Metabolic complications of in utero maternal HIV and antiretroviral exposure in HIV-exposed infants

Unique Profile of Inflammation and Immune Activation in Pregnant People With HIV in the United States

BACKGROUND

Little is known about inflammation/immune activation during pregnancy in people with HIV (PWH) and growth in their children who are HIV-exposed and uninfected (CHEU).

METHODS

Using data from the Pediatric HIV/AIDS Cohort Study and an HIV-seronegative comparison group, we assessed associations of (1) HIV status, mode of HIV acquisition (perinatally vs nonperinatally acquired), and type of antiretroviral therapy (ART) with inflammation/immune activation in pregnancy; and (2) inflammation/immune activation in pregnancy with growth of CHEU at 12 months. Interleukin 6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), soluble(s) TNF-α receptor 1 and 2 (sTNFR1, sTNFR2), sCD14, and sCD163 were measured between 13 and 27 weeks' gestation. Linear regression models were fit to estimate differences between groups for each log-transformed biomarker, adjusted for confounders.

RESULTS

Pregnant PWH (188 total, 39 perinatally acquired, 149 nonperinatally acquired) and 76 HIV-seronegative persons were included. PWH had higher IL-6, sTNFR1, sCD14, and sCD163 and lower sTNFR2 compared to HIV-seronegative persons in adjusted models. Among PWH, sCD163 was higher in those with perinatally versus nonperinatally acquired HIV and on PI-based versus INSTI-based ART. Higher maternal concentrations of IL-6, sTNFR2, and hs-CRP were associated with poorer growth at 12 months.

CONCLUSIONS

Maternal HIV status is associated with a distinct profile of inflammation/immune activation during pregnancy, which may influence child growth.

Body Composition Trajectories During the First 23 Months of Life Differ by HIV Exposure Among Infants in Western Kenya: A Prospective Study

BACKGROUND

Infants who are HIV-exposed and uninfected have suboptimal growth patterns compared to those who are HIV-unexposed and uninfected. However, little is known about how these patterns persist beyond 1 year of life.

OBJECTIVES

This study aimed to examine whether infant body composition and growth trajectories differed by HIV exposure during the first 2 years of life among Kenyan infants using advanced growth modeling.

METHODS

Repeated infant body composition and growth measurements (mean: 6; range: 2-7) were obtained from 6 weeks to 23 months in the Pith Moromo cohort in Western Kenya (n = 295, 50% HIV-exposed and uninfected, 50% male). Body composition trajectory groups were fitted using latent class mixed modeling (LCMM) and associations between HIV exposure and growth trajectories were examined using logistic regression analysis.

RESULTS

All infants exhibited poor growth. However, HIV-exposed infants generally grew suboptimally than unexposed infants. Across all body composition models except for the sum of skinfolds, HIV-exposed infants had a higher likelihood of belonging to the suboptimal growth groups identified by LCMM than the HIV-unexposed infants. Notably, HIV-exposed infants were 3.3 times more likely (95% CI: 1.5-7.4) to belong to the length-for-age z-score growth class that remained at a z-score of < -2, indicating stunted growth. HIV-exposed infants were also 2.6 times more likely (95% CI: 1.2-5.4) to belong to the weight-for-length-for-age z-score growth class that remained between 0 and -1, and were 4.2 times more likely (95% CI: 1.9-9.3) to belong to the weight-for-age z-score growth class that indicated poor weight gain besides stunted linear growth.

CONCLUSIONS

In a cohort of Kenyan infants, HIV-exposed infants grew suboptimally compared to HIV-unexposed infants beyond 1 year of age. These growth patterns and longer-term effects should be further investigated to support the ongoing efforts to reduce early-life HIV exposure-related health disparities.

In-utero HIV exposure and cardiometabolic health among children 5-8 years: findings from a prospective birth cohort in South Africa

OBJECTIVE

To evaluate if in-utero HIV exposure is associated with adverse cardiometabolic health outcomes at 5-8 years of age.

DESIGN

Prospective cohort study.

METHODS

We enrolled a random sample of HIV-exposed but uninfected (HEU) and HIV-unexposed children from the Drakenstein Child Health study, a longitudinal birth cohort study in Cape Town, South Africa, in a cardiometabolic health pilot study. Outcomes were assessed by trained study staff and included: anthropometry, body composition and size, blood pressure, fasting plasma glucose, HbA1c, lipids, and insulin resistance using HOMA-IR. We used multivariable linear and log-binomial regression to estimate associations between HIV-exposure and cardiometabolic outcomes, adjusted for child age, sex, height, body size, and maternal factors as appropriate.

RESULTS

We included 260 children (HEU n = 100, HIV-unexposed n = 160). HEU children had older mothers (median age 30 vs. 26 years), with minimal differences in gestational age and size at birth by HIV-exposure status. In multivariable analyses, HEU children had lower weight-for-age (mean difference -0.35, 95% confidence interval -0.66, -0.05), and height-for-age (mean difference -0.29, 95% confidence interval -0.56, -0.03; z-scores). There were no differences in adiposity, impaired glucose metabolism, or lipid levels by HIV-exposure status. Overall, 12% of children had blood pressure more than 90th percentile, with no differences by HIV-exposure status.

CONCLUSION

Overall, there were few differences in cardiometabolic outcomes between HEU and HIV-unexposed children in this South African cohort. Although these findings are reassuring, monitoring of cardiometabolic health is important as HEU and HIV-unexposed children enter adolescence and cardiometabolic risk trajectories become established.

Lower Insulin Sensitivity in Newborns With In Utero HIV and Antiretroviral Exposure Who Are Uninfected in Botswana

BACKGROUND

Few data exist on early-life metabolic perturbations in newborns with perinatal HIV and antiretroviral (ARV) exposure but uninfected (HEU) compared to those perinatally HIV unexposed and uninfected (HUU).

METHODS

We enrolled pregnant persons with HIV (PWH) receiving tenofovir (TDF)/emtricitabine or lamivudine (XTC) plus dolutegravir (DTG) or efavirenz (EFV), and pregnant individuals without HIV, as well as their liveborn infants. Newborns were randomized to receive either zidovudine (AZT) or nevirapine (NVP) postnatal prophylaxis. Preprandial homeostasis model assessment for insulin resistance (HOMA-IR) was assessed at birth and 1 month. Linear mixed models were fit to assess the association between in utero HIV/ARV exposure and average HOMA-IR from birth to 1 month, adjusting for confounders.

RESULTS

Of 450 newborns, 306 were HEU. HOMA-IR was higher in newborns HEU versus HUU after adjusting for confounders (mean difference of 0.068 in log HOMA-IR, P = .037). Among newborns HEU, HOMA-IR was not significantly different between TDF/XTC/DTG versus TDF/XTC/EFV in utero ARV exposure and between AZT versus NVP newborn postnatal prophylaxis arms.

CONCLUSIONS

Newborns HEU versus HUU had lower insulin sensitivity at birth and at 1 month of life, raising potential concern for obesity and other metabolic perturbations later in life for newborns HEU.

CLINICAL TRIALS REGISTRATION

NCT03088410.

Distinct cord blood C-peptide, adipokine, and lipidomic signatures by in utero HIV exposure

BACKGROUND

Early-life metabolic derangements in HIV-exposed uninfected (HEU) infants have been reported.

METHODS

Pregnant women with HIV and HIV-uninfected pregnant women were enrolled with their newborns in a US cohort from 2011 to 2015. We measured cord insulin, C-peptide, and metabolic cytokines of HEU and HIV-unexposed uninfected (HUU) newborns using ELISA and metabolites, lipid subspecies, and eicosanoids via liquid chromatography/mass spectrometry. Linear regression was employed to assess the association of intrauterine HIV/ART with insulin and C-peptide. Graphical lasso regression was used to identify differences between metabolite/lipid subspecies networks associated with C-peptide.

RESULTS

Of 118 infants, 56 were HEU, ART exposed. In adjusted analyses, mean cord insulin (β = 0.295, p = 0.03) and C-peptide (β = 0.522, p < 0.01) were significantly higher in HEU vs. HUU newborns. HEU neonates exhibited primarily positive associations between complex lipids and C-peptide, indicative of fuel storage, and augmented associations between cord eicosanoids and cytokines. HUU neonates exhibited negative associations with lipids and C-peptide indicative of increased fuel utilization.

CONCLUSION

Higher cord insulin and C-peptide in HEU vs. HUU newborns as well as differences in cord metabolites, metabolic-related cytokines, and eicosanoids may reflect a propensity for fuel storage and an inflammatory milieu suggestive of fetal metabolic changes associated with in utero HIV/ART exposure.

IMPACT

There is a paucity of studies assessing cord blood and neonatal metabolic health in HIV-exposed uninfected (HEU) newborns, an increasing population worldwide. Compared to HIV-unexposed uninfected (HUU) newborns, HEU newborns exhibit alterations in fuel homeostasis and an inflammatory milieu associated with in utero HIV/antiretroviral therapy (ART) exposure. The long-term implications of these neonatal findings are as yet unknown, but merit continued evaluation as this important and growing population ages into adulthood.

Relationship between pre-pregnancy maternal body mass index and infant weight trajectories in HIV-exposed and HIV-unexposed infants

BACKGROUND

Maternal HIV and antiretroviral therapy (ART) exposure in utero may influence infant weight, but the contribution of maternal y body mass index (BMI) to early life overweight and obesity is not clear.

OBJECTIVE

To estimate associations between maternal BMI at entry to antenatal care (ANC) and infant weight through approximately 1 year of age and to evaluate whether associations were modified by maternal HIV status, maternal HIV and viral load, breastfeeding intensity through 6 months or timing of entry into ANC.

METHODS

We followed HIV-uninfected and -infected pregnant women initiating efavirenz-based ART from first antenatal visit through 12 months postpartum. Infant weight was assessed via World Health Organization BMI and weight-for-length z-scores (WLZ) at 6 weeks, 3, 6, 9 and 12 months. We used multivariable linear mixed-effects models to estimate associations between maternal BMI and infant z-scores over time.

RESULTS

In 861 HIV-uninfected infants (454 HIV-exposed; 407 HIV-unexposed), nearly 20% of infants were overweight or obese by 12 months of age, regardless of HIV exposure status. In multivariable analyses, increasing maternal BMI category was positively associated with higher infant BMIZ and WLZ scores between 6 weeks and 12 months of age and did not differ by HIV exposure status. However, HIV-exposed infants had slightly lower BMIZ and WLZ trajectories through 12 months of age, compared with HIV-unexposed infants across all maternal BMI categories. Differences in BMIZ and WLZ scores by HIV exposure were not explained by timing of entry into ANC or maternal viral load pre-ART initiation, but z-scores were slightly higher for HIV-exposed infants who were predominantly or exclusively versus partially breastfed.

CONCLUSIONS

These findings suggest maternal BMI influences early infant weight gain, regardless of infant HIV exposure status. Intervention to reduce maternal BMI may help to address growing concerns about obesity among HIV-uninfected children.

Timing of Antiretroviral Therapy: Initiation and Birth Outcomes Among Pregnant Women With Human Immunodeficiency Virus in Tanzania

BACKGROUND

Combination antiretroviral therapy (cART) initiation during pregnancy reduces the risk of perinatal human immunodeficiency virus (HIV) transmission; however, studies have suggested that there may be unintended adverse consequences on birth outcomes for selected cART regimens.

METHODS

We analyzed adverse birth outcomes among a prospective cohort of 1307 pregnant women with HIV in Dar es Salaam who initiated cART during the first or second trimester of a singleton pregnancy. Our primary analysis compared birth outcomes by gestational age at cART initiation among these women initiating cART in pregnancy.

RESULTS

Among women who initiated cART in pregnancy, there was no relationship of gestational age at cART initiation with the risk of fetal death or stillbirth. However, women who initiated cART before 20 weeks of gestation compared with after 20 weeks had increased risk of preterm birth (risk ratio [RR], 1.30; 95% confidence interval [CI], 1.03-1.67) but decreased risk of small-for-gestational age birth (RR, 0.71; 95% CI, .55-.93).

CONCLUSIONS

With increasing use of cART preconception and early in pregnancy, clinicians should be aware of the benefits and potential risks of cART regimens to optimize birth outcomes.

Comparison of the Effects of Three Dual-Nucleos(t)ide Reverse Transcriptase Inhibitor Backbones on Placenta Mitochondria Toxicity and Oxidative Stress Using a Mouse Pregnancy Model

Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) are the backbone of HIV antiretroviral therapy (ART). ART use in pregnancy has been associated with adverse birth outcomes, in part due to NRTI-induced mitochondrial toxicity. Direct comparison on the effects of commonly used dual-NRTI regimens on placental mitochondria toxicity in pregnancy is lacking. We compared zidovudine/lamivudine, abacavir/lamivudine, and tenofovir/emtricitabine using a mouse model and examined markers of placental mitochondrial function and oxidative stress. Zidovudine/lamivudine and abacavir/lamivudine were associated with lower fetal and placental weights compared to controls, whereas tenofovir/emtricitabine was associated with the least fetal and placental weight reduction, as well as lower resorption rates. Placental mitochondrial DNA content, as well as placental expression of cytochrome c-oxidase subunit-II, DNA polymerase gamma, and citrate synthase, was higher in tenofovir/emtricitabine-treated mice compared to other groups. Zidovudine/lamivudine-treated mice had elevated malondialdehyde levels (oxidative stress marker) compared to other groups and lower mRNA levels of manganese superoxide dismutase and peroxisome proliferator-activated receptor gamma coactivator 1-alpha in the placenta compared to tenofovir/emtricitabine-treated mice. We observed differences in effects between NRTI regimens on placental mitochondrial function and birth outcomes. Tenofovir/emtricitabine was associated with larger fetuses, increased mtDNA content, and higher expression of mitochondrial-specific antioxidant enzymes and mitochondrial biogenesis enzymes, whereas zidovudine/lamivudine was associated with markers of placental oxidative stress.

Perinatally acquired HIV infection is associated with abnormal blood mitochondrial function during childhood/adolescence

OBJECTIVE

We assessed differences in mitochondrial function between youth living with perinatal HIV (YPHIV) and youth perinatally HIV-exposed but uninfected (YPHEU).

DESIGN

Cross-sectional analysis.

METHODS

We measured lactate and pyruvate values, as well as mitochondrial Complex I and Complex IV activity in peripheral blood mononuclear cells. Logistic or linear regression models were fit, as appropriate, to assess the association between PHIV status and each mitochondrial parameter, adjusted for confounders. We introduced interaction terms to assess effect modification of PHIV status on the relationship between anthropometric factors and each mitochondrial parameter. Among YPHIV, similar regression models were fit to assess the relationship between HIV-associated factors and each mitochondrial outcome.

RESULTS

A total of 243 YPHIV and 118 YPHEU were compared. On average, YPHIV had higher lactate/pyruvate ratio (β: 7.511, 95% confidence interval [95% CI]: 0.402, 14.620) and Complex IV activity (β: 0.037, 95% CI: 0.002, 0.072) compared to YPHEU, adjusted for confounders. Among YPHIV, body mass index Z score (BMIZ) and Complex I activity were inversely associated, whereas, among YPHEU, there was a positive association (β for interaction: -0.048, P = 0.003). Among YPHIV, current (β: -0.789, 95% CI: -1.174, -0.404) and nadir CD4+% (β: -0.605, 95% CI: -1.086, -0.125) were inversely associated with lactate/pyruvate ratio; higher current (4.491, 95% CI: 0.754, 8.229) and peak (7.978, 95% CI: 1.499, 14.457) HIV RNA levels were positively associated with lactate/pyruvate ratio in adjusted models.

CONCLUSIONS

Mitochondrial function and substrate utilization appear perturbed in YPHIV compared to YPHEU. Increasing immunosuppression and viremia are associated with mitochondrial dysfunction among YPHIV.

HIV-Exposed, Uninfected Infants in Uganda Experience Poorer Growth and Body Composition Trajectories than HIV-Unexposed Infants

BACKGROUND

HIV-uninfected infants of HIV-positive women may experience worse growth and health outcomes than infants of HIV-negative women, but this has not been thoroughly investigated under the World Health Organization's most recent recommendations to reduce vertical transmission.

OBJECTIVE

To determine whether HIV-exposed and -uninfected (HEU) infants whose mothers received Option B+ have higher odds of experiencing suboptimal growth trajectories than HIV-unexposed, -uninfected infants, and if this relationship is affected by food insecurity.

DESIGN

Repeated anthropometric measures were taken on 238 infants (HEU = 86) at 1 week and 1, 3, 6, 9, and 12 months after delivery in Gulu, Uganda. Latent class growth mixture modeling was used to develop trajectories for length-for-age z-scores, weight-for-length z-scores, mid-upper arm circumference, sum of skinfolds, and arm fat area. Multinomial logistic models were also built to predict odds of trajectory class membership, controlling for socioeconomic factors.

RESULTS

HEU infants had greater odds of being in the shortest 2 length-for-age z-scores trajectory classes [odds ratio (OR) = 3.80 (1.22-11.82), OR = 8.72 (1.80-42.09)] and higher odds of being in smallest sum of skinfolds trajectory class [OR = 3.85 (1.39-10.59)] vs. unexposed infants. Among HEU infants, increasing food insecurity was associated with lower odds of being in the lowest sum of skinfolds class [OR = 0.86 (0.76-0.98)].

CONCLUSIONS

There continues to be differences in growth patterns by HIV-exposure under the new set of World Health Organization guidelines for the prevention of mother-to-child transmission of HIV and the feeding of HEU infants in low-resource settings that are not readily identified through traditional mixed-effects modeling. Food insecurity was not associated with class membership, but differentially affected adiposity by HIV-exposure status.

Differences in Growth of HIV-exposed Uninfected Infants in Ethiopia According to Timing of In-utero Antiretroviral Therapy Exposure

BACKGROUND

There are concerns about the adverse effect of in-utero exposure to antiretroviral therapy (ART) on the growth of HIV exposed-uninfected (HEU) infants. We compared growth of HEU-infants according to the timing and type of ART exposure.

METHODS

A retrospective cohort study was conducted by abstracting clinical data from HIV-infected mothers and HEU-infants in Addis Ababa, Ethiopia between February 2013 and October 2016. Mixed-effects linear models were used to compare changes in weight and length and cox proportional hazard models were used to evaluate stunting (length-for-age z score <-2.0) and underweight (weight-for-age z score <-2.0).

RESULTS

A total of 624 HEU-infants were included in the analyses. Infants exposed to ART from conception had a lower rate of change in length [β = -0.54, 95% confidence interval (CI): -1.00 to -0.08] the first 3 months of life, as compared with infants exposed from late pregnancy. Risk of stunting was 51.9 per 100 person-years and risk of underweight was 26.7 per 100 person-years. Exposure to ART from conception was associated with a higher rate of stunting as compared with exposure from late pregnancy (adjusted hazard ratio = 1.95, 95% CI: 1.27-2.99). Infants born to mothers with advanced disease had a higher incidence of underweight compared with infants born to mothers with early-stage disease adjusted hazard ratio = 1.99, 95% CI: 1.32-3.03).

CONCLUSIONS

In HEU-infants, exposure to ART from conception was associated with decrease growth during early infancy and higher incidence of stunting compared with treatment exposure later in pregnancy. Close monitoring of HEU-infants' growth and prompt nutritional intervention is essential.

A Comparison of Metabolic Outcomes Between Obese HIV-Exposed Uninfected Youth From the PHACS SMARTT Study and HIV-Unexposed Youth From the NHANES Study in the United States

BACKGROUND

Metabolic perturbations in HIV-exposed uninfected (HEU) obese youth may differ from those in the general obese pediatric population.

METHODS

Metabolic parameters of obese (body mass index Z-score >95th percentile) HEU youth in the Pediatric HIV/AIDS Cohort Study (PHACS) Surveillance Monitoring of ART Toxicities (SMARTT) study were compared with a matched sample of obese youth from the US National Health and Nutrition Examination Survey (NHANES). We evaluated systolic and diastolic hypertension (blood pressure ≥90th percentile for age, sex, and height), total cholesterol >200 mg/dL, high-density lipoprotein cholesterol <35 mg/dL, low-density lipoprotein cholesterol >130 mg/dL, triglycerides (TGs) >150 mg/dL, and Homeostatic Model Assessment-Insulin Resistance >4.0. Modified Poisson regression models were fit to quantify the prevalence ratio (PR) of each outcome comparing the 2 cohorts, adjusting for confounders.

RESULTS

The blood pressure outcome analytic subgroup included 1096 participants (n = 304 HEU), the total cholesterol and high-density lipoprotein cholesterol subgroup 1301 participants (n = 385 HEU), and the low-density lipoprotein cholesterol, TG, and Homeostatic Model Assessment-Insulin Resistance subgroup 271 (n = 83 HEU). After adjustment, obese HEU youth had a higher prevalence of systolic and diastolic hypertension [PR = 3.34, 95% confidence interval (CI): 2.48 to 4.50; PR = 2.04, 95% CI: 1.18 to 3.52, respectively], but lower prevalence of insulin resistance (PR = 0.67, 95% CI: 0.54 to 0.85) and hypercholesterolemia (PR = 0.67, 95% CI: 0.44 to 1.01) compared with obese NHANES youth.

CONCLUSIONS

In the United States, obese HEU youth seem to have an increased risk of hypertension, but lower risk of insulin resistance and hypercholesterolemia, compared with a general obese pediatric population. Monitoring for cardiovascular morbidity in adulthood may be warranted in HEU children.

Growth and Neurodevelopment of HIV-Exposed Uninfected Children: a Conceptual Framework

PURPOSE OF REVIEW

The population of HIV-exposed uninfected (HEU) children is expanding rapidly, and over one million HEU infants are born each year globally. Several recent studies have reported that HEU children, particularly in low- and middle-income countries, are at risk of poor outcomes, including impaired growth and neurodevelopment. However, the reasons for poor clinical outcomes amongst HEU children remain unclear.

RECENT FINDINGS

We summarise the findings from recent large studies that have characterised growth and neurodevelopment in HEU children, identified risk factors and explored underlying mechanistic pathways. We propose a conceptual framework to explain how exposure to HIV and antiretroviral therapy (ART) may lead to adverse growth and neurodevelopment in uninfected children, and review the available evidence and research gaps. We propose that HEU children are affected both indirectly, through the augmentation of universal risk factors underlying poor growth and neurodevelopment, and directly through HIV/ART-specific pathways, which ultimately may converge through a series of common pathogenic mechanisms. In the era of universal ART, a better understanding of these pathways is crucial to inform future prevention and intervention strategies.

Mitochondrial DNA mutations accumulated in HIV-1-infected children who have an excellent virological response when exposed to long-term antiretroviral therapy

Objectives

There is growing concern about mitochondrial DNA (mtDNA) mutations with long-term NRTI exposure in HIV-1 infected children.

Methods

Twenty-four HIV-1 infected children who started ART more than 2 years earlier who had an excellent virological response and had not changed their regimen were enrolled retrospectively. Their corresponding PBMCs in 2009 (T1), 2010 (T2) and 2013 (T3) were included. Sequencing of the entire mtDNA using next-generation sequencing revealed the spectrum of mtDNA variants.

Results

The trend showed that the number of mtDNA mutations during ART occurred as T1 < T2 < T3 (P = 0.086). Interestingly, the numbers of whole mtDNA mutations at T3 (median 41, range 24-62) were significantly greater than at T1 (34, 25-46, P = 0.029). A positive correlation was found between total mtDNA mutations and treatment time (r = 0.352, P = 0.002). During the observation period, mtDNA mutations more frequently occurred in the D-loop, cytochrome b (CYTB) and 12S rRNA regions. The heteroplasmic ratio of T3 was higher than that of T1 in CYTB and 12S rRNA (P = 0.034 and P = 0.042, respectively). High heteroplasmic population levels were found at nt 263 (A263G, D-loop) and nt 8860 (A8860G, ATPase6). A significant difference in heteroplasmy between T1, T2 and T3 occurred at nt 14783 (T14783C, CYTB, P = 0.048, T3 > T2 > T1).

Conclusions

Our findings reveal the spectrum of mtDNA variants in HIV-1-infected children who had an excellent virological response. mtDNA mutations accumulated during ART may play an important role in facilitating the occurrence of mitochondrial dysfunction.

Decreased consumption of common weaning foods is associated with poor linear growth among HIV-exposed infants participating in the Kigali antiretroviral and breastfeeding assessment for the elimination of HIV (Kabeho) study

OBJECTIVE

The World Health Organization recommends that complementary foods that are adequate, safe, and appropriate be introduced to infants at age 6 months. Using an innovative modeling technique, we examine patterns of nutrient intake in HIV-exposed and uninfected (HEU) infants and establish their relationship with growth.

METHODS

Single-day dietary recalls and anthropometrics were collected every two to 3 months from 543 infants living in Kigali, Rwanda, and attending clinics for the prevention of mother-to-child HIV transmission. A common weaning food index (CWFI) was calculated in grams and nutrient density for infants to reflect the extent to which the infants consumed the weaning foods typical of this population at ages 6 to 10, 11 to 15, and 16 to 20 months. Regressions among the CWFI, length-for-age z-scores (LAZ), and weight-for-length z-scores (WLZ) were conducted to estimate the relationship between the dietary patterns and growth.

RESULTS

Mean absolute intake of zinc and calcium from complementary foods was insufficient. Increasing CWFI was related to increasing cow milk consumption. The density CWFI showed a decrease in the density of iron and folate as infants consume more of the weaning foods typical of this population. Density CWFI, breastfeeding, and caloric intake act on early LAZ and WLZ and interact with one another. Among breastfed infants, those who consume little of the common weaning foods and have a high caloric intake develop deficits in LAZ and have an elevated WLZ.

CONCLUSIONS

A diet that is more dominated by the typical weaning foods of this population may support a healthy growth pattern.

HIV in pregnancy: Identification of intrapartum and perinatal HIV exposures

The benefits of human immunodeficiency virus (HIV) testing in pregnancy, when combined with appropriate maternal antiretroviral therapy and intrapartum and postnatal prophylaxis, are well established. The vertical rate of transmission of HIV in North America is now well below 2%. Efforts must continue to ensure that these benefits are sustained. Women who have received little or no prenatal care and those who present for delivery with unknown HIV status need immediate testing. As more infants are exposed to antiretroviral agents, strategies need to be implemented to ensure adequate follow-up of these infants. Issues relating to the identification of HIV-exposed infants are highlighted.

Weight gain of HIV-exposed, uninfected children born before and after introduction of the 'Option B+' programme in Malawi

OBJECTIVE

To compare birth weight and weight gain in HIV-exposed, uninfected (HEU) infants up to 24 months old, who enrolled in the Malawian national HIV care clinic (HCC) programme either before or after Option B+ (OB+) was implemented.

DESIGN, SETTING AND PARTICIPANTS

HIV-exposed infants enrol in the HCC programme as soon as possible after birth and are followed up to at least 24 months old. This analysis includes HEU infants with recorded birth weight, date of birth, gender and at least one follow-up weight measurement from 21 health facilities in central and southern Malawi (January 2010-December 2014). Weight-for-age z scores (WAZ) were derived and compared by birth period using linear regression at birth and mixed effects models for postnatal weight gain up to 24 months old.

RESULTS

Of 6845 HEU infants included in this study, 88.5% were born after OB+. The proportion of infants exposed in utero to combination antiretroviral therapy (ART) significantly increased after OB+ was implemented, and infants were exposed to ART for a longer time. There was no significant difference in WAZ at birth (P = 0.654) among HEU infants by birth period, but postnatal weight gain was faster among HEU infants born in the Option B+ period than infants born pre-Option B+.

CONCLUSION

Birth weight was not affected by longer exposure to ART during pregnancy after OB+ was introduced, when weight gain in HEU infants was faster, possibly because their mothers were in better health.

Comparative safety and effectiveness of perinatal antiretroviral therapies for HIV-infected women and their children: Systematic review and network meta-analysis including different study designs

BACKGROUND

Nearly all newly infected children acquire Human Immunodeficiency virus (HIV) via mother-to-child transmission (MTCT) during pregnancy, labour or breastfeeding from untreated HIV-positive mothers. Antiretroviral therapy (ART) is the standard care for pregnant women with HIV. However, evidence of ART effectiveness and harms in infants and children of HIV-positive pregnant women exposed to ART has been largely inconclusive. The aim of our systematic review and network meta-analysis (NMA) was to evaluate the comparative safety and effectiveness of ART drugs in children exposed to maternal HIV and ART (or no ART/placebo) across different study designs.

METHODS

We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (inception until December 7, 2015). Primary outcomes were any congenital malformations (CMs; safety), including overall major and minor CMs, and mother-to-child transmission (MTCT; effectiveness). Random-effects Bayesian pairwise meta-analyses and NMAs were conducted. After screening 6,468 citations and 1,373 full-text articles, 90 studies of various study designs and 90,563 patients were included.

RESULTS

The NMA on CMs (20 studies, 7,503 children, 16 drugs) found that none of the ART drugs examined here were associated with a significant increase in CMs. However, zidovudine administered with lamivudine and indinavir was associated with increased risk of preterm births, zidovudine administered with nevirapine was associated with increased risk of stillbirths, and lamivudine administered with stavudine and efavirenz was associated with increased risk of low birth weight. A NMA on MTCT (11 studies, 10,786 patients, 6 drugs) found that zidovudine administered once (odds ratio [OR] = 0.39, 95% credible interval [CrI]: 0.19-0.83) or twice (OR = 0.43, 95% CrI: 0.21-0.68) was associated with significantly reduced risk of MTCT.

CONCLUSIONS

Our findings suggest that ART drugs are not associated with an increased risk of CMs, yet some may increase adverse birth events. Some ART drugs (e.g., zidovudine) effectively reduce MTCT.

Fetal Metabolic Stress Disrupts Immune Homeostasis and Induces Proinflammatory Responses in Human Immunodeficiency Virus Type 1- and Combination Antiretroviral Therapy-Exposed Infants

Increased morbidity and fetal growth restriction are reported in uninfected children born to human immunodeficiency virus type 1 (HIV-1)-infected women treated with antiretroviral (ARV) therapy. Viruses and/or pharmacological interventions such as ARVs can induce metabolic stress, skewing the cell's immune response and restricting (cell) growth. Novel metabolomic techniques provided the opportunity to investigate the impact of fetal HIV-1 and combination ARV therapy (cART) exposure on the infants' immune metabolome. Peroxidized lipids, generated by reactive oxygen species, were increased in cART/HIV-1-exposed infants, indicating altered mitochondrial functioning. The lipid metabolism was further dysregulated with increased triglyceride species and a subsequent decrease in phospholipids in cART/HIV-1-exposed infants compared to control infants. Proinflammatory immune mediators, lysophospholipids as well as cytokines such as CXCL10 and CCL3, were increased whereas anti-inflammatory metabolites from the cytochrome P450 pathway were reduced in cART/HIV-1-exposed infants. Taken together, these data demonstrate that the fetal metabolism is impacted by maternal factors (cART and HIV-1) and skews physiological immune responses toward inflammation in the newborn infant.

In Utero ART Exposure and Birth and Early Growth Outcomes Among HIV-Exposed Uninfected Infants Attending Immunization Services: Results From National PMTCT Surveillance, South Africa

BACKGROUND

Despite the recognized benefit of antiretroviral therapy (ART) for preventing and treating HIV, some studies have reported adverse birth outcomes with in utero ART exposure. We evaluated the effect of infant in utero HIV and ART exposure on preterm delivery (PTD), low birth weight (LBW), small for gestational age (SGA), and underweight for age (UFA) at 6 weeks.

METHODS

We surveyed 6179 HIV-unexposed-uninfected (HUU) and 2599 HIV-exposed-uninfected (HEU) infants. HEU infants were stratified into 3 groups: ART, Zidovudine alone, and no antiretrovirals (None). The ART group was further stratified to explore pre- or postconception exposure. Multivariable logistic regression evaluated effects of HIV and ARV exposure on the outcomes.

RESULTS

We found higher odds of PTD, LBW, SGA, and UFA in HEU than HUU infants. HEU in the None group (adjusted odds ratio [AOR], 1.9; 95% confidence interval [CI], 1.2-3.0) or those whose mothers initiated ART preconception (AOR, 1.7; 95% CI, 1.1-2.5) had almost twice the odds of PTD than infants whose mothers started ART postconception, but no increased odds for other outcomes.

CONCLUSIONS

There was an association between preconception ART and PTD. As ART access increases, pregnancy registers or similar surveillance should be in place to monitor outcomes to inform future policy.

Influence of maternal obesity on the long-term health of offspring

In addition to immediate implications for pregnancy complications, increasing evidence implicates maternal obesity as a major determinant of offspring health during childhood and later adult life. Observational studies provide evidence for effects of maternal obesity on her offspring's risks of obesity, coronary heart disease, stroke, type 2 diabetes, and asthma. Maternal obesity could also lead to poorer cognitive performance and increased risk of neurodevelopmental disorders, including cerebral palsy. Preliminary evidence suggests potential implications for immune and infectious-disease-related outcomes. Insights from experimental studies support causal effects of maternal obesity on offspring outcomes, which are mediated at least partly through changes in epigenetic processes, such as alterations in DNA methylation, and perhaps through alterations in the gut microbiome. Although the offspring of obese women who lose weight before pregnancy have a reduced risk of obesity, few controlled intervention studies have been done in which maternal obesity is reversed and the consequences for offspring have been examined. Because the long-term effects of maternal obesity could have profound public health implications, there is an urgent need for studies on causality, underlying mechanisms, and effective interventions to reverse the epidemic of obesity in women of childbearing age and to mitigate consequences for offspring.

Disclosing in utero HIV/ARV exposure to the HIV-exposed uninfected adolescent: is it necessary?

Introduction

The tremendous success of antiretroviral therapy has resulted in a diminishing population of perinatally HIV-infected children on the one hand and a mounting number of HIV-exposed uninfected (HEU) children on the other. As the oldest of these HEU children are reaching adolescence, questions have emerged surrounding the implications of HEU status disclosure to these adolescents. This article outlines the arguments for and against disclosure of a child's HEU status.

Discussion

Disclosure of a child's HEU status, by definition, requires disclosure of maternal HIV status. It is necessary to weigh the benefits and harms which could occur with disclosure in each of the following domains: psychosocial impact, long-term physical health of the HEU individual and the public health impact. Does disclosure improve or worsen the psychological health of the HEU individual and extended family unit? Do present data on the long-term safety of in utero HIV/ARV exposure reveal potential health risks which merit disclosure to the HEU adolescent? What research and public health programmes or systems need to be in place to afford monitoring of HEU individuals and which, if any, of these require disclosure?

Conclusions

At present, it is not clear that there is sufficient evidence on whether long-term adverse effects are associated with in utero HIV/ARV exposures, making it difficult to mandate universal disclosure. However, as more countries adopt electronic medical record systems, the HEU status of an individual should be an important piece of the health record which follows the infant not only through childhood and adolescence but also adulthood. Clinicians and researchers should continue to approach the dialogue around mother–child disclosure with sensitivity and a cogent consideration of the evolving risks and benefits as new information becomes available while also working to maintain documentation of an individual's perinatal HIV/ARV exposures as a vital part of his/her medical records. As more long-term adult safety data on in utero HIV/ARV exposures become available these decisions may become clearer, but at this time, they remain complex and multi-faceted.

Clinical outcomes of HIV-exposed, HIV-uninfected children in sub-Saharan Africa

OBJECTIVE

HIV-exposed but HIV-uninfected (HEU) children are widely considered at increased risk of mortality and morbidity. Recent advances in prevention of mother-to-child HIV transmission (PMTCT) strategies, incorporating life-long universal maternal antiretroviral therapy (ART, "Option B+") with extended breastfeeding, may improve HEU child health substantially. We critically reviewed reports of mortality/morbidity among HEU and HIV-unexposed (HU) children in sub-Saharan Africa.

METHODS

We searched Medline, EMBASE, CINAHL, PsycINFO, Academic Search Premier, Global Health & Psychosocial Instruments databases, conference abstracts, and reference lists for longitudinal studies from sub-Saharan Africa reporting mortality and clinical morbidity among HIV-uninfected children aged ≤10 years, by maternal HIV status. Studies were appraised by Newcastle-Ottawa Scale and ACROBAT-NRSI. Due to substantial heterogeneity of study designs, populations and results (I(2) = 75%), data were not synthesised.

RESULTS

We included 37 reports (28 studies, 11 164 HEU children); methodological and reporting quality were variable. Most reports came from settings without universal access to maternal ART (n = 35). Results were conflicting, with some studies indicating increased risk of mortality, hospitalisation and/or under-nutrition among HEU children, while others found no evidence of increased risk. In subanalyses, improved maternal health, ART use and breastfeeding were strongly protective for all outcomes. Only 39% (11/28) of studies adjusted for major confounders. Reports from settings using universal maternal ART with breastfeeding (n = 2) found no differences in growth or development but did not report mortality or infectious morbidity.

CONCLUSIONS

The existing literature provides little insight into HEU child health under recently adopted PMTCT strategies. There is a need for robust comparative data on HEU and HIV-unexposed child health outcomes under Option B+; optimising breastfeeding practices and increasing maternal use of ART should be urgent public health priorities.

Mitochondrial DNA mutations in blood samples from HIV-1-infected children undergoing long-term antiretroviral therapy

We have analyzed mutations in whole mitochondrial (mt) genomes of blood samples from HIV-1-infected children treated with long-term antiretroviral therapy (ART), who had an excellent virological response. HIV-1-infected children who have undergone ART for 4 y with an excellent virological response (group A; 15 children) and ten healthy children (controls) without HIV-1 infection were enrolled retrospectively. Peripheral blood mononuclear cells (PBMCs) were obtained and mt DNA mutations were studied. The total number of mtDNA mutations in group A was 3 H more than in the controls (59 vs. 19, P<0.001) and the same trend was seen in all mtDNA regions. Among these mtDNA mutations, 140 and 28 mutations were detected in group A and the controls, respectively. The D-loop, CYTB and 12s rRNA were the three most common mutation regions in both groups, with significant differences between the groups observed at nucleotide positions C309CC, T489C CA514deletion, T16249C and G16474GG (D-loop); T14783C, G15043A, G15301A, and A15662G (CYTB); and G709A (12s rRNA). G15043A and A15662G had been associated with mitochondrial diseases. Our findings suggest that mtDNA mutations occur frequently in long-term ART-treated, HIV-1-infected children who have an excellent virological response, although they did not have obvious current symptoms. The CYTB region may play an important role in mtDNA mutation during ART, which might contribute to the development of subsequent mitochondrial diseases.

Infant peripheral blood repetitive element hypomethylation associated with antiretroviral therapy in utero

The use of combination antiretroviral therapy (cART) to prevent HIV mother-to-child transmission during pregnancy and delivery is generally considered safe. However, vigilant assessment of potential risks of these agents remains warranted. Epigenetic changes including DNA methylation are considered potential mechanisms linking the in utero environment with long-term health outcomes. Few studies have examined the epigenetic effects of prenatal exposure to pharmaceutical agents, including antiretroviral therapies, on children. In this study, we examined the methylation status of the LINE-1 and ALU-Yb8 repetitive elements as markers of global DNA methylation alteration in peripheral blood mononuclear cells obtained from newborns participating in the Pediatric HIV/AIDS Cohort Study SMARTT cohort of HIV-exposed, cART-exposed uninfected infants compared to a historical cohort of HIV-exposed, antiretroviral-unexposed infants from the Women and Infants Transmission Study Cohort. In linear regression models controlling for potential confounders, we found the adjusted mean difference of AluYb8 methylation of the cART-exposed compared to the -unexposed was -0.568 (95% CI: -1.023, -0.149) and for LINE-1 methylation was -1.359 (95% CI: -1.860, -0.857). Among those exposed to cART, subjects treated with atazanavir (ATV), compared to those on other treatments, had less AluYb8 methylation (-0.524, 95% CI: -0.025, -1.024). Overall, these results suggest a small but statistically significant reduction in the methylation of these repetitive elements in an HIV-exposed, cART-exposed cohort compared to an HIV-exposed, cART-unexposed historic cohort. The potential long-term implications of these differences are worthy of further examination.

In Utero Exposure to Antiretroviral Drugs: Effect on Birth Weight and Growth Among HIV-exposed Uninfected Children in Brazil

BACKGROUND

There are concerns about the effects of in utero exposure to antiretroviral drugs (ARVs) on the development of HIV-exposed but uninfected (HEU) children. The aim of this study was to evaluate whether in utero exposure to ARVs is associated with lower birth weight/height and reduced growth during the first 2 years of life.

METHODS

This cohort study was conducted among HEU infants born between 1996 and 2010 in Tertiary children's hospital in Rio de Janeiro, Brazil. Weight was measured by mechanical scale, and height was measured by measuring board. Z-scores for weight-for-age (WAZ), length-for-age (LAZ) and weight-for-length were calculated. We modeled trajectories by mixed-effects models and adjusted for mother's age, CD4 cell count, viral load, year of birth and family income.

RESULTS

A total of 588 HEU infants were included of whom 155 (26%) were not exposed to ARVs, 114 (19%) were exposed early (first trimester) and 319 (54%) later. WAZ were lower among infants exposed early compared with infants exposed later: adjusted differences were -0.52 (95% confidence interval [CI]: -0.99 to -0.04, P = 0.02) at birth and -0.22 (95% CI: -0.47 to 0.04, P = 0.10) during follow-up. LAZ were lower during follow-up: -0.35 (95% CI: -0.63 to -0.08, P = 0.01). There were no differences in weight-for-length scores. Z-scores of infants exposed late during pregnancy were similar to unexposed infants.

CONCLUSIONS

In HEU children, early exposure to ARVs was associated with lower WAZ at birth and lower LAZ up to 2 years of life. Growth of HEU children needs to be monitored closely.

Paediatric HIV: Progress on Prevention, Treatment and Cure

PURPOSE OF REVIEW

This review provides an update on current developments with prevention, treatment and cure strategies in the field of pediatric HIV.

RECENT FINDINGS/SUMMARY

There has been tremendous progress in the prevention and treatment of pediatric HIV infection. With new strategies for prevention of mother-to-child transmission, we are growing ever closer towards elimination of pediatric HIV, though challenges with retention of pregnant woman and their HIV-exposed infants remain. Ongoing vigilance regarding the potential hazards of in utero ART exposure to infants continues with no significant alarms yet identified. Though cure has not been achieved, evidence of the impact of early treatment on reducing HIV-1 reservoir size with subsequent prolonged remission has enlivened efforts to rapidly identify and treat HIV-infected newborns. There is an increasing array of treatment options for pediatric patients and reassuring evidence regarding long-term complications of ART. Unfortunately, despite evidence suggesting the benefit of early treatment, timely identification and treatment of children remains a challenge. Better strategies for effective case-finding and engagement in care are urgently needed in addition to an improved understanding of how to retain HIV-positive children and adolescents on treatment. However, further emboldened by recent international commitments and robust global support, the future is hopeful.

Lower Preprandial Insulin and Altered Fuel Use in HIV/Antiretroviral-Exposed Infants in Cameroon

CONTEXT

Intrauterine HIV/antiretroviral (ARV) and postnatal ARVs are known to perturb energy metabolism and could have permanent effects on future metabolic health. Such maladaptive effects could be mediated by changes in mitochondrial function and intermediary metabolism due to fetal and early-life ARV exposure in HIV/ARV-exposed uninfected (HEU) infants.

OBJECTIVE

The objective of the study was to understand the relationship(s) between mitochondrial fuel use (assessed via acylcarnitines and branched chain amino acids) and preprandial insulin in infants exposed to in utero HIV/ARV plus postnatal zidovudine or nevirapine compared with HIV/ARV-unexposed uninfected (HUU) infants.

DESIGN

This was a prospective cohort study with the following three groups: 1) intrauterine HIV/ARV/postnatal zidovudine-exposed (HEU-A), 2) intrauterine HIV/ARV/postnatal nevirapine-exposed (HEU-N), and 3) HUU infants. Principal component analysis and linear regression modeling were performed to assess the association between in utero HIV/ARV exposure and infant insulin.

SETTING

The study was conducted at Cameroonian urban antenatal centers.

PARTICIPANTS

HIV-infected and -uninfected pregnant woman/infant dyads participated in the study.

MAIN OUTCOME

Preprandial insulin was the main outcome measured.

RESULTS

Of 366 infants, 38 were HEU-A, 118 HEU-N. Forty intermediary metabolites were consolidated into seven principal components. In a multivariate analysis, both HEU-A (β = -.116, P= .012) and HEU-N (β = -.070, P= .022) demonstrated lower insulin compared with HUU infants. However, at high levels of plasma metabolites, HEU-A (β = .027, P= .050) exhibited higher insulin levels than HEU-N or HUU infants. A unique array of short-chain acylcarnitines (β = .044, P= .001) and branched-chain amino acids (β = .033, P= .012) was associated with insulin.

CONCLUSION

HEU-A and HEU-N infants have lower preprandial insulin levels at 6 weeks of age and appear to use metabolic fuel substrates differently than HUU infants. Future studies are warranted to determine whether observed differences have lasting metabolic implications, such as later insulin resistance.

Tolerance of the newborn to antiretroviral drug exposure in utero

INTRODUCTION

The prevention of mother-to-child HIV-1 transmission by antiretroviral drug treatment is remarkably effective. The risk of transmission to the child is now almost zero for women optimally treated during pregnancy. The rapid expansion of this prophylactic treatment has led the World Health Organization to aspire to the virtual elimination of mother-to-child transmission and pediatric AIDS over the next few years. In 2014, more than 900,000 women worldwide were treated with antiretroviral drugs during pregnancy. The issue of fetal and neonatal antiretroviral drug tolerance is therefore extremely important.

AREAS COVERED

This review focuses on the possible impact of in utero exposure to antiretroviral drug on newborn health. To restrict analysis to this period is justified by the specificities of transplacental drug exposure and fetal vulnerability. Relevant data are available from trials and observational cohorts. The significance of various bio-markers detectable at birth is still unresolved, but merits a careful evaluation. Long-term assessment is associated with various logistical difficulties.

EXPERT OPINION

The health of 'exposed but not infected' children poses no major problem in the immense majority of cases, but a series of biological, clinical and imaging-based warning signs have emerged indicating the need for careful attention to be paid to this issue. Some effects that are straightforward to manage in industrialized countries may have more severe consequences in countries in which access to effective healthcare is limited. Nucleoside/nucleotide analogs are potentially genotoxic to mitochondrial and nuclear DNA, and the principal question to be addressed concerns their potential long-term effects.

Association between prenatal exposure to antiretroviral therapy and birth defects: an analysis of the French perinatal cohort study (ANRS CO1/CO11)

BACKGROUND

Antiretroviral therapy (ART) has major benefits during pregnancy, both for maternal health and to prevent mother-to-child transmission of HIV. Safety issues, including teratogenic risk, need to be evaluated. We estimated the prevalence of birth defects in children born to HIV-infected women receiving ART during pregnancy, and assessed the independent association of birth defects with each antiretroviral (ARV) drug used.

METHODS AND FINDINGS

The French Perinatal Cohort prospectively enrolls HIV-infected women delivering in 90 centers throughout France. Children are followed by pediatricians until 2 y of age according to national guidelines. We included 13,124 live births between 1994 and 2010, among which, 42% (n = 5,388) were exposed to ART in the first trimester of pregnancy. Birth defects were studied using both European Surveillance of Congenital Anomalies (EUROCAT) and Metropolitan Atlanta Congenital Defects Program (MACDP) classifications; associations with ART were evaluated using univariate and multivariate logistic regressions. Correction for multiple comparisons was not performed because the analyses were based on hypotheses emanating from previous findings in the literature and the robustness of the findings of the current study. The prevalence of birth defects was 4.4% (95% CI 4.0%-4.7%), according to the EUROCAT classification. In multivariate analysis adjusting for other ARV drugs, maternal age, geographical origin, intravenous drug use, and type of maternity center, a significant association was found between exposure to zidovudine in the first trimester and congenital heart defects: 2.3% (74/3,267), adjusted odds ratio (AOR) = 2.2 (95% CI 1.3-3.7), p = 0.003, absolute risk difference attributed to zidovudine +1.2% (95% CI +0.5; +1.9%). Didanosine and indinavir were associated with head and neck defects, respectively: 0.5%, AOR = 3.4 (95% CI 1.1-10.4), p = 0.04; 0.9%, AOR = 3.8 (95% CI 1.1-13.8), p = 0.04. We found a significant association between efavirenz and neurological defects (n = 4) using the MACDP classification: AOR = 3.0 (95% CI 1.1-8.5), p = 0.04, absolute risk +0.7% (95% CI +0.07%; +1.3%). But the association was not significant using the less inclusive EUROCAT classification: AOR = 2.1 (95% CI 0.7-5.9), p = 0.16. No association was found between birth defects and lopinavir or ritonavir with a power >85% for an odds ratio of 1.5, nor for nevirapine, tenofovir, stavudine, or abacavir with a power >70%. Limitations of the present study were the absence of data on termination of pregnancy, stillbirths, tobacco and alcohol intake, and concomitant medication.

CONCLUSIONS

We found a specific association between in utero exposure to zidovudine and heart defects; the mechanisms need to be elucidated. The association between efavirenz and neurological defects must be interpreted with caution. For the other drugs not associated with birth defects, the results were reassuring. Finally, whatever the impact that some ARV drugs may have on birth defects, it is surpassed by the major role of ART in the successful prevention of mother-to-child transmission of HIV. Please see later in the article for the Editors' Summary.