls (12% vs 0%, respectively, p = 0.017); which improved following treatment completion. Adolescents with tuberculosis both during and after treatment completion walked a shorter distance than controls. Interpretation: Adolescents with tuberculosis have impaired lung function even after treatment completion. It is crucial to include adolescents in trials on the prevention and treatment of tuberculosis-associated respiratory morbidity. Funding: EDCTP, National Institute of Health, Medical Research Council, BMBF.

Pharmacokinetics and cardiac safety of clofazimine in children with rifampicin-resistant tuberculosis.

Clofazimine is recommended for the treatment of rifampicin-resistant tuberculosis (RR-TB), but there is currently no verified dosing guideline for its use in children. There is only limited safety and no pharmacokinetic (PK) data available for children. We aimed to characterize clofazimine PK and its relationship with QT-interval prolongation in children. An observational cohort study of South African children <18 years old routinely treated for RR-TB with a clofazimine-containing regimen was analyzed. Clofazimine 100 mg gelatin capsules were given orally once daily (≥20 kg body weight), every second day (10 to <20 kg), or thrice weekly (<10 kg). PK sampling and electrocardiograms were completed pre-dose and at 1, 4, and 10 hours post-dose, and the population PK and Fridericia-corrected QT (QTcF) interval prolongation were characterized. Fifty-four children contributed both PK and QTcF data, with a median age (2.5th-97.5th centiles) of 3.3 (0.5-15.6) years; five children were living with HIV. Weekly area under the time-concentration curve at steady state was 79.1 (15.0-271) mg.h/L compared to an adult target of 60.9 (56.0-66.6) mg.h/L. Children living with HIV had four times higher clearance compared to those without. No child had a QTcF ≥500 ms. A linear concentration-QTcF relationship was found, with a drug effect of 0.05 (0.027, 0.075) ms/µg/L. In some of the first PK data in children, we found clofazimine exposure using an off-label dosing strategy was higher in children versus adults. Clofazimine concentrations were associated with an increase in QTcF, but severe prolongation was not observed. More data are required to inform dosing strategies in children.

Optimizing dosing of the cycloserine pro-drug terizidone in children with rifampicin-resistant tuberculosis.

There are no pharmacokinetic data in children on terizidone, a pro-drug of cycloserine and a World Health Organization (WHO)-recommended group B drug for rifampicin-resistant tuberculosis (RR-TB) treatment. We collected pharmacokinetic data in children <15 years routinely receiving 15-20 mg/kg of daily terizidone for RR-TB treatment. We developed a population pharmacokinetic model of cycloserine assuming a 2-to-1 molecular ratio between terizidone and cycloserine. We included 107 children with median (interquartile range) age and weight of 3.33 (1.55, 5.07) years and 13.0 (10.1, 17.0) kg, respectively. The pharmacokinetics of cycloserine was described with a one-compartment model with first-order elimination and parallel transit compartment absorption. Allometric scaling using fat-free mass best accounted for the effect of body size, and clearance displayed maturation with age. The clearance in a typical 13 kg child was estimated at 0.474 L/h. The mean absorption transit time when capsules were opened and administered as powder was significantly faster compared to when capsules were swallowed whole (10.1 vs 72.6 min) but with no effect on bioavailability. Lower bioavailability (-16%) was observed in children with weight-for-age z-score below -2. Compared to adults given 500 mg daily terizidone, 2022 WHO-recommended pediatric doses result in lower exposures in weight bands 3-10 kg and 36-46 kg. We developed a population pharmacokinetic model in children for cycloserine dosed as terizidone and characterized the effects of body size, age, formulation manipulation, and underweight-for-age. With current terizidone dosing, pediatric cycloserine exposures are lower than adult values for several weight groups. New optimized dosing is suggested for prospective evaluation.

Evaluating pediatric tuberculosis dosing guidelines: A model-based individual data pooled analysis.

BACKGROUND: The current World Health Organization (WHO) pediatric tuberculosis dosing guidelines lead to suboptimal drug exposures. Identifying factors altering the exposure of these drugs in children is essential for dose optimization. Pediatric pharmacokinetic studies are usually small, leading to high variability and uncertainty in pharmacokinetic results between studies. We pooled data from large pharmacokinetic studies to identify key covariates influencing drug exposure to optimize tuberculosis dosing in children. METHODS AND FINDINGS: We used nonlinear mixed-effects modeling to characterize the pharmacokinetics of rifampicin, isoniazid, and pyrazinamide, and investigated the association of human immunodeficiency virus (HIV), antiretroviral therapy (ART), drug formulation, age, and body size with their pharmacokinetics. Data from 387 children from South Africa, Zambia, Malawi, and India were available for analysis; 47% were female and 39% living with HIV (95% on ART). Median (range) age was 2.2 (0.2 to 15.0) years and weight 10.9 (3.2 to 59.3) kg. Body size (allometry) was used to scale clearance and volume of distribution of all 3 drugs. Age affected the bioavailability of rifampicin and isoniazid; at birth, children had 48.9% (95% confidence interval (CI) [36.0%, 61.8%]; p < 0.001) and 64.5% (95% CI [52.1%, 78.9%]; p < 0.001) of adult rifampicin and isoniazid bioavailability, respectively, and reached full adult bioavailability after 2 years of age for both drugs. Age also affected the clearance of all drugs (maturation), children reached 50% adult drug clearing capacity at around 3 months after birth and neared full maturation around 3 years of age. While HIV per se did not affect the pharmacokinetics of first-line tuberculosis drugs, rifampicin clearance was 22% lower (95% CI [13%, 28%]; p < 0.001) and pyrazinamide clearance was 49% higher (95% CI [39%, 57%]; p < 0.001) in children on lopinavir/ritonavir; isoniazid bioavailability was reduced by 39% (95% CI [32%, 45%]; p < 0.001) when simultaneously coadministered with lopinavir/ritonavir and was 37% lower (95% CI [22%, 52%]; p < 0.001) in children on efavirenz. Simulations of 2010 WHO-recommended pediatric tuberculosis doses revealed that, compared to adult values, rifampicin exposures are lower in most children, except those younger than 3 months, who experience relatively higher exposure for all drugs, due to immature clearance. Increasing the rifampicin doses in children older than 3 months by 75 mg for children weighing <25 kg and 150 mg for children weighing >25 kg could improve rifampicin exposures. Our analysis was limited by the differences in availability of covariates among the pooled studies. CONCLUSIONS: Children older than 3 months have lower rifampicin exposures than adults and increasing their dose by 75 or 150 mg could improve therapy. Altered exposures in children with HIV is most likely caused by concomitant ART and not HIV per se. The importance of the drug-drug interactions with lopinavir/ritonavir and efavirenz should be evaluated further and considered in future dosing guidance. TRIAL REGISTRATION: ClinicalTrials.gov registration numbers; NCT02348177, NCT01637558, ISRCTN63579542.

Human Cytomegalovirus Immunoglobulin G Response and Pulmonary Tuberculosis in Adolescents: A Case-Control Study.

Background: Emerging evidence suggests a link between infection with herpes viruses, particularly human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), and progression to tuberculosis disease. Methods: An unmatched case-control study was conducted among adolescents aged 10-19 years enrolled in an observational study (Teen TB) between November 2020 and November 2021, in Cape Town, South Africa. Fifty individuals with pulmonary tuberculosis and 51 healthy tuberculosis-exposed individuals without tuberculosis were included. Demographics and clinical data were obtained, and serum samples collected at enrolment were tested for HCMV immunoglobulin G (IgG) and EBV nuclear antigen (EBNA) IgG using 2 automated enzyme immunoassays. Odds ratios were estimated using unconditional logistic regression. Results: The median age of 101 participants was 15 years (interquartile range, 13-17 years); 55 (54%) were female. All participants were HCMV IgG seropositive, and 95% were EBNA IgG seropositive. Individuals with tuberculosis had higher HCMV IgG titers than healthy controls (P = .04). Individuals with upper-tertile HCMV IgG titers had 3.67 times greater odds of pulmonary tuberculosis than those with IgG titers in the lower tertile (95% confidence interval, 1.05-12.84; P = .04). There was a trend for increasing odds of pulmonary tuberculosis with increasing titers of HCMV IgG (P = .04). In contrast, there was no association between tuberculosis and higher EBNA IgG values. Conclusions: There is a high prevalence of sensitization to HCMV and EBV among adolescents in this high-tuberculosis-burden setting. Higher HCMV IgG titers were associated with pulmonary tuberculosis in adolescents.

Pharmacokinetics and optimized dosing of dispersible and non-dispersible levofloxacin formulations in young children.

BACKGROUND: Levofloxacin is used for treatment and prevention of rifampicin-resistant (RR)-TB in children. Recent data showed higher exposures with 100 mg dispersible compared with non-dispersible tablet formulations with potentially important dosing implications in children. We aimed to verify and better characterize this finding. METHODS: We conducted a crossover pharmacokinetic trial in children aged ≤5 years receiving levofloxacin RR-TB preventive therapy. Pharmacokinetic sampling was done after 15-20 mg/kg doses of levofloxacin with 100 mg dispersible and crushed 250 mg non-dispersible levofloxacin formulations. A population pharmacokinetic model was developed. RESULTS: Twenty-five children were included, median (IQR) weight and age 12.2 (10.7-15.0) kg and 2.56 (1.58-4.03) years, respectively. A two-compartment model with first-order elimination and transit compartment absorption best described levofloxacin pharmacokinetics. Allometric scaling adjusted for body size, and maturation of clearance with age was characterized. Typical clearance in a 12 kg child was estimated at 4.17 L/h. Non-dispersible tablets had 21.5% reduced bioavailability compared with the dispersible formulation, with no significant differences in other absorption parameters.Dosing simulations showed that current recommended dosing for both formulations result in median exposures below adult-equivalent exposures at a 750 mg daily dose, mainly in children >6 months. Higher levofloxacin doses of 16-30 mg/kg for dispersible and 20-38 mg/kg for crushed non-dispersible tablets may be required in children >6 months. CONCLUSIONS: The dispersible paediatric levofloxacin formulation has improved bioavailability compared with the crushed non-dispersible adult formulation, but exposures remain below those in adults. We propose optimized age- and weight-based dosing for levofloxacin, which require further evaluation.

Quantitation of Circulating Mycobacterium tuberculosis Antigens by Nanopore Biosensing in Children Evaluated for Pulmonary Tuberculosis in South Africa.

Nanopore sensing of proteomic biomarkers lacks accuracy due to the ultralow abundance of targets, a wide variety of interferents in clinical samples, and the mismatch between pore and analyte sizes. By converting antigens to DNA probes via click chemistry and quantifying their characteristic signals, we show a nanopore assay with several amplification mechanisms to achieve an attomolar level limit of detection that enables quantitation of the circulating Mycobacterium tuberculosis (Mtb) antigen ESAT-6/CFP-10 complex in human serum. The assay's nonsputum-based feature and low-volume sample requirements make it particularly well-suited for detecting pediatric tuberculosis (TB) disease, where establishing an accurate diagnosis is greatly complicated by the paucibacillary nature of respiratory secretions, nonspecific symptoms, and challenges with sample collection. In the clinical assessment, the assay was applied to analyze ESAT-6/CFP-10 levels in serum samples collected during baseline investigation for TB in 75 children, aged 0-12 years, enrolled in a diagnostic study conducted in Cape Town, South Africa. This nanopore assay showed superior sensitivity in children with confirmed TB (94.4%) compared to clinical "gold standard" diagnostic technologies (Xpert MTB/RIF 44.4% and Mtb culture 72.2%) and filled the diagnostic gap for children with unconfirmed TB, where these traditional technologies fell short. We envision that, in combination with automated sample processing and portable nanopore devices, this methodology will offer a powerful tool to support the diagnosis of pulmonary TB in children.

SARS-CoV-2 infection and pulmonary tuberculosis in children and adolescents: a case-control study.

BACKGROUND: The Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) pandemic has had an impact on the global tuberculosis (TB) epidemic but evidence on the possible interaction between SARS-CoV-2 and TB, especially in children and adolescents, remains limited. We aimed to evaluate the relationship between previous infection with SARS-CoV-2 and the risk of TB in children and adolescents. METHODS: An unmatched case-control study was conducted using SARS-CoV-2 unvaccinated children and adolescents recruited into two observational TB studies (Teen TB and Umoya), between November 2020 and November 2021, in Cape Town, South Africa. Sixty-four individuals with pulmonary TB (aged < 20 years) and 99 individuals without pulmonary TB (aged < 20 years) were included. Demographics and clinical data were obtained. Serum samples collected at enrolment underwent quantitative SARS-CoV-2 anti-spike immunoglobulin G (IgG) testing using the Abbott SARS-CoV-2 IgG II Quant assay. Odds ratios (ORs) for TB were estimated using unconditional logistic regression. RESULTS: There was no statistically significant difference in the odds of having pulmonary TB between those who were SARS-CoV-2 IgG seropositive and those who were seronegative (adjusted OR 0.51; 95% CI: 0.23-1.11; n = 163; p = 0.09). Of those with positive SARS-CoV-2 serology indicating prior infection, baseline IgG titres were higher in individuals with TB compared to those without TB (p = 0.04) and individuals with IgG titres in the highest tertile were more likely to have pulmonary TB compared to those with IgG levels in the lowest tertile (OR: 4.00; 95%CI: 1.13- 14.21; p = 0.03). CONCLUSIONS: Our study did not find convincing evidence that SARS-CoV-2 seropositivity was associated with subsequent pulmonary TB disease; however, the association between magnitude of SARS-CoV-2 IgG response and pulmonary TB warrants further investigation. Future prospective studies, evaluating the effects of sex, age and puberty on host immune responses to M. tuberculosis and SARS-CoV-2, will also provide more clarity on the interplay between these two infections.

QT Interval Prolongation with One or More QT-Prolonging Agents Used as Part of a Multidrug Regimen for Rifampicin-Resistant Tuberculosis Treatment: Findings from Two Pediatric Studies.

Rifampicin-resistant tuberculosis (RR-TB) involves treatment with many drugs that can prolong the QT interval; this risk may increase when multiple QT-prolonging drugs are used together. We assessed QT interval prolongation in children with RR-TB receiving one or more QT-prolonging drugs. Data were obtained from two prospective observational studies in Cape Town, South Africa. Electrocardiograms were performed before and after drug administration of clofazimine (CFZ), levofloxacin (LFX), moxifloxacin (MFX), bedaquiline (BDQ), and delamanid. The change in Fridericia-corrected QT (QTcF) was modeled. Drug and other covariate effects were quantified. A total of 88 children with a median (2.5th-to-97.5th range) age of 3.9 (0.5 to 15.7) years were included, of whom 55 (62.5%) were under 5 years of age. A QTcF interval of >450 ms was observed in 7 patient-visits: regimens were CFZ+MFX (n = 3), CFZ+BDQ+LFX (n = 2), CFZ alone (n = 1), and MFX alone (n = 1). There were no events with a QTcF interval of >500 ms. In a multivariate analysis, CFZ+MFX was associated with a 13.0-ms increase in change in QTcF (P < 0.001) and in maximum QTcF (P = 0.0166) compared to those when other MFX- or LFX-based regimens were used. In conclusion, we found a low risk of QTcF interval prolongation in children with RR-TB who received at least one QT-prolonging drug. Greater increases in maximum QTcF and ΔQTcF were observed when MFX and CFZ were used together. Future studies characterizing exposure-QTcF responses in children will be helpful to ensure safety with higher doses if required for effective treatment of RR-TB.

1-Year Incidence of Tuberculosis Infection and Disease Among Household Contacts of Rifampin- and Multidrug-Resistant Tuberculosis.

BACKGROUND: Tuberculosis infection (TBI) and TB disease (TBD) incidence remains poorly described following household contact (HHC) rifampin-/multidrug-resistant TB exposure. We sought to characterize TBI and TBD incidence at 1 year in HHCs and to evaluate TB preventive treatment (TPT) use in high-risk groups. METHODS: We previously conducted a cross-sectional study of HHCs with rifampin-/multidrug-resistant TB in 8 high-burden countries and reassessed TBI (interferon-gamma release assay, HHCs aged ≥5 years) and TBD (HHCs all ages) at 1 year. Incidence was estimated across age and risk groups (<5 years; ≥5 years, diagnosed with human immunodeficiency virus [HIV]; ≥5 years, not diagnosed with HIV/unknown, baseline TBI-positive) by logistic or log-binomial regression fitted using generalized estimating equations. RESULTS: Of 1016 HHCs, 850 (83.7%) from 247 households were assessed (median, 51.4 weeks). Among 242 HHCs, 52 tested interferon-gamma release assay-positive, yielding a 1-year 21.6% (95% confidence interval [CI], 16.7-27.4) TBI cumulative incidence. Sixteen of 742 HHCs developed confirmed (n = 5), probable (n = 3), or possible (n = 8) TBD, yielding a 2.3% (95% CI, 1.4-3.8) 1-year cumulative incidence (1.1%; 95% CI, .5-2.2 for confirmed/probable TBD). TBD relative risk was 11.5-fold (95% CI, 1.7-78.7), 10.4-fold (95% CI, 2.4-45.6), and 2.9-fold (95% CI, .5-17.8) higher in age <5 years, diagnosed with HIV, and baseline TBI high-risk groups, respectively, vs the not high-risk group (P = .0015). By 1 year, 4% (21 of 553) of high-risk HHCs had received TPT. CONCLUSIONS: TBI and TBD incidence continued through 1 year in rifampin-/multidrug-resistant TB HHCs. Low TPT coverage emphasizes the need for evidence-based prevention and scale-up, particularly among high-risk groups.

Optimising computer aided detection to identify intra-thoracic tuberculosis on chest x-ray in South African children.

Diagnostic tools for paediatric tuberculosis remain limited, with heavy reliance on clinical algorithms which include chest x-ray. Computer aided detection (CAD) for tuberculosis on chest x-ray has shown promise in adults. We aimed to measure and optimise the performance of an adult CAD system, CAD4TB, to identify tuberculosis on chest x-rays from children with presumptive tuberculosis. Chest x-rays from 620 children <13 years enrolled in a prospective observational diagnostic study in South Africa, were evaluated. All chest x-rays were read by a panel of expert readers who attributed each with a radiological reference of either 'tuberculosis' or 'not tuberculosis'. Of the 525 chest x-rays included in this analysis, 80 (40 with a reference of 'tuberculosis' and 40 with 'not tuberculosis') were allocated to an independent test set. The remainder made up the training set. The performance of CAD4TB to identify 'tuberculosis' versus 'not tuberculosis' on chest x-ray against the radiological reference read was calculated. The CAD4TB software was then fine-tuned using the paediatric training set. We compared the performance of the fine-tuned model to the original model. Our findings were that the area under the receiver operating characteristic curve (AUC) of the original CAD4TB model, prior to fine-tuning, was 0.58. After fine-tuning there was an improvement in the AUC to 0.72 (p = 0.0016). In this first-ever description of the use of CAD to identify tuberculosis on chest x-ray in children, we demonstrate a significant improvement in the performance of CAD4TB after fine-tuning with a set of well-characterised paediatric chest x-rays. CAD has the potential to be a useful additional diagnostic tool for paediatric tuberculosis. We recommend replicating the methods we describe using a larger chest x-ray dataset from a more diverse population and evaluating the potential role of CAD to replace a human-read chest x-ray within treatment-decision algorithms for paediatric tuberculosis.

A model-based approach for a practical dosing strategy for the short, intensive treatment regimen for paediatric tuberculous meningitis.

Following infection with Mycobacterium tuberculosis, young children are at high risk of developing severe forms of tuberculosis (TB) disease, including TB meningitis (TBM), which is associated with significant morbidity and mortality. In 2022, the World Health Organization (WHO) conditionally recommended that a 6-month treatment regimen composed of higher doses of isoniazid (H) and rifampicin (R), with pyrazinamide (Z) and ethionamide (Eto) (6HRZEto), be used as an alternative to the standard 12-month regimen (2HRZ-Ethambutol/10HR) in children and adolescents with bacteriologically confirmed or clinically diagnosed TBM. This regimen has been used in South Africa since 1985, in a complex dosing scheme across weight bands using fixed-dose combinations (FDC) available locally at the time. This paper describes the methodology used to develop a new dosing strategy to facilitate implementation of the short TBM regimen based on newer globally available drug formulations. Several dosing options were simulated in a virtual representative population of children using population PK modelling. The exposure target was in line with the TBM regimen implemented in South Africa. The results were presented to a WHO convened expert meeting. Given the difficulty to achieve simple dosing using the globally available RH 75/50 mg FDC, the panel expressed the preference to target a slightly higher rifampicin exposure while keeping isoniazid exposures in line with those used in South Africa. This work informed the WHO operational handbook on the management of TB in children and adolescents, in which dosing strategies for children with TBM using the short TBM treatment regimen are provided.

Recurrent Tuberculosis Treatment Episodes in Children Presenting With Presumptive Pulmonary Tuberculosis in Cape Town, South Africa.

BACKGROUND: Limited data are available on tuberculosis (TB) recurrence in children. The aim of this study was to explore the burden of and risk factors for recurrent TB treatment in children. METHODS: A prospective, observational cohort study of children (0-13 years) presenting with presumptive pulmonary TB in Cape Town, South Africa from March 2012 to March 2017. Recurrent TB was defined as more than 1 episode of TB treatment (microbiologically confirmed and unconfirmed). RESULTS: Of 620 children enrolled with presumptive pulmonary TB, data of 608 children were reviewed for TB recurrence after exclusions. The median age was 16.7 [interquartile range (IQR) 9.5-33.3] months, 324 (53.3%) were male and 72 (11.8%) children living with HIV (CLHIV). TB was diagnosed in 297 of 608 (48.8%), of whom 26 had previously received TB treatment, giving a prevalence of 8.8% recurrence: 22 (84.6%) had 1 and 4 (15.4%) had 2 prior TB treatment episodes. The median age of children with recurrent TB was 47.5 (IQR: 20.8-82.5) months at the current episode: 19 of 26 (73.1%) were CLHIV, of whom 12 of 19 (63.2%) were on antiretroviral therapy for a median 43.1 months and all 12 for longer than 6 months. None of the 9 children on antiretroviral treatment with available viral load (VL) data were virally suppressed (median VL, 22,983 copies/ml). Three of 26 (11.6%) children had documented microbiologically confirmed TB at 2 episodes. Four children (15.4%) received drug-resistant TB treatment at recurrence. CONCLUSIONS: There was a high rate of recurrent treatment for TB in this cohort of young children, with CLHIV at the highest risk.