Breastfeeding and HIV transmission in the developing world: past, present, future

Viruses and Human Milk: Transmission or Protection?

Human milk (HM) is considered the best source of nutrition for infant growth and health. This nourishment is unique and changes constantly during lactation to adapt to the physiological needs of the developing infant. It is also recognized as a potential route of transmission of some viral pathogens although the presence of a virus in HM rarely leads to a disease in an infant. This intriguing paradox can be explained by considering the intrinsic antiviral properties of HM. In this comprehensive and schematically presented review, we have described what viruses have been detected in HM so far and what their potential transmission risk through breastfeeding is. We have provided a description of all the antiviral compounds of HM, along with an analysis of their demonstrated and hypothesized mechanisms of action. Finally, we have also analyzed the impact of HM pasteurization and storage methods on the detection and transmission of viruses, and on the antiviral compounds of HM. We have highlighted that there is currently a deep knowledge on the potential transmission of viral pathogens through breastfeeding and on the antiviral properties of HM. The current evidence suggests that, in most cases, it is unnecessarily to deprive an infant of this high-quality nourishment and that the continuation of breastfeeding is in the best interest of the infant and the mother.

Vaccine-Induced, High-Magnitude HIV Env-Specific Antibodies with Fc-Mediated Effector Functions Are Insufficient to Protect Infant Rhesus Macaques against Oral SHIV Infection

Improved access to antiretroviral therapy (ART) and antenatal care has significantly reduced in utero and peripartum mother-to-child human immunodeficiency virus (HIV) transmission. However, as breast milk transmission of HIV still occurs at an unacceptable rate, there remains a need to develop an effective vaccine for the pediatric population. Previously, we compared different HIV vaccine strategies, intervals, and adjuvants in infant rhesus macaques to optimize the induction of HIV envelope (Env)-specific antibodies with Fc-mediated effector function. In this study, we tested the efficacy of an optimized vaccine regimen against oral simian-human immunodeficiency virus (SHIV) acquisition in infant macaques. Twelve animals were immunized with 1086.c gp120 protein adjuvanted with 3M-052 in stable emulsion and modified vaccinia Ankara (MVA) virus expressing 1086.c HIV Env. Twelve control animals were immunized with empty MVA. The vaccine prime was given within 10 days of birth, with booster doses being administered at weeks 6 and 12. The vaccine regimen induced Env-specific plasma IgG antibodies capable of antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Beginning at week 15, infants were exposed orally to escalating doses of heterologous SHIV-1157(QNE)Y173H once a week until infected. Despite the induction of strong Fc-mediated antibody responses, the vaccine regimen did not reduce the risk of infection or time to acquisition compared to controls. However, among vaccinated animals, ADCC postvaccination and postinfection was associated with reduced peak viremia. Thus, nonneutralizing Env-specific antibodies with Fc effector function elicited by this vaccine regimen were insufficient for protection against heterologous oral SHIV infection shortly after the final immunization but may have contributed to control of viremia. IMPORTANCE Women of childbearing age are three times more likely to contract HIV infection than their male counterparts. Poor HIV testing rates coupled with low adherence to antiretroviral therapy (ART) result in a high risk of mother-to-infant HIV transmission, especially during the breastfeeding period. A preventative vaccine could curb pediatric HIV infections, reduce potential health sequalae, and prevent the need for lifelong ART in this population. The results of the current study imply that the HIV Env-specific IgG antibodies elicited by this candidate vaccine regimen, despite a high magnitude of Fc-mediated effector function but a lack of neutralizing antibodies and polyfunctional T cell responses, were insufficient to protect infant rhesus macaques against oral virus acquisition.

Mothers living with HIV: replacing breastfeeding by infant formula

OBJECTIVE

To explore factors that interact and shape the meaning and experience of mothers of HIV-exposed children in relation to replacing breastfeeding by infant formula.

METHOD

A qualitative study was carried out with 23 mothers living with HIV, whose children were up to 18 months of age and under follow-up in a specialized care service. Symbolic Interactionism, semi-structured interviews and content analysis were adopted as theoretical framework.

RESULTS

The social symbols of breastfeeding, the (un)availability of the milk formula and the (lack of)support of health professionals influenced the mothers' experience with formula feeding. Social, cultural and economic constraints have proved capable of undermining the conditions necessary for the replacement of breastfeeding.

FINAL CONSIDERATIONS

The availability of infant formula, access to lactation inhibitor and quality of health services still represent challenges to eradicate new HIV infections in children.

[Development and challenges to breastfeeding in sub-Saharan Africa]

Since there is no doubt concerning the superiority of breastfeeding compared to other forms of infant feeding, the promotion of exclusive breastfeeding up to six months and continued breastfeeding up to two years and beyond are again embraced at the highest global nutrition agenda. The latest is the United Nations decade of action on nutrition 2016-2025, building on research results and the work by the World Health Organization (WHO) over the last two decades, and extensive societal, clinical, and academic discussions in the field of breastfeeding.While the discussion was about the optimal duration of exclusive breastfeeding around the millennium shift, the focus is on the most effective measures for the promotion and protection of breastfeeding. Contemporary breastfeeding rates are well behind the goals. In sub-Saharan Africa, almost all infants are breastfed, while exclusive breastfeeding is more seldom and not sufficient. Africa, being a vast and diverse continent with a myriad of cultural practices, has had some shared attitudes ranging from the west to east regarding views on motherhood, body fluids, including milk, infant feeding, and responsible others.The region still faces high maternal HIV infection rates and high infant and child mortality rates. However, due to effective antiretroviral therapies, it is now possible and safe for women living with HIV to breastfeed their infants and to ensure them HIV-free survival. However, there is need for improvement regarding availability, compliance, and adherence to these drugs. Research gaps include the long-term effects of antiretroviral therapy on the growth, health, and development of the exposed children.

UNICEF's contribution to the adoption and implementation of option B+ for preventing mother-to-child transmission of HIV: a policy analysis

BACKGROUND

Between 2011 and 2013, global and national guidelines for preventing mother-to-child transmission (PMTCT) of HIV shifted to recommend Option B+, the provision of lifelong antiretroviral treatment for all HIV-infected pregnant women.

METHODS

We aimed to analyse how Option B+ reached the policy agenda, and unpack the processes, actors and politics that explain its adoption, with a focus on examining UNICEF's contribution to these events. Analysis drew on published articles and other documentation, 30 key informants interviews with staff at UNICEF, partner organisations and government officials, and country case studies. Cameroon, India, South Africa and Zimbabwe were each visited for 5-8 days. Interview transcripts were analysed using Dedoose software, reviewed several times and then coded thematically.

RESULTS

A national policy initiative in Malawi in 2011, in which the country adopted Option B+, rather than existing WHO recommended regimens, irrevocably placed the policy on the global agenda. UNICEF and other organisations recognised the policy's potential impact and strategically crafted arguments to support it, framing these around operational considerations, cost-effectiveness and values. As 'policy entrepreneurs', these organisations vigorously promoted the policy through a variety of channels and means, overcoming concerted opposition. WHO, on the basis of scanty evidence, released a series of documents towards the policy's endorsement, paving the way for its widespread adoption. National-level policy transformation was rapid and definitive, distinct from previous incremental policy processes. Many organisations, including UNICEF, facilitated these changes in country, acting individually, or in concert.

CONCLUSIONS

The adoption of the Option B+ policy marked a departure from established processes for PMTCT policy formulation which had been led by WHO with the support of technical experts, and in which recommendations were developed following shifts in evidence. Rather, changes were spurred by a country-level initiative, and a set of strategically framed arguments that resonated with funders and country-level actors. This bottom-up approach, supported by normative agencies, was transformative. For UNICEF, alignment between the organisation's country focus and the policy's underpinning values, enabled it to work with partners and accelerate widespread policy change.

Early Sites of Virus Replication After Oral SIVmac251 Infection of Infant Macaques: Implications for Pathogenesis

Despite optimization of preventative measures for vertical HIV-1 transmission, daily, roughly 400 infants become HIV infected, most of them through breastfeeding. Viral entry has been presumed to occur in the gastrointestinal tract; however, the exact entry site(s) have not been defined. Therefore, we quantified simian immunodeficiency virus (SIV) RNA and DNA in oral, intestinal, and systemic tissues of 15 infant macaques within 48-96 h after oral SIV_mac251 exposure. SIV DNA was detected as early as 48 h, whereas SIV RNA was typically detected at later time points (72-96 h). Transmitted founder viruses were identical or very similar to a single genotype in the SIV_mac251 challenge stock. SIV RNA and DNA were most frequently found in lymph nodes (LNs) draining the oral cavity and in the ileum. Using in situ hybridization, SIV-infected cells in LNs were exclusively represented by CD3⁺ T cells. SIV RNA and DNA were also detected in the lungs of 20% of the animals, and 60% of the animals had detectable SIV DNA in the cerebrum. The early detection of viral RNA or DNA in lung and brain tissues emphasizes the need for early treatment of pediatric HIV infection to prevent damage not only to the immune system but also to the respiratory tract and central nervous system.

Challenges and opportunities of optimal breastfeeding in the context of HIV option B+ guidelines

Background

In 2013, the World Health Organization released a new set of guidelines widely known as Option B+. Prior to that there were guidelines released in 2010. Option B+ recommends lifelong antiretroviral treatment for all pregnant and breastfeeding women living with Human Immunodeficiency Virus. The study aimed at investigating challenges and opportunities in implementing Infant and Young Child Feeding in the context of Prevention of Mother To Child Transmission (PMTCT) guidelines among HIV positive mothers of children aged 0–24 months. The study also examined implications presented by implementing the 2013 PMTCT consolidated guidelines in the transition phase from the 2010 approach in Zambia.

Methods

A mixed methods approach was employed in the descriptive cross sectional study utilizing semi structured questionnaires and Focused Group Discussions. Further, data was captured from the Health Information Management System.

Results

During the PMTCT transition, associated needs and challenges in institutionalizing the enhanced guidelines from option A and B to option B+ were observed. Nonetheless, there was a decline in Mother to Child Transmission (MTCT) of HIV rates with an average of 4%. Mothers faced challenges in complying with optimal breastfeeding practices owing to lack of community support systems and breast infections due to poor breast feeding occasioned by infants’ oral health challenges. Moreover, some mothers were hesitant of lifelong ARVs. Health workers faced programmatic and operational challenges such as compromised counseling services.

Conclusion

Despite the ambitious timelines for PMTCT transition, the need to inculcate new knowledge and vary known practice among mothers and the shift in counseling content for health workers, the consolidated guidelines for PMTCT proved effective. Some mothers were hesitant of lifelong ARVs, rationalizing the debated paradigm that prolonged chemotherapy/polypharmacy may be a future challenge in the success of ART in PMTCT. Conflicting breast feeding practices was a common observation across mothers thus underpinning the need to strongly invigorate Infant and Young Child Feeding information sharing across the continuum of heath care from facility level to community and up to the family; for cultural norms, practices and attitudes enshrined within communities play a vital role in child care.

Ontogeny of CD4+ T Lymphocytes With Phenotypic Susceptibility to HIV-1 During Exclusive and Nonexclusive Breastfeeding in HIV-1-Exposed Ugandan Infants

Background

Among infants exposed to human immunodeficiency virus (HIV) type 1, mixed breastfeeding is associated with higher postnatal HIV-1 transmission than exclusive breastfeeding, but the mechanisms of this differential risk are uncertain.

Methods

HIV-1-exposed Ugandan infants were prospectively assessed during the first year of life for feeding practices and T-cell maturation, intestinal homing (β7hi), activation, and HIV-1 coreceptor (CCR5) expression in peripheral blood. Infants receiving only breast milk and those with introduction of other foods before 6 months were categorized as exclusive and nonexclusive, respectively.

Results

Among CD4+ and CD8+ T cells, the expression of memory, activation, and CCR5 markers increased rapidly from birth to week 2, peaking at week 6, whereas cells expressing the intestinal homing marker increased steadily in the central memory (CM) and effector memory T cells over 48 weeks. At 24 weeks, when feeding practices had diverged, nonexclusively breastfed infants showed increased frequencies and absolute counts of β7hi CM CD4+ and CD8+ T cells, including the HIV-1-targeted cells with CD4+β7hi/CCR5+ coexpression, as well as increased activation.

Conclusions

The T-cell phenotype associated with susceptibility to HIV-1 infection (CCR5+, gut-homing, CM CD4+ T cells) was preferentially expressed in nonexclusively breastfed infants, a group of infants at increased risk for HIV-1 acquisition.

Risk Factors for Presumed Bacterial Pneumonia Among HIV-uninfected Children Hospitalized in Soweto, South Africa

BACKGROUND

Pneumonia is a leading cause of child morbidity and death. Data on risk factors can guide prevention efforts. Within a study on pneumococcal conjugate vaccine effectiveness, we investigated risk factors for presumed bacterial pneumonia (PBP).

METHODS

PBP cases were human immunodeficiency virus (HIV) uninfected children with lower respiratory tract infection and consolidation on chest radiograph or nonconsolidated infiltrate with C-reactive protein ≥40 mg/L hospitalized at Chris Hani Baragwanath Academic Hospital (CHBAH) in Soweto. Age-matched community controls were identified using CHBAH birth records ±1 week of case birth date. Data were analyzed using conditional logistic regression.

RESULTS

A total of 889 PBP cases (median age 9 months) were matched to 2628 controls. Crowding was a significant risk factor among well-nourished children (adjusted odds ratio [aOR]: 2.29, 95% confidence interval [CI]: 1.89-2.78), but not in those with low weight-for-age. Malnutrition was associated with PBP; strength of association was highest in the absence of crowding (aOR: 6.68, 95% CI: 4.74-9.42). Exclusive breastfeeding was protective only among HIV-unexposed children (aOR: 0.65, 95% CI: 0.54-0.78). Self-reported maternal HIV infection was a risk factor among children exclusively breastfeed up to 4 months (aOR: 2.33, 95% CI: 1.53-3.55). Having indoor tap water was protective (aOR: 0.65, 95% CI: 0.54-0.78), whereas a primary care giver who smoked was a risk factor (aOR: 5.15, 95% CI: 2.94-9.03).

CONCLUSIONS

Our findings confirm several known pneumonia risk factors and highlight complex interactions between factors, including HIV exposure, breastfeeding, malnutrition and crowding. Improved housing, reduced secondhand smoke exposure and HIV prevention among women of reproductive age could lessen the child pneumonia burden.

Why invest, and what it will take to improve breastfeeding practices?

Despite its established benefits, breastfeeding is no longer a norm in many communities. Multifactorial determinants of breastfeeding need supportive measures at many levels, from legal and policy directives to social attitudes and values, women's work and employment conditions, and health-care services to enable women to breastfeed. When relevant interventions are delivered adequately, breastfeeding practices are responsive and can improve rapidly. The best outcomes are achieved when interventions are implemented concurrently through several channels. The marketing of breastmilk substitutes negatively affects breastfeeding: global sales in 2014 of US$44·8 billion show the industry's large, competitive claim on infant feeding. Not breastfeeding is associated with lower intelligence and economic losses of about $302 billion annually or 0·49% of world gross national income. Breastfeeding provides short-term and long-term health and economic and environmental advantages to children, women, and society. To realise these gains, political support and financial investment are needed to protect, promote, and support breastfeeding.

Influenza Transmission in the Mother-Infant Dyad Leads to Severe Disease, Mammary Gland Infection, and Pathogenesis by Regulating Host Responses

Seasonal influenza viruses are typically restricted to the human upper respiratory tract whereas influenza viruses with greater pathogenic potential often also target extra-pulmonary organs. Infants, pregnant women, and breastfeeding mothers are highly susceptible to severe respiratory disease following influenza virus infection but the mechanisms of disease severity in the mother-infant dyad are poorly understood. Here we investigated 2009 H1N1 influenza virus infection and transmission in breastfeeding mothers and infants utilizing our developed infant-mother ferret influenza model. Infants acquired severe disease and mortality following infection. Transmission of the virus from infants to mother ferrets led to infection in the lungs and mother mortality. Live virus was also found in mammary gland tissue and expressed milk of the mothers which eventually led to milk cessation. Histopathology showed destruction of acini glandular architecture with the absence of milk. The virus was localized in mammary epithelial cells of positive glands. To understand the molecular mechanisms of mammary gland infection, we performed global transcript analysis which showed downregulation of milk production genes such as Prolactin and increased breast involution pathways indicated by a STAT5 to STAT3 signaling shift. Genes associated with cancer development were also significantly increased including JUN, FOS and M2 macrophage markers. Immune responses within the mammary gland were characterized by decreased lymphocyte-associated genes CD3e, IL2Ra, CD4 with IL1β upregulation. Direct inoculation of H1N1 into the mammary gland led to infant respiratory infection and infant mortality suggesting the influenza virus was able to replicate in mammary tissue and transmission is possible through breastfeeding. In vitro infection studies with human breast cells showed susceptibility to H1N1 virus infection. Together, we have shown that the host-pathogen interactions of influenza virus infection in the mother-infant dyad initiate immunological and oncogenic signaling cascades within the mammary gland. These findings suggest the mammary gland may have a greater role in infection and immunity than previously thought.

Longitudinal analysis of mature breastmilk and serum immune composition among mixed HIV-status mothers and their infants

BACKGROUND & AIMS

Understanding mature breastmilk immunology may benefit infants chronically exposed to infectious pathogens in resource-limited regions.

METHODS

This prospective rural/semi-rural Tanzanian cohort of women (n = 102 at delivery; 38% HIV-positive) and their infants (n = 102) investigated breastmilk, maternal and infant serum immunoglobulins (IgA/IgG1-4/IgM) and cytokines (IL-1β/IL-2/IL-6/IL-10/IL-12p70/IL-13/IL-15/TNF-α/IFN-γ) at 1, 2, 3, 6-months postpartum.

RESULTS

Milk immunoglobulins followed an inverse U-shaped pattern, while cytokine patterns were mixed. Exclusive breastfeeding duration and feeding intensity were associated with greater breastmilk total immunoglobulin and IgA, IgG1-3 and IL-12p70 concentrations. Maternal mastitis, fever or cough was associated with higher breastmilk total cytokine concentrations, while infant fever was associated with lower milk immunoglobulins or cytokines. Strong (r ≥ 0.40) to weak (r = 0.20-0.29) positive correlations between maternal serum-breastmilk or breastmilk-infant serum immunoglobulins were evident. Breastmilk cytokines were moderate to weakly negatively correlated with infant serum. Breastmilk immunology did not differ by maternal malnutrition or HIV-seropositivity.

CONCLUSIONS

Mature breastmilk is a dynamic source of many specific and non-specific immune factors associated with maternal and infant health and infant nutrition. Breastfeeding practices are associated with differential breastmilk immunological composition providing immunological support for universal recommendations to exclusively breastfeed for 6-months.

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.

HIV monoclonal antibodies: a new opportunity to further reduce mother-to-child HIV transmission

Yegor Voronin and colleagues explore how monoclonal antibodies against HIV could provide a new opportunity to further reduce mother-to-child transmission of HIV and propose that new interventions should consider issues related to implementation, feasibility, and access. Please see later in the article for the Editors' Summary.