Initiation of Antiretroviral Therapy Before Pregnancy Reduces the Risk of Infection-related Hospitalization in Human Immunodeficiency Virus-exposed Uninfected Infants Born in a High-income Country

Maternal Risk Factors for Respiratory Syncytial Virus Lower Respiratory Tract Infection in Otherwise Healthy Preterm and Term Infants: A Systematic Review and Meta-analysis

BACKGROUND/OBJECTIVE

To date, there is no published, formal assessment of all maternal risk factors for respiratory syncytial virus lower respiratory tract infection (RSV-LRTI) in infants. A systematic literature review and meta-analysis were undertaken to ascertain: What maternal risk factors are associated with an increased risk of RSV-LRTI in infants?

METHODS

The systematic literature review used explicit methods to identify, select and analyze relevant data. PubMed, Embase and the Cochrane Library were searched (November 2022) using terms regarding: (1) RSV/LRTI; (2) risk factors; (3) pregnant/postpartum population. Bayesian meta-analysis compared RSV hospitalization (RSVH) risk in infants born to mothers with or without certain risk factors.

RESULTS

A total of 2353 citations were assessed and 20 were included in the final review (10 individual studies; 10 pooled analyses). In 10 studies examining infants (<1 year) without comorbidities (primary outcome), 10 maternal risk factors were associated with RSV-LRTI/RSVH in multivariate analyses. Meta-analysis revealed smoking while pregnant increased infant RSVH risk by 2.01 (95% credible interval: 1.52-2.64) times, while breast-feeding was protective (0.73, 95% credible interval: 0.58-0.90). Risk scoring tools have reported that maternal risk factors contribute between 9% and 21% of an infant's total risk score for RSVH.

CONCLUSIONS

A greater understanding of maternal risk factors and their relative contribution to infant RSV-LRTI will enable more accurate assessments of the impact of preventive strategies.

Clinical and immunological outcomes of HIV-exposed uninfected and HIV-unexposed uninfected children in the first 24 months of life in Western Kenya

BACKGROUND

Previous studies show increased morbidity in children who are HIV-exposed but uninfected (HEU) compared to children who are HIV-unexposed uninfected (HUU). We sought to evaluate the effects of prenatal HIV exposure on clinical and immunological outcomes in the first 24 months of life.

METHODS

Eighty-five HEU and 168 HUU children from Kenya were followed from birth to 24 months. All mothers living with HIV received combination antiretroviral therapy. Children who were HEU received standard-of-care cotrimoxazole prophylaxis through 18 months. Episodes of acute illness were identified through a combination of active and passive follow up. Trajectories of plasma cytokines, vaccine-specific antibodies, and antimalarial antibodies were examined.

RESULTS

Children who were HEU and children who were HUU had similar growth curves. Children who were HEU had lower rates of malaria (rate ratio 0.54, 95% CI 0.38, 0.77) and respiratory illness (rate ratio 0.80, 95% CI 0.68, 0.93). Trajectories of plasma cytokines and vaccine-specific antibodies were similar in children who were HEU and HUU. There were subtle differences in antimalarial antibody dynamics, in which children who were HEU had overall lower antibody levels against five of the 14 malaria antigens tested.

CONCLUSIONS

Children who were HEU and born to optimally treated mothers living with HIV had similar growth characteristics and immune profiles compared to children who were HUU. Children who were HEU had reduced risk for malaria and respiratory illness, which may be secondary to cotrimoxazole prophylaxis.

Maternal immunization in women living with HIV

Thanks to widespread use of antiretroviral therapy worldwide, women living with HIV (WLWH) are becoming pregnant and giving birth to HIV-exposed but uninfected (HEU) newborns. Both pregnancy and HIV infection-related factors such as low CD4+ T-cell count or uncontrolled viral load increase the risk of severe infections such as influenza, COVID-19, and others, making maternal immunization a valuable tool to decrease maternal morbidity among WLWH. Vaccines administered during pregnancy may also benefit the health of HEU infants. Indeed, HEU infants suffer from higher risk of morbidity of infectious origin, including respiratory syncytial virus (RSV), group B streptococcus (GBS), pneumococcus and pertussis infections. Maternal pertussis immunization is recommended in various high-income countries but not in many low-middle income countries where HIV prevalence is higher. GBS and RSV vaccines to be administered during pregnancy are currently in late-phase clinical trials in HIV-uninfected women and could represent a valuable tool to decrease morbidity during infancy. Decreased transfer of vaccine-specific IgG, accelerated waning of vaccine-induced antibody responses, linked to persistent maternal immune activation, and blunting of infant immune response to vaccines could hamper vaccine effectiveness among WLWH and HEU infants. Vaccine hesitancy could limit benefits of maternal immunization and strategies to tackle vaccine hesitancy should be part of HIV routine care. The aim of this review is to summarize the current knowledge regarding the immunogenicity and efficacy of available and upcoming vaccines recommended during pregnancy of WLWH.

Cell Type-Specific Biomarkers of Systemic Sclerosis Disease Severity Capture Cell-Intrinsic and Cell-Extrinsic Circuits

OBJECTIVE

Systemic sclerosis (SSc) is a multifactorial autoimmune fibrotic disorder involving complex rewiring of cell-intrinsic and cell-extrinsic signaling coexpression networks involving a range of cell types. However, the rewired circuits as well as corresponding cell-cell interactions remain poorly understood. To address this, we used a predictive machine learning framework to analyze single-cell RNA-sequencing data from 24 SSc patients across the severity spectrum as quantified by the modified Rodnan skin score (MRSS).

METHODS

We used a least absolute shrinkage and selection operator (LASSO)-based predictive machine learning approach on the single-cell RNA-sequencing data set to identify predictive biomarkers of SSc severity, both across and within cell types. The use of L1 regularization helps prevent overfitting on high-dimensional data. Correlation network analyses were coupled to the LASSO model to identify cell-intrinsic and cell-extrinsic co-correlates of the identified biomarkers of SSc severity.

RESULTS

We found that the uncovered cell type-specific predictive biomarkers of MRSS included previously implicated genes in fibroblast and myeloid cell subsets (e.g., SFPR2+ fibroblasts and monocytes), as well as novel gene biomarkers of MRSS, especially in keratinocytes. Correlation network analyses revealed novel cross-talk between immune pathways and implicated keratinocytes in addition to fibroblast and myeloid cells as key cell types involved in SSc pathogenesis. We then validated the uncovered association of key gene expression and protein markers in keratinocytes, KRT6A and S100A8, with SSc skin disease severity.

CONCLUSION

Our global systems analyses reveal previously uncharacterized cell-intrinsic and cell-extrinsic signaling coexpression networks underlying SSc severity that involve keratinocytes, myeloid cells, and fibroblasts.

Altered methionine-sulfone levels are associated with impaired growth in HIV-exposed-uninfected children

OBJECTIVE

To determine immune-metabolic dysregulation in children born to women living with HIV.

METHODS

Longitudinal immune-metabolomic analyses of plasma of 32 pregnant women with HIV (WHIV) and 12 uninfected women and their children up to 1.5 years of age were performed.

RESULTS

Using liquid chromatography-mass spectrometry and a multiplex bead assay, 280 metabolites (57 amino acids, 116 positive lipids, 107 signalling lipids) and 24 immune mediators (e.g. cytokines) were quantified. combinational antiretroviral therapy (cART) exposure was categorized as cART initiation preconception (long), cART initiation postconception up to 4 weeks before birth (medium) and cART initiation within 3 weeks of birth (short). Plasma metabolite profiles differed between HIV-exposed-uninfected (HEU)-children with long cART exposure compared to HIV-unexposed-children (HUU). Specifically, higher levels of methionine-sulfone, which is associated with oxidative stress, were detected in HEU-children with long cART exposure compared to HUU-children. High infant methionine-sulfone levels were reflected by high prenatal plasma levels in the mother. Increased methionine-sulfone levels in the children were associated with decreased growth, including both weight and length.

CONCLUSION

These findings based on longitudinal data demonstrate that dysregulation of metabolite networks associated with oxidative stress in children born to WHIV is associated with restricted infant growth.

Clinical and Immunological Outcomes of HIV-Exposed Uninfected and HIV-Unexposed Uninfected Children in the First 24 Months of Life in Western Kenya

Background

Previous studies show increased morbidity in children who are HIV-exposed but uninfected (HEU) compared to children who are HIV-unexposed uninfected (HUU). We sought to evaluate the effects of prenatal HIV exposure on clinical and immunological outcomes in the first 24 months of life.

Methods

Eighty-five HEU and 168 HUU children from Kenya were followed from birth to 24 months. All mothers with HIV received combination antiretroviral therapy. HEU children received standard-of-care cotrimoxazole prophylaxis through 18 months. Episodes of acute illness were identified through a combination of active and passive follow up. Trajectories of plasma cytokines, vaccine-specific antibodies, and antimalarial antibodies were examined.

Results

HEU and HUU children had similar growth curves. HEU children had lower rates of malaria and respiratory illness. Trajectories of plasma cytokines and vaccine-specific antibodies were similar in HEU and HUU children. There were subtle differences in antimalarial antibody dynamics, in which HEU children had overall lower antibody levels against five of the 14 malaria antigens tested.

Conclusions

HEU children born to optimally treated mothers living with HIV had similar growth characteristics and immune profiles compared to HUU children. HEU children had reduced risk for malaria and respiratory illness, which may be secondary to cotrimoxazole prophylaxis.

Risk and rates of hospitalisation in young children: a prospective study of a South African birth cohort

Introduction

Children in sub-Saharan Africa (SSA) are disproportionately affected by morbidity and mortality; there is also a growing vulnerable population of children who are HIV-exposed uninfected (HEU). Understanding reasons and risk factors for early-life child hospitalisation will help optimise interventions to improve health outcomes. We investigated hospitalisations from birth to two years in a South African birth cohort.

Methods

Mother-child pairs in the Drakenstein Child Health Study were followed from birth to two years with active surveillance for hospital admission and investigation of aetiology and outcome. Incidence, duration, cause, and factors associated with child hospitalisation were investigated, and compared between HEU and HIV-unexposed uninfected (HUU) children.

Results

Of 1136 children (247 HEU; 889 HUU), 314 (28%) children were hospitalised in 430 episodes despite >98% childhood vaccination coverage. The highest hospitalisation rate was from 0-6 months, decreasing thereafter; 20% (84/430) of hospitalisations occurred in neonates at birth. Amongst hospitalisations subsequent to discharge after birth, 83% (288/346) had an infectious cause; lower respiratory tract infection (LRTI) was the most common cause (49%;169/346) with respiratory syncytial virus (RSV) responsible for 31% of LRTIs; from 0-6 months, RSV-LRTI accounted for 22% (36/164) of all-cause hospitalisations. HIV exposure was a risk factor for hospitalisation in infants (IRR 1.63 [95% CI 1.29-2.05]) and longer hospital admission (p=0.004). Prematurity (HR 2.82 [95% CI 2.28-3.49]), delayed infant vaccinations (1.43 [1.12-1.82]), or raised maternal HIV viral load in HEU infants were risk factors; breastfeeding was protective (0.69 [0.53-0.90]).

Conclusion

Children in SSA continue to experience high rates of hospitalisation in early life. Infectious causes, especially RSV-LRTI, underly most hospital admissions. HEU children are at particular risk in infancy. Available strategies such as promoting breastfeeding, timely vaccination, and optimising antenatal maternal HIV care should be strengthened. New interventions to prevent RSV may have a large additional impact in reducing hospitalisation.

Hypertensive disorders of pregnancy and HIV: analysis of a province-wide cohort during 2018 and 2019

OBJECTIVE

We evaluated the prevalence of de novo hypertensive disorders of pregnancy (dnHDP) in pregnant people with HIV (PPHIV) in the Western Cape Province, South Africa in 2018-2019 by HIV and antiretroviral therapy (ART) status.

METHODS

All people with a pregnancy outcome from 1 January 2018 to 31 December 2019 in the Western Cape Provincial Health Data Centre (WCPHDC) were included. The WCPHDC integrates data from multiple electronic platforms according to unique identifiers. dnHDP was classified by ICD-10 code or first-time prescription of antihypertensive drugs less than 140 days before delivery. Pregnant people with preexisting hypertension without superimposed preeclampsia/eclampsia were not considered to have dnHDP. Adjusted prevalence ratios (aPR) for dnHDP by HIV/ART status were calculated using Poisson regression with robust variance.

RESULTS

Among 180 553 pregnant people studied, 13 677 (7.6%) had dnHDP and 33 978 (18.8%) were PPHIV. Among PPHIV, 11.3% ( N  = 3827) had no evidence of ART, 59.7% ( N  = 20 283) initiated ART preconception and 29.0% ( N  = 9868) had ART initiated during pregnancy. Compared to those without HIV (7.7%), dnHDP prevalence was lower in PPHIV with preconception [6.9%; aPR 0.78; 95% confidence interval (CI) 0.74-0.83] or pregnancy-initiated ART (7.0%; aPR 0.83; 95% CI 0.75-0.92) and higher in PPHIV without ART (9.8%; aPR 1.17; 95% CI 1.06-1.29) adjusted for maternal age, multiparity, multigestation pregnancy and preexisting hypertension. ART duration by delivery of at least 100 weeks versus pregnancy-initiated ART of 20-<40 weeks was protective (aPR 0.88; 95% CI 0.78-0.98).

CONCLUSIONS

In the context of universal ART, these findings are reassuring for most PPHIV. ART was not associated with increased dnHDP prevalence and longer ART duration was protective.

Adverse perinatal outcomes associated with antiretroviral therapy in women living with HIV: A systematic review and meta-analysis

Background

Maternal HIV infection is associated with an increased risk of adverse perinatal outcomes. The World Health Organization (WHO) recommends immediate initiation of lifelong antiretroviral therapy (ART) for all people living with HIV, including pregnant women living with HIV (WLHIV). We aimed to assess the risk of adverse perinatal outcomes in WLHIV receiving ART compared to ART-naïve WLHIV and HIV-negative women.

Materials and methods

We conducted a systematic literature review by searching PubMed, CINAHL, Global Health, and EMBASE for studies published between Jan 1, 1980, and April 20, 2020. Two investigators independently selected relevant studies and extracted data from studies reporting on the association of pregnant WLHIV receiving ART with adverse perinatal outcomes. Perinatal outcomes examined were preterm birth (PTB), very PTB, spontaneous PTB (sPTB), low birth weight (LBW), very LBW (VLBW), term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Random-effects meta-analyses examined the risk of adverse perinatal outcomes in WLHIV receiving ART compared to ART-naïve WLHIV and HIV-negative women. Subgroup and sensitivity analyses were performed based on country income status and study quality, and adjustment for confounding factors assessed.

Results

Of 94,594 studies identified, 73 cohort studies, including 424,277 pregnant women, met the inclusion criteria. We found that WLHIV receiving ART are associated with a significantly decreased risk of PTB (relative risk 0.79, 95% CI 0.67-0.93), sPTB (0.46, 0.32-0.66), LBW (0.86, 0.79-0.93), and VLBW (0.62, 0.39-0.97) compared to ART-naïve WLHIV. However, WLHIV receiving ART are associated with a significantly increased risk of PTB (1.42, 1.28-1.57), sPTB (2.20, 1.32-3.67), LBW (1.58, 1.36-1.84), term LBW (1.88, 1.23-2.85), SGA (1.69, 1.32-2.17), and VSGA (1.22, 1.10-1.34) compared to HIV-negative women.

Conclusion

ART reduces the risk of adverse perinatal outcomes in pregnant WLHIV, but the risk remains higher than in HIV-negative women. Our findings support the WHO recommendation of immediate initiation of lifelong ART for all people living with HIV, including pregnant WLHIV.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021248987.

A 12-month Prospective Study of HIV-infected and HIV-uninfected Women and Their Infants in Malawi: Comparative Analysis of Clinical Events and Infant Growth

Few studies have compared clinical outcomes in HIV-exposed uninfected (HEU) and HIV-unexposed uninfected (HUU) infants in the current scenario of universal and lifelong maternal antiretroviral therapy (ART). HIV-uninfected and HIV-infected Malawian women receiving ART and their breastfed infants were followed for 12 months postpartum, analyzing the rates of infectious and noninfectious events and assessing infant growth at 6 weeks, 6 months, and 12 months. The cohorts included 227 mothers (70 HIV-negative, 157 HIV-positive) and 235 infants (72 HUU, 163 HEU). No maternal or infant deaths occurred during follow-up. HIV-negative women were less likely to complete follow-up (48.6% versus 91.1%). Mothers with and without HIV had similar rates of both infectious and noninfectious events per person-month. Infants who were HEU, compared with HUU, had higher rates of events of any type, lower respiratory tract infections (LRTI), and noninfectious events. HEU had lower body mass index (BMI) at 6 weeks but did not differ from HUU in all anthropometric measures at 6 and 12 months; in growth between 6 weeks and 12 months; and in occurrence of stunting, underweight, and wasting at 6 weeks, 6 months, and 12 months. During the first year of life, infants who were HEU, compared with HUU, showed a transiently lower BMI and an increased risk of LRTI.

Children who are HIV-exposed and uninfected: evidence for action

Prior to widespread availability of antiretroviral therapy (ART) in sub-Saharan Africa, children who were HIV-exposed but uninfected (HEU) had increased mortality, morbidity and undernutrition compared with children who were HIV-unexposed. Scale-up of ART has led to impressive declines in vertical HIV transmission, but over 15 million children are now HEU, 90% of whom live in sub-Saharan Africa. There are ongoing health disparities among children who are HEU, with higher mortality, morbidity and stunting and modest impairments in early child development, which collectively hamper health and human capital in high prevalence countries. The underlying causes are multifactorial and include exposure to HIV, co-infections and a skewed antenatal inflammatory milieu, particularly if mothers start ART once they have advanced disease, as well as socioeconomic risk factors, which may cluster in HIV-affected households. Improving maternal health through early and sustained ART, ensuring optimal breastfeeding, and implementing evidence-based priority interventions for all children in areas of high HIV prevalence, will likely improve outcomes. A more comprehensive intervention package based on the Nurturing Care Framework may have particular benefits for children who are HEU, to close health gaps and ensure that the next generation of HIV-free children survive and thrive, and lead healthy and productive lives.

Increased risk of group B streptococcal sepsis and meningitis in HIV-exposed uninfected infants in a high-income country

The purpose of this study is to compare group B Streptococcus (GBS) infection incidence in HIV-exposed uninfected (HEU) and HIV-unexposed (HU) infants in a Spanish cohort. We conducted a retrospective study in 5 hospitals in Madrid (Spain). Infants ≤ 90 days of life with a GBS infection were included from January 2008 to December 2017. Incidence of GBS infection in HEU and HU children was compared. HEU infants presented a sevenfold greater risk of GBS infection and a 29-fold greater risk of GBS meningitis compared to HU, with statistical significance. Early-onset infection was tenfold more frequent in HEU children, with statistical significance, and late-onset infection was almost fivefold more frequent in the HUE infants' group, without statistical significance.

CONCLUSION

HEU infants presented an increased risk of GBS sepsis and meningitis. One in each 500 HEU infants of our cohort had a central nervous system infection and 1 in each 200, a GBS infection. Although etiological causes are not well understood, this should be taken into account by physicians when attending this population.

WHAT IS KNOWN

• HIV-exposed uninfected infants are at higher risk of severe infections. • An increased susceptibility of these infants to group B Streptococcus infections has been described in low- and high-income countries, including a higher risk of meningitis in a South African cohort.

WHAT IS NEW

• Group B Streptococcal meningitis is more frequent in HIV-exposed uninfected infants also in high-income countries. • Physicians should be aware of this increased risk when attending these infants.

Altered Maternal Antibody Profiles in Women With Human Immunodeficiency Virus Drive Changes in Transplacental Antibody Transfer

BACKGROUND

Human immunodeficiency virus (HIV)-exposed, uninfected (HEU) children have a higher risk of severe infection, but the causes are poorly understood. Emerging data point to altered antibody transfer in women with HIV (WHIV); however, specific perturbations and the influence of antiretroviral therapy (ART) and HIV viremia remain unclear.

METHODS

We evaluated antigen-specific transplacental antibody transfer across 14 antigens in paired maternal and umbilical cord plasma from 352 Ugandan women; 176 were WHIV taking ART. We measured antigen-specific immunoglobulin G (IgG) sub-class (IgG1, 2, 3, 4) levels and antibody Fcγ receptor (FcγRn, 2a, 2b, 3a, 3b) binding profiles. We used partial least squares discrimi-nant analysis to define antigen-specific transplacental antibody transfer features.

RESULTS

Global antibody transfer patterns were similar by maternal HIV serostatus, pointing to effective placental function in WHIV. However, HEU umbilical cord antibody profiles were altered, driven by perturbed WHIV seroprofiles, with higher levels of herpesvirus antibodies (P < .01 for Epstein-Barr virus, herpes simplex virus) and lower levels of classic vaccine-induced antibodies (P < .01 for tetanus, polio, Haemophilus influenzae type b), suggesting that umbilical cord antibody profile differences arise from imbalanced WHIV immunity. Abnormal WHIV antibody profiles were associated with HIV viremia, lower CD4 count, and postconception ART initiation (P = .01).

CONCLUSIONS

Perturbed immune-dominance profiles in WHIV shift the balance of immunity delivered to neonates. Perturbed HIV-associated maternal antibody profiles are a key determinant of com-promised neonatal immunity. Maternal vaccination interventions may promote transfer of relevant, effective antibodies to protect HEU children against early-life infections.

HIV-Infektion und -Exposition bei Kindern und Jugendlichen

Hintergrund

Seit 1997 steht mit den antiretroviralen, kombinierbaren Wirkstoffen eine effektive Prävention und Behandlung einer Infektion mit dem „human immunodeficiency virus“ (HIV) zur Verfügung.

Fragestellung

Was wurde in dieser Zeit durch die Transmissionsprophylaxe und Behandlung der HIV-Infektion bei Kindern in Deutschland erreicht?

Material und Methoden

Darstellung der Entwicklung der Transmissionsprophylaxe und der epidemiologischen Erhebungen des Robert Koch-Instituts, Darstellung der Arzneimittelentwicklung und der Leitlinien zur antiretroviralen Therapie (ART) bei Kindern und Jugendlichen, Vorstellung von Erhebungen der deutschen Kinder-HIV-Kohorte („German pediatric and adolescent HIV cohort“, GEPIC).

Ergebnisse

Die Einführung der HIV-Testung Schwangerer hat die regelmäßige ART HIV-positiver Schwangerer und die Einführung von transmissionsmindernden Maßnahmen möglich gemacht. Damit konnte das Risiko der vertikalen Transmission von ca. 30 % auf < 1 % gesenkt werden. Gegenwärtig wird untersucht, ob HIV-exponierte Kinder ohne Risiko gestillt werden können. Die ART bei Kindern hat die Überlebensraten sowie die körperliche und die kognitive Entwicklung HIV-positiver Kinder entscheidend verbessert. Neue Wirkstoffe haben ein günstigeres Nebenwirkungsprofil. In Deutschland konnten die WHO-Ziele, bei 90 % der Kinder eine vollständige Suppression der Viruslast zu erzielen, erreicht werden. Späte Diagnosen sind bei Kindern und Jugendlichen weiterhin mit schweren Infektionen verbunden. Die HIV-Infektion ist weiterhin eine Erkrankung mit Stigma geblieben und wird deswegen meist gegenüber den Kindern und ihrer Umwelt geheim gehalten.

Schlussfolgerung

Mit der jetzt möglichen Transmissionsprophylaxe und Therapie gelingt es, Transmissionen weitgehend zu verhindern und HIV-positiven Kindern bei frühzeitiger Diagnose ein weitgehend gesundes Leben zu ermöglichen. Das Ziel, dass Kinder ihre Krankheit ohne Angst kennen und nennen können, ist nach wie vor nicht erreicht.

Defective Monocyte Enzymatic Function and an Inhibitory Immune Phenotype in Human Immunodeficiency Virus-Exposed Uninfected African Infants in the Era of Antiretroviral Therapy

BACKGROUND

Human immunodeficiency virus-exposed uninfected (HEU) infants are a rapidly expanding population in sub-Saharan Africa and are highly susceptible to encapsulated bacterial disease in the first year of life. The mechanism of this increased risk is still poorly understood. We investigated whether human immunodeficiency virus (HIV)-exposure dysregulates HEU immunity, vaccine-antibody production, and human herpes virus amplify this effect.

METHODS

Thirty-four HIV-infected and 44 HIV-uninfected pregnant women were recruited into the birth cohort and observed up to 6 weeks of age; and then a subsequent 43 HIV-infected and 61 HIV-uninfected mother-infant pairs were recruited into a longitudinal infant cohort at either: 5-7 to 14-15; or 14-15 to 18-23 weeks of age. We compared monocyte function, innate and adaptive immune cell phenotype, and vaccine-induced antibody responses between HEU and HIV-unexposed uninfected (HU) infants.

RESULTS

We demonstrate (1) altered monocyte phagosomal function and B-cell subset homeostasis and (2) lower vaccine-induced anti-Haemophilus influenzae type b (Hib) and anti-tetanus toxoid immunoglobulin G titers in HEU compared with HU infants. Human herpes virus infection was similar between HEU and HU infants.

CONCLUSIONS

In the era of antiretroviral therapy-mediated viral suppression, HIV exposure may dysregulate monocyte and B-cell function, during the vulnerable period of immune maturation. This may contribute to the high rates of invasive bacterial disease and pneumonia in HEU infants.

Standardized Definitions of In Utero Human Immunodeficiency Virus and Antiretroviral Drug Exposure Among Children

In countries with high human immunodeficiency virus (HIV) prevalence, up to 30% of pregnant women are living with HIV, with fetal exposure to both HIV and antiretroviral therapy during pregnancy. In addition, pregnant women without HIV but at high risk of HIV acquisition are increasingly receiving HIV preexposure antiretroviral prophylaxis (PrEP). Investments are being made to establish and follow cohorts of children to evaluate the long-term effects of in utero HIV and antiretroviral exposure. Agreement on a key set of definitions for relevant exposures and outcomes is important both for interpreting individual study results and for comparisons across cohorts. Harmonized definitions of in utero HIV and antiretroviral drug (maternal treatment or PrEP) exposure will also facilitate improved classification of these exposures in future observational studies and clinical trials. The proposed definitions offer a uniform approach to facilitate the consistent description and estimation of effects of HIV and antiretroviral exposures on key child health outcomes.

HIV-associated alterations of the biophysical features of maternal antibodies correlate with their reduced transfer across the placenta

BACKGROUND

Human Immunodeficiency Virus (HIV) infection during pregnancy is associated with reduced transplacental transfer of maternal antibodies and increased risk of severe infections in children who are exposed and uninfected with HIV (CHEU). The basis of this reduced transfer of maternal immunity has not yet been defined but could involve modifications in the biophysical features of antibodies.

OBJECTIVE

To assess the impact of maternal HIV infection on the biophysical features of serum IgG and transplacental antibody transfer.

METHODS

Maternal serum IgG subclass levels, Fc glycosylation, Fc Receptor (FcR) binding, and transplacental transfer of pathogen-specific maternal IgG were measured in pregnant women living with HIV (WWH) and pregnant women testing negative for HIV (WNH) in Cape Town, South Africa.

RESULTS

Maternal antibody profiles were strikingly different between pregnant WWH and WNH. Antibody binding to FcγR2a and FcγR2b, IgG1 and IgG3 antibodies, and agalactosylated antibodies were all elevated in WLHIV, whereas digalactosylated and sialylated antibodies were reduced as compared to pregnant WNH. Antibody features that were elevated in WWH were also correlated with reduced transplacental transfer of vaccine antigen-specific antibodies.

CONCLUSION

HIV infection is associated with marked alterations of biophysical features of maternal IgG and reduced placental transfer-potentially impairing antimicrobial immunity.

Adverse perinatal outcomes associated with HAART and monotherapy: systematic review and meta-analysis

OBJECTIVES

Assess adverse perinatal outcomes in women living with HIV (WLHIV) receiving HAART or zidovudine (ZDV) monotherapy, compared with antiretroviral therapy (ART)-naive WLHIV and HIV-negative women.

DESIGN

Systematic review and meta-analysis.

METHODS

We conducted a systematic literature review by searching PubMed, CINAHL, Global Health, and EMBASE for studies published during 1 January 1980 to 20 April 2020. We included studies reporting on the association of pregnant WLHIV receiving HAART or ZDV monotherapy with 11 perinatal outcomes: preterm birth (PTB), very PTB, spontaneous PTB (sPTB), low birth weight (LBW), very LBW, term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Random-effects meta-analyses were conducted.

RESULTS

Sixty-one cohort studies assessing 409 781 women were included. WLHIV receiving ZDV monotherapy were associated with a decreased risk of PTB [relative risk 0.70, 95% confidence interval (CI) 0.62-0.79] and LBW (0.77, 0.67-0.88), and comparable risk of SGA, compared with ART-naive WLHIV. WLHIV receiving ZDV monotherapy had a comparable risk of PTB and LBW, and an increased risk of SGA (1.16, 1.04-1.30) compared with HIV-negative women. In contrast, WLHIV receiving HAART were associated with a comparable risk of PTB and LBW, and increased risk of SGA (1.38, 1.09-1.75), compared with ART-naive WLHIV. WLHIV receiving HAART were associated with an increased risk of PTB (1.55, 1.38-1.74), sPTB (2.09, 1.48-2.96), LBW (1.79, 1.51-2.13), term LBW (1.88, 1.23-2.85), SGA (1.80,1.34-2.40), and VSGA (1.22, 1.10-1.34) compared with HIV-negative women.

CONCLUSION

Pregnant WLHIV receiving HAART have an increased risk of a wide range of perinatal outcomes compared with HIV-negative women.

Essential Regression: A generalizable framework for inferring causal latent factors from multi-omic datasets

High-dimensional cellular and molecular profiling of biological samples highlights the need for analytical approaches that can integrate multi-omic datasets to generate prioritized causal inferences. Current methods are limited by high dimensionality of the combined datasets, the differences in their data distributions, and their integration to infer causal relationships. Here, we present Essential Regression (ER), a novel latent-factor-regression-based interpretable machine-learning approach that addresses these problems by identifying latent factors and their likely cause-effect relationships with system-wide outcomes/properties of interest. ER can integrate many multi-omic datasets without structural or distributional assumptions regarding the data. It outperforms a range of state-of-the-art methods in terms of prediction. ER can be coupled with probabilistic graphical modeling, thereby strengthening the causal inferences. The utility of ER is demonstrated using multi-omic system immunology datasets to generate and validate novel cellular and molecular inferences in a wide range of contexts including immunosenescence and immune dysregulation.

Higher Hospitalization Rates in Children Born HIV-exposed Uninfected in British Columbia, Canada, Between 1990 and 2012

BACKGROUND

Compared with children who are HIV-unexposed and uninfected (CHUU), children who are HIV-exposed and uninfected (CHEU) experience more clinical complications. We investigated hospitalizations among CHEU by antenatal antiretroviral therapy (ART) exposure, in British Columbia, Canada.

METHODS

This retrospective controlled cohort study used administrative health data from 1990 to 2012. CHEU and CHUU were matched 1:3 for age, sex and maternal geographical area of residence. We determined adjusted odds ratios (aORs) via conditional logistic regression, adjusting for maternal risk factors.

RESULTS

A total of 446 CHEU and 1333 CHUU were included. Compared with CHUU, more CHEU experienced one or more lifetime hospitalization (47.3% vs. 29.8%), one or more neonatal hospitalization (40.4% vs. 27.6%), and any intensive care unit admission (28.5% vs. 9.2%). In adjusted analyses, CHEU experienced higher odds of any lifetime hospitalization (aOR 2.30, 95% confidence interval 1.81-2.91) and neonatal hospitalization (aOR 2.14, 95% confidence interval 1.68-2.73), compared with CHUU. There was, however, no difference in infection-related hospitalizations (9.0% vs. 7.5%), which were primarily respiratory tract infections among both CHEU and CHUU. CHEU whose mothers-initiated ART preconception showed lower odds of infection-related hospitalizations than children whose mothers initiated ART during pregnancy or received no ART.

CONCLUSIONS

CHEU experienced increased odds of hospitalization relative to CHUU. A substantial number of CHEU hospitalizations occurred within the neonatal period and were ICU admissions. Initiating ART preconception may reduce the risk of infection-related hospitalizations. These findings reinforce the benefit of ART in pregnancy and the need for ongoing pediatric care to reduce hospitalizations.

From maternal breath to infant's cells: Impact of maternal respiratory infections on infants 'immune responses

In utero exposure to maternally-derived antigens following chronic infection is associated with modulation of infants 'immune response, differential susceptibility to post-natal infections and immune response toward vaccines. The maternal environment, both internal (microbiota) and external (exposure to environmental microbes) also modulates infant's immune response but also the clinical phenotype after birth. Vertical transmission of ubiquitous respiratory pathogens such as influenza and COVID-19 is uncommon. Evidence suggest that in utero exposure to maternal influenza and SARS-CoV-2 infections may have a significant impact on the developing immune system with activation of both innate and adaptive responses, possibly related to placental inflammation. Here in, we review how maternal respiratory infections, associated with airway, systemic and placental inflammation but also changes in maternal microbiota might impact infant's immune responses after birth. The clinical impact of immune modifications observed following maternal respiratory infections remains unexplored. Given the high frequencies of respiratory infections during pregnancy (COVID-19, influenza but also RSV and HMPV), the impact on global child health could be important.

Features of the Neonatal Period in Perinatally HIV-Exposed Children Receiving Combined Сhemoprophylaxis of mother-to-child Transmission of HIV

The aim. To study the features of the course of the neonatal period in children, perinatally exposed to HIV, who receive an enhanced regimen of chemoprophylaxis of HIV mother-to-child transmission.Patients and methods. A retrospective longitudinal cohort study of mother – child pairs for the period from 2017 to 2019 was carried out. The clinical observation group included HIV-positive women with a high risk of vertical transmission of the immunodeficiency virus (n = 213) and their newborn children (n = 214), who were prescribed an enhanced chemoprophylaxis regimen of HIV transmission from mother to child. Results. According to the results of the study of HIV-positive mothers we revealed a high prevalence of secondary diseases and a high per partum viremia – 1700 (222–18342) copies/ml. 35.9 % of children were born prematurely, 27.5 % – had low birth weight by gestational age. In newborns, diseases of the respiratory (24.3 %) and nervous (17.2 %) systems prevailed. 17.2 % of children developed intrauterine infection; HIV RNA was detected in 3.7 %. Congenital malformations were observed in 7.4 % of children. Symptoms of enteropathy were noted in 24.7 % of newborns. A decrease in red blood counts was found in all children by the 28th day of life (pw < 0.001).Conclusion. The study confirms the need for increased attention and improvement of approaches to medical support of children who were perinatally exposed to high risk of vertical HIV infection.

Increased infectious-cause hospitalization among infants who are HIV-exposed uninfected compared with HIV-unexposed

OBJECTIVES

Increased risk of morbidity and hospitalization has been observed in children who are HIV-exposed uninfected (HEU) compared with HIV-unexposed uninfected (HUU). Studies in the era of universal maternal antiretroviral treatment (ART) are limited.

DESIGN

Prospective cohort.

METHODS

We investigated hospitalization between 29 days and 12 months of life in a South African cohort of infants born between February 2017 and January 2019 (HEU = 455; HUU = 458). All mothers known with HIV during pregnancy received ART. We reviewed hospital records and classified and graded infectious diagnoses using a standardized tool. We examined factors associated with infectious-cause hospitalization using mixed-effects Poisson regression.

RESULTS

Infants HEU vs. HUU had higher all-cause and infectious-cause hospitalization (13 vs. 7%, P = 0.004 and 10 vs. 6%, P = 0.014, respectively). Infectious causes accounted for most hospitalizations (77%). More infants HEU were hospitalized with severe or very severe infections than those HUU (9 vs. 6%; P = 0.031). Mortality (<1%) did not differ between groups. HIV exposure was a significant risk factor for infectious-cause hospitalization [adjusted incidence rate ratios (aIRRs) = 2.8; 95% confidence interval (CI) 1.5-5.4]. Although increased incidence of preterm birth (14 vs. 10%; P < 0.05) and shorter duration of breastfeeding (44 vs. 68% breastfed for ≥3 months, P < 0.001) among infants HEU vs. HUU contributed to increased hospitalization, they did not account for all the increased risk.

CONCLUSION

Infectious-cause hospitalization incidence was higher among infants HEU vs. HUU, likely partly because of higher incidence of preterm birth and lower breastfeeding rates among infants HEU. The increased infectious disease burden in HEU infants has important implications for health services in sub-Saharan Africa.

Immunologic and Virologic Factors Associated With Hospitalization in Human Immunodeficiency Virus-Exposed, Uninfected Infants in the United States

BACKGROUND

Human immunodeficiency virus (HIV)-exposed, uninfected (HEU) infants experience higher rates of morbidity and mortality than HIV-unexposed, uninfected (HUU) infants. Few studies have examined whether particular infections and/or immune responses are associated with hospitalization among HEU infants born in the United States.

METHODS

We evaluated a subset of HEU infants enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group P1025 and/or Pediatric HIV/AIDS Cohort Study Surveillance Monitoring for ART Toxicities studies. We determined seroconversion to 6 respiratory viruses and measured antibody concentrations to 9 vaccine antigens using quantitative ELISA or electrochemiluminescence. Multivariable modified Poisson regression models were fit to evaluate associations of seroconversion to each respiratory virus/family and antibody concentrations to vaccine antigens with risk of hospitalization in the first year of life. Antibody concentrations to vaccine antigens were compared between HEU infants and HUU infants from a single site using multivariable linear regression models.

RESULTS

Among 556 HEU infants, seroconversion to respiratory syncytial virus (RSV) and parainfluenza was associated with hospitalization (adjusted risk ratio, 1.95 [95% CI, 1.21-3.15] and 2.30 [1.42-3.73], respectively). Antibody concentrations to tetanus toxoid, pertussis, and pneumococcal vaccine antigens were higher among 525 HEU compared with 100 HUU infants. No associations were observed between antibody concentrations with any vaccine and hospitalization among HEU infants.

CONCLUSIONS

RSV and parainfluenza contribute to hospitalization among HEU infants in the first year of life. HEU infants demonstrate robust antibody responses to vaccine antigens; therefore, humoral immune defects likely do not explain the increased susceptibility to infection observed in this population.

One vaccine for life: Lessons from immune ontogeny

There remains a general misconception that the immune status of the fetus and neonate is immature or insufficient. However, emerging research in immune ontogeny prompts reconsideration of this orthodoxy, reframing this period instead as one of unique opportunity. Vaccine responses (qualitative and quantitative) vary between individuals, and across demographic cohorts. Elements of baseline immune status and function predict vaccine response - some of these factors are well described, others remain a subject of ongoing research, especially with the rapidly expanding field of 'omics' research, enabled by development of highly granular immune profiling techniques and increasing computational capacity. Age is one of the strongest predictive factors associated with variability in the response to vaccination; and predictable variation in response to vaccination is a key to identify the crucial underlying mechanisms. Specifically, circulating maternal antibody in the young infant can modulate immune response to vaccination, acting as an 'undercover adjuvant' that, counter to current dogma, may offer a pathway to longer lasting, higher quality immune response to vaccination. Exciting avenues for novel research in this area have the potential to dramatically alter how we protect the world's most vulnerable population - the very young.

Preterm birth and severe morbidity in hospitalized neonates who are HIV exposed and uninfected compared with HIV unexposed

OBJECTIVES

Infants who are HIV exposed but uninfected (HEU) compared with HIV unexposed uninfected (HUU) have an increased risk of adverse birth outcomes, morbidity and hospitalization. In the era of universal maternal antiretroviral treatment, there are few insights into patterns of neonatal morbidity specifically.

DESIGN

A prospective cohort study.

METHODS

We compared neonatal hospitalizations among infants who were HEU (n = 463) vs. HUU (n = 466) born between 2017 and 2019 to a cohort of pregnant women from a large antenatal clinic in South Africa. We examined maternal and infant factors associated with hospitalization using logistic regression.

RESULTS

Hospitalization rates were similar between neonates who were HEU and HUU (13 vs. 16%; P = 0.25). Overall, most hospitalizations occurred directly after birth (87%); infection-related causes were identified in 34%. The most common reason for hospitalization unrelated to infection was respiratory distress (25%). Very preterm birth (<32 weeks) (29 vs. 11%; P = 0.01) as well as very low birthweight (<1500 g) (34 vs. 16%; P = 0.02) occurred more frequently among hospitalized neonates who were HEU. Of those hospitalized, risk of intensive care unit (ICU) admission was higher in neonates who were HEU (53%) than HUU (27%) [risk ratio = 2.1; 95% confidence interval (95% CI) 1.3-3.3]. Adjusted for very preterm birth, the risk of ICU admission remained higher among neonates who were HEU (aRR = 1.8; 95% CI 1.1-2.9).

CONCLUSION

Neonates who were HEU (vs. HUU) did not have increased all-cause or infection-related hospitalization. However, very preterm birth, very low birthweight and ICU admission were more likely in hospitalized neonates who were HEU, indicating increased severity of neonatal morbidity.

Reduced Placental Transfer of Antibodies Against a Wide Range of Microbial and Vaccine Antigens in HIV-Infected Women in Mozambique

Transplacental transfer of antibodies is essential for conferring protection in newborns against infectious diseases. We assessed the impact of different factors, including gestational age and maternal infections such as HIV and malaria, on the efficiency of cord blood levels and placental transfer of IgG subclasses. We measured total IgG and IgG subclasses by quantitative suspension array technology against 14 pathogens and vaccine antigens, including targets of maternal immunization, in 341 delivering HIV-uninfected and HIV-infected mother-infant pairs from southern Mozambique. We analyzed the association of maternal HIV infection, Plasmodium falciparum exposure, maternal variables and pregnancy outcomes on cord antibody levels and transplacental transfer. Our results show that maternal antibody levels were the main determinant of cord antibody levels. Univariable and multivariable analysis showed that HIV reduced the placental transfer and cord levels of IgG and IgG1 principally, but also IgG2 to half of the antigens tested. P. falciparum exposure and prematurity were negatively associated with cord antibody levels and placental transfer, but this was antigen-subclass dependent. Our findings suggest that lower maternally transferred antibodies may underlie increased susceptibility to infections of HIV-exposed infants. This could affect efficacy of maternal vaccination, especially in sub-Saharan Africa, where there is a high prevalence of HIV, malaria and unfavorable environmental factors.

HIV infection and placental malaria reduce maternal transfer of multiple antimalarial antibodies in Mozambican women

OBJECTIVES

Maternal Plasmodium falciparum-specific antibodies may contribute to protect infants against severe malaria. Our main objective was to evaluate the impact of maternal HIV infection and placental malaria on the cord blood levels and efficiency of placental transfer of IgG and IgG subclasses.

METHODS

In a cohort of 341 delivering HIV-negative and HIV-positive mothers from southern Mozambique, we measured total IgG and IgG subclasses in maternal and cord blood pairs by quantitative suspension array technology against eight P. falciparum antigens: Duffy-binding like domains 3-4 of VAR2CSA from the erythrocyte membrane protein 1, erythrocyte-binding antigen 140, exported protein 1 (EXP1), merozoite surface proteins 1, 2 and 5, and reticulocyte-binding-homologue-4.2 (Rh4.2). We performed univariable and multivariable regression models to assess the association of maternal HIV infection, placental malaria, maternal variables and pregnancy outcomes on cord antibody levels and antibody transplacental transfer.

RESULTS

Maternal antibody levels were the main determinants of cord antibody levels. HIV infection and placental malaria reduced the transfer and cord levels of IgG and IgG1, and this was antigen-dependent. Low birth weight was associated with an increase of IgG2 in cord against EXP1 and Rh4.2.

CONCLUSIONS

We found lower maternally transferred antibodies in HIV-exposed infants and those born from mothers with placental malaria, which may underlie increased susceptibility to malaria in these children.

Human Immunodeficiency Virus Exposure but Not Early Cytomegalovirus Infection Is Associated With Increased Hospitalization and Decreased Memory T-Cell Responses to Tetanus Vaccine

BACKGROUND

Human immunodeficiency virus (HIV)-exposed, uninfected (HEU) infants experience high rates of infectious morbidity. We hypothesized that early cytomegalovirus (CMV) infection was associated with increased hospitalization rates and decreased vaccine responses in HEU compared with HIV-unexposed (HUU) infants.

METHODS

Among infants enrolled in the Tshipidi study in Botswana, we determined CMV infection status by 6 months of age and compared hospitalization rates and responses to tetanus and Bacille Calmette-Guérin vaccines among HEU and HUU vaccinees.

RESULTS

Fifteen of 226 (6.6%) HEU infants and 17 (19.3%) of 88 HUU infants were CMV-infected by 6 months. The HEU infants were approximately 3 times as likely to be hospitalized compared with HUU infants (P = .02). The HEU peripheral blood cells produced less interleukin (IL)-2 (P = .004), but similar amounts of interferon-γ, after stimulation with tetanus toxoid. Antitetanus immunoglobulin G titers were similar between groups. Cellular responses to purified protein derivative stimulation did not differ between groups. Maternal receipt of 3-drug antiretroviral therapy compared with zidovudine was associated with increased IL-2 expression after tetanus toxoid stimulation. The infants' CMV infection status was not associated with clinical or vaccine response outcomes.

CONCLUSIONS

We observed that increased rates of hospitalization and decreased memory T-cell responses to tetanus vaccine were associated with HIV exposure and incomplete treatment of maternal HIV infection, but not early CMV infection.

Maternal HIV status skews transcriptomic response in infant cord blood monocytes exposed to Bacillus Calmette--Guerín

OBJECTIVES

HIV-exposed uninfected (HEU) infants exhibit altered vaccine responses and an increased mortality compared with HIV-unexposed infants. Here, vaccine responses in HEU and HIV-unexposed cord blood monocytes (CBMs) were assessed following Bacillus Calmette--Guerín (BCG) treatment.

DESIGN

Innate responses to in-vitro BCG treatment were assessed through transcriptional profiling using CBMs obtained from a Nigerian cohort of HIV-infected and uninfected women.

METHODS

HIV-unexposed (n = 9) and HEU (n = 10) infant CBMs were treated with BCG and transcriptionally profiled with the Nanostring nCounter platform. Differential expression and pathway enrichment analyses were performed, and transcripts were identified with enhanced or dampened BCG responses.

RESULTS

Following BCG stimulation, several pathways associated with inflammatory gene expression were upregulated irrespective of HIV exposure status. Both HIV-unexposed and HEU monocytes increased expression of several cytokines characteristic of innate BCG responses, including IL1β, TNFα, and IL-6. Using differential expression analysis, we identified genes significantly upregulated in HEU compared with HIV-unexposed monocytes including monocyte chemokine CCL7 and anti-inflammatory cytokine TNFAIP6. In contrast, genes significantly upregulated in HIV-unexposed compared with HEU monocytes include chemokine CCL3 and cytokine IL23A, both of which influence anti-mycobacterial T-cell responses. Finally, two genes, which regulate prostaglandin production, CSF2 and PTGS2, were also more significantly upregulated in the HIV-unexposed cord blood indicating that inflammatory mediators are suppressed in the HEU infants.

CONCLUSION

HEU monocytes exhibit altered induction of several key innate immune responses, providing mechanistic insights into dysregulated innate response pathways that can be therapeutically targeted to improve vaccine responses in HEU infants.

Innate Immune Responses and Gut Microbiomes Distinguish HIV-Exposed from HIV-Unexposed Children in a Population-Specific Manner

In both high- and low-income countries, HIV-negative children born to HIV-positive mothers (HIV exposed, uninfected [HEU]) are more susceptible to severe infection than HIV-unexposed, uninfected (HUU) children, with altered innate immunity hypothesized to be a cause. Both the gut microbiome and systemic innate immunity differ across biogeographically distinct settings, and the two are known to influence each other. And although the gut microbiome is influenced by HIV infection and may contribute to altered immunity, the biogeography of immune-microbiome correlations among HEU children have not been investigated. To address this, we compared the innate response and the stool microbiome of 2-y-old HEU and HUU children from Belgium, Canada, and South Africa to test the hypothesis that region-specific immune alterations directly correlate to differences in their stool microbiomes. We did not detect a universal immune or microbiome signature underlying differences between HEU versus HUU that was applicable to all children. But as hypothesized, population-specific differences in stool microbiomes were readily detected and included reduced abundances of short-chain fatty acid-producing bacteria in Canadian HEU children. Furthermore, we did not identify innate immune-microbiome associations that distinguished HEU from HUU children in any population. These findings suggest that maternal HIV infection is independently associated with differences in both innate immunity and the stool microbiome in a biogeographical population-specific way.

Association of Maternal Factors and HIV Infection With Innate Cytokine Responses of Delivering Mothers and Newborns in Mozambique

Maternal factors and exposure to pathogens have an impact on infant health. For instance, HIV exposed but uninfected infants have higher morbidity and mortality than HIV unexposed infants. Innate responses are the first line of defense and orchestrate the subsequent adaptive immune response and are especially relevant in newborns. To determine the association of maternal HIV infection with maternal and newborn innate immunity we analyzed the cytokine responses upon pattern recognition receptor (PRR) stimulations in the triad of maternal peripheral and placental blood as well as in cord blood in a cohort of mother-infant pairs from southern Mozambique. A total of 48 women (35 HIV-uninfected and 13 HIV-infected) were included. Women and infant innate responses positively correlated with each other. Age, gravidity and sex of the fetus had some associations with spontaneous production of cytokines in the maternal peripheral blood. HIV-infected women not receiving antiretroviral therapy (ART) before pregnancy showed decreased IL-8 and IL-6 PRR responses in peripheral blood compared to those HIV-uninfected, and PRR hyporesponsiveness for IL-8 was also found in the corresponding infant’s cord blood. HIV infection had a greater impact on placental blood responses, with significantly increased pro-inflammatory, T_H1 and T_H17 PRR responses in HIV-infected women not receiving ART before pregnancy compared to HIV-uninfected women. In conclusion, innate response of the mother and her newborn was altered by HIV infection in the women who did not receive ART before pregnancy. As these responses could be related to birth outcomes, targeted innate immune modulation could improve maternal and newborn health.

Vaccination strategies to enhance immunity in neonates

Neonates are particularly susceptible to infection. This vulnerability occurs despite their responsiveness to most vaccines. However, current vaccines do not target the pathogens responsible for most of the severe neonatal infections, and the time it takes to induce protective pathogen-specific immunity after vaccination limits protection in the first days to weeks of life. Alternative strategies include using vaccines to broadly stimulate neonatal immunity in a pathogen-agnostic fashion or vaccinating women during pregnancy to induce protective antibodies that are vertically transferred to offspring within their window of vulnerability. Protection may be further improved by integrating these approaches, namely vaccinating the neonate under the cover of vertically transferred maternal immunity. The rationale for and knowledge gaps related to each of these alternatives are discussed.

Contemporary Issues in Pregnancy (and Offspring) in the Current HIV Era

PURPOSE OF REVIEW

Although antiretroviral therapy (ART) has dramatically reduced mother to child transmission of HIV, data continue to mount that infants exposed to HIV in utero but are not infected (HEU) have serious negative health consequences compared to unexposed infants. This review evaluates recent literature on contemporary issues related to complications seen in pregnant women with HIV and their offspring.

RECENT FINDINGS

Current studies show that HEU infants are at a high risk of adverse outcomes, including premature birth, poor growth, neurodevelopmental impairment, immune dysfunction, infectious morbidity, and death. Etiologies for the observed clinical events and subclinical alterations are complex and multifactorial, and the long-term consequences of many findings are yet unknown. HEU infants have an unacceptable rate of morbidity and mortality from perinatal HIV and ART exposure, even in the modern ART era. Continual monitoring and reporting is imperative to protect this vulnerable population in our everchanging landscape of HIV treatment and prevention.

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.

Summary

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.

Maternal immunization confers protection against neonatal herpes simplex mortality and behavioral morbidity

Neonatal herpes simplex virus (nHSV) infections cause devastating morbidity and mortality in infants. Most nHSV cases are associated with primary maternal infection, consistent with the hypothesis that maternal immunity is protective. In humans, we found HSV-specific neutralizing antibodies in newborns of immune mothers, indicating that placentally transferred HSV-specific antibody is protective. Using a murine model, we showed that passive administration of HSV-specific antibody to dams prevented disseminated infection and mortality in pups. Maternal immunization with an HSV-2 replication-defective vaccine candidate, dl5-29, led to transfer of HSV-specific antibodies into neonatal circulation that protected against nHSV neurological disease and death. Furthermore, we observed considerable anxiety-like behavior in adult mice that had been infected with low doses of HSV as neonates, despite a notable lack of signs of infection. This phenotype suggests that nHSV infection can have an unsuspected and permanent impact on behavior. These behavioral sequelae of nHSV were prevented by maternal immunization with dl5-29, demonstrating an unexpected benefit of immunization. These findings also support the general concept that maternal immunization can prevent neurotropic neonatal infections and associated morbidity and mortality.

Improving Vaccine-Induced Immunity: Can Baseline Predict Outcome?

Immune signatures measured at baseline and immediately prior to vaccination may predict the immune response to vaccination. Such pre-vaccine assessment might allow not only population-based, but also more personalized vaccination strategies (‘precision vaccination’). If baseline immune signatures are predictive, the underlying mechanism they reflect may also determine vaccination outcome. Thus, baseline signatures might contribute to identifying interventional targets to be modulated prior to vaccination in order to improve vaccination responses. This concept has the potential to transform vaccination strategies and usher in a new approach to improve global health.

Extensive baseline variability in immune responses (e.g., antibody titers) among individuals in given populations is increasingly being appreciated as a major contributor to vaccine response heterogeneity.

The concept of ‘baseline may predict outcome’ has recently been reported for human influenza virus, yellow fever virus, and hepatitis B virus, as well as malaria vaccination. This concept might also apply to other vaccines.

The ability to predict who might respond to immunization (and to what extent) might offer avenues for optimization of current vaccination strategies.

We posit that this simple concept might be useful and significant for vaccine design: if ‘baseline determines outcome, then altering baseline prior to vaccination could alter outcome’.

This approach could potentially lead to tailored (precision) vaccines ensuring that the majority, or all individuals vaccinated, respond by eliciting a protective immune response (i.e., devoid of non-responder individuals). Presumably, this approach might also allow the administration of fewer vaccine doses, potentially arriving at one vaccine dose only.

Impact of HIV and antiretroviral drug exposure on lung growth and function over 2 years in an African Birth Cohort

Supplemental Digital Content is available in the text

Objective:

To assess the impact of HIV and antiretroviral exposure without infection on lung growth and function over the first 2 years of life.

Design:

Prospective observational study of an African birth cohort, Drakenstein Child Health Study.

Method:

Infants enrolled antenatally had lung function measured at 6 weeks, 1 and 2 years. HIV-infected women received antiretroviral therapy (ART) as per local guidelines. The association between HIV and antiretroviral exposure with lung function was assessed using mixed effects modelling.

Results:

Of 1143 infants born, two HIV-infected infants were excluded from analysis; 909 (80%) infants had lung function collected at 6 weeks [190 (21%) were HIV-exposed uninfected (HEU)]; 782 (69%) at 1 year and 741 (65%) at 2 years. At 6 weeks HEU infants had larger tidal volume compared with HIV-unexposed infants (1.13 ml, confidence interval: 0.02–2.23, P = 0.045). High maternal viral load was associated with a 17% lower expiratory flow over 2 years (0.17, confidence interval 0.00–0.34, P = 0.046). First-line ART initiated during pregnancy was associated with lower infant tidal volume at 6 weeks compared with those who initiated ART before pregnancy (−2.7 ml, −5.31 to −0.10, P = 0.042), and low maternal CD4⁺ cell counts associated with lower infant tidal over 2 years (−11.1 ml, −18.58–3.58, P = 0.004).

Conclusion:

HIV exposure is associated with altered lung function in early life, with a vulnerable HEU subgroup based on maternal disease severity, immunological compromise and ART exposure. These data highlight the importance of ongoing surveillance of respiratory health in HEU children.

Infectious morbidity of breastfed, HIV-exposed uninfected infants under conditions of universal antiretroviral therapy in South Africa: a prospective cohort study

BACKGROUND

Without breastfeeding and maternal antiretroviral therapy (ART), HIV-exposed uninfected (HEU) infants have greater infectious morbidity than HIV-unexposed (HU) infants. We hypothesised that with the introduction of universal maternal ART, breastfed HEU and HU infants would have similar morbidity.

METHODS

We prospectively studied a cohort of HIV-infected pregnant women initiating ART, and a parallel group of HIV-uninfected pregnant women, starting from their first antenatal care visit at the Gugulethu Midwife Obstetrics Unit in Cape Town, South Africa. All pregnant women attending their first antenatal care visit were eligible for enrolment if aged 18 years or older and planning to deliver in Cape Town, without gestational age restrictions. HIV-infected women were participants of the Maternal Child Health ART (MCH-ART) study, and HIV-uninfected women were participants of the HIV-Unexposed Uninfected (HU2) study. All enrolled women were followed up during pregnancy and through delivery. At the early neonatal visit (scheduled for the first week after birth), mother-infant pairs who practiced any breastfeeding in the first 7 days of life were eligible for further postnatal follow-up for at least 12 months post partum. HIV infection was excluded among HEU infants at ages 6 weeks and 12 months by PCR. We evaluated the effect of HIV exposure on two primary outcomes: hospitalisation (all-cause and infection-related admission to hospital) and longitudinal prevalence of child infectious illness (diarrhoea and presumed lower respiratory tract infection [LRTI]). Hospitalisation data were abstracted from routine health records. Crude and adjusted incidence rate ratios (aIRRs; with adjustment for maternal HIV disease severity, timing of ART initiation, breastfeeding, timely vaccination, and birth outcomes [gestational size and age]) for infection-related hospitalisations were calculated from Poisson regression models (with variance corrected for clustering). Prevalence of infant infectious illness was based on maternal self-report for the preceding 2 weeks of each visit, with questions based on Demographic and Health Survey (DHS) questionnaires. Infants who acquired HIV infection during follow-up were excluded from this analysis. MCH-ART is registered on ClinicalTrials.gov, NCT01933477.

FINDINGS

Pregnant women were recruited between March 20, 2013, and Aug 19, 2015. Mother-infant pairs (HEU, n=459; HU, n=410) were followed up for a median of 12 months until March 24, 2017. Compared with HU infants, HEU infants had more infection-related hospitalisations between the age of 8 days and 3 months (HEU, 34·2 admissions per 100 child-years [24·4-47·9] vs 9·8 per 100 child-years [95% CI 5·1-18·8]; IRR 3·50 [95% CI 1·68-7·30]), but rates were similar at other ages. In infants aged 8 days to 3 months, infection-related hospitalisations for HEU infants with healthier mothers (n=84; ART initiation at <24 weeks' gestation, CD4 count >350 cells per μL, HIV viral load <4·0 log10 copies per mL: 15·88 admissions per 100 child-years [5·12-49·23]) approximated those of HU infants (9·77 per 100 child-years [5·08-18·78]; aIRR 1·28 [0·27-6·05]). HEU infants of mothers with late ART initiation (at ≥24 weeks' gestation) and advanced disease (CD4 count ≤350 cells per μL and HIV viral load ≥4·0 log10 copies per mL; n=44) had the highest admission rate (40·44 per 100 child-years [15·18-107·74]; aIRR 5·01 [1·50-16·71]). In this age group, reduced admissions were seen in HEU infants with optimal breastfeeding (initiated within 1 h of birth and exclusive through age 3 months) and timely vaccination (required doses received within 2 weeks of indicated age; n=90; 9·63 admissions per 100 child-years [2·41-38·49]). Between birth and age 6 months, HEU infants had an almost five times greater prevalence of LRTIs than HU infants (aPR 4·69 [2·40-9·17]), and a three-times greater prevalence of diarrhoeal illness (aPR 2·93 [1·70-5·07]). After age 6 months, these associations were ameliorated.

INTERPRETATION

Despite ART in pregnancy, breastfed HEU infants versus breastfed HU infants had transiently increased infectious morbidity risks in early infancy. However, differences were driven by factors potentially amenable to intervention, including delayed diagnosis and ART initiation in HIV-positive mothers, and suboptimal breastfeeding and vaccination of their infants.

FUNDING

US National Institute of Child Health and Human Development, Elizabeth Glaser Pediatric AIDS Foundation, South African Medical Research Council, Fogarty Foundation and the Office of AIDS Research.

Immunobiological aspects of vaccines in pregnancy: Maternal perspective

Immunization during pregnancy is an efficient strategy to protect both the mother and the newborn infant against infectious pathogens. Pregnant women have an increased susceptibility to severe infections caused by some pathogens, but the mechanisms involved remain poorly understood. Pregnancy is associated with dynamic changes in maternal immune system that are critical for tolerance of the fetus. These changes could also play an important role in shaping maternal immune components that are transferred to the newborn infant following natural infection or vaccination to prevent infectious diseases in early life. As the momentum for maternal immunization is growing, there is a need to increase our understanding of the immunobiology of maternal immunization in order to better prevent infectious diseases in the pregnant women and the young infant.

Immunological mechanisms of inducing HIV immunity in infants

The potential advantages and unique challenges of the early life immune system for the development of HIV-specific broadly neutralizing antibodies were discussed during a workshop entitled "Immunological Mechanisms of Inducing HIV Immunity in Infants" sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH) in conjunction with the 2018 HIVR4P Conference held in Madrid, Spain. A safe and effective HIV vaccine remains a critical need in the fight against the HIV pandemic, especially to prevent emerging infections in infants, adolescents, and young adults. To successfully target these populations, a vaccine should ideally induce protective immune responses during childhood. Interestingly, several recent studies highlighting differences in immune responses between adults and children have suggested that the early life immune system could present advantages for the elicitation of broadly neutralizing antibodies (bnAbs), a response highly desired for an HIV vaccine. Notably, HIV-infected children develop bnAbs responses earlier and more frequently than infected adults; with emerging evidence that the pathways of elicitation of bnAb lineages may differ between adults and children. Moreover, there is precedent for the prevention of lifelong infections with pediatric immunization, and early life provides a unique window of opportunity for the administration of a multi-dose HIV vaccine that will likely be needed to achieve protective immunity. Further understanding of how the distinct early life immune system can be harnessed to trigger bnAb lineages for induction of durable and polyfunctional HIV-specific immunity is warranted. This strategy will include testing promising HIV vaccine candidates in pediatric populations in preclinical and clinical studies. Novel approaches to identify molecular markers of protection are also key to guide and accelerate pediatric HIV vaccine development.

Fc Glycan-Mediated Regulation of Placental Antibody Transfer

Despite the worldwide success of vaccination, newborns remain vulnerable to infections. While neonatal vaccination has been hampered by maternal antibody-mediated dampening of immune responses, enhanced regulatory and tolerogenic mechanisms, and immune system immaturity, maternal pre-natal immunization aims to boost neonatal immunity via antibody transfer to the fetus. However, emerging data suggest that antibodies are not transferred equally across the placenta. To understand this, we used systems serology to define Fc features associated with antibody transfer. The Fc-profile of neonatal and maternal antibodies differed, skewed toward natural killer (NK) cell-activating antibodies. This selective transfer was linked to digalactosylated Fc-glycans that selectively bind FcRn and FCGR3A, resulting in transfer of antibodies able to efficiently leverage innate immune cells present at birth. Given emerging data that vaccination may direct antibody glycosylation, our study provides insights for the development of next-generation maternal vaccines designed to elicit antibodies that will most effectively aid neonates.

Tuberculosis and HIV-An Update on the "Cursed Duet" in Children

HIV and tuberculosis (TB) often occur together with each exacerbating the other. Improvements in vertical transmission prevention has reduced the number of HIV-infected children being born and early antiretroviral therapy (ART) protects against tuberculosis. However, with delayed HIV diagnosis, HIV-infected infants often present with tuberculosis co-infection. The number of HIV exposed uninfected children has increased and these infants have high exposure to TB and may be more immunologically vulnerable due to HIV exposure in utero. Bacillus Calmette-Guérin (BCG) immunization shortly after birth is essential for preventing severe TB in infancy. With early infant HIV diagnosis and ART, disseminated BCG is no longer an issue. TB prevention therapy should be implemented for contacts of a source case and for all HIV-infected individuals over a year of age. Although infection can be identified through skin tests or interferon gamma release assays, the non-availability of these tests should not preclude prevention therapy, once active TB has been excluded. Therapeutic options have moved from isoniazid only for 6-9 months to shorter regimens. Prevention therapy after exposure to a source case with resistant TB should also be implemented, but should not prevent pivotal prevention trials already under way. A microbiological diagnosis for TB remains the gold standard because of increasing drug resistance. Antiretroviral therapy for rifampicin co-treatment requires adaptation for those on lopinavir-ritonavir, which requires super-boosting with additional ritonavir. For those with drug resistant TB, the main problems are identification and overlapping toxicity between antiretroviral and anti-TB therapy. In spite of renewed focus and improved interventions, infants are still vulnerable to TB.

Prevalence, Risk Factors, and Serotype Distribution of Group B Streptococcus Colonization in HIV-Infected Pregnant Women Living in Belgium: A Prospective Cohort Study

Background

Group B streptococcus (GBS) infection is a leading cause of severe neonatal infection. Maternal GBS carriage during pregnancy is the main risk factor for both early-onset and late-onset GBS disease. High incidence of GBS infection has been reported in HIV-exposed but -uninfected infants (HEU). We aimed to determine the prevalence, characteristics, and risk factors for GBS colonization in HIV-infected and HIV-uninfected pregnant women living in Belgium.

Methods

Between January 1, 2011, and December 31, 2013, HIV-infected (n = 125) and -uninfected (n = 120) pregnant women had recto-vaginal swabs at 35–37 weeks of gestation and at delivery for GBS detection. Demographic, obstetrical, and HIV infection–related data were prospectively collected. GBS capsular serotyping was performed on a limited number of samples (33 from HIV-infected and 16 from HIV-uninfected pregnant women).

Results

There was no significant difference in the GBS colonization rate between HIV-infected and -uninfected pregnant women (29.6% vs 24.2%, respectively). HIV-infected women were more frequently colonized by serotype III (36.4% vs 12.5%), and the majority of serotype III strains belonged to the hypervirulent clone ST-17. Exclusively trivalent vaccine serotypes (Ia, Ib, and III) were found in 57.6% and 75% of HIV-infected and -uninfected women, respectively, whereas the hexavalent vaccine serotypes (Ia, Ib, II, III, IV, and V) were found in 97% and 100%, respectively.

Conclusions

HIV-infected and -uninfected pregnant women living in Belgium have a similar GBS colonization rate. A trend to a higher colonization rate with serotype III was found in HIV-infected women, and those serotype III strains belong predominantly to the hypervirulent clone ST17.

The Fourth International Neonatal and Maternal Immunization Symposium (INMIS 2017): Toward Integrating Maternal and Infant Immunization Programs

This report provides an overview of the proceedings of the 4th International Maternal and Neonatal Immunization Symposium, where presentations focused on the state-of-the-art research on the development and implementation of vaccines given during pregnancy for the protection of mothers and infants.

Prevention of serious infections in pregnant mothers, newborns, and young infants through immunization during pregnancy and in early life has the potential to further reduce maternal and neonatal morbidity and mortality worldwide. In the past decade, research in this field has advanced substantially, from the understanding of the biology and immunology of pregnancy and early life, to the active development of several candidate vaccines, for which challenges and opportunities for global implementation are under consideration. Experts from academia, industry, regulatory and funding agencies, public health, and international organizations met in Brussels (Belgium) from 10 to 12 September 2017, at the 4th International Neonatal and Maternal Immunization Symposium (INMIS), to review the most relevant advances in maternal and neonatal immunization. The overarching focus of the conference was to identify the path forward to achieve integration of maternal and early life immunization strategies for the successful implementation of vaccines in antenatal care and pediatric programs for reduction of maternal and infant mortality worldwide.

IMPORTANCE This report provides an overview of the proceedings of the 4th International Maternal and Neonatal Immunization Symposium, where presentations focused on the state-of-the-art research on the development and implementation of vaccines given during pregnancy for the protection of mothers and infants.