Modeling the effects of different infant feeding strategies on infant survival and mother-to-child transmission of HIV

Unique genotypic features of HIV-1 C gp41 membrane proximal external region variants during pregnancy relate to mother-to-child transmission via breastfeeding

Mother-to-child transmission (MTCT) through breastfeeding remains a major source of pediatric HIV-1 infection worldwide. To characterize plasma HIV-1 subtype C populations from infected mothers during pregnancy that related to subsequent breast milk transmission, an exploratory study was designed to apply next generation sequencing and a custom bioinformatics pipeline for HIV-1 gp41 extending from heptad repeat region 2 (HR2) through the membrane proximal external region (MPER) and the membrane spanning domain (MSD). MPER harbors linear and highly conserved epitopes that repeatedly elicits HIV-1 neutralizing antibodies with exceptional breadth. Viral populations during pregnancy from women who transmitted by breastfeeding, compared to those who did not, displayed greater biodiversity, more frequent amino acid polymorphisms, lower hydropathy index and greater positive charge. Viral characteristics were restricted to MPER, failed to extend into flanking HR2 or MSD regions, and were unrelated to predicted neutralization resistance. Findings provide novel parameters to evaluate an association between maternal MPER variants present during gestation and lactogenesis with subsequent transmission outcomes by breastfeeding.

IMPORTANCE

HIV-1 transmission through breastfeeding accounts for 39% of MTCT and continues as a major route of pediatric infection in developing countries where access to interventions for interrupting transmission is limited. Identifying women who are likely to transmit HIV-1 during breastfeeding would focus therapies, such as broad neutralizing HIV monoclonal antibodies (bn-HIV-Abs), during the breastfeeding period to reduce MTCT. Findings from our pilot study identify novel characteristics of gestational viral MPER quasispecies related to transmission outcomes and raise the possibility for predicting MTCT by breastfeeding based on identifying mothers with high-risk viral populations.

Optimal breastfeeding durations for HIV-exposed infants: the impact of maternal ART use, infant mortality and replacement feeding risk

INTRODUCTION

In 2010, the WHO recommended women living with HIV breastfeed for 12 months while taking antiretroviral therapy (ART) to balance breastfeeding benefits against HIV transmission risks. To inform the 2016 WHO guidelines, we updated prior research on the impact of breastfeeding duration on HIV-free infant survival (HFS) by incorporating maternal ART duration, infant/child mortality and mother-to-child transmission data.

METHODS

Using the Cost-Effectiveness of Preventing AIDS Complications (CEPAC)-Infant model, we simulated the impact of breastfeeding duration on 24-month HFS among HIV-exposed, uninfected infants. We defined "optimal" breastfeeding durations as those maximizing 24-month HFS. We varied maternal ART duration, mortality rates among breastfed infants/children, and relative risk of mortality associated with replacement feeding ("RRRF"), modelled as a multiplier on all-cause mortality for replacement-fed infants/children (range: 1 [no additional risk] to 6). The base-case simulated RRRF = 3, median infant mortality, and 24-month maternal ART duration.

RESULTS

In the base-case, HFS ranged from 83.1% (no breastfeeding) to 90.2% (12-months breastfeeding). Optimal breastfeeding durations increased with higher RRRF values and longer maternal ART durations, but did not change substantially with variation in infant mortality rates. Optimal breastfeeding durations often exceeded the previous WHO recommendation of 12 months.

CONCLUSIONS

In settings with high RRRF and long maternal ART durations, HFS is maximized when mothers breastfeed longer than the previously-recommended 12 months. In settings with low RRRF or short maternal ART durations, shorter breastfeeding durations optimize HFS. If mothers are supported to use ART for longer periods of time, it is possible to reduce transmission risks and gain the benefits of longer breastfeeding durations.

Individualizing the WHO HIV and infant feeding guidelines: optimal breastfeeding duration to maximize infant HIV-free survival

OBJECTIVES

To determine how infant feeding recommendations can maximize HIV-free survival (HFS) among HIV-exposed, uninfected African infants, balancing risks of breast milk-associated HIV infection with setting-specific risks of illness and death associated with replacement feeding.

DESIGN

Validated mathematical model of HIV-exposed, uninfected infants, with published data from Africa.

METHODS

We projected 24-month HFS using combinations of: maternal CD4, antiretroviral drug availability, and relative risk of mortality among replacement-fed compared to breastfed infants ('RR-RF', range 1.0-6.0). For each combination, we identified the 'optimal' breastfeeding duration (0-24 months) maximizing HFS. We compared HFS under an 'individualized' approach, based on the above parameters, to the WHO 'public health approach' (12 months breastfeeding for all HIV-infected women).

RESULTS

Projected HFS was 65-93%. When the value of RR-RF is 1.0, replacement feeding from birth maximized HFS. At a commonly reported RR-RF value (2.0), optimal breastfeeding duration was 3-12 months, depending on maternal CD4 and antiretroviral drug availability. As the value of RR-RF increased, optimal breastfeeding duration increased. Compared to the public health approach, an individualized approach improved absolute HFS by less than 1% if RR-RF value was 2.0-4.0, by 3% if RR-RF value was 1.0 or 6.0, and by greater amounts if access to antiretroviral drugs was limited.

CONCLUSION

Tailoring breastfeeding duration to maternal CD4, antiretroviral drug availability, and local replacement feeding safety can optimize HFS among HIV-exposed infants. An individualized approach leads to moderate gains in HFS, but only when mortality risks from replacement feeding are very low or very high, or antiretroviral drug availability is limited. The WHO public health approach is beneficial in most resource-limited settings.

Trends of early infant feedings practices after counseling in infant born to HIV positive women in Yaoundé, Cameroon

The objective is to describe the trends of infant feedings choices in HIV context after infant feeding counseling. Descriptive retrospective study: Infant feeding counseling (IFC) sessions were offered to HIV pregnant women by the same team of counselors from April 2008 to December 2012. Counseling content was promoting either exclusive breastfeeding (EBF) or exclusive formula feeding (EFF) prior to 2010. Later on, versus EBF+ antiretroviral (ARV) drug given either to the mother or the infant or EFF was the gold standard. Mixed feeding was prohibited. Infants feeding were practices recorded at the first post natal visit. Main measurement: rate of EBF/ EFF per year and period. We included a total of 1114 live-born babies. During the five year the overall rate of EBF and EFF stood at 41% and 59% respectively. The rate of EBF/EFF was recorded as follow: varies from 25/75% in year one to 52/48% in year five(p≤0.001). The rate of mixed was virtually cancelled during the same period, 3/237 (1.2%) in year one to period 1/165 (0.6%) in the latest period. In conclusion, in Yaoundé, there is a slight increase in breastfeeding rate among HIV exposed infants during the first two months of life. Further investigations are required to confirm this tendency and analyze the new features of breastfeeding practices.

The comparative cost-effectiveness of an equity-focused approach to child survival, health, and nutrition: a modelling approach

Progress on child mortality and undernutrition has seen widening inequities and a concentration of child deaths and undernutrition in the most deprived communities, threatening the achievement of the Millennium Development Goals. Conversely, a series of recent process and technological innovations have provided effective and efficient options to reach the most deprived populations. These trends raise the possibility that the perceived trade-off between equity and efficiency no longer applies for child health--that prioritising services for the poorest and most marginalised is now more effective and cost effective than mainstream approaches. We tested this hypothesis with a mathematical-modelling approach by comparing the cost-effectiveness in terms of child deaths and stunting events averted between two approaches (from 2011-15 in 14 countries and one province): an equity-focused approach that prioritises the most deprived communities, and a mainstream approach that is representative of current strategies. We combined some existing models, notably the Marginal Budgeting for Bottlenecks Toolkit and the Lives Saved Tool, to do our analysis. We showed that, with the same level of investment, disproportionately higher effects are possible by prioritising the poorest and most marginalised populations, for averting both child mortality and stunting. Our results suggest that an equity-focused approach could result in sharper decreases in child mortality and stunting and higher cost-effectiveness than mainstream approaches, while reducing inequities in effective intervention coverage, health outcomes, and out-of-pocket spending between the most and least deprived groups and geographic areas within countries. Our findings should be interpreted with caution due to uncertainties around some of the model parameters and baseline data. Further research is needed to address some of these gaps in the evidence base. Strategies for improving child nutrition and survival, however, should account for an increasing prioritisation of the most deprived communities and the increased use of community-based interventions.

Estimation of potential effects of improved community-based drug provision, to augment health-facility strengthening, on maternal mortality due to post-partum haemorrhage and sepsis in sub-Saharan Africa: an equity-effectiveness model

BACKGROUND

Maternal mortality in Africa has changed little since 1990. We developed a mathematical model with the aim to assess whether improved community-based access to life-saving drugs, to augment a core programme of health-facility strengthening, could reduce maternal mortality due to post-partum haemorrhage or sepsis.

METHODS

We developed a mathematical model by considering the key events leading to maternal death from post-partum haemorrhage or sepsis after delivery. With parameter estimates from published work of occurrence of post-partum haemorrhage and sepsis, case fatality, and the effectiveness of drugs, we used this model to estimate the effect of three potential packages of interventions: 1) health-facility strengthening; 2) health-facility strengthening combined with improved drug provision via antenatal-care appointments and community health workers; and 3) all interventions in package two combined with improved community-based drug provision via female volunteers in villages. The model was applied to Malawi and sub-Saharan Africa.

FINDINGS

In the implementation of the model, the lowest risk deliveries were those in health facilities. With the model we estimated that of 2860 maternal deaths from post-partum haemorrhage or sepsis per year in Malawi, intervention package one could prevent 210 (7%) deaths, package two 720 (25%) deaths, and package three 1020 (36%) deaths. In sub-Saharan Africa, we estimated that of 182 000 of such maternal deaths per year, these three packages could prevent 21 300 (12%), 43 800 (24%), and 59 000 (32%) deaths, respectively. The estimated effect of community-based drug provision was greatest for the poorest women.

INTERPRETATION

Community provision of misoprostol and antibiotics to reduce maternal deaths from post-partum haemorrhage and sepsis could be a highly effective addition to health-facility strengthening in Africa. Investigation of such interventions is urgently needed to establish the risks, benefits, and challenges of widespread implementation.

FUNDING

Institute of Child Health and Faculty of Mathematical and Physical Sciences, University College London, and a donation from John and Ann-Margaret Walton.

Breast milk as the "water that supports and preserves life"--socio-cultural constructions of breastfeeding and their implications for the prevention of mother to child transmission of HIV in sub-Saharan Africa

OBJECTIVES

Complementary breastfeeding represents an important source of risk of HIV infection for infants born to HIV positive mothers. The World Health Organisation recommends that infants born to HIV positive mothers receive either replacement feeding or exclusive breastfeeding (EBF) followed by early weaning. Beyond the clinical and epidemiological debate, it remains unclear how acceptable and feasible the two options are for rural populations in sub-Saharan Africa. This qualitative study aims to fill this gap in knowledge by exploring both the socio-cultural construction and the practice of breastfeeding in the Nouna Health District, rural Burkina Faso.

METHODS

Information was collected through 32 individual interviews and 3 focus group discussions with women of all ages, and 6 interviews with local guérisseurs.

RESULTS

The findings highlight that breastfeeding is perceived as central to motherhood, but that women practice complementary, rather than exclusive, breastfeeding. The findings also indicate that women recognise both the nutritional value of breast milk and its potential to act as a source of disease transmission.

CONCLUSIONS

The findings suggest that given the socio-cultural importance attributed to breastfeeding and the prevailing poverty, it may be more acceptable and more feasible to promote EBF followed by early weaning than replacement feeding. A set of operational strategies are proposed to favour the prevention of mother to child transmission of HIV in the respect of the local socio-cultural setting.

Potential impact of infant feeding recommendations on mortality and HIV-infection in children born to HIV-infected mothers in Africa: a simulation

Background

Although breast-feeding accounts for 15–20% of mother-to-child transmission (MTCT) of HIV, it is not prohibited in some developing countries because of the higher mortality associated with not breast-feeding. We assessed the potential impact, on HIV infection and infant mortality, of a recommendation for shorter durations of exclusive breast-feeding (EBF) and poor compliance to these recommendations.

Methods

We developed a deterministic mathematical model using primarily parameters from published studies conducted in Uganda or Kenya and took into account non-compliance resulting in mixed-feeding practices. Outcomes included the number of children HIV-infected and/or dead (cumulative mortality) at 2 years following each of 6 scenarios of infant-feeding recommendations in children born to HIV-infected women: Exclusive replacement-feeding (ERF) with 100% compliance, EBF for 6 months with 100% compliance, EBF for 4 months with 100% compliance, ERF with 70% compliance, EBF for 6 months with 85% compliance, EBF for 4 months with 85% compliance

Results

In the base model, reducing the duration of EBF from 6 to 4 months reduced HIV infection by 11.8% while increasing mortality by 0.4%. Mixed-feeding in 15% of the infants increased HIV infection and mortality respectively by 2.1% and 0.5% when EBF for 6 months was recommended; and by 1.7% and 0.3% when EBF for 4 months was recommended. In sensitivity analysis, recommending EBF resulted in the least cumulative mortality when the a) mortality in replacement-fed infants was greater than 50 per 1000 person-years, b) rate of infection in exclusively breast-fed infants was less than 2 per 1000 breast-fed infants per week, c) rate of progression from HIV to AIDS was less than 15 per 1000 infected infants per week, or d) mortality due to HIV/AIDS was less than 200 per 1000 infants with HIV/AIDS per year.

Conclusion

Recommending shorter durations of breast-feeding in infants born to HIV-infected women in these settings may substantially reduce infant HIV infection but not mortality. When EBF for shorter durations is recommended, lower mortality could be achieved by a simultaneous reduction in the rate of progression from HIV to AIDS and or HIV/AIDS mortality, achievable by the use of HAART in infants.

Promotion of WHO feeding recommendations: a model evaluating the effects on HIV-free survival in African children

In Africa, HIV and feeding practices deeply affect child mortality. To prevent mother-to-child transmission, the World Health Organization recommends exclusive breastfeeding for 6 months and replacement feeding when acceptable, feasible, affordable, and sustainable. Determining the proportion and number of children saved with exclusive breastfeeding and replacement feeding is essential to design and implement crucial nationwide policies. Using data on 31 sub-Saharan countries and a decision tree for risk assessment, the authors estimated the number of children's lives potentially saved according to 6 scenarios that combine exclusive breastfeeding for 6 months or replacement feeding with 3 promotion strategies. Among all HIV-negative children born to HIV-positive mothers who die in sub-Saharan Africa per year, 52,315 (9.6%) would be saved yearly with exclusive breastfeeding versus 21,638 (4.0%) with replacement feeding. Promotion support would double these numbers (110,625 vs 45,330; ie, 20.3% vs 8.3%), and with additional prenatal group education, 132,633 versus 54,192 lives would be saved (24.3% vs 9.9%). Wherever replacement feeding is not possible, exclusive breastfeeding with promotion support and prenatal group education would save 1 of 4 exposed children.

Infant human immunodeficiency virus diagnosis in resource-limited settings: issues, technologies, and country experiences

Diagnosing human immunodeficiency virus (HIV) infection in infants is difficult because maternal HIV antibodies cross the placenta, causing positive serologic tests in HIV-exposed infants for the first several months of life. Early definitive diagnosis of HIV requires virologic testing such as polymerase chain reaction (PCR), which is the diagnostic standard in resource-rich settings but has been too complex and expensive for widespread use in most countries with high HIV prevalence. Early PCR testing can help HIV-infected infants access treatment, provide psychosocial benefits for families of uninfected infants, and help programs for prevention of mother-to-child transmission of HIV monitor their effectiveness. HIV testing, including PCR, is increasingly available for infants in resource-limited settings, but there are many barriers and complex policy decisions that need to be addressed before universal early testing can become standard. This paper reviews challenges and progress in the field and suggests ways to facilitate early infant testing in resource-limited settings.

A qualitative investigation into knowledge, beliefs, and practices surrounding mastitis in sub-Saharan Africa: what implications for vertical transmission of HIV?

BACKGROUND

Mastitis constitutes an important risk factor in HIV vertical transmission. Very little, however, is known on how women in sub-Saharan Africa conceptualise health problems related to breastfeeding, such as mastitis, and how they act when sick. We aimed at filling this gap in knowledge, by documenting the indigenous nosography of mastitis, health seeking behaviour, and remedies for prophylaxis and treatment in rural sub-Saharan Africa.

METHODS

The study was conducted in the Nouna Health District, rural Burkina Faso. We employed a combination of in-depth individual interviews and focus group discussions reaching both women and guérisseuers. All material was transcribed, translated, and analysed inductively, applying data and analyst triangulation.

RESULTS

Respondents perceived breast problems related to lactation to be highly prevalent and described a sequence of symptoms which resembles the biomedical understanding of pathologies related to breastfeeding, ranging from breast engorgement (stasis) to inflammation (mastitis) and infection (breast abscess). The aetiology of disease, however, differed from biomedical notions as both women and guerisseurs distinguished between "natural" and "unnatural" causes of health problems related to breastfeeding. To prevent and treat such pathologies, women used a combination of traditional and biomedical therapies, depending on the perceived cause of illness. In general, however, a marked preference for traditional systems of care was observed.

CONCLUSION

Health problems related to breastfeeding are perceived to be very common in rural Burkina Faso. Further epidemiological research to assess the actual prevalence of such pathologies is urgently needed to inform the design of adequate control measures, especially given the impact of mastitis on HIV vertical transmission. Our investigation into local illness concepts and health care seeking behaviour is useful to ensure that such measures be culturally sensitive. Further research into the efficacy of local customs and traditional healing methods and their effect on viral load in breast milk is also urgently needed.

Acceptability, feasibility and affordability of infant feeding options for HIV-infected women: a qualitative study in south-west Nigeria

The objective of this study was to explore the acceptability, feasibility, affordability, safety and sustainability of replacement feeding options for HIV-infected mothers in Ile-Ife, in south-west Nigeria. Six focus group discussions were conducted with a purposive sample of mothers, fathers and grandmothers. The HIV status of all participants was unknown to investigators. All text data were analysed using the Text-based Beta Software program. With regard to the acceptability of replacement feeds, respondents perceived the stigma associated with not breastfeeding to be an important consideration. In this community, breastfeeding is the norm--even though it is not necessarily exclusive. For infected mothers who choose to breastfeed exclusively and then to wean their infants before 6 months of age, respondents did not anticipate early cessation of breastfeeding to be problematic. Respondents noted that acceptable replacement foods included infant formula, soy milk and cow's milk. Barriers to replacement feeding that were mentioned included: the high costs of replacement foods and fuel for cooking; an unreliable supply of electrical power; poor access to safe water; and poor access to storage facilities. The research confirms the difficulty of replacement feeding for HIV-infected mothers in sub-Saharan Africa. The results also provide the basis for new issues and hypothesis for future research in other communities with similar socio-cultural and economic characteristics.

Protection, promotion and support of breastfeeding in low-income countries

The rates of exclusive breastfeeding and the duration of breastfeeding fall short of what is recommended by the Global Strategy on Infant and Young Child Feeding worldwide. In low-income countries this is associated with a great excess of avoidable childhood death and disease. A higher degree of protection, promotion and support of breastfeeding has the potential to avert the death of about 1.3 million children per year and to prevent much of the associated individual and social sufferings. This paper presents some evidence about interventions that are effective to protect, promote and support breastfeeding in the health system and in the community. These interventions should not be implemented in isolation, but as part of an integrated and intersectoral programme, with a participatory approach that takes local cultural characteristics into account. Lack of political will is probably the most important factor associated with inadequate protection, promotion and support of breastfeeding.

Biochemical analysis of human milk treated with sodium dodecyl sulfate, an alkyl sulfate microbicide that inactivates human immunodeficiency virus type 1

Reduction of transmission of human immunodeficiency virus type 1 (HIV-1) through human milk is needed. Alkyl sulfates such as sodium dodecyl sulfate (SDS) are microbicidal against HIV-1 at low concentrations, have little to no toxicity, and are inexpensive. The authors have reported that treatment of HIV-1-infected human milk with < or = 1% (10 mg/mL) SDS for 10 minutes inactivates cell-free and cell-associated virus. The SDS can be removed with a commercially available resin after treatment without recovery of viral infectivity. In this article, the authors report results of selective biochemical analyses (ie, protein, immunoglobulins, lipids, cells, and electrolytes) of human milk subjected to SDS treatment and removal. The SDS treatment or removal had no significant effects on the milk components studied. Therefore, the use of alkyl sulfate microbicides to treat milk from HIV-1-positive women may be a simple, practical, and nutritionally sound way to prevent or reduce transmission of HIV-1 while still feeding with mother's own milk.

Use of population-specific infant mortality rates to inform policy decisions regarding HIV and infant feeding

Mother-to-child transmission of HIV occurs during pregnancy, at the time of delivery, and through breastfeeding (BF). WHO recommends avoidance of all BF when replacement feeding (RF) is affordable, feasible, acceptable, sustainable, and safe. Otherwise, exclusive breastfeeding (EBF) followed by early BF cessation is recommended. Governments are currently scaling up programs to prevent infant HIV infection. Few data exist to guide policy decisions about the allocation of resources to prevent postnatal HIV transmission while minimizing the non-HIV-related risks of these policies. This paper presents an analysis of the impact of WHO infant feeding recommendations in different settings characterized by infant mortality rate (IMR). Mathematical simulation modeling is used to estimate the effects on HFS (HFS) through 24 mo of 3 intervention scenarios: RF from birth by HIV-positive mothers (RF24), EBF up to 6 mo followed by early BF cessation (EBF6), and the default scenario where there is no postnatal intervention (BF24). This analysis differs from earlier reports in that it uses the most recent data on risks of postnatal HIV transmission for mixed and exclusive BF. These simulations suggest that in settings where IMR is <25/1000 live births, RF24 results in the greatest HFS to 24 mo; EBF6 produces the best outcome where IMR > 25/1000 live births. RF24 results in lower HFS than no postnatal intervention where IMR >/= 101/1000. IMR-based analyses can help to guide government policy decisions about which infant feeding strategies to invest in and emphasize for HIV-positive mothers in different settings.