Despite the recent innovations in tuberculosis (TB) and multi-drug resistant TB (MDR-TB) diagnosis, culture remains vital for difficult-to-diagnose patients, baseline and end-point determination for novel vaccines and drug trials. Herein, we share our experience of establishing a BSL-3 culture facility in Uganda as well as 3-years performance indicators and post-TB vaccine trials (pioneer) and funding experience of sustaining such a facility.
Between September 2008 and April 2009, the laboratory was set-up with financial support from external partners. After an initial procedure validation phase in parallel with the National TB Reference Laboratory (NTRL) and legal approvals, the laboratory registered for external quality assessment (EQA) from the NTRL, WHO, National Health Laboratories Services (NHLS), and the College of American Pathologists (CAP). The laboratory also instituted a functional quality management system (QMS). Pioneer funding ended in 2012 and the laboratory remained in self-sustainability mode.
The laboratory achieved internationally acceptable standards in both structural and biosafety requirements. Of the 14 patient samples analyzed in the procedural validation phase, agreement for all tests with NTRL was 90% (P <0.01). It started full operations in October 2009 performing smear microscopy, culture, identification, and drug susceptibility testing (DST). The annual culture workload was 7,636, 10,242, and 2,712 inoculations for the years 2010, 2011, and 2012, respectively. Other performance indicators of TB culture laboratories were also monitored. Scores from EQA panels included smear microscopy >80% in all years from NTRL, CAP, and NHLS, and culture was 100% for CAP panels and above regional average scores for all years with NHLS. Quarterly DST scores from WHO-EQA ranged from 78% to 100% in 2010, 80% to 100% in 2011, and 90 to 100% in 2012.
From our experience, it is feasible to set-up a BSL-3 TB culture laboratory with acceptable quality performance standards in resource-limited countries. With the demonstrated quality of work, the laboratory attracted more research groups and post-pioneer funding, which helped to ensure sustainability. The high skilled experts in this research laboratory also continue to provide an excellent resource for the needed national discussion of the laboratory and quality management systems.
Electronic supplementary material
The online version of this article (doi:10.1186/1478-4505-13-4) contains supplementary material, which is available to authorized users.
Acceptable quality standards; Biosafety level 3; Feasibility; Resource limited countries; TB culture
To describe five year growth, survival and long-term safety among children exposed to nevirapine or zidovudine in an African perinatal prevention trial, HIVNET 012.
All study children who were alive at eighteen months of age were eligible for an extended follow-up study. Children whose families consented were enrolled and evaluated every six months from 24 to 60 months. At each visit, history, physical exam and growth measures were taken. From these measurements Z scores based on World Health Organization (WHO) standards were computed. Serious adverse event data were collected. Data from the initial and extended follow-up cohorts were included in the analysis.
528 study children were alive at age 18 months, and 491 (426 HIV uninfected; 65 infected) were enrolled into the follow-up study. Both exposed but uninfected children and HIV infected children were substantially below WHO growth standards for weight and height. Head circumference Z scores for uninfected children were comparable to WHO norms. Five-year survival rates were 93% for uninfected children versus 43% for infected children. Long-term safety and growth outcomes in the two study arms were similar.
Both infected and uninfected children in the five-year HIVNET 012 follow-up showed poor height and weight growth outcomes, underscoring the need for early nutritional interventions to improve long-term growth of all infants born to HIV-infected women in resource limited settings. Likewise, the low five year survival among HIV infected children support the importance of early initiation of antiretroviral therapy. Both peripartum nevirapine and zidovudine were safe.
The development of a safe and effective vaccine against human immunodeficiency virus type 1 (HIV-1) for prevention mother-to-child transmission of HIV would significantly advance the goal of eliminating HIV infection in children. Safety and feasibility results from Phase I, randomized, double blind, placebo-controlled trial of ALVAC-HIV vCP1521 in infants born to HIV-1-infected women in Uganda are reported.
HIV exposed infants were enrolled at birth and randomized (4:1) to receive vaccine or saline placebo intramuscular injections at birth, 4, 8 and 12 weeks of age. Vaccine reactogenicity was assessed at vaccination, and days 1 and 2 post-vaccination. Infants were followed until 24 months of age. HIV infection status was determined by HIV DNA PCR.
From October 2006 to May 2007, 60 infants (48 vaccine, 12 placebo) were enrolled with 98% retention at 24 months. One infant was withdrawn, but there were no missed visits or vaccinations among the 59 infants retained. Immune responses elicited by Diptheria, Polio, Hepatitis B and Heamophilus influenzae type B and measles vaccination were similar in the two arms. The vaccine was well tolerated with no severe or life-threatening reactogenicity events. Adverse events were equally distributed across both study arms. Four infants were diagnosed as HIV infected [3 at birth (2 vaccine, 1 placebo) and one in vaccine arm at 2 weeks of age].
The ALVAC-HIV vCP1521 vaccination was feasible and safe in infants born to HIV-infected women in Uganda. The conduct of high quality infant HIV vaccine trials is achievable in Africa.
HIV vaccine; ALVAC; infants; Africa; breast milk transmission
As part of site development for clinical trials in novel TB vaccines, a cohort of infants was enrolled in eastern Uganda to estimate the incidence of tuberculosis. The study introduced several mortality reduction strategies, and evaluated the mortality among study participants at two years. The specific of objective of this sub-study was to estimate 2 year mortality and associated factors in this community-based cohort.
A community based cohort of 2500 infants was enrolled from birth up to 8 weeks of age and followed for 1–2 years. During follow up, several mortality reduction activities were implemented to enhance cohort survival and retention. The verbal autopsy process was used to assign causes of death.
A total of 152 children died over a median follow up period of 2.0 years. The overall crude mortality rate was 60.8/1000 or 32.9/1000 person years with 40 deaths per 1000 for children who died in their first year of life. Anaemia, malaria, diarrhoeal diseases and pneumonia were the top causes of death. There was no death directly attributed to tuberculosis. Significant factors associated with mortality were young age of a mother and child’s birth place not being a health facility.
The overall two year mortality in the study cohort was unacceptably high and tuberculosis disease was not identified as a cause of death. Interventions to reduce mortality of children enrolled in the cohort study did not have a significant impact. Clinical trials involving infants and young children in this setting will have to strengthen local maternal and child health services to reduce infant and child mortality.
Mortality; Infants; Factors associated with mortality; Verbal autopsy
A pooled analysis of individual data from >5000 human immunodeficiency virus type 1 (HIV-1)–infected mothers and their infants from Africa and India who participated in 5 randomized trials shows that extended prophylaxis with nevirapine or with nevirapine and zidovudine significantly reduces postnatal HIV-1 infection.
Background. In resource-limited settings, mothers infected with human immunodeficiency virus type 1 (HIV-1) face a difficult choice: breastfeed their infants but risk transmitting HIV-1 or not breastfeed their infants and risk the infants dying of other infectious diseases or malnutrition. Recent results from observational studies and randomized clinical trials indicate daily administration of nevirapine to the infant can prevent breast-milk HIV-1 transmission.
Methods. Data from 5396 mother-infant pairs who participated in 5 randomized trials where the infant was HIV-1 negative at birth were pooled to estimate the efficacy of infant nevirapine prophylaxis to prevent breast-milk HIV-1 transmission. Four daily regimens were compared: nevirapine for 6 weeks, 14 weeks, or 28 weeks, or nevirapine plus zidovudine for 14 weeks.
Results. The estimated 28-week risk of HIV-1 transmission was 5.8% (95% confidence interval [CI], 4.3%–7.9%) for the 6-week nevirapine regimen, 3.7% (95% CI, 2.5%–5.4%) for the 14-week nevirapine regimen, 4.8% (95% CI, 3.5%–6.7%) for the 14-week nevirapine plus zidovudine regimen, and 1.8% (95% CI, 1.0%–3.1%) for the 28-week nevirapine regimen (log-rank test for trend, P < .001). Cox regression models with nevirapine as a time-varying covariate, stratified by trial site and adjusted for maternal CD4 cell count and infant birth weight, indicated that nevirapine reduces the rate of HIV-1 infection by 71% (95% CI, 58%–80%; P < .001) and reduces the rate of HIV infection or death by 58% (95% CI, 45%–69%; P < .001).
Conclusions. Extended prophylaxis with nevirapine or with nevirapine and zidovudine significantly reduces postnatal HIV-1 infection. Longer duration of prophylaxis results in a greater reduction in the risk of infection.
breast milk; HIV; nevirapine
We used a novel high resolution melting (HRM) diversity assay to analyze HIV diversity in Ugandan children (ages 0.6 to 12.4 years) who were enrolled in an observational study of antiretroviral treatment (ART). Children were maintained on ART if they were clinically and immunologically stable.
HIV diversity was measured prior to ART (baseline) in 76 children and after 48 or 96 weeks of ART in 14 children who were not virally suppressed. HIV diversity (expressed as HRM scores) was measured in six regions of the HIV genome (two in gag, one in pol, three in env).
Higher baseline HRM scores were significantly associated with older age (≥ 2 years, P ≤ 0.001 for all six regions). HRM scores from different regions were weakly correlated. Higher baseline HRM scores in three regions (one in gag, two in env) were associated with ART failure. HIV diversity was lower in four regions (two in gag, one in pol, one in env) after 48 to 96 weeks of non-suppressive ART compared to baseline.
Higher levels of HIV diversity were observed in older children prior to ART and higher levels of diversity in some regions of the HIV genome were associated with ART failure. Prolonged exposure to non-suppressive ART was associated with a significant decrease in viral diversity in selected regions of the HIV genome.
HIV; diversity; children; antiretroviral therapy
The world health organization (WHO) declared tuberculosis (TB) a global emergency, mainly affecting people in sub-Saharan Africa. However there is little data about the burden of TB among adolescents. We estimated the prevalence and incidence of TB and assessed factors associated with TB among adolescents aged 12–18 years in a rural population in Uganda in order to prepare the site for phase III clinical trials with novel TB vaccines among adolescents.
In a prospective cohort study, we recruited 5000 adolescents and followed them actively, every 6 months, for 1–2 years. Participants suspected of having TB were those who had any of; TB signs and symptoms, history of TB contact or a positive tuberculin skin test (TST) of ≥10 mm. Laboratory investigations included sputum smear microscopy and culture.
Of the 5000 participants, eight culture confirmed cases of TB were found at baseline: a prevalence of 160/100,000 (95% confidence interval (CI), 69–315). There were 13 incident TB cases detected in an average of 1.1 person years: an incidence of 235/100,000 person years (95% CI, 125–402). None of the confirmed TB cases were HIV infected. Predictors for prevalent TB disease were: a history of TB contact and a cough ≥ 2 weeks at baseline and being out of school, while the only predictor for incident TB was a positive TST during follow-up.
The TB incidence among adolescents in this rural part of Uganda seemed too low for a phase III TB vaccine trial. However, the study site demonstrated capability to handle a large number of participants with minimal loss to follow-up and its suitability for future clinical trials. Improved contact tracing in TB program activities is likely to increase TB case detection among adolescents. Future studies should explore possible pockets of higher TB incidence in urban areas and among out of school youth.
The benefits of long-term antiretroviral therapy (ART) are recognized all over the world with infected children maturing into adults and HIV infection becoming a chronic illness. However, the improved survival is associated with serious metabolic complications, including lipodystrophy (LD), dyslipidemia, insulin resistance, lactic acidosis and bone loss. In addition, the dyslipidemia mainly seen with protease inhibitors may increase the risk of cardiovascular disease in adulthood and potentially in children as they mature into adults. Nucleoside reverse transcriptase inhibitors, particularly stavudine, zidovudine and didanosine are linked to development of LD and lactic acidosis. Perinatally infected children initiate ART early in life; they require lifelong therapy with multiple drug regimens leading to varying toxicities, all potentially impacting their quality of life. LD has a significant impact on the mental health of older children and adolescents leading to poor self-image, depression and subsequent poor adherence to therapy. Reduced bone mineral density (BMD) is reported in both adults and children on ART with the potential for children to develop more serious bone complications than adults due to their rapid growth spurts and puberty. The role of vitamin D in HIV-associated osteopenia and osteoporosis is not clear and needs further study. Most resource-limited settings are unable to monitor lipid profiles or BMD, exposing infected children and adolescents to on-going toxicities with unclear long-term consequences. Improved interventions are urgently needed to prevent and manage these metabolic complications. Longitudinal cohort studies in this area should remain a priority, particularly in resource-limited settings where the majority of infected children reside.
children; adolescents; HIV; antiretroviral therapy; metabolic complications; cardiovascular disease
There is a critical need for improved diagnosis of tuberculosis in children, particularly in young children with intrathoracic disease as this represents the most common type of tuberculosis in children and the greatest diagnostic challenge. There is also a need for standardized clinical case definitions for the evaluation of diagnostics in prospective clinical research studies that include children in whom tuberculosis is suspected but not confirmed by culture of Mycobacterium tuberculosis. A panel representing a wide range of expertise and child tuberculosis research experience aimed to develop standardized clinical research case definitions for intrathoracic tuberculosis in children to enable harmonized evaluation of new tuberculosis diagnostic technologies in pediatric populations. Draft definitions and statements were proposed and circulated widely for feedback. An expert panel then considered each of the proposed definitions and statements relating to clinical definitions. Formal group consensus rules were established and consensus was reached for each statement. The definitions presented in this article are intended for use in clinical research to evaluate diagnostic assays and not for individual patient diagnosis or treatment decisions. A complementary article addresses methodological issues to consider for research of diagnostics in children with suspected tuberculosis.
Antiretroviral therapy (ART) is known to save lives. Among HIV-infected infants living in resource constrained settings, the short and long term benefits of ART are only partially known. This study was designed to determine the virologic, immunologic and clinical outcomes of antiretroviral therapy in a cohort of HIV-infected infants receiving care from an outpatient clinic in Kampala, Uganda.
A prospective cohort of HIV-infected infants receiving treatment at the Baylor-Uganda clinic was analyzed. Patients were diagnosed, enrolled and followed up at the clinic. HIV viral load, CD4 cell counts and clinical progress were assessed during follow-up. Descriptive statistical analysis and logistic regression modeling to determine predictors of treatment success were conducted.
Of 91 HIV-infected infants enrolled into the cohort, 53 (58.2%) infants were female; 43 (47.3%) were 6 months of age or younger, and 50 (55.6%) had advanced HIV/AIDS disease (Clinical stage 3 or 4). Eighty four infants started ART and 78 (92.9%) completed 6 months of treatments. Fifty six (71.8%) infants attained virologic suppression by month-6 of ART, and at month-12 of ART, the cumulative probability of attaining viral suppression was 83.1%. None of the baseline infant factors (age, sex, WHO stage, CD4 cell percent, weight for age, or height for age z-score) predicted treatment success. There was an increase in CD4 cells from a baseline mean of 23% to 30% at month-6 of treatment (p<0.001) and by month-24 of ART, the mean CD4 percent was 36%. A total of 7 patients died while on ART and another 7 experienced adverse events that were related to treatment.
Our results show that, even among very young patients from resource constrained settings, ART dramatically suppresses HIV replication, allows immune recovery and clinical improvement, and is safe. However, baseline characteristics do not predict recovery in this age group.
Infant; HIV; Antiretroviral therapy; Mortality; Malnutrition
In resource-rich countries, bolus fluid expansion is routinely used for the treatment of poor perfusion and shock, but is less commonly used in many African settings. Controversial results from the recently completed FEAST (Fluid Expansion As Supportive Therapy) trial in African children have raised questions about the use of intravenous bolus fluid for the treatment of shock. Prior to the start of the trial, the Independent data monitoring committee (IDMC) developed stopping rules for the proof of benefit that bolus fluid resuscitation would bring. Although careful safety monitoring was put in place, there was less expectation that bolus fluid expansion would be harmful and differential stopping rules for harm were not formulated.
In July 2010, two protocol amendments were agreed to increase the sample size from 2,880 to 3,600 children, and to increase bolus fluid administration. There was a non-significant trend against bolus treatment, but although the implications were discussed, the IDMC did not comment on the results, or on the amendments, in order to avoid inadvertent partial unblinding of the study.
In January 2011, the trial was stopped for futility, as the combined intervention arms had significantly higher mortality (relative risk 1.46, 95% CI 1.13 to 1.90, P = 0.004) than the control arm. The stopping rule for proof of benefit was not achieved, and the IDMC stopped the trial with a lower level of significance (P = 0.01) due to futility and an increased risk of mortality from bolus fluid expansion in children enrolled in the trial. The basis for this decision was that the local standard of care was not to use bolus fluid for the care of children with shock in these African countries, and this was a different standard of care to that used in the UK. These decisions emphasize two important principles: firstly, the IDMC should avoid inadvertent unblinding of the trial by commenting on amendments, and secondly, when considering stopping a trial, the IDMC should be guided by the local standard of care rather than standards of care in other parts of the world.
The diagnosis of childhood tuberculosis remains a challenge worldwide. The Xpert MTB/RIF test, a rapid mycobacteria tuberculosis diagnostic tool, was recommended for use in children based on data from adult studies. We evaluated the performance of the Xpert MTB/RIF test for the diagnosis of childhood pulmonary tuberculosis using one induced sputum sample and described clinical characteristics associated with a positive Xpert MTB/RIF test. The sputum culture on both Lowenstein-Jensen (LJ) and Mycobacteria Growth Indicator Tube (MGIT) was the gold standard.
We consecutively enrolled 250 Ugandan children aged 2 months to 12 years with suspected pulmonary tuberculosis between January 2011 and January 2012 into a cross-sectional diagnostic study at a tertiary care facility in Uganda.
We excluded data from 15 children (13 contaminated culture and 2 indeterminate MTB/RIF test results) and analysed 235 records. The Xpert MTB/RIF test had a sensitivity of 79.4% (95% CI 63.2 - 89.7) and a specificity of 96.5% (95% CI 93 – 98.3). The Xpert MTB/RIF test identified 13 of the 14 (92.9%) smear positive-culture positive and 14 of the 20 (70%) smear negative -culture positive cases. The Xpert MTB/RIF identified twice as many cases as the smear microscopy (79.4% Vs 41.2%). Age > 5 years (OR 3.3, 95% CI 1.4 – 7.4, p value 0.005), a history of Tuberculosis (TB) contact (OR 2.4, 95% CI 1.1 – 5.2, p value 0.03), and a positive tuberculin skin test (OR 4.1, 95% CI 1.7 – 10, p value 0.02) was associated with a positive Xpert MTB/RIF test. The median time to TB detection was 49.5 days (IQR 38.4-61.2) for LJ, and 6 days (IQR 5 – 11.5) for MGIT culture and 2 hours for the Xpert MTB/RIF test.
The Xpert MTB/RIF test on one sputum sample rapidly and correctly identified the majority of children with culture confirmed pulmonary tuberculosis with high specificity.
Children; Pulmonary tuberculosis; Sensitivity; Specificity; Xpert MTB/RIF
Smear microscopy, a mainstay of tuberculosis (TB) diagnosis in developing countries, cannot differentiate M. tuberculosis complex from NTM infection, while pulmonary TB shares clinical signs with NTM disease, causing clinical and diagnostic dilemmas. This study used molecular assays to identify species and assess genotypic diversity of non-tuberculous mycobacteria (NTM) isolates from children investigated for pulmonary tuberculosis at a demographic surveillance site in rural eastern Uganda.
Children were investigated for pulmonary tuberculosis as part of a TB vaccine surveillance program (2009–2011). Two cohorts of 2500 BCG vaccinated infants and 7000 adolescents (12–18 years) were recruited and followed up for one to two years to determine incidence of tuberculosis. Induced sputum and gastric aspirates were processed by the standard N-acetyl L-cysteine (NALC)-NaOH method. Sediments were cultured in the automated MGIT (Becton Dickson) liquid culture system and incubated at 37°C for at least six weeks. Capilia TB assay was used to classify mycobacteria into MTC and NTM. The GenoType CM/AS assays were performed to identify species while Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR genotyping was used to assess genetic diversity of the strains within each species.
Among 2859 infants and 2988 adolescents screened, the numbers of TB suspects were 710 and 1490 infants and adolescents respectively. The prevalence of NTM in infant suspects was 3.7% (26/710) (95% CI 2.5–5.2) while that in adolescent suspects was 4.6% (69/1490) (95% CI 3.6–5.8). On culture, 127 isolates were obtained, 103 of which were confirmed as mycobacteria comprising of 95 NTM and eight M. tuberculosis complex. The Genotype CM/AS assay identified 63 of the 95 NTM isolates while 32 remained un-identified. The identified NTM species were M. fortuitum (40 isolates, 63.5%), M. szulgai (9 isolates, 14.3%), M. gordonae (6 isolates, 9.5%), M. intracellulare (3 isolates, 4.7%), M. scrofulaceum (2 isolates, 3.2%), M. lentiflavum (2 isolates, 3.2%), and M. peregrinum (1 isolate, 1.6%). Genotyping did not reveal any clustering in M. intracellulare, M. gordonae and M. szulgai species. M. fortuitum, on the other hand, had two clusters, one with three isolates of M. fortuitum 1 and the other with two isolates of M. fortuitum 2 subspecies. The remaining 35 of the 40 isolates of M. fortuitum had unique fingerprint patterns.
M. fortuitum is the most common cause of infection by NTM among Infants and adolescents in rural Uganda. There is a varied number of species and genotypes, with minimal clustering within species, suggesting ubiquitous sources of infection to individuals in this community.
A high prevalence of tuberculosis (TB) in children presenting with severe pneumonia has previously been reported in South Africa. However, little is known about TB among children with pneumonia in Uganda and other resource limited countries. Moreover, TB is associated with high morbidity and mortality among such children. We conducted this study to establish the burden of pulmonary TB in children admitted with severe pneumonia in our setting.
A cross-sectional study was conducted at Mulago, a National Referral and teaching hospital in Uganda. Hospitalised children 2 months to 12 years of age with severe pneumonia based on WHO case definition were enrolledfrom February to June 2011. Children with a previous TB diagnosis or receiving anti-TB treatment were excluded. Each child was screened for TB using Tuberculin skin test, Chest X-ray, induced sputum samples and blood culture for mycobacterium. Sputum smears were examined using fluorescent microscopy, and cultured on both Lowenstein Jensen media (LJ) and Mycobacterial Growth Indicator Tubes (MGIT).
Of the 270 children with severe pneumonia who were recruited over a 5-month period in 2011, the incidence ratio of pulmonary TB in children admitted with severe pneumonia was 18.9% (95% CI 14.6 – 23.9). The proportion of culture confirmed PTB was 6.3% (95% CI 3.8 – 9.7). Age group under 1 year and 1 to 5 years (OR 2.8 (95% CI 1.7 – 7.4) and OR 2.4 (95% CI 1.05 – 5.9) respectively) were more likely to be associated with pulmonary TB compared to those children over 5 years of age. A history of TB smear positive contact was associated with pulmonary TB (OR 3.0 (95% CI 1.3–6.5).
We found a high burden of pulmonary TB in children admitted with severe pneumonia. These data highlight the need for TB screening in children admitted with severe pneumonia so as to improve TB case finding and child survival.
Nevirapine given once-daily for the first 6, 14, or 28 weeks of life to infants exposed to HIV-1via breastfeeding reduces transmission through this route compared with single-dose nevirapine at birth or neonatally. We aimed to assess incremental safety and efficacy of extension of such prophylaxis to 6 months.
In our phase 3, randomised, double-blind, placebo-controlled HPTN 046 trial, we assessed the incremental benefit of extension of once-daily infant nevirapine from age 6 weeks to 6 months. We enrolled breastfeeding infants born to mothers with HIV-1 in four African countries within 7 days of birth. Following receipt of nevirapine from birth to 6 weeks, infants without HIV infection were randomly allocated (by use of a computer-generated permuted block algorithm with random block sizes and stratified by site and maternal antiretroviral treatment status) to receive extended nevirapine prophylaxis or placebo until 6 months or until breastfeeding cessation, whichever came first. The primaryefficacy endpoint was HIV-1 infection in infants at 6 months and safety endpoints were adverse reactions in both groups. We used Kaplan-Meier analyses to compare differences in the primary outcome between groups. This study is registered with ClinicalTrials.gov, number NCT00074412.
Between June 19, 2008, and March 12, 2010, we randomly allocated 1527 infants (762 nevirapine and 765 placebo); five of whom had HIV-1 infection at randomisation and were excluded from the primary analyses. In Kaplan-Meier analysis, 1.1% (95% CI 0.3–1.8) of infants who received extended nevirapine developed HIV-1 between 6 weeks and 6 months compared with 2.4% (1.3–3.6) of controls (difference 1.3%, 95% CI 0–2.6), equating to a 54% reduction in transmission (p=0.049). However, mortality (1.2% for nevirapine vs 1.1% for placebo; p=0.81) and combined HIV infection and mortality rates (2.3% vs 3.2%; p=0.27) did not differ between groups at 6 months. 125 (16%) of 758 infants given extended nevirapine and 116 (15%) of 761 controls had serious adverse events, but frequency of adverse events, serious adverse events, and deaths did not differ significantly between treatment groups.
Nevirapine prophylaxis can safely be used to provide protection from mother-to-child transmission of HIV-1 via breastfeeding for infants up to 6 months of age.
US National Institutes of Health.
The World Health Organization (WHO) recommends collection of two sputum samples for tuberculosis (TB) diagnosis, with at least one being an early morning (EM) using smear microscopy. It remains unclear whether this is necessary even when sputum culture is employed. Here, we determined the diagnostic yield from spot and the incremental yield from the EM sputum sample cultures among TB-suspected adolescents from rural Uganda.
Sputum samples (both spot and early-morning) from 1862 adolescents were cultured by the Lowenstein-Jensen (LJ) and Mycobacterium Growth Indicator Tube (MGIT) methods. For spot samples, the diagnostic yields for TB were 19.0% and 57.1% with LJ and MGIT, respectively, whereas the incremental yields (not totals) of the early-morning sample were 9.5% and 42.9% (P < 0.001) with LJ and MGIT, respectively. Among TB-suspected adolescents in rural Uganda, the EM sputum culture has a high incremental diagnostic yield. Therefore, EM sputum in addition to spot sample culture is necessary for improved TB case detection.
This phase III randomized clinical trial compared single dose nevirapine (sdNVP) plus HIV immunoglobulin (HIVIGLOB) to sdNVP alone for preventing maternal-to-child transmission (PMTCT) of HIV.
Primary objectives were to determine rates of HIV infection among infants, and to assess the safety of HIVIGLOB in combination with sdNVP in HIV-infected Ugandan pregnant women and their infants.
Mother-infant pairs were randomized to receive 200mg of NVP to women in labor and 2mg/kg NVP to newborns within 72 hours after birth (sdNVP arm) or to receive sdNVP plus a single intravenous 240ml dose of HIVIGLOB given to women at 36-38 weeks gestation and a single intravenous 24ml dose to newborns within 18 hours of birth (HIVIGLOB/sdNVP arm). Risk of HIV infection was determined using Kaplan-Meier and risk ratio estimates at birth, 2, 6, 14 weeks, 6 and 12 months of age.
Intent-to-treat analysis included 198 HIVIGLOB/sdNVP and 294 sdNVP mother-infant pairs. At 6 months of age, the primary endpoint, there was no statistically significant difference in HIV transmission in the HIVIGLOB/sdNVP arm versus the sdNVP arm (18.7% vs.15.0%; RR =1.240 [95% CI: 0.833-1.846]; p= 0.290). Similarly, the proportion of serious adverse events in the HIVIGLOB/sdNVP and sdNVP arms, respectively for mothers (18.9% vs. 19.3%; p= 0.91) and infants (62.6% vs. 59.5%; p=0.51), were not significantly different.
Giving mother-infant pairs an infusion of peripartum HIV hyperimmunoglobulin in addition to sdNVP for PMTCT was as safe as sdNVP alone, but was no more effective than sdNVP alone in preventing HIV transmission.
HIV; HIVIGLOB; sdNVP; breastfeeding; PMTCT; Uganda
The proportional odds model may serve as a useful alternative to the Cox proportional hazards model to study association between covariates and their survival functions in medical studies. In this article, we study an extended proportional odds model that incorporates the so-called “external” time-varying covariates. In the extended model, regression parameters have a direct interpretation of comparing survival functions, without specifying the baseline survival odds function. Semiparametric and maximum likelihood estimation procedures are proposed to estimate the extended model. Our methods are demonstrated by Monte-Carlo simulations, and applied to a landmark randomized clinical trial of a short course Nevirapine (NVP) for mother-to-child transmission (MTCT) of human immunodeficiency virus type-1 (HIV-1). Additional application includes analysis of the well-known Veterans Administration (VA) Lung Cancer Trial.
Counting process; Estimating function; HIV/AIDS; Maximum likelihood estimation; Semiparametric model; Time-varying covariate
Andrew Prendergast and colleagues consider the evidence for a change in policy for the treatment of young children infected with HIV.
HIV-infected infants may have CXCR4-using (X4-tropic) HIV, CCR5-using (R5-tropic) HIV, or a mixture of R5-tropic and X4-tropic HIV (dual/mixed, DM HIV). The level of infectivity for R5 virus (R5-RLU) varies among HIV-infected infants. HIV tropism and R5-RLU were measured in samples from HIV-infected Ugandan infants using a commercial assay. DM HIV was detected in 7/72 (9.7%) infants at the time of HIV diagnosis (birth or 6–8 weeks of age, 4/15 (26.7%) with subtype D, 3/57 (5.3 %) with other subtypes, P=0.013). A transition from R5-tropic to DM HIV was observed in only two (6.7%) of 30 infants over 6–12 months. Six (85.7%) of seven infants with DM HIV died, compared to 21/67 (31.3%) infants with R5-tropic HIV (p=0.09). Higher R5-RLU at 6–8 weeks was not associated with decreased survival. Infants with in utero infection had a higher median R5-RLU than infants who were HIV-uninfected at birth (p=0.025).
CCR5; CXCR4; HIV-1; infant; survival; transmission; tropism
HIV viruses are usually genetically homogeneous shortly after infection, and become more heterogeneous over time. We developed a high-resolution melting (HRM) assay to analyze HIV diversity without sequencing. Plasma samples from the HIVNET 012 trial were obtained from nine Ugandan mother–infant pairs. DNA amplified from the HIV gag region was analyzed to determine the number of degrees over which the DNA melted (HRM score). HRM gag DNA was also cloned and sequenced (50 clones/mother; 20 clones/infant). The median HRM score for infants (4.3, range 4.2–5.3) was higher than that for control plasmids (3.4, range 3.2–3.8, p < 0.001) and lower than that for mothers (5.7, range 4.4–7.7, p = 0.005, exact Wilcoxon rank sum test). The intraclass correlation coefficient reflecting assay reproducibility was 94% (95% CI: 89–98%). HRM scores were also compared to sequenced-based measures of HIV diversity; higher HRM scores were associated with higher genetic diversity (p < 0.001), complexity (p = 0.009), and Shannon entropy (p = 0.022), but not with length variation (p = 0.111). The HRM assay provides a novel, rapid method for assessing HIV diversity without sequencing. This assay could be applied to any region of the HIV genome or to other genetic systems that exhibit DNA diversity.
We analyzed drug resistance in HIV-infected Ugandan children who received antiretroviral therapy in a prospective, observational study (2004–2006); some children had prior single-dose nevirapine (sdNVP) exposure. Children received stavudine (d4T), lamivudine (3TC), and nevirapine (NVP); treatment was continued if they were clinically and immunologically stable. Samples with >1,000 copies/ml HIV RNA were analyzed by using the ViroSeq HIV Genotyping System (ViroSeq). Subtype A and D pretreatment samples also were analyzed with the LigAmp assay (for K103N, Y181C, and G190A). ViroSeq results were obtained for 74 pretreatment samples (35 from sdNVP-exposed children (median age, 19 months) and 39 from sdNVP-unexposed children (median age, 84 months). This included 39 subtype A, 22 subtype D, 1 subtype C, and 12 inter-subtype recombinant samples. One sample had nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance, one had nucleoside reverse transcriptase inhibitor (NRTI) resistance, and three had protease inhibitor (PI) resistance. Y181C was detected by using LigAmp in five pretreatment samples [four (14.8%) of 37 samples from sdNVP-exposed children, one (4.2%) of 24 samples from children without prior sdNVP exposure; p = 0.35]. Among children who were not virally suppressed at 48 weeks of treatment, all 12 tested had NNRTI resistance, as well as resistance to 3TC and emtricitibine (FTC); three had resistance to other NRTIs. Seven of those children had a ViroSeq result at 96 weeks of treatment; four of the seven acquired resistance to additional NRTIs by 96 weeks. In Uganda, clinically and immunologically stable children receiving nonsuppressive antiretroviral treatment regimens are at risk for development of drug resistance.
Single-dose nevirapine is the cornerstone of the regimen for prevention of mother-to-child transmission of human immunodeficiency virus (HIV) in resource-limited settings, but nevirapine frequently selects for resistant virus in mothers and children who become infected despite prophylaxis. The optimal antiretroviral treatment strategy for children who have had prior exposure to single-dose nevirapine is unknown.
We conducted a randomized trial of initial therapy with zidovudine and lamivudine plus either nevirapine or ritonavir-boosted lopinavir in HIV-infected children 6 to 36 months of age, in six African countries, who qualified for treatment according to World Health Organization (WHO) criteria. Results are reported for the cohort that included children exposed to single-dose nevirapine prophylaxis. The primary end point was virologic failure or discontinuation of treatment by study week 24. Enrollment in this cohort was terminated early on the recommendation of the data and safety monitoring board.
A total of 164 children were enrolled. The median percentage of CD4+ lymphocytes was 19%; a total of 56% of the children had WHO stage 3 or 4 disease. More children in the nevirapine group than in the ritonavir-boosted lopinavir group reached a primary end point (39.6% vs. 21.7%; weighted difference, 18.6 percentage-points; 95% confidence interval, 3.7 to 33.6; nominal P = 0.02). Baseline resistance to nevirapine was detected in 18 of 148 children (12%) and was predictive of treatment failure. No significant between-group differences were seen in the rate of adverse events.
Among children with prior exposure to single-dose nevirapine for perinatal prevention of HIV transmission, antiretroviral treatment consisting of zidovudine and lamivudine plus ritonavir-boosted lopinavir resulted in better outcomes than did treatment with zidovudine and lamivudine plus nevirapine. Since nevirapine is used for both treatment and perinatal prevention of HIV infection in resource-limited settings, alternative strategies for the prevention of HIV transmission from mother to child, as well as for the treatment of HIV infection, are urgently required. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00307151.)
The level of viral diversity in an HIV-infected individual can change during the course of HIV infection, reflecting mutagenesis during viral replication and selection of viral variants by immune and other selective pressures. Differences in the level of viral diversity in HIV-infected infants may reflect differences in viral dynamics, immune responses, or other factors that may also influence HIV disease progression. We used a novel high resolution melting (HRM) assay to measure HIV diversity in Ugandan infants and examined the relationship between diversity and survival through 5 years of age.
Plasma samples were obtained from 31 HIV-infected infants (HIVNET 012 trial). The HRM assay was used to measure diversity in two regions in the gag gene (Gag1 and Gag2) and one region in the pol gene (Pol).
HRM scores in all three regions increased with age from 6–8 weeks to 12–18 months (for Gag1: P = 0.005; for Gag2: P = 0.006; for Pol: P = 0.016). Higher HRM scores at 6–8 weeks of age (scores above the 75th percentile) were associated with an increased risk of death by 5 years of age (for Pol: P = 0.005; for Gag1/Gag2 (mean of two scores): P = 0.003; for Gag1/Gag2/Pol (mean of three scores): P = 0.002). We did not find an association between HRM scores and other clinical and laboratory variables.
Genetic diversity in HIV gag and pol measured using the HRM assay was typically low near birth and increased over time. Higher HIV diversity in these regions at 6–8 weeks of age was associated with a significantly increased risk of death by 5 years of age.
To assess serious gastroenteritis risk and mortality associated with early cessation of breastfeeding in infants enrolled in two prevention-of-maternal-to-child-HIV-transmission trials in Uganda.
We used hazard rates to evaluate serious gastroenteritis events by month of age and mortality among HIV-exposed uninfected infants enrolled in the HIVNET 012 (1997-2001) and HIVIGLOB/NVP (2004-2007) trials. HIV-infected mothers were counseled using local infant feeding guidelines current at the time.
Breastfeeding cessation occurred earlier in HIVIGLOB/NVP compared to HIVNET 012 (median 4.0 vs. 9.3 months, p<0.001). Rates of serious gastroenteritis were higher in HIVIGLOB/NVP (8.0/1000 child-months) compared to HIVNET 012 (3.1/1000 child-months; p < 0.001). Serious gastroenteritis events also peaked earlier at 3-4 and 7-8 months (16.2/1000 and 15.0/1000 child-months, respectively) compared to HIVNET 012 at 9 to10 months (20.8/1000 child-months). All cause-infant mortality did not statistically differ between the HIVIGLOB/NVP and the HIVNET 012 trials [3.2/1000 versus 2.0/1000 child-months respectively, (p=0.10)]
Early breastfeeding cessation seen in the HIVIGLOB/NVP trial was associated with increased risk of serious gastroenteritis among HIV-exposed uninfected infants when compared to later breastfeeding cessation in the HIVNET 012 trial. Testing interventions which could decrease HIV transmission through breastfeeding and allow safe breastfeeding into the second year of life are urgently needed.
HIV; infants; breastfeeding cessation; serious gastroenteritis; mortality; Uganda