Risk factors for postnatal mother-child transmission of HIV-1

Infant Feeding for Persons Living With and at Risk for HIV in the United States: Clinical Report

Pediatricians and pediatric health care professionals caring for infants born to people living with and at risk for HIV infection are likely to be involved in providing guidance on recommended infant feeding practices. Care team members need to be aware of the HIV transmission risk from breastfeeding and the recommendations for feeding infants with perinatal HIV exposure in the United States. The risk of HIV transmission via breastfeeding from a parent with HIV who is receiving antiretroviral treatment (ART) and is virally suppressed is estimated to be less than 1%. The American Academy of Pediatrics recommends that for people with HIV in the United States, avoidance of breastfeeding is the only infant feeding option with 0% risk of HIV transmission. However, people with HIV may express a desire to breastfeed, and pediatricians should be prepared to offer a family-centered, nonjudgmental, harm reduction approach to support people with HIV on ART with sustained viral suppression below 50 copies per mL who desire to breastfeed. Pediatric health care professionals who counsel people with HIV who are not on ART or who are on ART but without viral suppression should recommend against breastfeeding. Pediatric health care professionals should recommend HIV testing for all pregnant persons and HIV preexposure prophylaxis to pregnant or breastfeeding persons who test negative for HIV but are at high risk of HIV acquisition.

Inferring Viral Transmission Time from Phylogenies for Known Transmission Pairs

When the time of an HIV transmission event is unknown, methods to identify it from virus genetic data can reveal the circumstances that enable transmission. We developed a single-parameter Markov model to infer transmission time from an HIV phylogeny constructed of multiple virus sequences from people in a transmission pair. Our method finds the statistical support for transmission occurring in different possible time slices. We compared our time-slice model results to previously described methods: a tree-based logical transmission interval, a simple parsimony-like rules-based method, and a more complex coalescent model. Across simulations with multiple transmitted lineages, different transmission times relative to the source's infection, and different sampling times relative to transmission, we found that overall our time-slice model provided accurate and narrower estimates of the time of transmission. We also identified situations when transmission time or direction was difficult to estimate by any method, particularly when transmission occurred long after the source was infected and when sampling occurred long after transmission. Applying our model to real HIV transmission pairs showed some agreement with facts known from the case investigations. We also found, however, that uncertainty on the inferred transmission time was driven more by uncertainty from time calibration of the phylogeny than from the model inference itself. Encouragingly, comparable performance of the Markov time-slice model and the coalescent model-which make use of different information within a tree-suggests that a new method remains to be described that will make full use of the topology and node times for improved transmission time inference.

Inferring viral transmission time from phylogenies for known transmission pairs

When the time of an HIV transmission event is unknown, methods to identify it from virus genetic data can reveal the circumstances that enable transmission. We developed a single-parameter Markov model to infer transmission time from an HIV phylogeny constructed of multiple virus sequences from people in a transmission pair. Our method finds the statistical support for transmission occurring in different possible time slices. We compared our time-slice model results to previously-described methods: a tree-based logical transmission interval, a simple parsimony-like rules-based method, and a more complex coalescent model. Across simulations with multiple transmitted lineages, different transmission times relative to the source's infection, and different sampling times relative to transmission, we found that overall our time-slice model provided accurate and narrower estimates of the time of transmission. We also identified situations when transmission time or direction was difficult to estimate by any method, particularly when transmission occurred long after the source was infected and when sampling occurred long after transmission. Applying our model to real HIV transmission pairs showed some agreement with facts known from the case investigations. We also found, however, that uncertainty on the inferred transmission time was driven more by uncertainty from time-calibration of the phylogeny than from the model inference itself. Encouragingly, comparable performance of the Markov time-slice model and the coalescent model-which make use of different information within a tree-suggests that a new method remains to be described that will make full use of the topology and node times for improved transmission time inference.

Understanding Viral and Immune Interplay During Vertical Transmission of HIV: Implications for Cure

Despite the significant progress that has been made to eliminate vertical HIV infection, more than 150,000 children were infected with HIV in 2019, emphasizing the continued need for sustainable HIV treatment strategies and ideally a cure for children. Mother-to-child-transmission (MTCT) remains the most important route of pediatric HIV acquisition and, in absence of prevention measures, transmission rates range from 15% to 45% via three distinct routes: in utero, intrapartum, and in the postnatal period through breastfeeding. The exact mechanisms and biological basis of these different routes of transmission are not yet fully understood. Some infants escape infection despite significant virus exposure, while others do not, suggesting possible maternal or fetal immune protective factors including the presence of HIV-specific antibodies. Here we summarize the unique aspects of HIV MTCT including the immunopathogenesis of the different routes of transmission, and how transmission in the antenatal or postnatal periods may affect early life immune responses and HIV persistence. A more refined understanding of the complex interaction between viral, maternal, and fetal/infant factors may enhance the pursuit of strategies to achieve an HIV cure for pediatric populations.

Orale Immunkompetenz in der Corona-Pandemie vs. Systemrelevanz der Zahnmedizin

Die Covid-19-Pandemie hat das deutsche Gesundheitssystem im Jahr 2020 vor erhebliche Herausforderungen gestellt. In diesem Zusammenhang ist es bemerkenswert, dass für die Zahnmedizin kein sogenannter Rettungsschirm aufgespannt wurde. Dies bedeutet, dass nach Ansicht der Bundesregierung Zahnärzte als nicht systemrelevant eingestuft wurden und somit offiziell auch nicht zu den Ärzten gehören. Diese Annahme ist grundfalsch und gefährlich, wie im Folgenden anhand eines wichtigen Beispiels erörtert wird.

Das SARS-CoV-2-Virus führt bei infizierten Personen zu einem Beschwerdebild von leichten Erkältungszeichen bis hin zu lebensbedrohlichen beatmungsbedürftigen COVID-19-Pneumonien. Ein besonderes Risiko für schwere Verläufe haben Menschen höheren Alters sowie Patienten mit Diabetes, Bluthochdruck und anderen schweren Erkrankungen. Die Haupteintrittspforte für das SARS-CoV-2-Virus in den menschlichen Körper ist u. a. die orale Mukosa, denn die Viren reichern sich dort bevorzugt an und der ACE2-Rezeptor wird dort hochgradig exprimiert. Dieser Penetrationsweg erklärt die häufigeren schweren Verläufe bei älteren Diabetespatienten, deren Immunsystem bereits generell beeinträchtigt ist. Diabetes mellitus induziert eine chronische systemische Entzündung, die sich gerade im Mundbereich regelmäßig als Parodontitis manifestiert. Bei Diabetikern zwangsläufig oft auftretende Hyperglykämien schwächen die Mukosa-Barriere zusätzlich. Es ist daher dringend ratsam, bei Präventionsmaßnahmen für Diabetespatienten den Mund- und Rachenraum nicht zu ignorieren. Neben der parodontalprophylaktischen Betreuung ist gerade in Absenz von Zahnärzten die aktivierte Matrix-Metalloproteinase 8 (aMMP8) ein etablierter Biomarker. Die aktuellen Empfehlungen zur Prävention der SARS-CoV-2-assoziierten COVID-19-Erkrankung sollte daher um die Aspekte der Messung und Sanierung des Mund- und Rachenraums sowie einer regelmäßigen Desinfektion der oralen Mukosa erweitert werden.

Impact of attitudes and beliefs on antiretroviral treatment adherence intention among HIV-positive pregnant and breastfeeding women in Zambia

OBJECTIVE

The aim of this study was to investigate if attitudes or behavioral beliefs about antiretroviral therapy (ART) influence ART adherence intention among pregnant and breastfeeding women in Zambia.

METHODS

We recruited 150 HIV-positive women receiving ART in urban (Lusaka) and rural (Sinazongwe) districts of Zambia. Generalized modified Poisson regression models were used to assess the extent to which adherence intention was influenced by attitude toward ART or behavioral beliefs about ART.

RESULTS

Intention to adhere to ART differed significantly by income, knowledge about HIV transmission, attitudes, and behavioral beliefs (all Ps < .05). In addition, strong intention to adhere to ART differed by urban (69%) and rural (31%) place of residence (P ≤ .01). In adjusted models, women in the weak adherence intention group were more likely to be older, have less knowledge about HIV transmission, and have a more negative attitude toward ART (PR 0.74; 95% CI 0.67-0.82). Behavioral belief about ART, however, was significant in unadjusted model (PR 0.85; 95% CI 0.76-0.94) but not significant after adjusting for covariates such as age, knowledge of transmission, and district locality.

CONCLUSION

Compared to behavioral beliefs, attitudes about ART were more influential for intention to adhere. This knowledge will help inform effective and appropriate ART counseling for pregnant and breastfeeding women at different points along their ART time course.

Women living with HIV in high-income settings and breastfeeding

Guidelines in high-income settings recommend breastfeeding avoidance amongst women living with HIV (WLWH). Increasingly, WLWH in high-income settings, who are well-treated with fully suppressed viral loads, are choosing to breastfeed their infants, even with these recommendations. The purpose of this article is to review existing research and guidance on infant feeding amongst WLWH in high-income countries and to identify gaps in this evidence that require further investigation. Current evidence on the risk of HIV transmission through breastfeeding in the context of antiretroviral therapy (ART), the significance of cell-associated virus, transmission risk factors, retention in care and adherence postpartum, infant prophylaxis and antiretroviral exposure, and monitoring of the breastfeeding WLWH are summarized. A latent HIV reservoir is persistently present in breast milk, even in the context of ART. Thus, suppressive maternal ART significantly reduces, but does not eliminate, the risk of postnatal transmission of HIV. There are currently limited data to guide the optimal frequency of virologic monitoring and the clinical actions to take in case of maternal detectable viral load whilst breastfeeding. Moreover, retention in care and adherence to ART in the postpartum period may be difficult and more research is needed to understand what clinical and psychosocial support would benefit these mothers so that successful engagement in care can be achieved. The long-term effects of antiretroviral drug exposure in the infants also need further exploration. Thus, there is a need for collecting enhanced surveillance data on WLWH who breastfeed and their infants to augment clinical guidance in high-income settings.

Analysis of experiences with exclusive breastfeeding among HIV-positive mothers in Lusaka, Zambia

BACKGROUND

Exclusive breastfeeding in the first 6 months offers protection from postnatal HIV infection but remains low in resource-poor settings. Documentation of experiences with exclusive breastfeeding is needed to strengthen infant feeding counselling by health care workers.

OBJECTIVE

To explore HIV-positive mothers' experiences with exclusive breastfeeding during the first 6 months of the infant's life.

DESIGN

A health facility- and community-based exploratory qualitative study was conducted among 30 HIV-positive mothers practising exclusive breastfeeding and meeting the selection criteria. In-depth interviews were conducted four times with the same participants at 6 days, 6 weeks, 12 weeks and 18 weeks after giving birth. Interviews were transcribed verbatim and files were imported into QRS NVivo Version 10 for coding, and data were analysed using the framework analysis.

RESULTS

We found that mothers were aware of the risks of mother-to-child transmission of HIV through breastmilk and recognised the benefits of exclusive breastfeeding to their exposed babies. However, they were particularly concerned about achieving HIV-free survival for their exposed infants because of problems faced during the first 6 months of infant feeding. Although they reported being supported by their families and/or friends, their poor health and nutrition impacted how well they cared for their infants' well-being.

CONCLUSIONS

We conclude that exclusive breastfeeding was difficult to achieve because of individual circumstances. Therefore, prevention of mother-to-child transmission interventions that adopt a once-off infant feeding counselling do not achieve adequate preparation on the part of mothers to practice exclusive breastfeeding. There is a need to provide frontline health care workers with steps for consideration during infant feeding counselling.

Linking Susceptibility to Infectious Diseases to Immune System Abnormalities among HIV-Exposed Uninfected Infants

HIV-exposed uninfected (HEU) infants experience increased overall mortality from infectious causes when compared to HIV-unexposed uninfected (HU) infants. This is the case in both the resource-rich and resource-limited settings. Here, we explore the concept that specific types of infectious diseases that are more common among HEU infants could provide clues as to the potential underlying immunological abnormalities. The most commonly reported infections in HEU vs. HU infants are caused by encapsulated bacteria, suggesting the existence of a less effective humoral (antibody, complement) immune response. Decreased transplacental transfer of protective maternal antibodies has consistently been observed among HEU newborns, suggesting that this may indeed be one of the key drivers of their susceptibility to infections with encapsulated bacteria. Reassuringly, HEU humoral response to vaccination appears to be well conserved. While there appears to be an increase in overall incidence of acute viral infections, no specific pattern of acute viral infections has emerged; and although there is evidence of increased chronic viral infection from perinatal transmission of hepatitis C and cytomegalovirus, no data exist to suggest an increase in adverse outcomes. Thus, no firm conclusions about antiviral effector mechanisms can be drawn. However, the most unusual of reported infections among the HEU have been opportunistic infections, suggesting the possibility of underlying defects in CD4 helper T cells and overall immune regulatory function. This may relate to the observation that the immunological profile of HEUs indicates a more activated T cell profile as well as a more inflammatory innate immune response. However, both of these observations appear transient, marked in early infancy, but no longer evident later in life. The causes of these early-life changes in immune profiles are likely multifactorial and may be related to in utero exposure to HIV, but also to increased environmental exposure to pathogens from sicker household contacts, in utero and postnatal antiretroviral drug exposure, and, in certain circumstances, differences in mode of feeding. The relative importance of each of these factors will be important to delineate in an attempt to identify those HEU at highest risk of adverse outcomes for targeted interventions.

Performing Drug Safety Research During Pregnancy and Lactation: Biomedical HIV Prevention Research as a Template

Evidence-based guidance regarding use of nearly all pharmaceuticals by pregnant and lactating women is limited. Models for performing research may assist in filling these knowledge gaps. Internationally, reproductive age women are at high risk of human immunodeficiency virus (HIV) acquisition. Susceptibility to HIV infection may be increased during pregnancy, and risk of maternal-child transmission is increased with incident HIV infection during pregnancy and lactation. A multidisciplinary meeting of experts was convened at the United States National Institutes of Health to consider paradigms for drug research in pregnancy and lactation applicable to HIV prevention. This report summarizes the meeting proceedings and describes a framework for research on candidate HIV prevention agent use during pregnancy and lactation that may also have broader applications to other pharmaceutical products.

Comparative cost-effectiveness of Option B+ for prevention of mother-to-child transmission of HIV in Malawi

OBJECTIVE

To estimate the cost-effectiveness of prevention of mother-to-child transmission (MTCT) of HIV with lifelong antiretroviral therapy (ART) for pregnant and breastfeeding women ('Option B+') compared with ART during pregnancy or breastfeeding only unless clinically indicated ('Option B').

DESIGN

Mathematical modelling study of first and second pregnancy, informed by data from the Malawi Option B+ programme.

METHODS

Individual-based simulation model. We simulated cohorts of 10 000 women and their infants during two subsequent pregnancies, including the breastfeeding period, with either Option B+ or B. We parameterized the model with data from the literature and by analysing programmatic data. We compared total costs of antenatal and postnatal care, and lifetime costs and disability-adjusted life-years of the infected infants between Option B+ and Option B.

RESULTS

During the first pregnancy, 15% of the infants born to HIV-infected mothers acquired the infection. With Option B+, 39% of the women were on ART at the beginning of the second pregnancy, compared with 18% with Option B. For second pregnancies, the rates MTCT were 11.3% with Option B+ and 12.3% with Option B. The incremental cost-effectiveness ratio comparing the two options ranged between about US$ 500 and US$ 1300 per DALY averted.

CONCLUSION

Option B+ prevents more vertical transmissions of HIV than Option B, mainly because more women are already on ART at the beginning of the next pregnancy. Option B+ is a cost-effective strategy for PMTCT if the total future costs and lost lifetime of the infected infants are taken into account.

Evaluation of factors associated with vertical HIV-1 transmission

OBJECTIVE

To compare the prevalence and factors associated with vertical transmission of human immunodeficiency virus 1 (HIV-1) among pregnant women treated in the periods of 1998-2004 and 2005-2011 in a reference service for the care of HIV-infected patients in southern Brazil.

METHODS

This was a descriptive and analytical study that used the databases of laboratories from the CD4 and STDs/AIDS Viral Load National Laboratory Network of the Brazilian Ministry of Health. HIV-1-infected pregnant women were selected after an active search for clinical information and obstetric and neonatal data from their medical records between the years of 1998 and 2011.

RESULTS

102 pregnant women were analyzed between 1998 and 2004 and 251 in the period between 2005 and 2011, totaling 353 children born to pregnant women with HIV-1. It was observed that the vertical transmission rate was 11.8% between 1998 and 2004 and 3.2% between 2005 and 2011 (p<0.001). The increased use of antiretroviral drugs (p=0.02), the decrease in viral load (p<0.001), and time of membrane rupture lower than 4h (p<0.001) were associated with the decrease of vertical transmission factors when comparing the two periods.

CONCLUSION

It was observed a decrease in the rate of vertical transmission in recent years. According to the studied variables, is suggested that the risk factors for vertical transmission of HIV-1 were absence of antiretroviral therapy, high viral load in the pregnant women, and membrane rupture time >4h.

Non-Cationic Proteins Are Associated with HIV Neutralizing Activity in Genital Secretions of Female Sex Workers

Objective

Cationic proteins found in cervicovaginal secretions (CVS) are known to contribute to the early antiviral immune response against HIV-infection in vitro. We here aimed to define additional antiviral factors that are over-expressed in CVS from female sex workers at high risk of infection.

Methods

CVS were collected from Kenyan HIV-seronegative (n = 34) and HIV-seropositive (n = 12) female sex workers, and were compared with those from HIV-seronegative low-risk women (n = 12). The highly exposed seronegative (HESN) sex workers were further divided into those with less (n = 22) or more (n = 12) than three years of documented sex work. Cationic protein-depleted CVS were assessed for HIV-neutralizing activity by a PBMC-based HIV-neutralizing assay, and then characterized by proteomics.

Results

HIV neutralizing activity was detected in all unprocessed CVS, however only CVS from the female sex worker groups maintained its HIV neutralizing activity after cationic protein-depletion. Differentially abundant proteins were identified in the cationic protein-depleted secretions including 26, 42, and 11 in the HESN>3yr, HESN<3yr, and HIV-positive groups, respectively. Gene ontology placed these proteins into functional categories including proteolysis, oxidation-reduction, and epidermal development. The proteins identified in this study include proteins previously associated with the HESN phenotype in other cohorts as well as novel proteins not yet associated with anti-HIV activities.

Conclusion

While cationic proteins appear to contribute to the majority of the intrinsic HIV neutralizing activity in the CVS of low-risk women, a broader range of non-cationic proteins were associated with HIV neutralizing activity in HESN and HIV-positive female sex workers. These results indicate that novel protein factors found in CVS of women with high-risk sexual practices may have inherent antiviral activity, or are involved in other aspects of anti-HIV host defense, and warrant further exploration into their mode of action.

Natural killer cell and T-cell subset distributions and activation influence susceptibility to perinatal HIV-1 infection

OBJECTIVE

To determine neonatal immunologic factors that correlate with mother-to-child-transmission of HIV-1.

DESIGN

This case-control study compared cord blood natural killer (NK) and T-cell populations of HIV-1 exposed infants who subsequently acquired infection by 1 month (cases) to those who remained uninfected by 1 year of life (controls). Control specimens were selected by proportional match on maternal viral load.

METHODS

Cryopreserved cord blood mononuclear cells (CBMCs) were thawed and stained for multiparameter flow cytometry to detect NK and T-cell subsets and activation status. CBMCs were also used in a viral suppression assay to evaluate NK cell inhibition of HIV-1 replication in autologous CD4 T cells.

RESULTS

Cord blood from cases contained a skewed NK cell repertoire characterized by an increased proportion of CD16CD56 NK cells. In addition, cases displayed less-activated CD16CD56 NK cells and CD8 T cells, based on HLA-DRCD38 costaining. NK cell suppression of HIV-1 replication ex vivo correlated with the proportion of acutely activated CD68CD16CD56 NK cells. Finally, we detected a higher proportion of CD27CD45RA effector memory CD4 and CD8 T cells in cord blood from cases compared with controls.

CONCLUSION

When controlled for maternal viral load, cord blood from infants who acquired HIV-1 had a higher proportion of CD16CD56 NK cells, lower NK cell activation and higher levels of mature T cells (potential HIV-1 targets) than control infants who remained uninfected. Our data provide evidence that infant HIV-1 acquisition may be influenced by both innate and adaptive immune cell phenotypes and activation status.

Presence of CD8+ T cells in the ectocervical mucosa correlates with genital viral shedding in HIV-infected women despite a low prevalence of HIV RNA-expressing cells in the tissue

The female genital tract is a portal of entry for sexual HIV transmission and a possible viral reservoir. In this study, the ectocervical CD8+ T cell distribution was explored in situ and was related to expression of CD3 and HLA-DR and presence of HIV RNA. For this purpose, ectocervical tissue samples and genital secretions were collected from HIV-seropositive (HIV+) Kenyan female sex workers (FSWs) (n = 20), HIV-seronegative (HIV-) FSWs (n = 17), and HIV(-) lower-risk women (n = 21). Cell markers were assessed by in situ staining and by quantitative PCR. HIV RNA expression in tissue was analyzed by in situ hybridization, and viral shedding was assessed by quantitative PCR. The HIV+ FSW group had a higher amount of total cells and CD8+, CD3+, and HLA-DR+ cells compared with the HIV(-)FSW group and HIV- lower-risk women. The majority of CD8+ cells were CD3+ T cells, and the numbers of CD8+ cells correlated significantly with plasma and cervical viral load. HIV RNA expression in situ was found in 4 of the 20 HIV+FSW women but did not correlate with cervical or plasma viral load. Thus, the HIV+ women displayed high numbers of CD8+, CD3+, and HLA-DR+ cells, as well as a limited number of HIV RNA+ cells, in their ectocervical mucosa; hence, this localization cannot be neglected as a potential viral reservoir. The elevated levels of CD8+ T cells may play a role in the immunopathogenesis of HIV in the female genital tract.

Infant feeding counselling of HIV-infected women in two areas in Kenya in 2008

While WHO no longer recommends individual infant feeding counselling to HIV-positive women, it may still be practised in some settings and for specific cases. In any case, lessons can be learned by examining how well front line health workers are able to take on counselling tasks. This qualitative study was designed to assess how counsellors deal with challenges they face in two Kenyan provinces. It consisted of brief post-counselling exit interviews with 80 mothers, observations of 21 counselling sessions and 11 key informant interviews. Much infant feeding counselling was of reasonable quality, better than often reported elsewhere. However, nutrition and infant feeding were given low priority, counsellors' training was inadequate, individual postnatal counselling as well as growth monitoring and promotion were rarely done and complementary feeding was inadequately covered. Acceptable, feasible, affordable, sustainable and safe (AFASS) assessments were not of satisfactory quality. Breast milk expression was mentioned only to a minority and the possibility of heat treatment during the transition to cessation was not mentioned. Counsellors were often biased in discussing risks of breastfeeding and replacement feeding. Implementing the new WHO guidance will reduce the need for AFASS assessments, greatly simplifying both the government's and counsellors' tasks.

The oral mucosa immune environment and oral transmission of HIV/SIV

The global spread of human immunodeficiency virus (HIV) is dependent on the ability of this virus to efficiently cross from one host to the next by traversing a mucosal membrane. Unraveling how mucosal exposure of HIV results in systemic infection is critical for the development of effective therapeutic strategies. This review focuses on understanding the immune events associated with the oral route of transmission (via breastfeeding or sexual oral intercourse), which occurs across the oral and/or gastrointestinal mucosa. Studies in both humans and simian immunodeficiency virus (SIV) monkey models have identified viral changes and immune events associated with oral HIV/SIV exposure. This review covers our current knowledge of HIV oral transmission in both infants and adults, the use of SIV models in understanding early immune events, oral immune factors that modulate HIV/SIV susceptibility (including mucosal inflammation), and interventions that may impact oral HIV transmission rates. Understanding the factors that influence oral HIV transmission will provide the foundation for developing immune therapeutic and vaccine strategies that can protect both infants and adults from oral HIV transmission.

Immunology of pediatric HIV infection

Most infants born to human immunodeficiency virus (HIV)-infected women escape HIV infection. Infants evade infection despite an immature immune system and, in the case of breastfeeding, prolonged repetitive exposure. If infants become infected, the course of their infection and response to treatment differs dramatically depending upon the timing (in utero, intrapartum, or during breastfeeding) and potentially the route of their infection. Perinatally acquired HIV infection occurs during a critical window of immune development. HIV's perturbation of this dynamic process may account for the striking age-dependent differences in HIV disease progression. HIV infection also profoundly disrupts the maternal immune system upon which infants rely for protection and immune instruction. Therefore, it is not surprising that infants who escape HIV infection still suffer adverse effects. In this review, we highlight the unique aspects of pediatric HIV transmission and pathogenesis with a focus on mechanisms by which HIV infection during immune ontogeny may allow discovery of key elements for protection and control from HIV.

Factors associated with HIV infection among children born to mothers on the prevention of mother to child transmission programme at Chitungwiza Hospital, Zimbabwe, 2008

Background

Zimbabwe is one of the five countries worst affected by the HIV/AIDS pandemic with HIV infection contributing increasingly to childhood morbidity and mortality. Among the children born to HIV positive mothers participating in the PMTCT programme, 25% tested positive to HIV. We investigated factors associated with HIV infection among children born to mothers on the PMTCT programme.

Methods

A 1:1 unmatched case–control study was conducted at Chitungwiza Hospital, Zimbabwe, 2008. A case was defined as a child who tested HIV positive, born to a mother who had been on PMTCT programme. A control was a HIV negative child born to a mother who had been on PMTCT programme. An interviewer-administered questionnaire was used to collect data on demographic characteristics, risk factors associated with HIV infection and immunization status.

Results

A total of 120 mothers were interviewed. Independent risk factors associated with HIV infection among children included maternal CD4 count of less than 200 during pregnancy [aOR = 7.1, 95% CI (2.6-17)], mixed feeding [aOR = 29, 95% CI (4.2-208)], being hospitalized since birth [aOR = 2.9, 95% CI (1.2-4.8)] whilst being exclusively breast fed for less than 6 months [aOR = 0.1 (95% CI 0.03-0.4)] was protective.

Conclusions

HIV infection among children increased if the mother’s CD4 count was ≤200 cells/μL and if the child was exposed to mixed feeding. Breastfeeding exclusively for less than six months was protective. We recommended exclusive breast feeding period for the first six months and stop breast feeding after 6 months if affordable, sustainable and safe.

Dynamics of breast milk HIV-1 RNA with unilateral mastitis or abscess

BACKGROUND

Mastitis and abscess in HIV-infected women increase the risk of breastfeeding transmission of HIV. Guidelines encourage women to stop breastfeeding on the affected breast and feed on the contralateral breast. However, impact of breast pathology on breast milk HIV dynamics is unknown.

METHODS

HIV RNA was quantified in 211 breast milk samples collected before, during, and after a clinical mastitis or an abscess diagnosis from 38 HIV-infected women participating in a Zambian breastfeeding study. HIV RNA quantity was compared between affected and unaffected breasts over time using generalized estimating equation models. A sample of 115 women without breast pathology was selected as a control group.

RESULTS

In the affected breast, breast milk HIV RNA quantity increased from the pre- to during-pathology period by log(10) 0.45 copies per milliliter [95% confidence interval (CI): 0.16 to 0.74], and after symptom resolution, HIV RNA levels were no different from prepathology levels (log10 -0.04 copies per milliliter 95% CI: -0.33 to 0.25). In the contralateral, unaffected breast, HIV RNA quantity did not significantly increase (log(10) 0.15 copies per milliliter, 95% CI: -0.41 to 0.10). Increase was more marked in women with abscess or with a greater number of mastitis symptoms. HIV RNA was not significantly different between affected and unaffected women, except at the time of diagnosis.

CONCLUSIONS

Breast milk HIV RNA increased modestly in the affected breast with unilateral mastitis or abscess and returned to prepathology levels with symptom resolution. Contralateral HIV RNA was not affected. Results support guidelines encouraging feeding from the contralateral breast to minimize the risk of HIV transmission associated with unilateral breast pathology.

Lack of B cell dysfunction is associated with functional, gp120-dominant antibody responses in breast milk of simian immunodeficiency virus-infected African green monkeys

The design of an effective vaccine to reduce the incidence of mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) via breastfeeding will require identification of protective immune responses that block postnatal virus acquisition. Natural hosts of simian immunodeficiency virus (SIV) sustain nonpathogenic infection and rarely transmit the virus to their infants despite high milk virus RNA loads. This is in contrast to HIV-infected women and SIV-infected rhesus macaques (RhMs), nonnatural hosts which exhibit higher rates of postnatal virus transmission. In this study, we compared the systemic and mucosal B cell responses of lactating, SIV-infected African green monkeys (AGMs), a natural host species, to that of SIV-infected RhMs and HIV-infected women. AGMs did not demonstrate hypergammaglobulinemia or accumulate circulating memory B cells during chronic SIV infection. Moreover, the milk of SIV-infected AGMs contained higher proportions of naive B cells than RhMs. Interestingly, AGMs exhibited robust milk and plasma Env binding antibody responses that were one to two logs higher than those in RhMs and humans and demonstrated autologous neutralizing responses in milk at 1 year postinfection. Furthermore, the plasma and milk Env gp120-binding antibody responses were equivalent to or predominant over Env gp140-binding antibody responses in AGMs, in contrast to that in RhMs and humans. The strong gp120-specific, functional antibody responses in the milk of SIV-infected AGMs may contribute to the rarity of postnatal transmission observed in natural SIV hosts.

The role of co-infections in mother-to-child transmission of HIV

In HIV-infected women, co-infections that target the placenta, fetal membranes, genital tract, and breast tissue, as well as systemic maternal and infant infections, have been shown to increase the risk for mother-to-child transmission of HIV (MTCT). Active co-infection stimulates the release of cytokines and inflammatory agents that enhance HIV replication locally or systemically and increase tissue permeability, which weakens natural defenses to MTCT. Many maternal or infant co-infections can affect MTCT of HIV, and particular ones, such as genital tract infection with herpes simplex virus, or systemic infections such as hepatitis B, can have substantial epidemiologic impact on MTCT. Screening and treatment for co-infections that can make infants susceptible to MTCT in utero, peripartum, or postpartum can help reduce the incidence of HIV infection among infants and improve the health of mothers and infants worldwide.

Feasibility and safety of cervical biopsy sampling for mucosal immune studies in female sex workers from Nairobi, Kenya

BACKGROUND

There is an urgent need to improve our understanding of the mucosal immuno-pathogenesis of HIV acquisition in the female genital tract, particularly in high-risk women such as female sex workers (FSWs). Cervical biopsy samples offer technical advantages over cytobrush sampling, but there are concerns that this might increase HIV acquisition, particularly if healing is slow and/or women do not abstain from sex during healing.

METHODOLOGY/PRINCIPAL FINDINGS

Cervical biopsy samples and cervico-vaginal swabs for co-infection diagnostics, prostate specific antigen (PSA) and immune studies were collected from 59 women, including HIV seropositive and HIV-exposed seronegative (HESN) FSWs as well as lower risk women from Nairobi, Kenya. A clinical-demographic questionnaire was administered and women were instructed to avoid sexual intercourse, douching and the insertion of tampons for 14 days. All participants underwent a repeat exam to assess healing within the 14 days, and had HIV diagnostics at six months. Cervical sampling was well tolerated, and 82% of participants had healed macroscopically by 5 days. Both self-report and PSA screening suggested high levels of compliance with pre- and post-procedure abstinence. Delayed healing was associated with vulvovaginal candidiasis (VVC) and HESN status. At six-month follow up all low-risk and HESN participants remained HIV seronegative.

CONCLUSION

Cervical biopsy sampling is a safe and well-tolerated method to obtain cervical biopsies in this context, particularly if participants with VVC are excluded. As healing could be delayed up to 11 days, it is important to support (both financially and with rigorous counseling) a period of post-procedure abstinence to minimize HIV risk.

Immunology of infants through adolescents: responses to emulate for HIV vaccines

PURPOSE OF REVIEW

The major target groups for an HIV vaccine include breastfeeding infants and adolescents. Differential immune maturity in these age groups may significantly impact vaccine efficacy, and should be taken into account when developing vaccines. Here we review these differences, with an emphasis on the immune response to vaccines for HIV and other pathogens. Recommendations for potential adaptation of current HIV vaccines are also made.

RECENT FINDINGS

An effective neonatal vaccine needs to be immunogenic in the presence of maternal antibody, and must induce cytotoxic T-lymphocyte responses, neutralizing antibody responses, both systemic and mucosal. There is renewed hope in the possibility of stimulating neutralizing antibodies with HIV vaccination. DNA vaccines are promising for neonates, but will need appropriate boosting. Certain adjuvants and vector delivery systems are more suitable for neonates. Adolescents may have stronger immune responses to HIV vaccines than adults, and will also require induction of mucosal neutralizing humoral and cellular immunity.

SUMMARY

Some current HIV vaccine strategies may need adaptation for neonates and suitable product development should be accelerated. Vaccines could induce better responses in adolescents and therefore should not be discarded prematurely. Development of vaccines that have potential for these age groups is an urgent global priority.

Surgical implications of human immunodeficiency virus infections

Pediatric HIV (human immunodeficiency virus) is a pandemic predominantly in sub-Saharan Africa. Approximately 2.2 million children aged less than 15 years are infected with HIV, representing almost 95% of the total number of children globally infected with HIV. Therefore, increasing numbers of HIVi or -exposed but uninfected children can be expected to require a surgical procedure to assist in the diagnosis of an HIV/acquired immune deficiency syndrome-related complication, to address a life-threatening complication of the disease, or for routine surgery encountered in HIV-unexposed children. HIVi children may present with both conditions unique to HIV infection and surgical conditions routine in pediatric surgical practice. HIV exposure confers an increased risk of complications and mortality for all children after surgery, whether they are HIV infected or not. This risk of complications is higher in the HIVi group of patients. These findings seem to be independent of whether patients undergo an elective or emergency procedure, but the risk of an adverse outcome is higher for a major procedure. Surgical implications of HIV infection are comprehensively reviewed in this article.

The contribution of maternal HIV seroconversion during late pregnancy and breastfeeding to mother-to-child transmission of HIV

BACKGROUND

The prevention of mother-to-child transmission (PMTCT) of HIV has been focused mainly on women who are HIV positive at their first antenatal visit, but there is uncertainty regarding the contribution to overall transmission from mothers who seroconvert after their first antenatal visit and before weaning.

METHOD

A mathematical model was developed to simulate changes in mother-to-child transmission of HIV over time, in South Africa. The model allows for changes in infant feeding practices as infants age, temporal changes in the provision of antiretroviral prophylaxis and counseling on infant feeding, as well as temporal changes in maternal HIV prevalence and incidence.

RESULTS

The proportion of mother-to-child transmission (MTCT) from mothers who seroconverted after their first antenatal visit was 26% [95% confidence interval (CI): 22% to 30%] in 2008, or 15,000 of 57,000 infections. It is estimated that by 2014, total MTCT will reduce to 39,000 per annum, and transmission from mothers seroconverting after their first antenatal visit will reduce to 13,000 per annum, accounting for 34% (95% CI: 29% to 39%) of MTCT. If maternal HIV incidence during late pregnancy and breastfeeding were reduced by 50% after 2010, and HIV screening were repeated in late pregnancy and at 6-week immunization visits after 2010, the average annual number of MTCT cases over the 2010-2015 period would reduce by 28% (95% CI: 25% to 31%), from 39,000 to 28,000 per annum.

CONCLUSION

Maternal seroconversion during late pregnancy and breastfeeding contributes significantly to the pediatric HIV burden and needs greater attention in the planning of prevention of MTCT programs.

Infant feeding practice and associated factors of HIV positive mothers attending prevention of mother to child transmission and antiretroviral therapy clinics in Gondar Town health institutions, Northwest Ethiopia

Background

It has been estimated that 430,000 children under 15 years of age were newly infected with HIV in 2008, and more than 71% are living in sub-Saharan Africa. In the absence of intervention to prevent mother-to-child transmission, 30-45% of infants born to HIV-positive mothers in developing countries become infected during pregnancy, delivery and breastfeeding. The aim of this study was to assess infant feeding practice and associated factors of HIV positive mothers attending prevention of mother to child transmission and antiretroviral therapy clinics of Northwest Ethiopia.

Methods

Institution based cross sectional study was conducted from January to May 2011 among all HIV positive mothers with less than two years old child attending prevention of mother to child transmission and antiretroviral therapy clinics in Gondar Town health institutions. A structured pre-tested questionnaire using interview technique was used for data collection. The data was entered and analyzed using SPSS version 16 statistical package.

Results

A total of 209 HIV positive mothers were included in the study. Of these, 187 (89.5%) had followed the recommended way of infant feeding practice while significant percentage (10.5%) had practiced mixed breast feeding. In multivariate analysis, disclosure of HIV status with their spouse, insufficient breast milk and occupational status were found to be independently associated (p-value of < 0.05) with recommended infant feeding practice. Lack of resource, stigma of HIV/AIDS, and husband opposition were also obtained as factors that influenced choice of infant feeding options by respondents.

Conclusions

Higher proportion of respondents used the recommended way of infant feeding practice by WHO as well as by Ethiopian Ministry of Health. However, mixed feeding in the first 6 months of age, an undesirable practice in infant feeding, were reported in this study. Infant feeding education that is aligned to national policy should be strengthened in primary health care, particularly in situations where prevention of mother to child transmission of HIV is prioritized.

Mother's CD4+ count moderates the risk associated with higher parity for late postnatal HIV-free survival of breastfed children: an individual patient data meta-analysis of randomized controlled trials

Risk association studies of late postnatal outcomes for children breastfed by HIV-1 positive mothers have had inconsistent findings and have not explored interactions among risk factors. This study addresses these limitations through an individual patient data (IPD) meta-analysis of HIV-free survival outcomes of nine randomized controlled trials to prevent early mother-to-child transmission of HIV-1. The pooled sample consisted of 3,324 African children in resource-limited settings who survived to age 28 days and were at-risk of acquiring HIV through breast milk. Based on a proportional hazards mixed effects meta-analysis, the composite endpoint of HIV-1 infection and all-cause mortality was found to be significantly associated with maternal immune status (CD4(+) ≥350 cells/mm(3), HR 0.59 95% CI (0.39, 0.87)), infant preterm delivery (gestational age <37 weeks, 1.40 (1.03, 1.89)), infant oral candidiasis infection (1.87, (1.53, 2.29)), and occurrence of breast abnormality before breastfeeding cessation (2.56 (1.90, 3.46)). A significant interaction between mother's parity (any previous pregnancy) and CD4(+) count ≥350 (HR 0.63 (0.40, 0.99), P-value = 0.045) suggested that higher CD4(+) count offsets the risk associated with higher parity. Further research is needed to elucidate the moderating effect of immune status on the risk associated with high parity and adverse late postnatal outcomes for infants breastfed by HIV-infected mothers in the absence of antiretroviral treatment.

Human immunodeficiency virus type 1 mother-to-child transmission and prevention: successes and controversies

The World Health Organization (WHO) and United Nations Programme on HIV/AIDS (UNAIDS) estimated that an additional 370 000 new human immunodeficiency virus type 1 (HIV-1) infections occurred in children in 2009, mainly through mother-to-child transmission (MTCT). Intrapartum transmission contributes to approximately 20-25% of infections, in utero transmission to 5-10% and postnatal transmission to an additional 10-15% of cases. MTCT accounts for only a few hundred infected newborns in those countries in which services are established for voluntary counselling and testing of pregnant women, and a supply of antiretroviral drugs is available throughout pregnancy with recommendations for elective Caesarean section and avoidance of breastfeeding. The single-dose nevirapine regimen has provided the momentum to initiate MTCT programmes in many resource-limited countries; however, regimens using a combination of antiretroviral drugs are needed also to effectively reduce transmission via breastfeeding.

Host factors that influence mother-to-child transmission of HIV-1: genetics, coinfections, behavior and nutrition

Mother-to-child transmission (MTCT) is the most important mode of HIV-1 acquisition among infants and children and it can occur in utero, intrapartum and postnatally through breastfeeding. Great progress has been made in preventing MTCT through use of antiretroviral regimens during gestation, labor/delivery and breastfeeding. The mechanisms of MTCT, however, are multifactorial and remain incompletely understood. This review focuses on select host factors affecting MTCT, in particular genetic factors, coexisting infections, behavioral factors and nutrition. Whereas much emphasis has been placed on decreasing maternal HIV-1 viral load, an important determinant of MTCT, through use of antiretroviral agents, complementary focus on overall maternal health is often neglected. By addressing coinfections in mothers and infants, improving the mother's nutritional status and modifying risky behaviors and practices, not only is maternal and child health improved, but a direct benefit in reducing MTCT can be derived. The study of genetic variations in susceptibility to HIV-1 infection is rapidly evolving, and the future is likely to bring revolutionary changes in HIV-1 prevention by enhancing natural resistance to infection and by individually tailoring pharmacologic regimens.

Exclusive breastfeeding, maternal HIV disease, and the risk of clinical breast pathology in HIV-infected, breastfeeding women

OBJECTIVE

The objective of the study was to examine the relationship between breastfeeding patterns, markers of maternal human immunodeficiency virus (HIV) disease, and woman's breast pathology.

STUDY DESIGN

Secondary data analysis from a randomized breastfeeding trial including 947 HIV-infected women (n = 5982 visits) from breastfeeding initiation until 6 months postpartum; 1 month after breastfeeding cessation; or loss to follow-up or death. Generalized estimating equations assessed the effects of breastfeeding pattern and maternal HIV status on breast pathology.

RESULTS

One hundred ninety women (20.1%) had a breast problem; 86 (9.1%) had mastitis; and 31 (3.3%) had abscess. After confounder adjustment, nonexclusively breastfeeding women had an increased risk of breast problems (odds ratio, 1.98; 95% confidence interval, 1.33-2.95) and mastitis (odds ratio, 2.87, 95% confidence interval, 1.69-4.88) compared with exclusive breastfeeders. Women with a CD4 count less than 200 cells/μL tended to have an increased risk of abscess.

CONCLUSION

Nonexclusive breastfeeding significantly increased the risk of breast pathology. Exclusive breastfeeding is not only optimal for infant health but it also benefits mothers by reducing breast problems.

The magnitude and kinetics of the mucosal HIV-specific CD8+ T lymphocyte response and virus RNA load in breast milk

BACKGROUND

The risk of postnatal HIV transmission is associated with the magnitude of the milk virus load. While HIV-specific cellular immune responses control systemic virus load and are detectable in milk, the contribution of these responses to the control of virus load in milk is unknown.

METHODS

We assessed the magnitude of the immunodominant GagRY11 and subdominant EnvKY9-specific CD8+ T lymphocyte response in blood and milk of 10 A*3002+, HIV-infected Malawian women throughout the period of lactation and correlated this response to milk virus RNA load and markers of breast inflammation.

RESULTS

The magnitude and kinetics of the HIV-specific CD8+ T lymphocyte responses were discordant in blood and milk of the right and left breast, indicating independent regulation of these responses in each breast. However, there was no correlation between the magnitude of the HIV-specific CD8+ T lymphocyte response and the milk virus RNA load. Further, there was no correlation between the magnitude of this response and markers of breast inflammation.

CONCLUSIONS

The magnitude of the HIV-specific CD8+ T lymphocyte response in milk does not appear to be solely determined by the milk virus RNA load and is likely only one of the factors contributing to maintenance of low virus load in milk.

Outcome of HIV-exposed uninfected children undergoing surgery

BACKGROUND

HIV-exposed uninfected (HIVe) children are a rapidly growing population that may be at an increased risk of illness compared to HIV-unexposed children (HIVn). The aim of this study was to investigate the morbidity and mortality of HIVe compared to both HIVn and HIV-infected (HIVi) children after a general surgical procedure.

METHODS

A prospective study of children less than 60 months of age undergoing general surgery at a paediatric referral hospital from July 2004 to July 2008 inclusive. Children underwent age-definitive HIV testing and were followed up post operatively for the development of complications, length of stay and mortality.

RESULTS

Three hundred and eighty children were enrolled; 4 died and 11 were lost to follow up prior to HIV testing, thus 365 children were included. Of these, 38(10.4%) were HIVe, 245(67.1%) were HIVn and 82(22.5%) were HIVi children.The overall mortality was low, with 2(5.2%) deaths in the HIVe group, 0 in the HIVn group and 6(7.3%) in the HIVi group (p = 0.0003). HIVe had a longer stay than HIVn children (3 (2-7) vs. 2 (1-4) days p = 0.02). There was no significant difference in length of stay between the HIVe and HIVi groups. HIVe children had a higher rate of complications compared to HIVn children, (9 (23.7%) vs. 14(5.7%) (RR 3.8(2.1-7) p < 0.0001) but a similar rate of complications compared to HIVi children 34 (41.5%) (RR = 0.6 (0.3-1.1) p = 0.06).

CONCLUSION

HIVe children have a higher risk of developing complications and mortality after surgery compared to HIVn children. However, the risk of complications is lower than that of HIVi children.

High cell-free virus load and robust autologous humoral immune responses in breast milk of simian immunodeficiency virus-infected african green monkeys

The design of immunologic interventions to prevent postnatal transmission of human immunodeficiency virus (HIV) will require identification of protective immune responses in this setting. Simian immunodeficiency virus (SIV)-infected rhesus monkeys (RMs), a species that develops an AIDS-like illness following experimental infection, transmit the virus at a high rate during breastfeeding. In contrast, postnatal transmission of SIV occurs rarely or not at all in natural, asymptomatic primate hosts of SIV. These contrasting transmission patterns provide a unique opportunity to study mechanisms that evolved to protect suckling infants from SIV infection. We compared the virologic and immunologic properties of milk of SIV-infected and uninfected natural hosts of SIV, African green monkeys (AGMs), to that of RMs. Interestingly, despite a low number of milk CD4(+) T lymphocytes in uninfected AGMs, milk virus RNA load in SIV-infected AGMs was comparable to that of SIV-infected RMs and that in AGM plasma. This observation is in contrast to the relatively low virus load in milk compared to that in plasma of SIV-infected RMs and HIV-infected women. Milk of SIV-infected AGMs also displayed robust virus-specific cellular immune responses. Importantly, an autologous challenge virus-specific neutralization response was detected in milk of five of six SIV-infected AGMs that was comparable in magnitude to that in plasma. In contrast, autologous challenge virus neutralization was not detectable in milk of SIV-infected RMs. The autologous virus-specific adaptive immune responses in breast milk of AGMs may contribute to impedance of virus transmission in the infant oral/gastrointestinal tract and the rarity of postnatal virus transmission in natural hosts of SIV.

Current knowledge and future research on infant feeding in the context of HIV: basic, clinical, behavioral, and programmatic perspectives

In 2008, between 129,000 and 194,000 of the 430,000 pediatric HIV infections worldwide were attributable to breastfeeding. Yet in many settings, the health, economic, and social consequences of not breastfeeding would have dire consequences for many more children. In the first part of this review we provide an overview of current knowledge about infant feeding in the context of HIV. Namely, we describe the benefits and risks of breastmilk, the evolution of recommended infant feeding modalities in high-income and low-income countries in the last two decades, and contextualize the recently revised guidelines for infant feeding in the context of HIV current knowledge. In the second section, we suggest areas for future research on the postnatal prevention of mother-to-child transmission of HIV (PMTCT) in developing and industrialized countries. We suggest two shifts in perspective. The first is to evaluate PMTCT interventions more holistically, to include the psychosocial and economic consequences as well as the biomedical ones. The second shift in perspective should be one that contextualizes postnatal PMTCT efforts in the cascade of maternal health services. We conclude by discussing basic, clinical, behavioral, and programmatic research questions pertaining to a number of PMTCT efforts, including extended postnatal ARV prophylaxis, exclusive breastfeeding promotion, counseling, breast milk pasteurization, breast milk banking, novel techniques for making breast milk safer, and optimal breastfeeding practices. We believe the research efforts outlined here will maximize the number of healthy, thriving, HIV-free children around the world.

New approaches to Candida and oral mycotic infections: Workshop 2A

This workshop reviewed aspects of the following: oral fungal disease in HIV-infected patients and the predictive value of oral mucosal disease in HIV progression; the role of the oral biofilms in mucosal disease; microbial virulence factors and the pseudomembranous oral mucosal disease process; the role that oral mucosal disease may have in HIV transmission; and the available topical antifungal treatment. This article summarizes the ensuing discussions and raises pertinent problems and potential research directions associated with oral fungal disease in HIV-infected patients, including the frequency of oral candidosis, the role of the intraoral biofilm in the development of oral mucosal disease, and host-pathogen interactions, as well as the development of the fetal oral mucosa, neonatal nutrition, and the role of oral candidosis in this setting. Finally, discussions are summarized on the use of inexpensive effective antifungal mouthwashes in resource-poor countries, the potential stigmata that may be associated with their use, as well as novel topical medications that may have clinical applicability in managing oral candidal infections in HIV-infected patients.

Origin and evolution of HIV-1 in breast milk determined by single-genome amplification and sequencing

HIV transmission via breastfeeding accounts for a considerable proportion of infant HIV acquisition. However, the origin and evolution of the virus population in breast milk, the likely reservoir of transmitted virus variants, are not well characterized. In this study, HIV envelope (env) genes were sequenced from virus variants amplified by single-genome amplification from plasmas and milk of 12 chronically HIV-infected, lactating Malawian women. Maximum likelihood trees and statistical tests of compartmentalization revealed interspersion of plasma and milk HIV env sequences in the majority of subjects, indicating limited or no compartmentalization of milk virus variants. However, phylogenetic tree analysis further revealed monotypic virus variants that were significantly more frequent in milk (median proportion of identical viruses, 29.5%; range, 0 to 61%) than in plasma (median proportion of identical viruses, 0%; range, 0 to 26%) (P = 0.002), suggesting local virus replication in the breast milk compartment. Moreover, clonally amplified virus env genes in milk produced functional virus Envs that were all CCR5 tropic. Milk and plasma virus Envs had similar predicted phenotypes and neutralization sensitivities to broadly neutralizing antibodies in both transmitting and nontransmitting mothers. Finally, phylogenetic comparison of longitudinal milk and plasma virus env sequences revealed synchronous virus evolution and new clonal amplification of evolved virus env genes in milk. The limited compartmentalization and the clonal amplification of evolving, functional viruses in milk indicate continual seeding of the mammary gland by blood virus variants, followed by transient local replication of these variants in the breast milk compartment.

Perinatal HIV and its prevention: progress toward an HIV-free generation

This article reviews the epidemiology of perinatal (HIV)-1 in the United States in the past 2 decades and the international HIV epidemic among pregnant women and their infants. Since the peak of 1700 reported cases of pediatric AIDS in 1992, there has been dramatic progress in decreasing perinatal HIV transmission in the United States with fewer than 50 new cases of AIDS annually (>96% reduction) and fewer than 300 annual perinatal HIV transmissions in 2005. This success has been due to use of combination antiretrovirals given to mothers during pregnancy and labor/delivery, obstetric interventions that reduce the risk of transmission, provision of zidovudine (ZDV) prophylaxis for 6 weeks to HIV-exposed newborns and use of formula. Internationally, the burden of mother-to-child HIV transmission remains heavy with 2.1 million children less than 15 years of age estimated to be living with HIV and 430,000 new HIV infections in infants occurring each year, with most cases occurring in Africa. Current international efforts are directed at scaling up successful prevention of mother-to-child transmission interventions and new research directed at making breastfeeding safer using antiretroviral prophylaxis to either mothers or their infants.

HIV-1 and breastfeeding: biology of transmission and advances in prevention

Breastfeeding accounts for about 40% of mother-to-child transmission of HIV-1 worldwide and carries an estimated risk of transmission of 0.9% per month after the first month of breastfeeding. It is recommended that HIV-1-infected women completely avoid breastfeeding in settings where safe feeding alternatives exist. However, as replacement feeding is not safely available in many parts of the world, and because breastfeeding provides optimal nutrition and protection against other infant infections, there is intense ongoing research to make breastfeeding safe for HIV-1-infected mothers in resource-limited settings. More research is needed to determine the optimal duration of breastfeeding, optimal weaning practices, and which individual antiretroviral prophylactic regimen is best for HIV-1-infected mothers and their infants in a particular setting.

Bloody traditional procedures performed during infancy in the oropharyngeal area among HIV+ children: implication from the perspective of mother-to-child transmission of HIV

Although bloody traditional procedures are very common in Ethiopia, this is the first report on infants. None of the literature attributed such practices as risk factor for mother-to-child transmission (MTCT) of HIV. Analysis was done to 1,163 children and found that 552 (47.5%) bloody traditional procedures were performed in the oral cavity to 399 (34.3%): uvulectomy 41.8%, milk tooth extraction 33.7% and tonsillectomy 24.5%. Multinomial logistic regression showed strong association of uvulectomy with Tigray ethnicity. Milk teeth extractions were highest among girls, rural residence, Tigray and Amhara ethnicity. When procedures performed, children were under 1 month (88.9% of tonsillectomies), under 6 months (83.5% of uvulectomies) and 4-6 months (54.3% of milk tooth extractions) of age. More than 97% for whom procedures performed were breast fed, and about 88% were from the northern part of the country. Taking into account the deep invasiveness of the procedures, they are assumed as one of the strong risk factors for MTCT of HIV during lactation.

Mother-to-child transmission of HIV: pathogenesis, mechanisms and pathways

More than 400,000 children were infected with (HIV-1) worldwide in 2008, or more than 1000 children per day. Mother-to-child transmission (MTCT) of HIV-1 is the most important mode of HIV acquisition in infants and children. MTCT of HIV-1 can occur in utero, intrapartum, and postnatally through breastfeeding. Great progress has been made in preventing such transmission, through the use of antiretroviral prophylactic regimens to the mother during gestation and labor and delivery and to either mother or infant during breast feeding. The timing and mechanisms of transmission, however, are multifactorial and remain incompletely understood. This article summarizes what is known about the pathogenetic mechanisms and routes of MTCT of HIV-1, and includes virologic, immunologic, genetic, and mucosal aspects of transmission.

Robust vaccine-elicited cellular immune responses in breast milk following systemic simian immunodeficiency virus DNA prime and live virus vector boost vaccination of lactating rhesus monkeys

Breast milk transmission of HIV remains an important mode of infant HIV acquisition. Enhancement of mucosal HIV-specific immune responses in milk of HIV-infected mothers through vaccination may reduce milk virus load or protect against virus transmission in the infant gastrointestinal tract. However, the ability of HIV/SIV strategies to induce virus-specific immune responses in milk has not been studied. In this study, five uninfected, hormone-induced lactating, Mamu A*01(+) female rhesus monkey were systemically primed and boosted with rDNA and the attenuated poxvirus vector, NYVAC, containing the SIVmac239 gag-pol and envelope genes. The monkeys were boosted a second time with a recombinant Adenovirus serotype 5 vector containing matching immunogens. The vaccine-elicited immunodominant epitope-specific CD8(+) T lymphocyte response in milk was of similar or greater magnitude than that in blood and the vaginal tract but higher than that in the colon. Furthermore, the vaccine-elicited SIV Gag-specific CD4(+) and CD8(+) T lymphocyte polyfunctional cytokine responses were more robust in milk than in blood after each virus vector boost. Finally, SIV envelope-specific IgG responses were detected in milk of all monkeys after vaccination, whereas an SIV envelope-specific IgA response was only detected in one vaccinated monkey. Importantly, only limited and transient increases in the proportion of activated or CCR5-expressing CD4(+) T lymphocytes in milk occurred after vaccination. Therefore, systemic DNA prime and virus vector boost of lactating rhesus monkeys elicits potent virus-specific cellular and humoral immune responses in milk and may warrant further investigation as a strategy to impede breast milk transmission of HIV.

Vertical transmission of HIV-an update

One of the greatest successes in AIDS research to date has by far been the discovery of successful interventions that interrupt the transmission of HIV from mother to child. It is however important to note that these successes have occurred largely in countries with great resources and the least burden of perinatal transmission of HIV. In the developing world wherein currently 95% of vertical transmission of HIV occurs, it is highly condemnable that still every minute an infected infant is said to be born in spite of the fact that vertical transmission is largely preventable, mainly because translating knowledge into practice is not always possible or feasible; This has led to a continuous growing numbers of children with HIV, thereby making pediatric HIV a looming problem rapidly draining the already burdened health care system of these countries. It is the need of the hour to appropriately address the challenges to achieve zero percent transmission of HIV from an infected mother to her child thereby giving a hope for an AIDS-free new generation worldwide.