Breast-feeding and HIV-1 transmission in resource-limited settings

Role of TIM-4 in exosome-dependent entry of HIV-1 into human immune cells

Exosomes, 30–200 nm nanostructures secreted from donor cells and internalized by recipient cells, can play an important role in the cellular entry of some viruses. These microvesicles are actively secreted into various body fluids, including blood, urine, saliva, cerebrospinal fluid, and breast milk. We successfully isolated exosomes from human breast milk and plasma. The size and concentration of purified exosomes were measured by nanoparticle tracking, while Western blotting confirmed the presence of the exosomal-associated proteins CD9 and CD63, clathrin, and T cell immunoglobulin and mucin proteins (TIMs). Through viral infection assays, we determined that HIV-1 utilizes an exosome-dependent mechanism for entry into human immune cells. The virus contains high amounts of phosphatidylserine (PtdSer) and may bind PtdSer receptors, such as TIMs. This mechanism is supported by our findings that exosomes from multiple sources increased HIV-1 entry into T cells and macrophages, and viral entry was potently blocked with anti-TIM-4 antibodies.

The function and affinity maturation of HIV-1 gp120-specific monoclonal antibodies derived from colostral B cells

Despite the risk of transmitting HIV-1, mothers in resource-poor areas are encouraged to breastfeed their infants because of beneficial immunologic and nutritional factors in milk. Interestingly, in the absence of antiretroviral prophylaxis, the overwhelming majority of HIV-1-exposed, breastfeeding infants are naturally protected from infection. To understand the role of HIV-1 envelope (Env)-specific antibodies in breast milk in natural protection against infant virus transmission, we produced 19 HIV-1 Env-specific monoclonal antibodies (mAbs) isolated from colostrum B cells of HIV-1-infected mothers and investigated their specificity, evolution, and anti-HIV-1 functions. Despite the previously reported genetic compartmentalization and gp120-specific bias of colostrum HIV Env-specific B cells, the colostrum Env-specific mAbs described here demonstrated a broad range of gp120 epitope specificities and functions, including inhibition of epithelial cell binding and dendritic cell-mediated virus transfer, neutralization, and antibody-dependent cellular cytotoxicity. We also identified divergent patterns of colostrum Env-specific B-cell lineage evolution with respect to crossreactivity to gastrointestinal commensal bacteria, indicating that commensal bacterial antigens play a role in shaping the local breast milk immunoglobulin G (IgG) repertoire. Maternal vaccine strategies to specifically target this breast milk B-cell population may be necessary to achieve safe breastfeeding for all HIV-1-exposed infants.

Evaluation of a community health worker intervention and the World Health Organization's Option B versus Option A to improve antenatal care and PMTCT outcomes in Dar es Salaam, Tanzania: study protocol for a cluster-randomized controlled health systems implementation trial

Background

Mother-to-child transmission of HIV remains an important public health problem in sub-Saharan Africa. As HIV testing and linkage to PMTCT occurs in antenatal care (ANC), major challenges for any PMTCT option in developing countries, including Tanzania, are delays in the first ANC visit and a low overall number of visits. Community health workers (CHWs) have been effective in various settings in increasing the uptake of clinical services and improving treatment retention and adherence. At the beginning of this trial in January 2013, the World Health Organization recommended either of two medication regimens, Option A or B, for prevention of mother-to-child transmission of HIV (PMTCT). It is still largely unclear which option is more effective when implemented in a public healthcare system. This study aims to determine the effectiveness, cost-effectiveness, acceptability, and feasibility of: (1) a community health worker (CWH) intervention and (2) PMTCT Option B in improving ANC and PMTCT outcomes.

Methods/Design

This study is a cluster-randomized controlled health systems implementation trial with a two-by-two factorial design. All 60 administrative wards in the Kinondoni and Ilala districts in Dar es Salaam were first randomly allocated to either receiving the CHW intervention or not, and then to receiving either Option B or A. Under the standard of care, facility-based health workers follow up on patients who have missed scheduled appointments for PMTCT, first through a telephone call and then with a home visit. In the wards receiving the CHW intervention, the CHWs: (1) identify pregnant women through home visits and refer them to antenatal care; (2) provide education to pregnant women on antenatal care, PMTCT, birth, and postnatal care; (3) routinely follow up on all pregnant women to ascertain whether they have attended ANC; and (4) follow up on women who have missed ANC or PMTCT appointments.

Trial registration

ClinicalTrials.gov:EJF22802. Registration date: 14 May 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/1745-6215-15-359) contains supplementary material, which is available to authorized users.

HIV status, breastfeeding modality at 5 months and postpartum maternal weight changes over 24 months in rural South Africa

OBJECTIVE

To determine the effect of infant feeding practices on postpartum weight change among HIV-infected and -uninfected women in South Africa.

METHODS

In a non-randomised intervention cohort study of antiretroviral therapy-naïve women in South Africa, infants were classified as exclusive (EBF), mixed (MF) or non-breastfed (NBF) at each visit. We analysed infant feeding cumulatively from birth to 5 months using 24-hour feeding history (collected weekly for each of the preceding 7 days). Using generalised estimating equation mixed models, allowing for repeated measures, we compared postpartum weight change (kg) from the first maternal postpartum weight within the first 6 weeks (baseline weight) to each subsequent visit through 24 months among 2340 HIV-infected and -uninfected women with live births and at least two postpartum weight measurements.

RESULTS

HIV-infected (-0.2 kg CI: -1.7 to 1.3 kg; P = 0.81) and -uninfected women (-0.5 kg; 95% CI: -2.1 to 1.2 kg; P = 0.58) had marginal non-significant weight loss from baseline to 24 months postpartum. Adjusting for HIV status, socio-demographic, pregnancy-related and infant factors, 5-month feeding modality was not significantly associated with postpartum weight change: weight change by 24 months postpartum, compared to the change in the reference EBF group, was 0.03 kg in NBF (95% CI: -2.5 to +2.5 kg; P = 0.90) and 0.1 kg in MF (95% CI: -3.0 to +3.2 kg; P = 0.78).

CONCLUSION

HIV-infected and -uninfected women experienced similar weight loss over 24 months. Weight change postpartum was not associated with 5-month breastfeeding modality among HIV-infected and -uninfected women.

Adaptive HIV-specific B cell-derived humoral immune defenses of the intestinal mucosa in children exposed to HIV via breast-feeding

Background

We evaluated whether B cell-derived immune defenses of the gastro-intestinal tract are activated to produce HIV-specific antibodies in children continuously exposed to HIV via breast-feeding.

Methods

Couples of HIV-1-infected mothers (n = 14) and their breastfed non HIV-infected (n = 8) and HIV-infected (n = 6) babies, and healthy HIV-negative mothers and breastfed babies (n = 10) as controls, were prospectively included at the Complexe Pédiatrique of Bangui, Central African Republic. Immunoglobulins (IgA, IgG and IgM) and anti-gp160 antibodies from mother’s milk and stools of breastfed children were quantified by ELISA. Immunoaffinity purified anti-gp160 antibodies were characterized functionally regarding their capacity to reduce attachment and/or infection of R5- and X4- tropic HIV-1 strains on human colorectal epithelial HT29 cells line or monocyte-derived-macrophages (MDM).

Results

The levels of total IgA and IgG were increased in milk of HIV-infected mothers and stools of HIV-exposed children, indicating the activation of B cell-derived mucosal immunity. Breast milk samples as well as stool samples from HIV-negative and HIV-infected babies exposed to HIV by breast-feeding, contained high levels of HIV-specific antibodies, mainly IgG antibodies, less frequently IgA antibodies, and rarely IgM antibodies. Relative ratios of excretion by reference to lactoferrin calculated for HIV-specific IgA, IgG and IgM in stools of HIV-exposed children were largely superior to 1, indicating active production of HIV-specific antibodies by the intestinal mucosa. Antibodies to gp160 purified from pooled stools of HIV-exposed breastfed children inhibited the attachment of HIV-1NDK on HT29 cells by 63% and on MDM by 77%, and the attachment of HIV-1JRCSF on MDM by 40%; and the infection of MDM by HIV-1JRCSF by 93%.

Conclusions

The intestinal mucosa of children exposed to HIV by breast-feeding produces HIV-specific antibodies harbouring in vitro major functional properties against HIV. These observations lay the conceptual basis for the design of a prophylactic vaccine against HIV in exposed children.

Maternal and infant antiretroviral regimens to prevent postnatal HIV-1 transmission: 48-week follow-up of the BAN randomised controlled trial

BACKGROUND

In resource-limited settings where no safe alternative to breastfeeding exists, WHO recommends that antiretroviral prophylaxis be given to either HIV-infected mothers or infants throughout breastfeeding. We assessed the effect of 28 weeks of maternal or infant antiretroviral prophylaxis on postnatal HIV infection at 48 weeks.

METHODS

The Breastfeeding, Antiretrovirals, and Nutrition (BAN) Study was undertaken in Lilongwe, Malawi, between April 21, 2004, and Jan 28, 2010. 2369 HIV-infected breastfeeding mothers with a CD4 count of 250 cells per μL or more and their newborn babies were randomly assigned with a variable-block design to one of three, 28-week regimens: maternal triple antiretroviral (n=849); daily infant nevirapine (n=852); or control (n=668). Patients and local clinical staff were not masked to treatment allocation, but other study investigators were. All mothers and infants received one dose of nevirapine (mother 200 mg; infant 2 mg/kg) and 7 days of zidovudine (mother 300 mg; infants 2 mg/kg) and lamivudine (mothers 150 mg; infants 4 mg/kg) twice a day. Mothers were advised to wean between 24 weeks and 28 weeks after birth. The primary endpoint was HIV infection by 48 weeks in infants who were not infected at 2 weeks and in all infants randomly assigned with censoring at loss to follow-up. This trial is registered with ClinicalTrials.gov, number NCT00164736.

FINDINGS

676 mother-infant pairs completed follow-up to 48 weeks or reached an endpoint in the maternal-antiretroviral group, 680 in the infant-nevirapine group, and 542 in the control group. By 32 weeks post partum, 96% of women in the intervention groups and 88% of those in the control group reported no breastfeeding since their 28-week visit. 30 infants in the maternal-antiretroviral group, 25 in the infant-nevirapine group, and 38 in the control group became HIV infected between 2 weeks and 48 weeks of life; 28 (30%) infections occurred after 28 weeks (nine in maternal-antiretroviral, 13 in infant-nevirapine, and six in control groups). The cumulative risk of HIV-1 transmission by 48 weeks was significantly higher in the control group (7%, 95% CI 5-9) than in the maternal-antiretroviral (4%, 3-6; p=0·0273) or the infant-nevirapine (4%, 2-5; p=0·0027) groups. The rate of serious adverse events in infants was significantly higher during 29-48 weeks than during the intervention phase (1·1 [95% CI 1·0-1·2] vs 0·7 [0·7-0·8] per 100 person-weeks; p<0·0001), with increased risk of diarrhoea, malaria, growth faltering, tuberculosis, and death. Nine women died between 2 weeks and 48 weeks post partum (one in maternal-antiretroviral group, two in infant-nevirapine group, six in control group).

INTERPRETATION

In resource-limited settings where no suitable alternative to breastfeeding is available, antiretroviral prophylaxis given to mothers or infants might decrease HIV transmission. Weaning at 6 months might increase infant morbidity.

FUNDING

US Centers for Disease Control and Prevention.

HIV-1 envelope-dependent restriction of CXCR4-using viruses in child but not adult untransformed CD4+ T-lymphocyte lines

Phytohemagglutin-stimulated child and adult leukocytes equally supported CCR5-dependent (R5) and CXCR4-dependent (X4) HIV-1 replication. In contrast, when phytohemagglutin-stimulated leukocytes from either healthy or congenitally immunodeficient children were cultured on feeder cells, they well supported R5, but not X4 HIV-1 replication, whereas both viruses equally spread in adult cells maintained in similar conditions. Both child and adult cells showed similar levels of proliferation and surface expression of CD4, CCR5, CXCR4, CD25, CD69, and HLA-DR. Lack of X4 HIV-1 replication in child versus adult cells was not caused by a differential expression of several known HIV-1 restriction factors. Similar levels of HIV DNA synthesis occurred in child cells infected with R5 and X4 viruses up to 48 hours after infection when R5 HIV-1 showed a significantly superior capacity to spread in culture than X4 virus. Cultured child cells well supported single round vescicular stomatitis virus-G pseudotyped virus replication, whereas superinfection of R5-infected cells with X4 HIV-1 (or vice versa) rescued the replication of this latter virus. Thus, child cells exposed to feeder cell culture represent a novel model system in which the superior capacity of R5 versus X4 viruses to spread can be investigated in primary, untransformed CD4+ cells.

Efficacy and safety of an extended nevirapine regimen in infant children of breastfeeding mothers with HIV-1 infection for prevention of postnatal HIV-1 transmission (HPTN 046): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Nevirapine given once-daily for the first 6, 14, or 28 weeks of life to infants exposed to HIV-1 via breastfeeding reduces transmission through this route compared with single-dose nevirapine at birth or neonatally. We aimed to assess incremental safety and efficacy of extension of such prophylaxis to 6 months.

METHODS

In our phase 3, randomised, double-blind, placebo-controlled HPTN 046 trial, we assessed the incremental benefit of extension of once-daily infant nevirapine from age 6 weeks to 6 months. We enrolled breastfeeding infants born to mothers with HIV-1 in four African countries within 7 days of birth. Following receipt of nevirapine from birth to 6 weeks, infants without HIV infection were randomly allocated (by use of a computer-generated permuted block algorithm with random block sizes and stratified by site and maternal antiretroviral treatment status) to receive extended nevirapine prophylaxis or placebo until 6 months or until breastfeeding cessation, whichever came first. The primary efficacy endpoint was HIV-1 infection in infants at 6 months and safety endpoints were adverse reactions in both groups. We used Kaplan-Meier analyses to compare differences in the primary outcome between groups. This study is registered with ClinicalTrials.gov, number NCT00074412.

FINDINGS

Between June 19, 2008, and March 12, 2010, we randomly allocated 1527 infants (762 nevirapine and 765 placebo); five of whom had HIV-1 infection at randomisation and were excluded from the primary analyses. In Kaplan-Meier analysis, 1·1% (95% CI 0·3-1·8) of infants who received extended nevirapine developed HIV-1 between 6 weeks and 6 months compared with 2·4% (1·3-3·6) of controls (difference 1·3%, 95% CI 0-2·6), equating to a 54% reduction in transmission (p=0·049). However, mortality (1·2% for nevirapine vs 1·1% for placebo; p=0·81) and combined HIV infection and mortality rates (2·3%vs 3·2%; p=0·27) did not differ between groups at 6 months. 125 (16%) of 758 infants given extended nevirapine and 116 (15%) of 761 controls had serious adverse events, but frequency of adverse events, serious adverse events, and deaths did not differ significantly between treatment groups.

INTERPRETATION

Nevirapine prophylaxis can safely be used to provide protection from mother-to-child transmission of HIV-1 via breastfeeding for infants up to 6 months of age.

FUNDING

US National Institutes of Health.

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

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

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

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

Implementing programs for the prevention of mother-to-child HIV transmission in resource-constrained settings: Horizons studies, 1999-2007

An estimated 430,00 new human immunodeficiency virus (HIV) infections occurred among children younger than 15 years of age in 2008, most in sub-Saharan Africa and most due to mother-to-child transmission (MTCT). In marked contrast, MTCT of HIV has been virtually eliminated in well-resourced settings through the use of combinations of antiretroviral (ARV) drugs for the mother during pregnancy and labor and for the infant postpartum; cesarean delivery to reduce the infant's exposure to trauma and infection in the birth canal; and formula feeding to protect the infant from transmission from breastfeeding. While effective, these interventions are costly and require strong health-care systems. From 1999 to 2003, Horizons conducted operations research to determine how interventions successful in the clinical trial setting would translate to the real-world environments of maternal and child healthcare delivery in low-resource settings. A second set of Horizons studies (2004-2007) sought to address gaps in adherence to ARV prophylaxis; examine roles of family planning in prevention of MTCT (PMTCT) programs; show the value of psychosocial support for HIV-positive mothers; and identify ways to improve the quality of care and follow-up for women in the postpartum period. This article provides an assessment of the findings of Horizons studies on PMTCT interventions from 1999 to 2007 and identifies needs for follow-on efforts.

Awareness and attitudes about HIV among pregnant women in Aksu, northwest China

The Xinjiang Uyghur Autonomous Region has a firmly established HIV epidemic among its intravenous drug user (IDU) population. Local sex workers were also found to be positive in 1998. A descriptive, cross-sectional survey of knowledge about HIV/AIDS and attitudes among consecutively selected pregnant women was conducted November 2005 in Aksu Prefecture, north-western China, with a population on 2 million with about 25 000 pregnancies per year. A total of 291 pregnant women participated. We found a limited knowledge on mother-to child transmission with several misconceptions. The AIDS campaigns have been successful in making all the women aware of HIV as a sexually transmitted disease. However, the common belief that social contact causes transmission gives a high risk that patients are stigmatized. Obviously, it is important to design HIV information strategies that target pregnant women in north-western China.

Preventing mother-to-child transmission of HIV in resource-limited settings: the Elizabeth Glaser Pediatric AIDS Foundation experience

OBJECTIVES

In September 1999, the Elizabeth Glaser Pediatric AIDS Foundation initiated a multicountry, service-based programmatic effort in the developing world to reduce perinatally acquired HIV infection. We review 6(1/2) years of one of the world's largest programs for the prevention of mother-to-child transmission (PMTCT) of HIV.

METHODS

Each PMTCT facility records patient data in antenatal clinics and labor and delivery settings about counseling, testing, HIV status, and antiretroviral prophylaxis and submits the data to foundation staff.

RESULTS

More than 2.6 million women have accessed foundation-affiliated services through June 2006. Overall, 92.9% of women who received antenatal care or were eligible for PMTCT services in labor and delivery have been counseled, and 82.8% of those counseled accepted testing. Among women identified as HIV positive, 75.0% received antiretroviral prophylaxis (most a single dose of nevirapine), as did 45.6% of their infants.

CONCLUSIONS

The foundation's experience has demonstrated that opt-out testing, supplying mothers with medication at time of diagnosis, and providing the infant dose early have measurably improved program efficiency. PMTCT should be viewed as an achievable paradigm and an essential part of the continuum of care.

Vitamin content of breast milk from HIV-1-infected mothers before and after flash-heat treatment

BACKGROUND

World Health Organization advocates heat treatment of expressed breastmilk (EBM) as one method to reduce postnatal transmission of human immunodeficiency virus (HIV) in developing countries. Flash-heat is a simple heat treatment method shown to inactivate cell-free HIV.

OBJECTIVE

To determine the effect of flash-heat on vitamin content of milk.

METHODS

Fresh EBM was collected from 50 HIV+ mothers in Durban, South Africa. Mothers washed their hands and then manually expressed 75-150 mL EBM into sterile jars. Milk was aliquoted to unheated controls or flash-heat (50 mL EBM in a glass jar heated in a 450-mL water jacket in an aluminum pan until water boiled, then EBM removed) simulating field conditions with an open flame. Samples were stored at -70 degrees C and then analyzed for the effect of flash-heat on vitamins [A, ascorbic acid, riboflavin (B2), pyridoxal-5-phosphate (B6), folate, and B12].

RESULTS

Vitamin A was not significantly affected by flash-heat and vitamins B12 and C and folate increased significantly. Vitamins B2 and B6 were decreased to 59% (95% confidence interval 44 to 81) and 96% (95% confidence interval 92 to 99), respectively, of that found in unheated milk.

CONCLUSIONS

The percentage remaining after flash-heat suggests that most vitamin concentrations are retained after heating. Flash-heat may be a practical and nutritious infant feeding method for mothers in developing countries.

Early mixed feeding and breastfeeding beyond 6 months increase the risk of postnatal HIV transmission: ANRS 1201/1202 Ditrame Plus, Abidjan, Côte d'Ivoire

OBJECTIVE

To evaluate the risk of postnatal HIV transmission among women in Abidjan, Côte d'Ivoire offered alternatives to prolonged breastfeeding, and to assess the impact of the breastfeeding pattern and duration on this risk.

METHODS

In 2001-2003, HIV-infected pregnant women received peri-partum antiretroviral prophylaxis and were counselled antenatally regarding infant feeding options: formula feeding or exclusive breastfeeding with early cessation from 4 months of age. The primary outcome was HIV postnatal transmission by 18 months of age, defined by a positive HIV test after a negative test > or =30 days. The effect of the pattern (mixed feeding, defined as breastmilk plus food-based fluid, solid food or non-human milk) and duration (less vs. more than 6 months) of breastfeeding on postnatal transmission was assessed.

RESULTS

Of 622 live-born infants who were HIV uninfected at or after 30 days, 15 were infected postnatally, 13/324 among breastfed, and 2/298 among formula-fed infants. The 18-month probability of remaining free from HIV infection was 0.95 [95% CI, 0.92-0.97] and 0.99 [95% CI, 0.97-1.00] in the breastfeeding and formula-feeding groups respectively (p<0.001). In adjusted analysis, breastfeeding for more than 6 months and mixed feeding during the first month of life were independently associated with a 7.5 (AOR 95% CI, 2.0-28.2, p=0.003)- and a 6.3 (95% CI, 1.1-36.4, p=0.04)-fold increase of postnatal transmission among breastfed children.

CONCLUSIONS

Mixed feeding during the first month of life and breastfeeding beyond 6 months are strong determinants of HIV transmission and should be avoided when replacement feeding after breastfeeding cessation can be safely and sustainably provided.

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.

Molecular epidemiological analysis of a nosocomial outbreak of respiratory syncytial virus associated pneumonia in a kangaroo mother care unit in South Africa

Respiratory syncytial virus (RSV) may cause severe lower respiratory tract disease in premature infants. Prolonged viral shedding has been reported in patients with underlying immunosuppressive disorders, such as human immunodeficiency virus 1 (HIV-1) infection. During March to May 2006, 23 preterm pediatric patients developed nosocomial pneumonia in a district hospital in the Gauteng Province of South Africa due to RSV infection. The patients were identified using routine diagnostic testing. All had been admitted with their mothers to a Kangaroo Mother Care (KMC) ward from birth--a low care unit for the management of stable low birth weight infants. The HIV-1 seroprevalence among the mothers to these infants was 52.6%, translating to a 52.6% perinatal exposure. A multiplex nested RT-PCR was used to subtype RSV positive nasopharyngeal aspirates. Sequencing and phylogenetic analysis of part of the G-protein gene was used for molecular epidemiological analysis of the outbreak. In total, 19 of the 23 RSV positive specimens could be PCR amplified and sequenced. The subtype A, GA5 genotype was identified in 14 specimens and the BA genotype, a new subtype B genotype not previously recognized in South Africa, in seven. One patient had an infection with both genotypes. Phylogenetic analysis demonstrated eight separate introductions. Two of the strains identified in this outbreak were identical to strains circulating in a general pediatric ward of this hospital during the preceding month. Inadequate infection control measures by health care providers and mothers to children in KMC units may increase potentially the risk of severe RSV infection in a population group with compounded risk factors.

Development of a highly efficient extraction technique and specific multiplex assay for measuring antiretroviral drug concentrations in breast milk

Understanding the pharmacology of drugs in breast milk is important for the health of both mother and baby. Current methods to measure drug concentrations in breast milk are not easily validated for precision or accuracy, primarily because of suboptimal sample clean-up. We report here an optimized clean-up method to remove both proteins and fat from milk, thereby enhancing the extraction efficiency of antiretroviral drugs. Recoveries were consistently above 91% for all drugs, demonstrating that this method successfully and reliably released drugs from fat globules. With use of 200 muL of human breast milk, an high-performance liquid chromatography/ultraviolet method for simultaneously detecting lamivudine, stavudine, zidovudine, and nevirapine was validated over the range of 20 to 20,000 ng/mL. Intra- and interday precision (average percent relative standard deviation) and accuracy (average percent deviation from nominal) was less than 3.6% and 7.5%, respectively. Intra- and interday accuracy (average percent deviation from nominal) was less than 0.25% and 1.3%, respectively. This novel method efficiently, reliably, and accurately measured antiretroviral drugs in breast milk and can be applied to any matrix containing fat and protein.

Infant feeding and prevention of mother-to-child transmission of HIV-1

PURPOSE OF REVIEW

To review new studies and directions regarding infant feeding and HIV-1 transmission.

RECENT FINDINGS

With antiretroviral drugs and shortened breastfeeding, breast milk HIV-1 transmission risk can be decreased from 16 to less than 5%. In the context of peripartum antiretroviral drugs/short breastfeeding, replacement feeding provides negligible benefit in decreasing the risk of HIV-1/death in contrast to previous studies of no antiretroviral drugs/unlimited breastfeeding in which it offered benefit. One study noted a high risk of infant HIV-1 or death (>/=17%) after 4 months, with no difference in risk in infants with shortened breastfeeding versus indefinite breastfeeding. This study suggests that shortened breastfeeding needs caution in implementation. Other African studies have noted minimal risk of HIV-1 or death (< 2%) after shortened breastfeeding, underscoring the heterogeneity of infant survival in different settings and the potential to improve infant survival.

SUMMARY

Antiretroviral drugs and shortened breastfeeding markedly decrease breastfeeding HIV-1 transmission, shifting the balance to make replacement feeding less beneficial. In some settings shortened breastfeeding poses similar risks as replacement feeding and provides no infant health benefit compared with extended breastfeeding. Programmes aimed at decreasing infant HIV-1 need to do so in the context of promoting infant survival. Strengthening systems to promote infant health is critical.

Cabergoline for suppression of puerperal lactation in a prevention of mother-to-child HIV-transmission programme in rural Malawi

This study shows that cabergoline (single oral-dose) is an acceptable, safe and effective drug for suppressing puerperal lactation. It could be of operational benefit not only for artificial feeding, but also for weaning in those that breast-feed within preventive mother-to-child HIV transmission programmes in resource-limited settings.

Deactivation of human immunodeficiency virus type 1 in medium by copper oxide-containing filters

Human immunodeficiency virus type 1 (HIV-1) can be transmitted through breast-feeding and through contaminated blood donations. Copper has potent biocidal properties and has been found to inactivate HIV-1 infectivity. The objective of this study was to determine the capacity of copper-based filters to inactivate HIV-1 in culture media. Medium spiked with high titers of HIV-1 was exposed to copper oxide powder or copper oxide-impregnated fibers or passed through copper-based filters, and the infectious viral titers before and after treatment were determined. Cell-free and cell-associated HIV-1 infectivity was inhibited when exposed to copper oxide in a dose-dependent manner, without cytotoxicity at the active antiviral copper concentrations. Similar dose-dependent inhibition occurred when HIV-1 was exposed to copper-impregnated fibers. Filtration of HIV-1 through filters containing the copper powder or copper-impregnated fibers resulted in viral deactivation of all 12 wild-type or drug-resistant laboratory or clinical, macrophage-tropic and T-cell-tropic, clade A, B, or C, HIV-1 isolates tested. Viral inactivation was not strain specific. Thus, a novel means to inactivate HIV-1 in medium has been developed. This inexpensive methodology may significantly reduce HIV-1 transmission from "mother to child" and/or through blood donations if proven to be effective in breast milk or plasma and safe for use. The successful application of this technology may impact HIV-1 transmission, especially in developing countries where HIV-1 is rampant.

Flash-heat inactivation of HIV-1 in human milk: a potential method to reduce postnatal transmission in developing countries

BACKGROUND

Up to 40% of all mother-to-child transmission of HIV occurs by means of breast-feeding; yet, in developing countries, infant formula may not be a safe option. The World Health Organization recommends heat-treated breast milk as an infant-feeding alternative. We investigated the ability of a simple method, flash-heat, to inactivate HIV in breast milk from HIV-positive mothers.

METHODS

Ninety-eight breast milk samples, collected from 84 HIV-positive mothers in a periurban settlement in South Africa, were aliquoted to unheated control and flash-heating. Reverse transcriptase (RT) assays (lower detection limit of 400 HIV copies/mL) were performed to differentiate active versus inactivated cell-free HIV in unheated and flash-heated samples.

RESULTS

We found detectable HIV in breast milk samples from 31% (26 of 84) of mothers. After adjusting for covariates, multivariate logistic regression showed a statistically significant negative association between detectable virus in breast milk and maternal CD4+ T-lymphocyte count (P=0.045) and volume of breast milk expressed (P=0.01) and a positive association with use of multivitamins (P=0.03). All flash-heated samples showed undetectable levels of cell-free HIV-1 as detected by the RT assay (P<0.00001).

CONCLUSIONS

Flash-heat can inactivate HIV in naturally infected breast milk from HIV-positive women. Field studies are urgently needed to determine the feasibility of in-home flash-heating breast milk to improve infant health while reducing postnatal transmission of HIV in developing countries.

International recommendations on antiretroviral drugs for treatment of HIV-infected women and prevention of mother-to-child HIV transmission in resource-limited settings: 2006 update

The World Health Organization recommends that countries adopt more effective antiretroviral regimens to increase the effectiveness of the prevention of mother-to-child human immunodeficiency virus (HIV) transmission programs. The 2006 guidelines recommend a tiered approach for the delivery of antiretroviral to pregnant women who are infected with HIV and include triple-drug antiretroviral treatment for those women who are eligible. Those women who are not eligible for antiretroviral treatment should receive a combination prophylaxis antiretroviral regimen, preferably zidovudine from 28 weeks of gestation; zidovudine, lamivudine, and a single dose of nevirapine during delivery; and zidovudine and lamivudine for 7 days after delivery to reduce the development of nevirapine resistance. Newborn infants should receive a single dose of nevirapine and 1-4 weeks of zidovudine, depending on the duration of the regimen received by the mother. Although steps are being taken to provide more effective regimens, the use of single-dose nevirapine alone should still be used in situations in which more effective regimens are not yet feasible or available. HIV transmission through breastfeeding remains a problem, and several interventions are under evaluation that include maternal and/or infant antiretroviral prophylaxis during breastfeeding.

Site-specific interventions to improve prevention of mother-to-child transmission of human immunodeficiency virus programs in less developed settings

This article reviews the experiences of programs designed to provide access to prevention of mother-to-child transmission services with the goal of improving services in resource-constrained settings. The article reports new data from the Elizabeth Glaser Pediatric AIDS Foundation's prevention of mother-to-child transmission program in sub-Saharan Africa, which has provided human immunodeficiency virus testing to more than 1,300,000 pregnant women and antiretroviral prophylaxis to 134,000 human immunodeficiency virus-infected pregnant women and more than 78,000 human immunodeficiency virus-exposed infants. Review of qualitative program data highlights the practical innovations that sites are implementing to improve the uptake of prevention of mother-to-child transmission services. Recommendations discussed include opt-out counseling and testing, rapid human immunodeficiency virus testing in antenatal care, counseling and testing in maternity, and provision of antiretroviral prophylaxis for mother and infant at the time of human immunodeficiency virus testing. Successful programmatic innovations need to be disseminated widely as more aggressive prevention strategies must be implemented to increase access to more than 10% of pregnant women worldwide.

Mother-to-child transmission of HIV-1: timing and implications for prevention

This article provides a synthesis of clinical trial data with an aim to deduce the timing of mother-to-child transmission of HIV-1. Because transmission of the infection to the infant through breastfeeding is one of the main challenges in fighting paediatric HIV/AIDS in the developing world, we present separate estimates for the timing of HIV transmission for non-breastfeeding and breastfeeding populations. Our estimates predict that, for non-breastfeeding populations, 50% of HIV infections are transmitted to the infant at the very end of pregnancy, near to the time of labour. For breastfeeding populations, the postnatal period accounts for most of the HIV infections transmitted to the infant. We discuss the potential benefit of exclusive breastfeeding for the first 6 months of life as a policy to decrease the magnitude of HIV transmission. Furthermore, we present the hypothesis, based on recent research findings of viral latency, that the time when a fetus initially encounters the virus might not be when infection is established. We discuss the implications of this hypothesis and how it could lead to new interventions for the prevention of mother-to-child HIV transmission.

Diagnosis of pediatric human immunodeficiency virus infection in resource-constrained settings

The majority of children infected with human immunodeficiency virus live in resource-constrained settings and die without an established diagnosis. Definitive laboratory diagnosis in children younger than 12-18 months requires virologic testing; however, antibody testing is often the only option available. Antibody testing provides a definitive diagnosis in older children but is frequently not used. Children meeting clinical criteria should be treated regardless of availability of laboratory diagnoses.

Risk of HIV-1 transmission by breastfeeding among mothers infected with recombinant and non-recombinant HIV-1 genotypes

BACKGROUND

Viral genotype and intersubtype recombination may influence the rate and/or timing of mother-to-child HIV-1 transmission.

METHODS

We determined the HIV-1 subtype of the C2-C5 env and 5'LTR regions from milk and blood samples of 61 Tanzanian mothers who transmitted the virus through breastfeeding and their HIV-1 positive non-transmitting controls. Cases and controls were matched on infant's age at sample collection. All mothers resided in Dar es Salaam, Tanzania.

RESULTS

Most infections among cases were due to recombinant viruses (41.0%), followed by HIV-1 subtype A (26.2%), subtype D (19.7%), and subtype C (13.1%). In multivariate analysis including maternal CD4+ cell counts, HIV disease stage, and proviral load in breast milk, the odds of breast milk transmission were 7.2 times higher if the mother carried an intersubtype recombinant genome in comparison to a subtype C virus (p=0.02). Viruses with recombinant LTRs were 4.9 times more likely to be transmitted through breastfeeding than viruses with non-recombinant LTRs of subtype A, C or D combined (p=0.01).

CONCLUSIONS

This suggested that intersubtype recombinant genomes, and especially recombination within the LTR, might render HIV-1 more fit for transmission via breast milk in comparison with non-recombinant subtypes A, C, and D.

Vaccines to prevent transmission of HIV-1 via breastmilk: scientific and logistical priorities

Mother-to-child transmission (MTCT) of HIV-1 is the major mode of paediatric infection. The rapidly increasing incidence of MTCT worldwide has resulted in an urgent need for preventive strategies. Antiretroviral regimens can prevent intrapartum HIV transmission; however, these regimens do not prevent HIV transmission through breastfeeding. Furthermore, children who escape MTCT are again at risk of infection when they become sexually active as adolescents. An infant vaccine regimen, begun at birth, would hence be a more attractive strategy and might also provide the basis for lifetime protection. Unique features of MTCT and paediatric HIV disease could be helpful in understanding correlates of immune protection and could facilitate rapid assessment of vaccine efficacy. Thus, there is compelling rationale to develop safe, effective HIV vaccines for use in infants and children. Here, we discuss the scientific and logistical challenges for the development of paediatric HIV vaccines; available vaccines and completed or planned paediatric vaccine trials are also discussed.

Perinatally Acquired HIV-1 Infection: Prevention and Evaluation of HIV-Exposed Infants

Perinatal transmission of human immunodeficiency virus type 1 (HIV-1) is the primary cause of pediatric HIV infections. In recent years, perinatal HIV-1 transmission rates in the United States have declined markedly because of several factors that include enhanced voluntary counseling and HIV-1 testing (VCT) for pregnant women, widespread use of antiretroviral prophylaxis or combination antiretroviral therapy, avoidance of breastfeeding, and elective cesarean delivery. However, perinatal transmission of HIV-1 still occurs, and 300 to 400 infected infants are born annually, primarily because of missed prevention opportunities. The pediatrician plays a vital role in the prevention of perinatal transmission of HIV-1 by identifying newborns born to infected mothers who were not tested during pregnancy, administering antiretroviral prophylaxis, and ensuring follow-up to confirm or exclude the diagnosis of HIV-1 infection in early infancy. This article reviews recent advances in the prevention of perinatal transmission of HIV-1, discusses evaluation and treatment of infants exposed to HIV-1, and highlights certain unique features of HIV-1 infections in infants, with a focus on early diagnosis, clinical manifestations, treatment, and prognosis.

Prevention of mother-to-child transmission of HIV in São Paulo State, Brazil: an update

BACKGROUND

São Paulo State has had the largest number of paediatric AIDS cases in Brazil. Since 1996, São Paulo (and Brazil nationally) has implemented an aggressive programme to reduce perinatal transmission. We have gathered available indicators to examine the programme's impact.

METHODS

We obtained data on reported AIDS cases from the AIDS surveillance system; data on the number of mother/infant pairs treated with zidovudine from the state logistics office responsible for distributing HIV medication; and the rates of perinatal transmission from a multicity study of the Brazilian Pediatric Society that includes a number of São Paulo facilities, which were compared with an independent study in 1995. The years for which data were available varied according to the source of the indicator.

RESULTS

Annual reported cases of AIDS as a result of perinatal transmission fell 58.9% from 1997 to 2002. The number of cases treated with zidovudine increased 73.7% from 1997 to 2004. The rate of perinatal transmission among babies born to HIV-positive mothers fell from 16% in 1995 to 2.4% in 2002 in the reference clinics that participated in the Brazilian Pediatric Society study.

CONCLUSION

Both process and outcome indicators point to the effectiveness of efforts to reduce perinatal transmission in São Paulo State.

Potential cost-effectiveness of maternal and infant antiretroviral interventions to prevent mother-to-child transmission during breast-feeding

INTRODUCTION

One-third of maternal-to-child HIV transmission occurs during breast-feeding (BF). Several trials are currently evaluating the efficacy of postpartum antiretrovirals to reduce BF transmission.

METHODS

This study used Markov modeling to define the circumstances under which the following interventions would be cost-effective: BF for 6 months with daily infant nevirapine (NVP) prophylaxis; maternal combination antiretroviral therapy (ART) during pregnancy and for 6 months of BF; and maternal combination ART only for women who meet CD4 criteria. Each was compared to: BF for 12 months; BF for 6 months; and formula feeding for 12 months. Strategies were evaluated for a hypothetical cohort of 40,000 pregnant women in sub-Saharan Africa, in the context of available voluntary counseling and testing in antenatal care. Model estimates were derived from the literature and local sources. Sensitivity analyses were performed on uncertain estimates. The perspective used was that of a government health district.

RESULTS

Using base case estimates, BF for 6 months was the economically preferred strategy: it cost 806,995 dollars and generated 446,208 quality-adjusted life-years (QALYs). Providing daily infant NVP cost an additional 93,638 dollars and generated 1183 additional QALYs, but its incremental cost-effectiveness ratio (ICER) of 79 dollars/QALY exceeded the standard willingness to pay (64 dollars/QALY) for most resource-poor settings. Maternal combination ART was potentially very effective but too costly for most resource-poor settings (ICER: 87 dollars/QALY). In order for daily infant NVP during BF to be preferred, it must have >/=44% relative efficacy or cost </=5.00 dollars/mo. If NVP were donated, it would only have to be minimally effective to be the economically preferred strategy. If ART cost </=34.50 dollars/mo, ART to all mothers would become the preferred strategy under our assumption of 82% efficacy.

CONCLUSIONS

Providing antiretrovirals during BF represents a promising alternative, should their effectiveness, and feasibility be proven.

Role of P-glycoprotein in distribution of nelfinavir across the blood-mammary tissue barrier and blood-brain barrier

As a first approach in understanding the possible efficacy and toxicity of human immunodeficiency virus protease inhibitors during breast feeding, the milk-to-plasma ratio of nelfinavir was determined in lactating rats. The milk-to-plasma ratio of nelfinavir was determined to be 0.56 +/- 0.10 (means +/- standard deviations). Western blotting indicated that P-glycoprotein is expressed in rat mammary and brain tissue; however, the multidrug-resistant modulator GF120918 showed a significant effect only at the blood-brain barrier and not at the mammary-epithelial tissue barrier.

Estimating the net effect of HIV on child mortality in African populations affected by generalized HIV epidemics

For a given prevalence, HIV has a relatively higher impact on child mortality when mortality from other causes is low. To project the effect of the epidemic on child mortality, it is necessary to estimate a realistic schedule of "net" age-specific mortality rates that would operate if HIV were the only cause of child death observable. We assume that this net pattern would be independent of mortality from other causes. We used African studies that measured the survival of HIV-infected children (direct data) or survival of children of HIV-infected mothers (indirect data). We developed a mathematic procedure to estimate the mortality of infected children from indirect data sources and obtained net HIV mortality patterns for each study population. The net age-specific HIV mortality pattern for infected children can be described by a double Weibull curve fitted to empiric data; this gives a functional representation of age-specific mortality rates that decline after infancy and rise in the preteens. The fitted curve that we would expect if HIV were the only effective cause of death shows 67% net survival at 1 year and 39% at 5 years. The curve also predicts 13% net survival at 10 years using constraints based on survival of infected adults.

Putting copper into action: copper-impregnated products with potent biocidal activities

Copper ions, either alone or in copper complexes, have been used for centuries to disinfect liquids, solids, and human tissue. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide, and antibacterial and antifouling agent. Copper also displays potent antiviral activity. We hypothesized that introducing copper into clothing, bedding, and other articles would provide them with biocidal properties. A durable platform technology has been developed that introduces copper into cotton fibers, latex, and other polymeric materials. This study demonstrates the broad-spectrum antimicrobial (antibacterial, antiviral, antifungal) and antimite activities of copper-impregnated fibers and polyester products. This technology enabled the production of antiviral gloves and filters (which deactivate HIV-1 and other viruses), antibacterial self-sterilizing fabrics (which kill antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci), antifungal socks (which alleviate symptoms of athlete's foot), and anti-dust mite mattress covers (which reduce mite-related allergies). These products did not have skin-sensitizing properties, as determined by guine pig maximization and rabbit skin irritation tests. Our study demonstrates the potential use of copper in new applications. These applications address medical issues of the greatest importance, such as viral transmissions; nosocomial, or healthcare-associated, infections; and the spread of antibiotic-resistant bacteria.

Child mortality and HIV infection in Africa: a review

OBJECTIVES

To review the available data relating to child mortality in Africa by the HIV infection status of mothers and children.

RESULTS

Child survival is influenced by the HIV epidemic through several mechanisms. Mother-to-child transmission of HIV ranges from 15 to 45%, with up to 15-20% resulting from breastfeeding. HIV-infected children have high mortality rates. For example, a recent community-based study in Rakai, Uganda, showed 2-year mortality rates of 547, 166 and 128 per thousand among HIV-infected children, HIV-negative children of HIV-positive mothers, and HIV-negative children of HIV-negative women, respectively. Child mortality estimates from community-based cohorts demonstrate that the children of HIV-infected mothers have higher mortality rates than the children of uninfected mothers, and that child mortality is closely linked with maternal health status, but because the proportion of vertically infected children is unknown, the value of these studies is limited. Models that use HIV surveillance data together with a set of assumptions indicate that child mortality caused by HIV/AIDS has increased throughout the 1990s to reach close to 10% by 2002.

CONCLUSION

Both disparate trends in HIV prevalence and varying levels of non-HIV-associated child mortality will ensure very different impacts in different countries. To improve the projections of the overall effect that the HIV epidemic will have on child mortality at the population level in countries with generalized epidemics, reliable age-specific mortality rates in infected and uninfected children are needed.

Advances in the prevention of vertical transmission of human immunodeficiency virus

The major mode of acquisition of human immunodeficiency virus (HIV) for children is through mother-to-child transmission, which can occur during pregnancy or labor and delivery, or postnatally through breastfeeding. In resource-rich countries, mother-to-child HIV transmission has decreased to less than 2 percent after recommendations for universal prenatal HIV counseling and testing, antiretroviral prophylaxis and elective cesarean delivery, and avoidance of breastfeeding were implemented. In resource-limited settings, effective, shorter, and less expensive antiretroviral prophylaxis interventions also have been identified, but implementation has been slower, and continued transmission through breastfeeding remains a significant problem. This review summarizes recent advances made in prevention of mother-to-child transmission of HIV in the United States and other resource-rich countries, as well as progress in resource-limited countries.

HIV-1 viral load and other risk factors for mother-to-child transmission of HIV-1 in a breast-feeding population in Cote d'Ivoire

Short-course antiretroviral regimens have been evaluated to reduce mother-to-child transmission of HIV in resource-limited settings. This report from Abidjan, Cote d'Ivoire, examines the risk factors for HIV transmission by 1 and 24 months among breast-feeding women. Eligible HIV-1-seropositive pregnant women enrolled in this randomized double-blind clinical trial were randomly assigned to receive either oral zidovudine (ZDV) (n = 126) prophylaxis or placebo (n = 124). Maternal prophylaxis began at 36 weeks of gestation (300 mg ZDV twice daily antepartum and 300 mg every 3 hours intrapartum); there was no neonatal prophylaxis component. The cumulative risk of transmission in the treatment group was 11.9% and 22.1% by 1 and 24 months, respectively. In adjusted analyses, viral load at enrollment was the strongest predictor of transmission (per log increment: odds ratio [OR] = 4.8, 95% confidence interval [CI]: 2.5-9.5 at 1 month; OR = 5.7; 95% CI: 3.1-10.8 at 24 months). Overall, ZDV prophylaxis was not significantly protective for infection at 1 or 24 months. Comparing ZDV with placebo following dichotomization of viral load (<50,000 vs. > or =50,000 copies/mL) at enrollment, however, there was a significant effect of ZDV seen only among those women with a low viral load at enrollment. The substantial risk of transmission despite ZDV prophylaxis, particularly among those with higher viral loads, underscores the need to find more effective regimens appropriate for use in resource-limited settings.

Prevention of perinatal HIV transmission: a review of novel strategies

Significant progress has been made in preventing transmission of HIV-1 from mother to infant. With combination antiretroviral therapies, transmission rates lower than 2% have been achieved in clinical studies. Abbreviated regimens covering labour and the first few days of neonatal life have shown considerable promise in the developing world. Several questions and challenges remain, however. These include choice of the optimal antiretroviral agent(s) and duration of the regimens, availability of antiretroviral agents in developing countries, long-term safety of antiretrovirals during pregnancy and early neonatal life and the problem of breastfeeding transmission in countries where alternatives to breastfeeding are not available. A wider array of strategies for prevention of mother-to-child transmission of HIV-1 during breastfeeding, including passive and active immunisation, may offer much needed answers to the problem of continued HIV transmission from mother to infant.

Low adherence to recommended infant feeding strategies among HIV-infected women: results from the pilot phase of a randomized trial to prevent mother-to-child transmission in Botswana

Little is known about the ability of women to adhere to recommended feeding strategies to prevent mother-to-child HIV transmission (MTCT) from breast milk. We conducted a pilot study in rural Botswana to prevent MTCT from breast milk. Women were randomized to formula feed their infants or to exclusively breastfeed while providing prophylactic zidovudine. Women who chose to formula feed independently were also followed. Among those with > or = 3 postpartum visits, none of 31 women assigned to breastfeed did so exclusively for 5 months. Seven (22%) of 32 women in the formula arm definitely or probably breastfed by self-report or as witnessed in maternity, and evidence of breast milk on physical examination was present in 50% of women in > or = 2 visits beyond 1 month. Three (18%) of 17 women choosing formula definitely or probably breastfed, and breast milk was present on exam in 53%. We conclude that adherence to 5 months of exclusive breastfeeding did not occur, and that adherence to exclusive formula feeding was sub-optimal and potentially over reported. Breast examination may be a useful adjunct to self-report, but needs to be validated and standardized. Low adherence to infant feeding strategies that differ from local norms will reduce their effectiveness in preventing MTCT.