Primary Isoniazid Prophylaxis against Tuberculosis in HIV-Exposed Children

Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases and the Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa.
New England Journal of Medicine (Impact Factor: 55.87). 07/2011; 365(1):21-31. DOI: 10.1056/NEJMoa1011214
Source: PubMed


The dual epidemic of human immunodeficiency virus (HIV) and tuberculosis is a major cause of sickness and death in sub-Saharan Africa. We conducted a double-blind, randomized, placebo-controlled trial of preexposure isoniazid prophylaxis against tuberculosis in HIV-infected children and uninfected children exposed to HIV during the perinatal period.
We randomly assigned 548 HIV-infected and 804 HIV-uninfected infants (91 to 120 days of age) to isoniazid (10 to 20 mg per kilogram of body weight per day) or matching placebo for 96 weeks. All patients received bacille Calmette-Guérin (BCG) vaccination against tuberculosis within 30 days after birth. HIV-infected children had access to antiretroviral therapy. The primary outcome measures were tuberculosis disease and death in HIV-infected children and latent tuberculosis infection, tuberculosis disease, and death in HIV-uninfected children within 96 to 108 weeks after randomization.
Antiretroviral therapy was initiated in 98.9% of HIV-infected children during the study. Among HIV-infected children, protocol-defined tuberculosis or death occurred in 52 children (19.0%) in the isoniazid group and 53 (19.3%) in the placebo group (P=0.93). Among HIV-uninfected children, there was no significant difference in the combined incidence of tuberculosis infection, tuberculosis disease, or death between the isoniazid group (39 children, 10%) and the placebo group (45 children, 11%; P=0.44). The rate of tuberculosis was 121 cases per 1000 child-years (95% confidence interval [CI], 95 to 153) among HIV-infected children as compared with 41 per 1000 child-years (95% CI, 31 to 52) among HIV-uninfected children. There were no significant differences in clinical or severe laboratory toxic effects between treatment groups.
Primary isoniazid prophylaxis did not improve tuberculosis-disease-free survival among HIV-infected children or tuberculosis-infection-free survival among HIV-uninfected children immunized with BCG vaccine. Despite access to antiretroviral therapy, the burden of tuberculosis remained high among HIV-infected children. (Funded by the National Institutes of Health and Secure the Future; number, NCT00080119.).

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Available from: Shabir A Madhi
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    • "Table 1 provides information about the characteristics of the trials included in the analysis. Among the eight studies, two included participants (n = 810) who were HIV-infected [18,19]; one included HIV negative participants born to HIV-infected mothers (n = 806) [19], and the other five included only HIV negative participants (n = 8,703) irrespective of their exposure status [20-24]. Three of the eight studies included participants who were tuberculin skin test (TST) positive only [21,22,24], and two studies excluded participants who had BCG scars [22,24]. "
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    ABSTRACT: Children are highly susceptible to tuberculosis; thus, there is need for safe and effective preventive interventions. Our objective was to evaluate the efficacy of isoniazid in prevention of tuberculosis morbidity and mortality in children aged 15 years or younger by performing a meta-analysis of randomized controlled trials. To our knowledge, this is the first meta-analysis evaluating efficacy of isoniazid prophylaxis in prevention of tuberculosis in children. A systematic search of the literature was done to identify randomized controlled trials evaluating isoniazid prophylaxis efficacy among children. Each study was evaluated for relevance and validity for inclusion in the analysis. Subgroup analyses were conducted based on study quality, HIV status, tuberculosis endemicity, type of prophylaxis and age of participants. Eight studies comprising 10,320 participants were included in this analysis. Upon combining data from all eight studies, isoniazid prophylaxis was found to be efficacious in preventing development of tuberculosis, with a pooled RR of 0.65 (95% CI 0.47, 0.89) p = 0.004 , with confidence intervals adjusted for heterogeneity. Among the sub-group analyses conducted, only age of the participants yielded dramatic differences in the summary estimate of efficacy, suggesting that age might be an effect modifier of the efficacy of isoniazid among children, with no effect realised in children initiating isoniazid at four months of age or earlier and an effect being present in older children. Excluding studies in which isoniazid was initiated at four months of age or earlier yielded an even stronger effect (RR = 0.41 (95% CI 0.31, 0.55) p <0.001). Data on the effect of isoniazid on all-cause mortality, excluding studies in which isoniazid was initiated in infants, yielded an imprecise estimate of mortality benefit (RR = 0.58 (95% CI 0.31, 1.09) p = 0.092). Isoniazid prophylaxis reduces the risk of developing tuberculosis by 59% among children aged 15 years or younger excluding children initiated during early infancy for primary prophylaxis (RR = 0.41, 95% CI 0.31, 0.55 p < 0.001) . However, further studies are needed to assess effects on mortality and to determine prophylaxis effectiveness in very young children and among HIV-infected children.
    Full-text · Article · Feb 2014 · BMC Infectious Diseases
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    • "Zar and colleagues in a South African clinical trial including nearly 300 children showed that IPT halved mortality (8% versus 16%) and reduced TB incidence from 10% to 4%, reducing the chance of developing TB (confirmed or probable) by 72% [84]. However a recently conducted large double-blind, randomized, placebo-controlled trial of pre-exposure isoniazid prophylaxis against tuberculosis on 548 HIV infected children and 804 HIV uninfected children immunized with BCG vaccine, showed no significant difference in the combined incidence of tuberculosis infection, tuberculosis disease, or death between the isoniazid group and the placebo group irrespective of HIV status [85]. "
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    ABSTRACT: HIV is the top and tuberculosis is the second leading cause of death from infectious disease worldwide, with an estimated 8.7 million incident cases of tuberculosis and 2.5 million new HIV infections annually. The World Health Organization estimates that HIV prevalence among children with tuberculosis, in countries with moderate to high prevalence, ranges from 10 to 60%. The mechanisms promoting susceptibility of people with HIV to tuberculosis disease are incompletely understood, being likely caused by multifactorial processes. Paediatric tuberculosis and HIV have overlapping clinical manifestations, which could lead to missed or late diagnosis. Although every effort should be made to obtain a microbiologically-confirmed diagnosis in children with tuberculosis, in reality this may only be achieved in a minority, reflecting their paucibacillary nature and the difficulties in obtain samples. Rapid polymerase chain reaction tests, such as Xpert MTB/RIF assay, are increasingly used in children. The use of less or non invasive methods of sample collection, such as naso-pharyngeal aspirates and stool samples for a polymerase chain reaction-based diagnostic test tests and mycobacterial cultures is promising technique in HIV negative and HIV positive children. Anti-tuberculosis treatment should be started immediately at diagnosis with a four drug regimen, irrespective of the disease severity. Moreover, tuberculosis disease in an HIV infected child is considered to be a clinical indication for initiation of antiretroviral treatment. The World Health Organization recommends starting antiretroviral treatment in children as soon as anti-tuberculosis treatment is tolerated and within 2- 8 weeks after initiating it. The treatment of choice depends on the child’s age and availability of age-appropriate formulations, and potential drug interactions and resistance. Treatment of multi-drug resistant tuberculosis in HIV-infected children follows same principles as for HIV uninfected children. There are conflicting results on effectiveness of isoniazid preventive therapy in reducing incidence of tuberculosis disease in children with HIV. Conclusion Data on HIV/TB co-infection in children are still lacking. There are on-going large clinical trials on the prevention and treatment of TB/HIV infection in children that hopefully will help to guide an evidence-based clinical practice in both resource-rich and resource-limited settings.
    Full-text · Article · Jan 2014 · BMC Infectious Diseases
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    • "However, identifying individuals who have latent M. tuberculosis infection or a high risk for developing tuberculosis is a major challenge; tuberculin skin tests (TSTs) and the recently developed interferon γ–release assays are poor at predicting which individuals with latent infection will subsequently go on to develop tuberculosis, particularly in human immunodeficiency virus (HIV)–positive populations [6]. The need to identify groups at risk of tuberculosis is highlighted by the fact that isoniazid preventive therapy is most effective among TST-positive patients [7, 8] as opposed TST-negative individuals [9]. "
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    ABSTRACT: Background. Eight decades ago, the ratio of monocytes to lymphocytes (hereafter, the “ML ratio”) was noted to affect outcomes of mycobacterial infection in rabbits. Recent transcriptomic studies support a role for relative proportions of myeloid and lymphoid transcripts in tuberculosis outcomes. The ML ratio in peripheral blood is known to be governed by hematopoietic stem cells with distinct biases. Methods. The predictive value of the baseline ML ratio was modeled in 2 prospective cohorts of HIV-infected adults starting cART in South Africa (primary cohort, 1862 participants; replication cohort, 345 participants). Incident tuberculosis was diagnosed with clinical, radiographic, and microbiologic methods per contemporary guidelines. Kaplan-Meier survival analyses and Cox proportional hazards modeling were conducted. Results. The incidence rate of tuberculosis differed significantly by baseline ML ratio: 32.61 (95% confidence interval [CI], 15.38–61.54), 16.36 (95% CI, 12.39–21.23), and 51.80 (95% CI, 23.10–101.71) per 1000 patient-years for ML ratios of less than the 5th percentile, between the 5th and 95th percentiles, and greater than the 95th percentile, respectively (P = .007). Neither monocyte counts nor lymphocyte counts alone were associated with tuberculosis. After adjustment for sex, World Health Organization human immunodeficiency virus disease stage, CD4+ T-cell counts, and previous history of tuberculosis, hazards of disease were significantly higher for patients with ML ratios of less than the 5th percentile or greater than the 95th percentile (adjusted hazard ratio, 2.47; 95% CI, 1.39–4.40; P = .002). Conclusions. The ML ratio may be a useful, readily available tool to stratify the risk of tuberculosis and suggests involvement of hematopoietic stem cell bias in tuberculosis pathogenesis.
    Full-text · Article · Sep 2013 · The Journal of Infectious Diseases
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