Predictors of TB disease in HIV-exposed children from Southern Africa.

BACKGROUND: P1041 was a randomised, placebo-controlled isoniazid prophylaxis trial in South Africa. We studied predictors for TB in HIV-exposed children participating in the P1041 trial.METHODS: We included data from entry until Week 108. Predictors considered were type of housing, overcrowding, age, sex, ethnicity, tobacco exposure, weight-for-age percentile Z-score (WAZ), CD4%, viral load (VL), antiretroviral therapy (ART) and number of household smokers.RESULTS: Of 543 HIV-positive (HIV+) and 808 HIV-exposed uninfected (HEU) infants at entry, median age was 96 days (interquartile range: 92-105). Of 1,351 caregivers, 125 (9%) had a smoking history, and 62/1,351 reported current smoking. In 594/1,351 (44%) households, there was at least one smoker. Smoking caregivers consumed 1-5 cigarettes daily. In the HIV+ cohort, significant baseline TB predictors after adjusting covariates were as follows: WAZ (adjusted hazard ratio [aHR] 0.76, P = 0.002) and log10 HIV RNA copies/ml (aHR 1.50, P = 0.009). Higher CD4% (aHR 0.88, P = 0.002) and ART (aHR 0.50, P = 0.006) were protective. In the HEU cohort, smoking exposure was associated with reduced TB-free survival on univariate analysis, but not after adjustment in the multivariate model.CONCLUSION: Low WAZ and high VL were strong predictors of TB disease or death. Rising CD4 percentage and being on ART were protective in the HIV+ cohort.

Use of antiretrovirals in HIV-infected children in a tuberculosis prevention trial: IMPAACT P1041.

SETTING: International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) P1041, a tuberculosis (TB) prevention trial conducted among children enrolled from 2004 to 2008 during South Africa's roll-out of combination antiretroviral therapy (ART). OBJECTIVE: To estimate TB incidence and mortality and the effect of ART. DESIGN: Children were pre-screened to exclude TB disease and exposure, actively screened 3-monthly for TB exposure and symptoms, and provided post-exposure isoniazid prophylaxis therapy (IPT). TB diagnoses were definite, probable, or possible, and mortality all-cause. Testing was at the 5% significance level. RESULTS: In 539 children (aged 3-4 months) followed up for a median of 74 weeks (interquartile range [IQR] 48-116), incidence/100 person-years (py) was 10.67 (95%CI 8.47-13.26) for any TB and 2.89 (95%CI 1.85-4.31) for definite/probable TB. Any TB incidence was respectively 9.39, 13.59, and 9.83/100 py before, <180 days after, and 180 days after ART initiation. Adjusted analysis showed a non-significant increase in any TB (HR 1.32, 95%CI 0.71-2.52, P = 0.38) and a significant reduction in mortality (HR 0.39, 95%CI 0.17-0.82, P = 0.017) following ART initiation. CONCLUSIONS: ART reduced mortality but not TB incidence in human immunodeficiency virus (HIV) infected children in IMPAACT P1041, possibly attributable to active screening for TB exposure and symptoms with post-exposure IPT. Research into this as a strategy for TB prevention in high HIV-TB burden settings may be warranted.

Source case identification in HIV-exposed infants and tuberculosis diagnosis in an isoniazid prevention study.

BACKGROUND: Identifying source cases of children exposed to tuberculosis (TB) is challenging. We examined the time-point of obtaining contact information of TB source cases in human immunodeficiency virus (HIV) infected and HIV-exposed uninfected (HEU) children in a randomised, placebo-controlled trial of pre-exposure to isoniazid prophylaxis. METHODS: A total of 543 HIV-infected and 808 HEU infants without TB exposure aged 3-4 months were enrolled between 2004 and 2008. At 3-monthly follow-up, infants were evaluated for TB and care givers were asked about new TB exposure. RESULTS: In total, 128 cases of TB disease and 40 deaths were recorded among 19% (105/543) of the HIV-infected and 8% (63/808) of the HEU children; 229 TB contact occasions were reported in 205/1351 (15%) children, of which 83% (189/229) were in the household. Of the 189 household contacts, 108 (53%) underwent microbiological evaluations; 81% (87/108) were positive. HIV-infected and HEU infants had similar frequencies of TB contact: in 48% of infants with definite TB, 58% with probable TB and 43% with possible TB. Of 128 children diagnosed with TB, a TB contact was identified for 59. Of these, 29/59 (49%) were identified at or after the child's TB diagnosis. CONCLUSION: TB source cases are often identified at or after a child's TB diagnosis. More effort is required for earlier detection.

Understanding NIH clinical case definitions for pediatric intrathoracic TB by applying them to a clinical trial.

SETTING: Standardized clinical case definitions represent the best option for pediatric tuberculosis (TB) disease diagnosis and classification. OBJECTIVE: To apply published guidelines for intrathoracic TB classification for use in reporting diagnostic studies with passive case finding to presumed TB patients from International Maternal Pediatric Adolescent AIDS Clinical Trials P1041, a trial of isoniazid prophylaxis in healthy human immunodeficiency virus exposed, bacille Calmette-Guérin vaccinated infants which employed active surveillance to assess a novel application of these guidelines in this setting. METHODS: P1041 presumed TB patients were retrospectively cross-classified by protocol-defined and National Institutes of Health (NIH) classifications, and agreement was assessed. RESULTS: Of 219 TB suspects, 166 had signs/symptoms, with 158 considered TB (21 confirmed, 92 probable, 45 possible) and 8 not TB (6 TB unlikely, 2 alternative diagnoses). Weight loss and failure to thrive represented the majority of the observed signs/symptoms. Among those with signs/symptoms, agreement between definitions was poor. Furthermore, 53 TB presumptives were without signs/symptoms, including 33 classified by the P1041 protocol as TB. CONCLUSION: Poor agreement between P1041 and NIH classifications reflects cases identified through active vs. passive surveillance, the latter reflecting the intended use of NIH definitions. Given the interest in standardized definitions for broader application, future efforts could focus on expanding TB disease classification to presumed TB patients identified through active surveillance.

Loss to follow-up among infants in a study of isoniazid prophylaxis (P1041) in South Africa.

OBJECTIVE: To assess risk factors for loss to follow-up (LFU) from the IMPAACT P1041 study, an isoniazid (INH) prophylaxis study conducted in southern Africa. DESIGN: Infants in two cohorts, human immunodeficiency virus-infected (HIV+) and HIV-exposed but non-infected (HIV-), were randomized to INH or placebo for 96 weeks. LFU was evaluated at week 96. RESULTS: Of 1351 infants, 12.9% were LFU (10.4% HIV+, 14.7% HIV-); 65% of the HIV+ cohort was asymptomatic. Among HIV+ infants, large household size (>6 vs. <4 members, P = 0.035) and presence of an elder (≥55 years, P = 0.05) were associated with better retention. Although attenuated in adjusted analysis, these associations held among HIV- infants. Among HIV- infants, having a younger mother increased the risk (P = 0.008) and maternal history of TB reduced the risk of LFU, the latter by nearly 70% (P = 0.048 univariate, 0.09 adjusted). LFU was largely due to inability to contact the participant (58% HIV+, 30% HIV-), and inability to attend the clinic and withdrawal of consent (HIV-). CONCLUSIONS: Household support was an important factor in participant retention, particularly for the non-HIV-infected cohort, as young maternal age was a risk factor for LFU. Retaining study participants from this mobile population can be challenging and may warrant additional support.

High prevalence of drug resistance amongst HIV-exposed and -infected children in a tuberculosis prevention trial.

An emergence of drug-resistant tuberculosis (DR-TB) in settings affected by human immunodeficiency virus (HIV) and tuberculosis (TB) has been observed. We investigated the prevalence of DR-TB in P1041, a multicentered, randomised, double-blind trial which compared the administration of isoniazid (INH) to placebo, in HIV-exposed, non-infected and -infected African infants in the absence of any documented TB exposure. The prevalence of multidrug-resistant TB (MDR-TB) was 22.2% (95%CI 8.5-45.8) and INH monoresistance 5.6% (95%CI 0.1-27.6) among culture-confirmed cases, with all MDR-TB occurring in a single site. There was no association between INH treatment or placebo group, or between HIV infection status, and DR-TB prevalence. There was a high prevalence of DR-TB among HIV-exposed and -infected children. Surveillance of DR-TB among children in high-burden TB-HIV settings should be routine.

Early antiretroviral treatment reduces risk of bacille Calmette-Guérin immune reconstitution adenitis.

SETTING: Two centres in Soweto and Cape Town, South Africa. OBJECTIVE: To assess the effects of timing of initiation of antiretroviral treatment (ART) and other factors on the risk of bacille Calmette-Guérin (BCG) related regional adenitis due to immune reconstitution inflammatory syndrome (BCG-IRIS) in human immunodeficiency virus (HIV) infected infants. DESIGN: HIV-infected infants aged 6-12 weeks with CD4 count ≥25% enrolled in the Children with HIV Early Antiretroviral Therapy (CHER) Trial received early (before 12 weeks) or deferred (after immunological or clinical progression) ART; infants with CD4 count <25% all received early ART. All received BCG vaccination after birth. Reactogenicity to BCG was assessed prospectively during routine study follow-up. RESULTS: Of 369 infants, 32 (8.7%) developed BCG-IRIS within 6 months of starting ART, 28 (88%) within 2 months after ART initiation. Of the 32 cases, 30 (93.8%) had HIV-1 RNA > 750 000 copies/ml at initiation. Incidence of BCG-IRIS was 10.9 and 54.3 per 100 person-years (py) among infants with CD4 count ≥25% at enrolment receiving early (at median age 7.4 weeks) vs. deferred (23.2 weeks) ART, respectively (HR 0.24, 95%CI 0.11-0.53, P < 0.001). Infants with CD4 count <25% receiving early ART had intermediate incidence (41.7/100 py). Low CD4 counts and high HIV-1 RNA at initiation were the strongest independent risk factors for BCG-IRIS. CONCLUSIONS: Early ART initiation before immunological and/or clinical progression substantially reduces the risk of BCG-IRIS regional adenitis.

HAART and risk of tuberculosis in HIV-infected South African children: a multi-site retrospective cohort.

SETTING: Four human immunodeficiency virus (HIV) clinics located at South African tertiary hospitals. OBJECTIVE: To assess the effectiveness of highly active antiretroviral therapy (HAART) in reducing incident tuberculosis (TB) in HIV-infected children. DESIGN: Retrospective cohort. RESULTS: A total of 1132 children's records were included in the study. At entry to the cohort, the median (interquartile range [IQR]) age, CD4%, CD4 count and viral load of all children was respectively 6.3 years (4.1-8.8), 15% (9.0-22.2), 576 cells/mm(3) (287-960) and 160 000 copies/ml (54 941.5-449 683); 75.9% were started on HAART. The male:female ratio was 1:1, and median follow-up time was 1.7 years. In children whose follow-up included both pre-HAART and on-HAART periods, the incidence of clinically diagnosed TB was respectively 21.1 per 100 person-years (py; 95%CI 18.2-24.4) and 6.4/100 py (95%CI 4.8-8.1), and when restricted to confirmed cases, respectively 3.1/100 py (95%CI 2.2-4.2) and 0.8/100 py (95%CI 0.5-1.4). Only 23% of all cases of TB were microbiologically confirmed. Multivariate analyses showed that HAART reduced incident TB by approximately 70%, both for confirmed and all TB cases. CONCLUSIONS: In this high TB burden country, the incidence of diagnosis of TB in HIV-infected children is at least as high as that of adults. HAART reduces incident TB, but further prospective TB preventive and diagnostic studies are urgently needed in children.

Hopes, fears, knowledge and misunderstandings: responses of HIV-positive mothers to early knowledge of the status of their baby.

Little is known about how HIV-positive mothers experience and react to knowing the HIV status of their baby as diagnosed by the polymerase chain reaction (PCR) test at 4-6 weeks. This qualitative study drew on interviews with 20 mothers of HIV-negative and 18 mothers of HIV-positive babies after receiving their baby's PCR results. Thematic analysis combined exploration of themes that appeared significant to the participants and those relevant to health care. Amongst the themes identified were the following: The period before getting the results involved active mental preparation and was emotionally stressful. Most women accepted the results, but some had doubts about their reliability. Mothers of HIV-negative babies were relieved, but mothers of HIV-positive babies were generally very distressed and expressed a sense of responsibility and guilt. Both groups of mothers had similar hopes for the future of their babies, but the timelines of mothers of HIV-positive babies tended to be shorter. Most women experienced significant levels of stress, but were able to call on support networks and use various individual coping mechanisms to manage their stress. Most women were formula feeding their babies, but regretted not being able to breastfeed. Many women had not planned their current baby and most did not intend to have more children, but many of the latter had not taken active steps to prevent further pregnancy. The findings provide pointers to shortcomings in health worker communication and suggest that more effective communication should take account of normative community views and be more closely attuned to the changing needs and experiences of HIV-positive mothers.