Childhood tuberculosis guidelines of the Southern African Society for Paediatric Infectious Diseases

Risk factors associated with surgical intervention in childhood pleural tuberculosis

Surgical intervention use is common in the management of childhood pleural tuberculosis (TB), however, its associated risk factors remain unclear. Between January 2006 and December 2019, consecutive children patients (≤ 15 years old) who had a diagnosis of pleural TB were included for the analysis. Surgical intervention was defined as debridement (such as breaking loculations), decortication, and thoracic surgery (such as lobectomy or segmental resection). Patients undergoing surgery were included as surgical group, without surgery were classified as non-surgical group, surgical risk factors were then estimated. Univariate and multivariate logistic regression analysis were performed to evaluate the risk factors for surgical interventions. A total of 154 children diagnosed as pleural TB (definite, 123 cases; possible, 31 cases) were included in our study. Of them, 29 patients (18.8%) were classified as surgical group and 125 patients (81.2%) were classified as non-surgical group. Surgical treatments were analyzed in 29 (18.8%) patients, including debridement (n = 4), decortication (n = 21), and thoracic surgery (n = 4). Further multivariate analysis revealed that empyema (age- and sex-adjusted OR = 27.3, 95% CI 8.6, 87.1; P < 0.001) and frequency of hospitalization (age- and sex-adjusted OR = 1.53, 95% CI 1.11, 2.11; P < 0.01) were associated with the use of surgical interventions in children with pleural TB. In China, surgical interventions are still required in a significant proportion of children with pleural TB, and the surgical risk is found to be associated with the frequency of hospitalization and empyema. These findings may be helpful to improve the management of children with pleural TB and minimize the risk of poor outcomes.

A phase 1b randomized study of the safety and immunological responses to vaccination with H4:IC31, H56:IC31, and BCG revaccination in Mycobacterium tuberculosis-uninfected adolescents in Cape Town, South Africa

BACKGROUND

Tuberculosis (TB) remains the leading cause of infectious disease-related death. Recently, a trial of BCG revaccination and vaccination with H4:IC31, a recombinant protein vaccine, in South African adolescents (Aeras C-040-404) showed efficacy in preventing sustained QuantiFERON (QFT) conversion, a proxy for Mycobacterium tuberculosis (M.tb) infection. A phase 1b trial of 84 South African adolescents was conducted, concurrent with Aeras C-040-404, to assess the safety and immunogenicity of H4:IC31, H56:IC31 and BCG revaccination, and to identify and optimize immune assays for identification of candidate correlates of protection in efficacy trials.

METHODS

Two doses of H4:IC31 and H56:IC31 vaccines were administered intramuscularly (IM) 56 days apart, and a single dose of BCG (2-8 × 10⁵ CFU) was administered intradermally (ID). T-cell and antibody responses were measured using intracellular cytokine staining and binding antibody assays, respectively. Binding antibodies and CD4+/CD8+ T-cell responses to H4- and H56-matched antigens were measured in samples from all participants. The study was designed to characterize safety and immunogenicity and was not powered for group comparisons. (Clinicaltrials.gov NCT02378207).

FINDINGS

In total, 481 adolescents (mean age 13·9 years) were screened; 84 were enrolled (54% female). The vaccines were generally safe and well-tolerated, with no reported severe adverse events related to the study vaccines. H4:IC31 and H56:IC31 elicited CD4+ T cells recognizing vaccine-matched antigens and H4- and H56-specific IgG binding antibodies. The highest vaccine-induced CD4+ T-cell response rates were for those recognizing Ag85B in the H4:IC31 and H56:IC31 vaccinated groups. BCG revaccination elicited robust, polyfunctional BCG-specific CD4+ T cells, with no increase in H4- or H56-specific IgG binding antibodies. There were few antigen-specific CD8+ T-cell responses detected in any group.

INTERPRETATION

BCG revaccination administered as a single dose ID and both H4:IC31 and H56:IC31 administered as 2 doses IM had acceptable safety profiles in healthy, QFT-negative, previously BCG-vaccinated adolescents. Characterization of the assays and the immunogenicity of these vaccines may help to identify valuable markers of protection for upcoming immune correlates analyses of C-040-404 and future TB vaccine efficacy trials.

FUNDING

NIAID and Aeras.

Assessment of current practices in management of childhood TB among frontline clinicians in Southern Nigeria

BACKGROUND

Poor competence of clinicians may be a critical factor responsible for the under-diagnosis of childhood TB in high-burden settings. Our objective was to assess the current practices of management of childhood TB among clinicians in Nigeria.

METHODS

A cross-sectional survey was conducted among clinicians recruited through a three-stage sampling technique from 76 health facilities in Southern Nigeria. A semi-structured questionnaire was administered to all participants.

RESULTS

Of 106 clinicians who completed the survey, 73 (68.9%) were <40 years and 67 (63.2%) were males. Also, 14 (13.2%) were paediatricians, 22 (20.8%) were paediatric specialist trainees and 70 (66%) were medical officers in primary and secondary care health facilities. About 94% of the respondents perceived diagnosis of childhood TB a challenge in Nigeria. The overall mean (SD) knowledge score was 3.8±0.9 (maximum 5), and 68 (64.2%) had good knowledge of childhood TB. The mean (SD) appropriate practice score was 4.0±1.7 (maximum 10) and, only 8 (7.5%) of them were considered to have adopted appropriate practices regarding childhood TB care.

CONCLUSIONS

There are gaps in practices adopted by frontline clinicians in the management of childhood TB in Nigeria. Focused training of health workers on childhood TB care is urgently recommended.

A Novel Sample Processing Method for Rapid Detection of Tuberculosis in the Stool of Pediatric Patients Using the Xpert MTB/RIF Assay

BACKGROUND

Tuberculosis (TB) is difficult to diagnose in children using molecular tests, because children have difficulty providing respiratory samples. Stool could replace sputum for diagnostic TB testing if adequate sample processing techniques were available.

METHODS

We developed a rapid method to process large volumes of stool for downstream testing by the Xpert MTB/RIF (Xpert) TB-detection assay. The method was tested and optimized on stool samples spiked with known numbers of M. tuberculosis colony forming units (CFU), and stools from M. tuberculosis-infected cynomolgus macaques (Macaca fascicularis). Performance was scored on number of positive Xpert tests, the cycle thresholds (Cts) of the Xpert sample-processing control (SPC), and the Cts of the M. tuberculosis-specific rpoB probes. The method was then validated on 20 confirmed TB cases and 20 controls in Durban, South Africa.

RESULTS

The assay's analytical limit of detection was 1,000 CFU/g of stool. As much as one gram of spiked stool could be tested without showing increased PCR inhibition. In analytical spiking experiments using human stool, 1g samples provided the best sensitivity compared to smaller amounts of sample. However, in Macaques with TB, 0.6g stool samples performed better than either 0.2g or 1.2g samples. Testing the stool of pediatric TB suspects and controls suggested an assay sensitivity of 85% (95% CI 0.6-0.9) and 84% (95% CI 0.6-0.96) for 0.6g and 1.2g stool samples, respectively, and a specificity of 100% (95% CI 0.77-1) and 94% (95% CI 0.7-0.99), respectively.

CONCLUSION

This novel approach may permit simple and rapid detection of TB using pediatric stool samples.

The effect of tuberculosis treatment on virologic and immunologic response to combination antiretroviral therapy among South African children

BACKGROUND

Many HIV-infected children are diagnosed with tuberculosis (TB), but the effect of TB treatment on virologic and immunologic response to combination antiretroviral therapy (cART) is not well documented.

METHODS

Secondary analysis of a prospective cohort of cART-naive HIV-infected South African children aged 0-8 years initiating cART to assess the effect of TB treatment at the time of cART initiation on virologic suppression (HIV RNA < 50 copies/mL), virologic rebound (HIV RNA > 1000 copies/mL after suppression), and CD4 cell percent (CD4%) increase during the first 24 months of cART.

RESULTS

Of 199 children (median age 2.1 years), 92 (46%) were receiving TB treatment at cART initiation. Children receiving and not receiving TB treatment at cART initiation had similar median baseline HIV RNA (5.4 vs. 5.6 copies/mL), median time to virologic suppression (6.2 months in each group, adjusted hazard ratio, 1.36, 95% confidence interval: 0.94 to 1.96), and rates of virologic rebound by 24 months (23% vs. 24%, adjusted hazard ratio 1.53, 95% confidence interval: 0.71 to 3.30). Children on TB treatment had significantly lower median CD4% at baseline (15.3% vs. 18.8%, P < 0.01) and during the first 12 months of cART but experienced similar median increases in CD4% at 6 months (9.9% vs. 9.6%), 12 months (14.2% vs. 11.9%), and 24 months of cART (14.5% vs. 14.2%). Exploratory analyses suggest that children receiving lopinavir/ritonavir-based cART and TB treatment may have inferior virologic and immunologic response compared with children receiving efavirenz-based cART.

CONCLUSIONS

Receiving TB treatment at the time of cART initiation did not substantially affect virologic or immunologic response to cART in young children.

Tuberculosis in childhood: a systematic review of national and international guidelines

BACKGROUND

Paediatric tuberculosis (TB) represents a major public health concern worldwide. About 1 million children aged less than 15 years develop TB each year, contributing to 3-25% of the total TB caseload. The aim of this review is to evaluate national and international guidelines concerning tuberculosis in childhood and compare them in terms of diagnosis and treatment strategies.

METHODS

A literature search of the Pubmed database was performed from January 2000 to August 2013, using the terms "tuberculosis" and "children". The search was limited to guidelines and consensus conferences, human species and full text availability, with no language restrictions.

RESULTS

Twenty-seven national and international guidelines are identified. Several discrepancies on the diagnosis workup of TB are underlined. The main points of disagreement are represented by the interpretation of tuberculin skin test (TST) result and the recommendations on the use of TST and/or interferon-gamma release assay (IGRA) for the diagnosis of TB infection. Otherwise, all guidelines are in agreement that a microbiological confirmation should always be sought. Similarly, susceptibility drug testing and genotyping should be performed whenever it is possible on the basis of resources availability. On the contrary, the use of nucleic acid amplification tests (NAATs) for the M. tuberculosis detection is still controversial. A general consensus exists, otherwise, on TB treatment and only minor discrepancies are evidenced, such as the recommendations on daily or intermittent treatment regimens.

CONCLUSIONS

Despite advances in TB diagnostic tools have been reached during the last decade, a lack of uniformity in their availability, indication and interpretation has relevant consequences for clinical practice. Further studies need to be performed to clarify this issue and identify a reliable and reproducible diagnostic workup. Moreover, future studies should analyze the drug metabolism and the efficacy of intermittent dosing regimes in childhood, as well as new treatment regimens in order to improve the therapy compliance.

Pharmacokinetics of nevirapine in HIV-infected children under 3 years on rifampicin-based antituberculosis treatment

OBJECTIVE

There is an urgent need to optimize cotreatment for children with tuberculosis and HIV infection. We described nevirapine pharmacokinetics in Zambian children aged less than 3 years, cotreated with nevirapine, lamivudine and stavudine in fixed-dose combination (using WHO weight bands) and rifampicin-based antituberculosis treatment.

DESIGN

Twenty-two children received antituberculosis and antiretroviral therapy (ART) concurrently for 4 weeks before pharmacokinetic sampling. Plasma nevirapine concentrations were determined in samples taken immediately before, and 1, 2 and 6 h after an observed dose. Nevirapine pharmacokinetics were compared with those in 16 children aged less than 3 years without tuberculosis.

RESULTS

Twenty-two children were treated for HIV/TB coinfection, 10 of whom were girls. One boy was excluded from analysis for nonadherence. The median age was 1.6 years (range: 0.7-3.2). Median weight was 8.0 kg (range: 5.1-10.5). The baseline CD4% was 13.1 (range: 3.9-43.6). Median predose concentration of nevirapine was 2.93 mg/l (range: 1.06-11.4), and peak concentration was 6.33 mg/l (range: 2.61-14.5). The nevirapine AUC up to 12 h was estimated as 52.0 mg.h/l (range: 22.6-159.7) compared with 90.9 mg.h/l (range: 40.4-232.1) in children without tuberculosis (P < 0.001). Predose concentrations of nevirapine were less than 3.0 mg/l in 11 children on tuberculosis treatment versus none of the 16 children without tuberculosis treatment (P = 0.001). AUC was 41% (95% CI: 23-54%) lower in children with tuberculosis than without tuberculosis (P < 0.001) after adjusting for dose per square meter.

CONCLUSION

: We found substantial reductions in nevirapine concentrations in young children receiving rifampicin. Further studies are needed to define the pharmacokinetics, safety and efficacy of adjusted doses of nevirapine-based ART in young children with tuberculosis.

Pharmacokinetics of isoniazid, rifampin, and pyrazinamide in children younger than two years of age with tuberculosis: evidence for implementation of revised World Health Organization recommendations

The World Health Organization (WHO) recently issued revised first-line antituberculosis (anti-TB) drug dosage recommendations for children. No pharmacokinetic studies for these revised dosages are available for children <2 years. The aim of the study was to document the pharmacokinetics of the first-line anti-TB agents in children <2 years of age comparing previous and revised WHO dosages of isoniazid (INH; 5 versus 10 mg/kg/day), rifampin (RMP; 10 versus 15 mg/kg/day), and pyrazinamide (PZA; 25 versus 35 mg/kg/day) and to investigate the effects of clinical covariates, including HIV coinfection, nutritional status, age, gender, and type of tuberculosis (TB), and the effect of NAT2 acetylator status. Serum INH, PZA, and RMP levels were prospectively assessed in 20 children <2 years of age treated for TB following the previous and the revised WHO dosage recommendations. Samples were taken prior to dosing and at 0.5, 1.5, 3, and 5 h following dosing. The maximum drug concentration in serum (C(max)), the time to C(max) (t(max)), and the area under the concentration-time curve (AUC) were calculated. Eleven children had pulmonary and 9 had extrapulmonary TB. Five were HIV infected. The mean C(max) (μg/ml) following the administration of previous/revised dosages were as follows: INH, 3.19/8.11; RMP, 6.36/11.69; PZA, 29.94/47.11. The mean AUC (μg·h/ml) were as follows: INH, 8.09/20.36; RMP, 17.78/36.95; PZA, 118.0/175.2. The mean C(max) and AUC differed significantly between doses. There was no difference in the t(max) values achieved. Children less than 2 years of age achieve target concentrations of first-line anti-TB agents using revised WHO dosage recommendations. Our data provided supportive evidence for the implementation of the revised WHO guidelines for first-line anti-TB therapy in young children.

The use of diagnostic systems for tuberculosis in children

Effective management of tuberculosis (TB) in children and important data of disease burden continue to rely on a clinical approach to diagnosis, as diagnosis of childhood TB is not confirmed in the majority. Many diagnostic scoring systems have been developed to aid with diagnosis. This article reviews the use and evaluation of these approaches. The diagnostic systems are often closely related and all rely on the well-known clinical features associated with TB disease in children. The scoring systems are not well validated and validation is limited by the lack of a gold standard for comparison. When they have been validated, some systems perform reasonably well but may bias to identify the most obvious clinical cases. They perform less well in important sub-groups that pose the greatest diagnostic challenge and are at greatest risk for poor outcome, such as the young, malnourished or HIV-infected. There is marked variation in performance between these diagnostic approaches. The better validated systems may have a role as a screening tool in some settings, but this would need careful consideration as to the most useful and safest approach. More attention is being given to improving diagnosis and management of child TB, including within National TB Programmes. Research with new diagnostics should include children so that there is less reliance on clinical features alone. However, the clinical approach will continue to be relevant and so it is important to strive to improve the diagnostic approach to TB in children, and to validate the approach in different settings.