Postnatal transmission of human immunodeficiency virus type 1 from mother to infant. A prospective cohort study in Kigali, Rwanda

"My body my baby": a qualitative study examining drivers of infant-feeding choices among women living with HIV in Philadelphia, United States

Before national guidelines related to infant feeding among people living with HIV (PLHIV) in the United States were changed in 2023, PLHIV were discouraged from breastfeeding due to the potential risk of perinatal HIV transmission. Potential health benefits to both mother and child coupled with the ability to mitigate HIV transmission risk with modern treatments now make feeding decisions more complex for PLHIV. This study examined personal and social determinants of feeding choice among PLHIV in the Philadelphia area just prior to the change in national guidelines. In 2022 and 2023, we conducted in-depth interviews with 28 PLHIV between the ages of 18-50 years old that had previously given birth, 22 while living with HIV. Participants who gave birth while living with HIV expressed that they had not been given the choice to breastfeed. When probed about how they would consider choice in a hypothetical future pregnancy in the new guidelines era, participants' own knowledge and beliefs about what was best for their babies and themselves were consistently raised as the most influential factors. They relied strongly on their health providers for up-to-date knowledge. Advice from partners, family, and community was considered less influential for most.

Predictors of maternal HIV acquisition during pregnancy and lactation in sub-Saharan Africa: A systematic review and narrative synthesis

OBJECTIVES

To eliminate vertical transmission of HIV, global institutions recommend using a risk-guided approach for HIV prevention services in antenatal and postnatal settings. Identifying predictors of maternal HIV acquisition can inform the development of risk-guided approaches, but individual studies of predictors can have limited power and generalizability.

METHODS

We conducted a systematic review and narrative synthesis to identify common predictors of maternal HIV acquisition in sub-Saharan Africa (SSA). We searched four databases for full-text articles that estimated associations between at least one predictor and risk of HIV acquisition among pregnant and/or lactating women (PLW) in SSA. We restricted our synthesis to predictors assessed in at least four study populations. For these predictors, we summarized how each predictor was defined and used vote counting and descriptive statistics to characterize overall trends.

RESULTS

We identified 26 eligible publications that summarized results from 24 unique studies. Studies were implemented in 12 countries between 1988 and 2021 and enrolled a total of 164,480 PLW at risk of acquiring HIV. Of the 66 predictors evaluated, 16 met our inclusion criteria. Estimated associations tended to be imprecise and variability in how predictors were measured precluded meta-analyses. We observed trends towards a higher risk of maternal HIV acquisition among young women and women who reported early coital debut, multiple partnerships, sexually transmitted infections, being unaware of partner HIV status, or having a partner living with HIV. In most studies, PLW in stable, monogamous relationships experienced a lower risk of acquiring HIV than those who were single, separated, or in a polygynous marriage. HIV risk perception, condom use, and vaginal drying were also commonly associated with HIV acquisition risk.

CONCLUSIONS

In our systematic review and narrative synthesis, we identified several easily measured characteristics that were associated with HIV acquisition among PLW in multiple study populations across SSA. Such findings can support the development and refinement of risk-guided approaches for HIV prevention in the region.

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.

Preventing breast milk HIV transmission using broadly neutralizing monoclonal antibodies: One size does not fit all

Passive immunoprophylaxis with broadly neutralizing monoclonal antibodies (bNAbs) could be a game changer in the prevention of human immunodeficiency virus (HIV) acquisition. The prevailing view is that available resources should be focused on identifying a fixed combination of at least three bNAbs for universal use in therapeutic and preventive protocols, regardless of target populations or routes of transmission. HIV transmission through breastfeeding is unique: it involves free viral particles and cell‐associated virus from breast milk and, in the case of acute/recent maternal infection, a viral population with restricted Env diversity. HIV transmission through breastfeeding in high incidence/prevalence areas could potentially be eliminated by subcutaneous administration to all newborns of one or two long‐acting bNAbs with extended breadth, high potency, and effector properties (ADCC, phagocytosis) against circulating HIV strains.

The End Is in Sight: Current Strategies for the Elimination of HIV Vertical Transmission

PURPOSE OF REVIEW

The goal of this review is to highlight and interpret recent trends and developments in the diagnosis, treatment, and prevention of HIV vertical transmission from a clinical perspective.

RECENT FINDINGS

Universal third-trimester retesting and partner testing may better identify incident HIV among pregnant patients and result in early initiation of antiretroviral therapy to prevent vertical transmission. The proven safety and efficacy of integrase inhibitors such as dolutegravir may be particularly useful in suppressing viremia in pregnant persons who present late for ART treatment. Pre-exposure prophylaxis (PrEP) during pregnancy may play a role in preventing HIV acquisition; however, its role in preventing vertical transmission is difficult to elucidate. Substantial progress has been made in recent years to eliminate HIV perinatal transmission. Future research hinges upon a multipronged approach to improving HIV detection, risk-stratified treatment strategies, and prevention of primary HIV infection among pregnant persons.

Prevention of the Vertical Transmission of HIV; A Recap of the Journey so Far

In 1989, one in four (25%) infants born to women living with HIV were infected; by the age of 2 years, there was 25% mortality among them due to HIV. These and other pieces of data prompted the development of interventions to offset vertical transmission, including the landmark Pediatric AIDS Clinical Trial Group Study (PACTG 076) in 1994. This study reported a 67.5% reduction in perinatal HIV transmission with prophylactic antenatal, intrapartum, and postnatal zidovudine. Numerous studies since then have provided compelling evidence to further optimize interventions, such that annual transmission rates of 0% are now reported by many health departments in the US and elimination has been validated in several countries around the world. Despite this success, the elimination of HIV's vertical transmission on the global scale remains a work in progress, limited by socioeconomic factors such as the prohibitive cost of antiretrovirals. Here, we review some of the key trials underpinning the development of guidelines in the US as well as globally, and discuss the evidence through a historic lens.

Impact of Option B+ Combination Antiretroviral Therapy on Mother-to-Child Transmission of HIV-1, Maternal and Infant Virologic Responses to Combination Antiretroviral Therapy, and Maternal and Infant Mortality Rates: A 24-Month Prospective Follow-Up Study at a Primary Health Care Clinic, in Harare, Zimbabwe

We conducted a 24-month prospective follow-up study, at a primary health care clinic in Harare, Zimbabwe, to determine cumulative mother-to-child transmission of HIV-1 (MTCT) rate and the contributions of intrauterine (IU), intrapartum (IP), and postpartum (PP) to MTCT, as well as maternal and infant mortality rates in the era of Option B⁺ combination antiretroviral therapy (cART). Plasma for viral load (VL) quantitation was obtained from 475 mothers enrolled into the study. VL was quantified at enrolment and every 6 months thereafter up to 24 months using the Cepheid GeneXpert HIV-1 Quantitative test. Dried blood spots were collected from 453 infants at birth, 4–6 weeks, 3 months, and every 3 months thereafter up to 24 months. HIV-1 infant diagnosis was conducted using the Cepheid GeneXpert HIV-1 Qualitative test. Absolute, cumulative MTCT rates and mortality rate were calculated. Seven mothers (1.55%) transmitted HIV-1 infection to their infants by 24 months. Four infants (0.88%; 95% CI 0.26–2.33%), one infant (0.22%; 95% CI 0–1.4%), and two infants (0.44%; 95% CI 0.01–1.7%) were infected IU, IP, and PP, respectively. By 24 months, 88.94% of the mothers and 80% of the infants had undetectable VL. The maternal and infant mortality rates were 0.21% and 1.78%, respectively. In the first 24 months of life, IU transmission is the major route of MTCT. The cumulative MTCT rate of 1.55% and low maternal and infant mortality rates of 0.21% and 1.78%, respectively, contribute to growing evidence that Option B⁺ cART not only drastically reduces MTCT but also maternal and infant mortality.

Implementation of HIV Retesting During Pregnancy and Postpartum in Kenya: A Cross-Sectional Study

INTRODUCTION

HIV retesting during pregnancy/postpartum can identify incident maternal HIV infection and prevent mother-to-child HIV transmission (MTCT). Guidelines recommend retesting HIV-negative peripartum women, but data on implementation are limited. We conducted a cross-sectional study in Kenya to measure the prevalence of maternal HIV retesting in programs and HIV incidence.

METHODS

Programmatic HIV retesting data was abstracted from maternal and child health booklets among women enrolled in a cross-sectional and/or seeking services during pregnancy, delivery, or 9 months postpartum in Kenya between January 2017 and July 2019. Retesting was defined as any HIV test conducted by MTCT programs after the initial antenatal care test or conducted as part of retesting policies at/after delivery for women not tested during pregnancy. Poisson generalized linear regression was used to identify correlates of programmatic retesting among women enrolled at 9 months postpartum.

RESULTS

Among 5,894 women included in the analysis, 3,124 only had data abstracted and 2,770 were enrolled in a cross-sectional study. Overall prevalence of programmatic HIV retesting was higher at 6 weeks (65%) and 9 months postpartum (72%) than in pregnancy (32%), at delivery (23%) and 6 months postpartum (28%) (P<.001 for all comparisons). HIV incidence was 0.72/100 person-years (PY) (95% confidence interval (CI)=0.43,1.22) in pregnancy and 0.23/100 PY (95% CI=0.09, 0.62) postpartum (incidence rate ratio: 3.09; 95% CI=0.97, 12.90; P=.02).

CONCLUSION

Maternal retest coverage was high at 6 weeks and 9 months postpartum but low during pregnancy. Strategies to ensure high retesting coverage and detect women with incident maternal HIV infection are needed.

Revisiting Koch's postulate to determine the plausibility of viral transmission by human milk

As breastfeeding is of utmost importance for child development and survival, identifying whether breast milk is a route of transmission for human viruses is critical. Based on the principle of Koch's postulate, we propose an analytical framework to determine the plausibility of viral transmission by breast milk. This framework is based on five criteria: viral infection in children receiving breast milk from infected mothers; the presence of virus, viral antigen, or viral genome in the breast milk of infected mothers; the evidence for the virus in breast milk being infectious; the attempts to rule out other transmission modalities; and the reproduction of viral transmission by oral inoculation in an animal model. We searched for evidence in published reports to determine whether the 5 criteria are fulfilled for 16 human viruses that are suspected to be transmissible by breast milk. We considered breast milk transmission is proven if all 5 criteria are fulfilled, as probable if 4 of the 5 criteria are met, as possible if 3 of the 5 criteria are fulfilled, and as unlikely if less than 3 criteria are met. Only five viruses have proven transmission through breast milk: human T-cell lymphotropic virus 1, human immunodeficiency virus, human cytomegalovirus, dengue virus, and Zika virus. The other 11 viruses fulfilled some but not all criteria and were categorized accordingly. Our framework analysis is useful for guiding public health recommendations and for identifying knowledge gaps amenable to original experiments.

Tonse Pamodzi: Developing a combination strategy to support adherence to antiretroviral therapy and HIV pre-exposure prophylaxis during pregnancy and breastfeeding

To eliminate mother-to-child transmission of HIV (EMTCT), scalable strategies to enhance antiretroviral adherence for both antiretroviral therapy (ART) and pre-exposure prophylaxis (PrEP) are needed as part of integrated HIV and maternal-child health services. We developed Tonse Pamodzi ("all of us together"), an adaptable intervention integrating biomedical and behavioral components to support HIV treatment and prevention. We describe our intervention development process, which comprised formative qualitative research, a review of the literature, and technical input from stakeholders representing the community, health systems, and policymakers. The resulting intervention, described herein, integrates patient-centered counseling and engagement of a patient-selected adherence supporter for pregnant and breastfeeding women initiating ART or PrEP. Patients receiving the intervention engage in Integrated Next Step Counseling (iNSC) sessions delivered by trained counselors to build and maintain adherence skills. Each patient also has the option of selecting an adherence supporter (partner, family member, or friend) who may participate in iNSC sessions and provide adherence support outside of these sessions. This flexible intervention is adaptable not only to ART or PrEP use, but also to the needs and preferences of each woman and the clinical context. If shown to be acceptable and feasible, the Tonse Pamodzi intervention may be an important tool in continuing efforts for EMTCT.

Mother-to-child transmission of HIV-1 and infant mortality in the first six months of life, in the era of Option B Plus combination antiretroviral therapy

OBJECTIVES

The aim of this study was to determine the contributions of intrauterine (IU), intrapartum (IP), and postpartum (PP) transmission to mother-to-child transmission of HIV-1 (MTCT) and infant mortality in the first 6 months of life, in the era of Option B Plus combination antiretroviral therapy.

METHODS

Plasma for virus load (VL) quantitation was obtained from 451 women enrolled into the study. VL was quantified using the Cepheid GeneXpert HIV-1 quantitative test. Dried blood spots were collected from 453 infants at birth, 4-6 weeks, 3 months, and 6 months. HIV-1 infant diagnosis was conducted using the Cepheid GeneXpert HIV-1 qualitative test. Absolute and cumulative MTCT rates, and the mortality rate by 6 months were calculated.

RESULTS

Seven mothers (1.55%) had transmitted HIV-1 infection to their infants by 6 months. Four infants (0.88%, 95% confidence interval (CI) 0.26-2.33%) were infected IU, one infant (0.22%, 95% CI 0-1.4%) was infected IP, and two infants (0.44%, 95% CI 0.01-1.7%) were infected PP. The infant mortality rate was 0.88% (95% CI 0.26-2.33%).

CONCLUSIONS

In the first 6 months of life, in the era of Option B Plus combination antiretroviral therapy, IU transmission is the major route of MTCT. The cumulative MTCT rate of 1.55% in a breastfeeding population contributes to growing evidence that complete elimination of MTCT is possible.

Eliminating postnatal HIV transmission in high incidence areas: need for complementary biomedical interventions

The rate of mother-to-child transmission (MTCT) of HIV from breastfeeding is increasing relative to other causes of MTCT. Early effective preconception and antenatal antiretroviral therapy (ART) reduces intrauterine and intrapartum MTCT, whereas maternal post-partum HIV acquisition, untreated maternal HIV, and suboptimal postnatal maternal ART adherence increase the risk of MTCT through breastfeeding. Although the absolute number of cases of MTCT acquired through breastfeeding is decreasing, the rate of decrease is less than the decrease in intrauterine and intrapartum MTCT. Unless current strategies are universally applied, they might not be sufficient to eliminate MTCT due to breastfeeding. Urgent action is needed to evaluate and implement additional preventive biomedical strategies in high HIV prevalence and incidence settings to eliminate MTCT from breastfeeding. Preventive strategies include: pre-exposure prophylaxis in breastfeeding women who have an increased risk of acquiring HIV; postnatal reinforcement strategies, such as maternal retesting for HIV, maternal care reinforcement, and prophylaxis in infants exposed to HIV via breastmilk; and active (vaccine) or passive immunoprophylaxis with long-acting broadly neutralising antibodies.

Timing of HIV testing among pregnant and breastfeeding women and risk of mother-to-child HIV transmission in Malawi: a sampling-based cohort study

INTRODUCTION

Pregnant women living with HIV can achieve viral suppression and prevent HIV mother-to-child transmission (MTCT) with timely HIV testing and early ART initiation and maintenance. Although it is recommended that pregnant women undergo HIV testing early in antenatal care in Malawi, many women test positive during breastfeeding because they did not have their HIV status ascertained during pregnancy, or they tested negative during pregnancy but seroconverted postpartum. We sought to estimate the association between the timing of last positive HIV test (during pregnancy vs. breastfeeding) and outcomes of maternal viral suppression and MTCT in Malawi's PMTCT programme.

METHODS

We conducted a two-stage cohort study among mother-infant pairs in 30 randomly selected high-volume health facilities across five nationally representative districts of Malawi between 1 July 2016 and 30 June 2017. Log-binomial regression was used to estimate prevalence ratios (PR) and risk ratios (RR) for associations between timing of last positive HIV test (i.e. breastfeeding vs. pregnancy) and maternal viral suppression and MTCT, controlling for confounding using inverse probability weighting.

RESULTS

Of 822 mother-infant pairs who had available information on the timing of the last positive HIV test, 102 mothers (12.4%) had their last positive test during breastfeeding. Women who lived one to two hours (PR = 2.15; 95% CI: 1.29 to 3.58) or >2 hours (PR = 2.36; 95% CI: 1.37 to 4.10) travel time to the nearest health facility were more likely to have had their last positive HIV test during breastfeeding compared to women living <1 hour travel time to the nearest health facility. The risk of unsuppressed VL did not differ between women who had their last positive HIV test during breastfeeding versus pregnancy (adjusted RR [aRR] = 0.87; 95% CI: 0.48 to 1.57). MTCT risk was higher among women who had their last positive HIV test during breastfeeding compared to women who had it during pregnancy (aRR = 6.57; 95% CI: 3.37 to 12.81).

CONCLUSIONS

MTCT in Malawi occurred disproportionately among women with a last positive HIV test during breastfeeding. Testing delayed until the postpartum period may lead to higher MTCT. To optimize maternal and child health outcomes, PMTCT programmes should focus on early ART initiation and providing targeted testing, prevention, treatment and support to breastfeeding women.

[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.

Perspectives on HIV partner notification, partner HIV self-testing and partner home-based HIV testing by pregnant and postpartum women in antenatal settings: a qualitative analysis in Malawi and Zambia

INTRODUCTION

HIV testing male partners of pregnant and postpartum women can lead to improved health outcomes for women, partners and infants. However, in sub-Saharan Africa, few male partners get HIV tested during their partner's pregnancy in spite of several promising approaches to increase partner testing uptake. We assessed stakeholders' views and preferences of partner notification, home-based testing and secondary distribution of self-test kits to understand whether offering choices for partner HIV testing may increase acceptability.

METHODS

Interviewers conducted semi-structured interviews with HIV-negative (N = 39) and HIV-positive (N = 41) pregnant/postpartum women, male partners of HIV-negative (N = 14) and HIV-positive (N = 14) pregnant/postpartum women, healthcare workers (N = 19) and policymakers (N = 16) in Malawi and Zambia. Interviews covered views of each partner testing approach and preferred approaches; healthcare workers were also asked about perceptions of a choice-based approach. Interviews were transcribed, translated and analysed to compare perspectives across country and participant types.

RESULTS

Most participants within each stakeholder group considered all three partner testing strategies acceptable. Relationship conflict was discussed as a potential adverse consequence for each approach. For partner notification, additional barriers included women losing letters, being fearful to give partners letters, being unable to read and men refusing to come to the clinic. For home-based testing, additional barriers included lack of privacy or confidentiality and fear of experiencing community-level HIV stigma. For HIV self-test kits, additional barriers included lack of counselling, false results and poor linkage to care. Preferred male partner testing options varied. Participants preferred partner notification due to their respect for clinical authority, home-based testing due to their desire to prioritize convenience and clinical authority, and self-test kits due to their desire to prioritize confidentiality. Less than half of couples interviewed selected the same preferred male partner testing option as their partner. Most healthcare workers felt the choice-based approach would be acceptable and feasible, but noted implementation challenges in personnel, resources or space.

CONCLUSIONS

Most stakeholders considered different approaches to partner HIV testing to be acceptable, but concerns were raised about each. A choice-based approach may allow women to select their preferred method of partner testing; however, implementation challenges need to be addressed.

A threshold delay model of HIV infection of newborn infants through breastfeeding

The breast milk of HIV infected women contains HIV virus particles, therefore children can become infected through breastfeeding. We develop a mathematical epidemiological model of HIV infection in infants, infected children and infected women that represents infection of an infant/child as a series of exposures, by incorporating within-host virus dynamics in the individuals exposed to the virus through breastfeeding. We show that repeated exposures of the infant/child via breastfeeding can cause bi-stability dynamics and, subsequently, infection persistence even when the epidemiological basic reproduction number R0 is less than unity. This feature of the model, due to a backward bifurcation, gives new insight into the control mechanisms of HIV disease through breastfeeding.

Pediatric HIV-1 Acquisition and Lifelong Consequences of Infant Infection

Increased availability of antiretroviral therapy to pregnant and breastfeeding women in resource-limited areas has proven remarkably successful at reducing HIV vertical transmission rates over the past several decades. Yet, still more than 170,000 children are infected annually due to failures in therapy implementation, monitoring, and adherence. Mother-to-child transmission (MTCT) of HIV-1 can occur at one of several distinct stages of infant development - intrauterine, intrapartum, and postpartum. The heterogeneity of the maternal-fetal interface at each of these modes of transmission poses a challenge for the implementation of immune interventions to prevent all modes of HIV MTCT. However, using mother-infant human cohorts and nonhuman primate models of infant simian immunodeficiency virus (SIV) acquisition, investigators have made important observation about the biology of pediatric HIV infection and have identified unique protective immune factors for each mode of transmission. Knowledge of immune factors protective against HIV MTCT will be critical to the development of targeted immune therapies to prevent infant HIV acquisition and to bring an end to the pediatric AIDS epidemic.

Maternal Syphilis: An Independent Risk Factor for Mother to Infant Human Immunodeficiency Virus Transmission

Syphilis is associated with increased human immunodeficiency virus acquisition and sexual transmission; we examined impact on human immunodeficiency virus mother-to-child transmission among mother-infant pairs enrolled in the India Six-Week Extended-Dose Nevirapine study. Maternal syphilis, diagnosed serologically using Venereal Disease Research Laboratory titer plus Treponema Pallidum Hemagglutination Assay, was associated with 2.5-fold greater risk.

Birth control counseling for HIV seropositive pregnant women

Testing for HIV antibody at the antenatal clinic in Siriraj Hospital started on 1 July 1991. It was found that the percentage of HIV seropositive pregnant women rapidly increased from 1.2% in 1992 to 1.9% in 1993. During those 2 years, 487 seropositive women were admitted for delivery or abortion; 23.8% were adolescents and 47.0%, young adults. Prevention of HIV transmission from mother-to-baby was birth control; 95 women (19.5%) chose to abort their pregnancy. After termination of all pregnancies by abortion or delivery, 83% requested sterilization, 12.9% accepted Norplant, 1.8% the pill and only 2.3% refused anything at all. Condoms were used regularly for prevention of HIV infection by 29.4% of men although Thai men generally do not accept them for birth control. Seropositive Norplant users had more bleeding than general Norplant users but treatments were the same.

Whose Epidemic is it? Reviewing the Literature on Women and AIDS

AIDS is widely presented as a critical problem for women, which raises special issues of prevention and care. Although it is suggested that women are particularly vulnerable physiologically to HIV infection, biomedical research into treatment and prevention options specifically for women has been limited. Considerable social science research at both the theoretical and applied level has been documented. While analyses have tended to highlight broad structural factors, interventions have often been at individual/group level. The literature demonstrates the dilemma of AIDS being seen as women's responsibility, although they lack the power and means to implement safe sex. Gender imbalances in depictions of and responses to AIDS need to be attended to if the epidemic is to be effectively addressed.

Estimating mother-to-child HIV transmission rates in Cameroon in 2011: a computer simulation approach

BACKGROUND

Despite the progress in the Prevention of the Mother-to-Child Transmission of HIV (PMTCT), the paediatric HIV epidemic remains worrying in Cameroon. HIV prevalence rate for the population of pregnant women was 7.6% in 2010 in Cameroon. The extent of the paediatric HIV epidemic is needed to inform policymakers. We developed a stochastic simulation model to estimate the number of new paediatric HIV infections through MTCT based on the observed uptake of services during the different steps of the PMTCT cascade in Cameroon in 2011. Different levels of PMTCT uptake was also assessed.

METHODS

A discrete events computer simulation-based approach with stochastic structure was proposed to generate a cohort of pregnant women followed-up until 6 weeks post-partum, and optionally until complete breastfeeding cessation in both prevalent and incident lactating HIV-infected women. The different parameters of the simulation model were fixed using data sources available from the 2011 national registry surveys, and from external cohorts in Cameroon. Different PMTCT coverages were simulated to assess their impact on MTCT. Available data show a low coverage of PMTCT services in Cameroon in 2011.

RESULTS

Based on a simulation approach on a population of 995, 533 pregnant women, the overall residual MTCT rate in 2011 was estimated to be 22.1% (95 % CI: 18.6%-25.2%), the 6-week perinatal MTCT rate among prevalent HIV-infected mothers at delivery is estimated at 12.1% (95% CI: 8.1%-15.1%), with an additional postnatal MTCT rate estimated at 13.3% (95% CI: 9.3%-17.8%). The MTCT rate among children whose mothers seroconverted during breastfeeding was estimated at 20.8% (95% CI: 14.1%-26.9%). Overall, we estimated the number of new HIV infections in children in Cameroon to be 10, 403 (95% CI: 9, 054-13, 345) in 2011. When PMTCT uptake have been fixed at 100%, 90% and 80%, global MTCT rate failed to 0.9% (9% CI: 0.5%-1.7%), 2.0% (95% CI: 0.9%-3.2%) and 4.3% (95% CI: 2.4%-6.7%) respectively.

CONCLUSIONS

This model is helpful to provide MTCT estimates to guide the national HIV policy in Cameroon. Increasing supply and uptake of PMTCT services among prevalent HIV infected pregnant women, as well as HIV-prevention interventions including the offer and acceptance of HIV testing and counselling in lactating women could reduce significantly the residual HIV MTCT in Cameroon. A public health effort should be made to encourage health care workers and pregnant women to use PMTCT services until complete breastfeeding cessation.

Cytomegalovirus, and possibly Epstein-Barr virus, shedding in breast milk is associated with HIV-1 transmission by breastfeeding

OBJECTIVE

Postnatal HIV-1 mother-to-child transmission (MTCT) occurs in spite of antiretroviral therapy. Co-infections in breast milk with cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are associated with increased HIV-1 shedding in this compartment. We investigated CMV levels and EBV detection in breast milk as potential risk factors for MTCT of HIV-1 via breastfeeding.

METHODS

Cell-free HIV-1 RNA, cell-associated HIV-1 DNA, CMV and EBV DNA were quantified in breast milk from 62 HIV-infected mothers and proven postnatal MTCT of HIV-1 via breastfeeding. Controls were 62 HIV-positive mothers with HIV-uninfected infants.

RESULTS

Median (interquartile range) CMV DNA viral load was significantly higher in cases [88,044 (18,586-233,904)] than in controls [11,167 (3221-31,152)] copies/10 breast milk cells (P < 0.001). Breast milk CMV DNA level correlated positively with breast milk HIV-1 RNA level in cases and controls. EBV DNA was detectable in a higher proportion of breast milk samples of cases (37.1%) than controls (16.1%; P = 0.009). HIV-1 MTCT was strongly associated with HIV-1 RNA shedding in breast milk and plasma. In multivariable analysis, every 1 log10 increase in breast milk CMV DNA was associated with a significant 2.5-fold greater odds of MTCT of HIV-1, independent of breast milk and plasma HIV-1 levels; the nearly three-fold increased risk of HIV-1 MTCT with breast milk EBV DNA detection did not reach significance.

CONCLUSION

We provide the first evidence of an independent association between CMV in breast milk, and postnatal MTCT of HIV-1. This association could fuel persistent shedding of HIV-1 in breast milk in women receiving antiretroviral therapy. EBV DNA detection in breast milk may also be associated with MTCT of HIV-1, but only marginally so.

Morbidity in relation to feeding mode in African HIV-exposed, uninfected infants during the first 6 mo of life: the Kesho Bora study

BACKGROUND

Refraining from breastfeeding to prevent HIV transmission has been associated with increased morbidity and mortality in HIV-exposed African infants.

OBJECTIVE

The objective was to assess risks of common and serious infectious morbidity by feeding mode in HIV-exposed, uninfected infants ≤6 mo of age with special attention to the issue of reverse causality.

DESIGN

HIV-infected pregnant women from 5 sites in Burkina Faso, Kenya, and South Africa were enrolled in the prevention of mother-to-child transmission Kesho Bora trial and counseled to either breastfeed exclusively and cease by 6 mo postpartum or formula feed exclusively. Maternal-reported morbidity (fever, diarrhea, and vomiting) and serious infectious events (SIEs) (gastroenteritis and lower respiratory tract infections) were investigated for 751 infants for 2 age periods (0-2.9 and 3-6 mo) by using generalized linear mixed models with breastfeeding as a time-dependent variable and adjustment for study site, maternal education, economic level, and cotrimoxazole prophylaxis.

RESULTS

Reported morbidity was not significantly higher in nonbreastfed compared with breastfed infants [OR: 1.31 (95% CI: 0.97, 1.75) and 1.21 (0.90, 1.62) at 0-2.9 and 3-6 mo of age, respectively]. Between 0 and 2.9 mo of age, never-breastfed infants had increased risks of morbidity compared with those of infants who were exclusively breastfed (OR: 1.49; 95% CI: 1.01, 2.2; P = 0.042). The adjusted excess risk of SIEs in nonbreastfed infants was large between 0 and 2.9 mo (OR: 6.0; 95% CI: 2.2, 16.4; P = 0.001). Between 3 and 6 mo, the OR for SIEs was sensitive to the timing of breastfeeding status, i.e., 4.3 (95% CI: 1.2, 15.3; P = 0.02) when defined at end of monthly intervals and 2.0 (95% CI: 0.8, 5.0; P = 0.13) when defined at the beginning of intervals. Of 52 SIEs, 3 mothers reported changes in feeding mode during the SIE although none of the mothers ceased breastfeeding completely.

CONCLUSIONS

Not breastfeeding was associated with increased risk of serious infections especially between 0 and 2.9 mo of age. The randomized controlled trial component of the Kesho Bora study was registered at Current Controlled Trials (www.controlled-trials.com) as ISRCTN71468401.

HIV transmission through breastfeeding: still possible in developed countries

We describe here the case of a 13-month-old boy who acquired HIV infection postnatally through breastfeeding in a developed country in 2012. His mother had regular pregnancy follow-up and was found to be seronegative for HIV on 2 consecutive screening tests (during pregnancy and just after delivery). However, 1 year later, diagnosis of HIV infection arose in both of them after a pediatric emergency department visit for bronchitis when unexplained hepatosplenomegaly and inflammatory syndrome were noted. The negative maternal viral load found just after delivery confirmed that the mother's seroconversion occurred postnatally, which allowed for active HIV transmission during lactation and lack of the efficient preventive measures that have implemented in Belgium for years. We discuss this uncommon but still existing mode of HIV transmission in industrialized countries and highlight the importance of implementing new targeted health education interventions in addition to constant clinicians' awareness.

Incident HIV during pregnancy and postpartum and risk of mother-to-child HIV transmission: a systematic review and meta-analysis

BACKGROUND

Women may have persistent risk of HIV acquisition during pregnancy and postpartum. Estimating risk of HIV during these periods is important to inform optimal prevention approaches. We performed a systematic review and meta-analysis to estimate maternal HIV incidence during pregnancy/postpartum and to compare mother-to-child HIV transmission (MTCT) risk among women with incident versus chronic infection.

METHODS AND FINDINGS

We searched PubMed, Embase, and AIDS-related conference abstracts between January 1, 1980, and October 31, 2013, for articles and abstracts describing HIV acquisition during pregnancy/postpartum. The inclusion criterion was studies with data on recent HIV during pregnancy/postpartum. Random effects models were constructed to pool HIV incidence rates, cumulative HIV incidence, hazard ratios (HRs), or odds ratios (ORs) summarizing the association between pregnancy/postpartum status and HIV incidence, and MTCT risk and rates. Overall, 1,176 studies met the search criteria, of which 78 met the inclusion criterion, and 47 contributed data. Using data from 19 cohorts representing 22,803 total person-years, the pooled HIV incidence rate during pregnancy/postpartum was 3.8/100 person-years (95% CI 3.0-4.6): 4.7/100 person-years during pregnancy and 2.9/100 person-years postpartum (p = 0.18). Pooled cumulative HIV incidence was significantly higher in African than non-African countries (3.6% versus 0.3%, respectively; p<0.001). Risk of HIV was not significantly higher among pregnant (HR 1.3, 95% CI 0.5-2.1) or postpartum women (HR 1.1, 95% CI 0.6-1.6) than among non-pregnant/non-postpartum women in five studies with available data. In African cohorts, MTCT risk was significantly higher among women with incident versus chronic HIV infection in the postpartum period (OR 2.9, 95% CI 2.2-3.9) or in pregnancy/postpartum periods combined (OR 2.3, 95% CI 1.2-4.4). However, the small number of studies limited power to detect associations and sources of heterogeneity.

CONCLUSIONS

Pregnancy and the postpartum period are times of persistent HIV risk, at rates similar to "high risk" cohorts. MTCT risk was elevated among women with incident infections. Detection and prevention of incident HIV in pregnancy/postpartum should be prioritized, and is critical to decrease MTCT.

Elevated concentrations of milk β2-microglobulin are associated with increased risk of breastfeeding transmission of HIV-1 (Vertical Transmission Study)

There is increasing evidence to support a relationship between human immunodeficiency virus (HIV-1) transmission through breastfeeding and milk host factors. We analyzed skim milk proteome to further determine the contribution of host factors to the risk of mother-to-child transmission of HIV-1. Quantitative mass spectrometry analysis was performed on nine case-control pairs of HIV+ transmitter/nontransmitter mothers, and specific biochemical assays on two selected proteins were assessed in an independent validation set of 127 samples. 33 identified proteins were differentially expressed between HIV+ transmitter and nontransmitter mothers. Among them, β2-microglobulin was significantly higher in the maternal transmitter than in the nontransmitter groups (p value = 0.0007), and S100A9 was significantly higher in the early maternal transmitter cases (before 4 months of age) compared with the nontransmitters (p value = 0.004). β2-Microglobulin correlated with milk and plasma HIV viral load and CD4+ cell count, whereas S100A9 correlated with the estimated timing of infection of the infant through breastfeeding. Finally, β2-microglobulin concentration in milk could accurately predict the risk of HIV-1 postnatal transmission by breastfeeding (p value < 0.0001, log-rank test). In conclusion, milk β2-microglobulin and S100A9 are host factors that are found to be associated with mother-to-child transmission of HIV-1.

Infant feeding modes and determinants among HIV-1-infected African Women in the Kesho Bora Study

OBJECTIVE

To assess breastfeeding modes and determinants in a prevention of mother-to-child transmission study.

DESIGN

HIV-1-infected pregnant women from 5 sites in Burkina Faso, Kenya, and South Africa were enrolled in the study that comprised 2 prospective cohorts and 1 randomized controlled trial. Women were counseled to either breastfeed exclusively up to 6 months or formula feed from birth.

METHODS

Determinants of breastfeeding initiation and continuation by 3 months postpartum were investigated using multiple logistic regression analysis. Neonatal morbidity was defined as mother-reported fever, diarrhea, or vomiting during the first month of life.

RESULTS

Among 1028, 781 women (76%) initiated breastfeeding and 565 of 995 (56%) were still breastfeeding at 3 months postpartum (30% exclusively, 18% predominantly, and 8% partially). Study site (Durban, Mombasa, and Nairobi compared with Bobo-Dioulasso), CD4 cell count (<200 cells/mm), secondary schooling (compared with none), and emergency cesarean delivery (compared with vaginal delivery) were independently associated with a lower probability of ever breastfeeding. The odds of still breastfeeding by 3 months postpartum (among those breastfeeding by 1 month) were lower in Mombasa, Nairobi, and Somkhele (compared with Bobo-Dioulasso) and among infants with neonatal morbidity [0.60 (0.37-0.976)]. The odds of exclusive breastfeeding (EBF) by 3 months (if EBF by 1 month) were lower in Mombasa and Nairobi, in ill neonates [0.54 (0.31-0.93)] and boys [0.51 (0.34-0.77)].

CONCLUSIONS

EBF was of short duration, particularly for boys. The importance of neonatal morbidity for breastfeeding cessation requires further investigation. Infant feeding counseling might need adaptation to better support mothers of boys and ill neonates.

Estimates of peripartum and postnatal mother-to-child transmission probabilities of HIV for use in Spectrum and other population-based models

BACKGROUND

The Global Plan Towards the Elimination of New HIV Infections among Children and Keeping Their Mothers Alive aims to reduce by 2015 the number of new infections in children, in 22 priority countries, by at least 90% from 2009 levels. Mathematical models, such as Spectrum, are used to estimate national and global trends of the number of infants infected through mother-to-child transmission (MTCT). However, other modelling exercises have also examined MTCT under different settings. MTCT probabilities applied in models to populations that are assumed to receive antiretroviral interventions need to reflect the most current risk estimates.

METHODS

The UNAIDS Reference Group on Estimates, Modelling and Projections held a consultation to review data on MTCT probabilities. Published literature, recent conferences and data from personal communications with principle investigators were reviewed. Based on available data, peripartum and postnatal transmission probabilities were estimated for different antiretroviral drug regimens and maternal CD4 levels including for women with incident infection.

RESULTS

Incident infections occurring during pregnancy are estimated to be associated with a 30% probability of MTCT; incident infections during breast feeding lead to a 28% probability of postnatal MTCT. The 2010 WHO recommended regimens (Options A or B) are estimated to be associated with a 2% peripartum transmission probability and 0.2% transmission probability per month of breast feeding. Peripartum and postnatal transmission probabilities were lowest for women who were taking antiretroviral therapy before the pregnancy namely 0.5% peripartum and 0.16% per month of breast feeding, respectively.

DISCUSSION

These updated probabilities of HIV transmission (applied to Spectrum in April 2011) will be used to estimate new child HIV infections and track progress towards the 2015 targets of the Global Plan.

Care of the HIV-exposed child--to breast feed or not?

Breast milk is the best form of nutrition for infants. However, it places infants born to HIV infected women at risk of acquiring HIV infection. Total avoidance of breastfeeding is the only way of completely avoiding HIV transmission through breast milk. However, this strategy has not proved to be viable in resource constrained nations. A high infection related mortality and morbidity, and a high prevalence of malnutrition have been observed in HIV exposed infants on replacement feeding. Exclusive breastfeeding for the first six months followed by rapid weaning has also not proved to be a good strategy, with a surge in infection related morbidity and malnutrition reported after weaning. Current evidence indicates that continued use of ARV prophylaxis to mother/infant starting during pregnancy and continued to cover the entire duration of breastfeeding offers the infant best chance of HIV free survival, combining the benefits of breast milk with safety induced by ARV prophylaxis.

Materno-fetal transmission of human immune deficiency virus

Mother-to-child transmission of human immune deficiency virus (HIV) is a multifactorial event highly associated with advanced maternal HIV disease and obstetric incidents taking place during parturition. Thus, various approaches to prevention may be beneficial. Although the time and the route of materno-fetal HIV transmission are still not sufficiently clear, much speaks in favor of a late HIV transmission, most probably taking place during parturition or the phase before the delivery. The fetus is remarkably protected by the placenta and the intact fetal membranes against many viral infections during gestation. These conditions change at parturition and the chance for a transition of HIV-infected carrier cells or virus into the fetal compartment increases. Proinflammatory cytokines secreted at the materno-fetal interface accumulate in amniotic fluid and may chemoattract and stimulate potentially HIV-infected immunocytes. After rupture of membranes, maternal cells of the decidua are directly exposed to the amniotic fluid. Aside from the contamination of the fetal skin at vaginal delivery as a debatable route of infection, blood-to-blood contacts and the fetal swallowing of contaminated amniotic fluid may be the major path of fetal HIV infection. For the fetal prophylaxis of an intrauterine infection, the application of zidovudine is recommended. However, cesarian section before the onset of labor leads also to a diminution of the transmission rate. As the transmission seems to have both systemic and local causes, it makes sense to combine different intervention strategies. Whether a combination of zidovudine and elective cesarean section can lower the transmission risk further has to be evaluated.

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.

Expressed breast milk on a neonatal unit: a hazard analysis and critical control points approach

With the increasing use of human milk and growing evidence of the benefits of mother's milk for preterm and ill newborns, guidelines to ensure its quality and safety are an important part of daily practice in neonatal intensive care units. Operating procedures based on hazard analysis and critical control points can standardize the handling of mother's expressed milk, thereby improving nutrition and minimizing the risk of breast milk-induced infection in susceptible newborns. Because breast milk is not sterile, microorganisms can multiply when the milk is not handled properly. Additional exogenous contamination should be prevented. Strict hygiene and careful temperature and time control are important during the expression, collection, transport, storage, and feeding of maternal milk. In contrast to formula milk, no legal standards exist for the use of expressed maternal milk. The need for additional measures, such as bacteriological screening or heat treatment, remains unresolved.

Plausibility of HIV-1 Infection of Oral Mucosal Epithelial Cells

The AIDS pandemic continues. Little is understood about how HIV gains access to permissive cells across mucosal surfaces, yet such knowledge is crucial to the development of successful topical anti-HIV-1 agents and mucosal vaccines. HIV-1 rapidly internalizes and integrates into the mucosal keratinocyte genome, and integrated copies of HIV-1 persist upon cell passage. The virus does not appear to replicate, and the infection may become latent. Interactions between HIV-1 and oral keratinocytes have been modeled in the context of key environmental factors, including putative copathogens and saliva. In keratinocytes, HIV-1 internalizes within minutes; in saliva, an infectious fraction escapes inactivation and is harbored and transferable to permissive target cells for up to 48 hours. When incubated with the common oral pathogen Porphyromonas gingivalis, CCR5- oral keratinocytes signal through protease-activated receptors and Toll-like receptors to induce expression of CCR5, which increases selective uptake of infectious R5-tropic HIV-1 into oral keratinocytes and transfer to permissive cells. Hence, oral keratinocytes-like squamous keratinocytes of other tissues-may be targets for low-level HIV-1 internalization and subsequent dissemination by transfer to permissive cells.

Incident HIV infection in pregnant and lactating women and its effect on mother-to-child transmission in South Africa

We described HIV incidence and mother-to-child transmission (MTCT) among women during pregnancy and lactation. Forty-eight (3.4%) of 1396 women seroconverted during pregnancy or <12 mo after delivery. This group of HIV-exposed children was at 2.3 times higher risk of infection (MTCT 20.5% [8 of 39] vs 9.0% (83 of 925]). An estimated 20% with CD4+ cell counts <350 would have been eligible for antiretroviral therapy (ART), yet all women with incident HIV infections are more likely to transmit HIV to their children. To ensure optimal prevention of MTCT, all women who seroconvert during pregnancy or lactation should be considered for ART for the purpose of prevention of MTCT, and women with CD4+ <350 should continue to receive ART.

Triple-antiretroviral prophylaxis to prevent mother-to-child HIV transmission through breastfeeding--the Kisumu Breastfeeding Study, Kenya: a clinical trial

BACKGROUND

Effective strategies are needed for the prevention of mother-to-child HIV transmission (PMTCT) in resource-limited settings. The Kisumu Breastfeeding Study was a single-arm open label trial conducted between July 2003 and February 2009. The overall aim was to investigate whether a maternal triple-antiretroviral regimen that was designed to maximally suppress viral load in late pregnancy and the first 6 mo of lactation was a safe, well-tolerated, and effective PMTCT intervention.

METHODS AND FINDINGS

HIV-infected pregnant women took zidovudine, lamivudine, and either nevirapine or nelfinavir from 34-36 weeks' gestation to 6 mo post partum. Infants received single-dose nevirapine at birth. Women were advised to breastfeed exclusively and wean rapidly just before 6 mo. Using Kaplan-Meier methods we estimated HIV-transmission and death rates from delivery to 24 mo. We compared HIV-transmission rates among subgroups defined by maternal risk factors, including baseline CD4 cell count and viral load. Among 487 live-born, singleton, or first-born infants, cumulative HIV-transmission rates at birth, 6 weeks, and 6, 12, and 24 mo were 2.5%, 4.2%, 5.0%, 5.7%, and 7.0%, respectively. The 24-mo HIV-transmission rates stratified by baseline maternal CD4 cell count <500 and ≥500 cells/mm(3) were 8.4% (95% confidence interval [CI] 5.8%-12.0%) and 4.1% (1.8%-8.8%), respectively (p = 0.06); the corresponding rates stratified by baseline maternal viral load <10,000 and ≥10,000 copies/ml were 3.0% (1.1%-7.8%) and 8.7% (6.1%-12.3%), respectively (p = 0.01). None of the 12 maternal and 51 infant deaths (including two second-born infants) were attributed to antiretrovirals. The cumulative HIV-transmission or death rate at 24 mo was 15.7% (95% CI 12.7%-19.4%).

CONCLUSIONS

This trial shows that a maternal triple-antiretroviral regimen from late pregnancy through 6 months of breastfeeding for PMTCT is safe and feasible in a resource-limited setting. These findings are consistent with those from other trials using maternal triple-antiretroviral regimens during breastfeeding in comparable settings.

Mother to child transmission of HIV among Zimbabwean women who seroconverted postnatally: prospective cohort study

OBJECTIVES

To estimate the rates and timing of mother to infant transmission of HIV associated with breast feeding in mothers who seroconvert postnatally, and their breast milk and plasma HIV loads during and following seroconversion, compared with women who tested HIV positive at delivery.

DESIGN

Prospective cohort study.

SETTING

Urban Zimbabwe.

PARTICIPANTS

14 110 women and infants enrolled in the Zimbabwe Vitamin A for Mothers and Babies (ZVITAMBO) trial (1997-2001).

MAIN OUTCOME MEASURES

Mother to child transmission of HIV, and breast milk and maternal plasma HIV load during the postpartum period.

RESULTS

Among mothers who tested HIV positive at baseline and whose infant tested HIV negative with polymerase chain reaction (PCR) at six weeks (n=2870), breastfeeding associated transmission was responsible for an average of 8.96 infant infections per 100 child years of breast feeding (95% CI 7.92 to 10.14) and varied little over the breastfeeding period. Breastfeeding associated transmission for mothers who seroconverted postnatally (n=334) averaged 34.56 infant infections per 100 child years (95% CI 26.60 to 44.91) during the first nine months after maternal infection, declined to 9.50 (95% CI 3.07 to 29.47) during the next three months, and was zero thereafter. Among women who seroconverted postnatally and in whom the precise timing of infection was known (≤90 days between last negative and first positive test; n=51), 62% (8/13) of transmissions occurred in the first three months after maternal infection and breastfeeding associated transmission was 4.6 times higher than in mothers who tested HIV positive at baseline and whose infant tested HIV negative with PCR at six weeks. Median plasma HIV concentration in all mothers who seroconverted postnatally declined from 5.0 log(10) copies/mL at the last negative enzyme linked immunosorbent assay (ELISA) to 4.1 log(10) copies/mL at 9-12 months after infection. Breast milk HIV load in this group was 4.3 log(10) copies/mL 0-30 days after infection, but rapidly declined to 2.0 log(10) copies/mL and <1.5 log(10) copies/mL by 31-90 days and more than 90 days, respectively. Among women whose plasma sample collected soon after delivery tested negative for HIV with ELISA but positive with PCR (n=17), 75% of their infants were infected or had died by 12 months. An estimated 18.6% to 20.4% of all breastfeeding associated transmission observed in the ZVITAMBO trial occurred among mothers who seroconverted postnatally.

CONCLUSIONS

Breastfeeding associated transmission is high during primary maternal HIV infection and is mirrored by a high but transient peak in breast milk HIV load. Around two thirds of breastfeeding associated transmission by women who seroconvert postnatally may occur while the mother is still in the "window period" of an antibody based test, when she would test HIV negative using one of these tests. Trial registration Clinical trials.gov NCT00198718.

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.

[A case of HIV-1 infection that showed Western blot analysis for HIV-1 negative after antiretroviral therapy]

Western blot (WB) is the most widely accepted confirmatory assay for detecting antibodies to the human immunodeficiency virus 1 (HIV-1). We report the case of an HIV-1 patient whose WB was negative for over two years. A 41-year-old Japanese man with Pneumocystis pneumonia (PCP) and pulmonary tuberculosis referred in March 2005 was found to have positive HIV-1 ELISA and HIV RNA PCR, but HIV-1 WB with only two bands, at gp160 and p18, and no WB HIV-2 band. The CD4 count was 37/microL, and total immunoglobulin, IgG, IgM, and IgG subclasses were normal. The man was treated for PCP and pulmonary tuberculosis, then underwent antiretroviral therapy. He had taken short-terms steroids to treat a drug allergy and immune reconstitution syndrome. Six months later, his serological ELISA tests for HIV-1 and HIV DNA PCR were negative and WB showed no positive band. The CD4 count recovered gradually, and exceeded 350/microL two years later, but WB remained negative. Lymphoproliferative assays and interferon y expression against HIV-pl7, p24, and p41 were studied and compared to those of other HIV-1 infected patients. Our patient showed no response to p17 or p24 and only a weak response to p41. Other patients showed a response to HIV-antigens, but patients with antiretroviral therapy or with histories of steroid use responded more weakly than those with neither. These findings show that HIV-specific lymphocytes decline with antiretroviral therapy and steroid treatment within early HIV infection. It is therefore important to interpret negative serological tests carefully in patients such as ours.