Mother-to-child transmission of human immunodeficiency virus type 1

Breastfeeding in HIV-positive mothers under optimized conditions: 'real-life' results from a well-resourced healthcare setting

OBJECTIVES

Global guidelines increasingly support breastfeeding among women living with HIV (WLWH) under optimized conditions. However, outcome data from high-resource settings remain limited.

METHODS

We retrospectively analyzed WLWH who delivered at Charité - Universitätsmedizin Berlin between 2017 and 2023. Eligibility for breastfeeding required VL<50 cop/mL.

RESULTS

Of 409 WLWH, 365 (89.2 %) were eligible and 77 (18.8 %) initiated breastfeeding. No case of mother-to-child transmission (MTCT) was observed. Sustained viral suppression and ART adherence were key. Exclusive breastfeeding was associated with longer duration (p=0.001), midwifery care promoted exclusivity (p=0.009), and vaginal delivery was linked to longer duration (p=0.005).

CONCLUSIONS

Breastfeeding with VL<50 cop/mL appears safe in high-resource settings. Findings support individualized counseling, close monitoring, and multidisciplinary care. The increasing breastfeeding trend reflects a shift in clinical practice.

Providers Have a Responsibility to Discuss Options for Infant Feeding With Pregnant People With Human Immunodeficiency Virus in High-Income Countries

Guidelines in high-income countries generally recommend against breastfeeding for a pregnant person with HIV due to the historical risk of transmission to the infant and generally acceptable, safe, and sustainable access to formula. Maternal antiretroviral therapy and infant prophylaxis have been shown to significantly decrease the risk of transmission during breastfeeding. In addition, formula may not be acceptable to patients for a variety of cultural, social, or personal reasons, and its sustainability is called into question in the setting of the current nationwide formula shortage. Providers caring for pregnant people with HIV have a responsibility to discuss infant feeding with their patients, and help them weigh the risks and benefits within the limits of the current body of evidence. We outline a process, including a written agreement, that can be used to discuss infant feeding with all patients and help them make the best decision for their family.

Cost-effectiveness analysis of the prevention of mother-to-child transmission of HIV

BACKGROUND

The number of HIV-positive pregnant women accounted for about 10% of China's total over the past few years in Liangshan Prefecture, Sichuan province in China. Although cost-effectiveness of the PMTCT of HIV have been evaluated in other previous studies, no specific study has been conducted in Liangshan prefecture, nor has the expenses paid individually by HIV-positive pregnant women been included. The purpose of this study was to evaluate both the short-term and long-term cost-effectiveness of PMTCT of HIV in Liangshan Prefecture from the social perspective.

METHODS

From December 2018 to January 2019, individual expenses and the other costs were collected: individual expenses of 133 recruited HIV-positive pregnant women registered in the National Information System of Prevention of Mother-to-Child Transmission of HIV, Syphilis, and HBV, and the other costs from local maternal and child healthcare hospitals, Centers for Disease Control and Prevention, and general hospitals. The costs, the number of pediatric infections averted from being HIV infected were analyzed. And, Life years gained by pediatric infections averted were calculated by using a life table. Besides, Direct benefit was calculated through a Markov mode. Furthermore, One-way sensitivity analysis was conducted for key variables affecting the benefit-cost ratio.

RESULTS

The estimated number of pediatric infections averted was 164.The total cost was USD 114.1 million, including direct medical costs, direct non-medical costs, and indirect costs, which were USD 54.2 million, USD 53.4 million, and USD 6.5 million, respectively. 630.6 person-years discounted to 2017 were gained at a 3% annual rate, and cost per life year gained was USD 1809.50. Direct benefits were USD 198.4 million, indirect benefits USD 82.5 million, and the benefit-cost ratio was 1.5. The sensitivity analysis showed that if PMTCT costs hypothetically ranged from USD 85.6 million to USD 142.6 million, benefit-cost ratio would vary from 1.0 to 2.3.

CONCLUSIONS

PMTCT of HIV in Liangshan Prefecture was very cost-effective. It was a great economic burden of PMTCT on HIV-positive pregnant women and their families to take individual expenses. Therefore, it could be suggested that individual expenses should be covered as much as possible by different types of financing.

Vertical HIV-1 Transmission in the Setting of Maternal Broad and Potent Antibody Responses

Despite the worldwide availability of antiretroviral therapy (ART), approximately 150,000 pediatric HIV infections continue to occur annually. ART can dramatically reduce HIV mother-to-child transmission (MTCT), but inconsistent drug access and adherence, as well as primary maternal HIV infection during pregnancy and lactation are major barriers to eliminating vertical HIV transmission. Thus, immunologic strategies to prevent MTCT, such as an HIV vaccine, will be required to attain an HIV-free generation. A primary goal of HIV vaccine research has been to elicit broadly neutralizing antibodies (bnAbs) given the ability of passive bnAb immunization to protect against sensitive strains, yet we previously observed that HIV-transmitting mothers have more plasma neutralization breadth than nontransmitting mothers. Additionally, we have identified infant transmitted/founder (T/F) viruses that escape maternal bnAb responses. In this study, we examine a cohort of postpartum HIV-transmitting women with neutralization breadth to determine if certain maternal bnAb specificities drive the selection of infant T/F viruses. Using HIV pseudoviruses that are resistant to neutralizing antibodies targeting common bnAb epitopes, we mapped the plasma bnAb specificities of this cohort. Significantly more transmitting women with plasma bnAb activity had a mappable plasma bnAb specificity (six of seven, or 85.7%) compared to that of nontransmitting women with plasma bnAb activity (7 of 21, or 33.3%, P = 0.029 by 2-sided Fisher exact test). Our study suggests that having multispecific broad activity and/or uncommon epitope-specific bnAbs in plasma may be associated with protection against the vertical HIV transmission in the setting of maternal bnAb responses. IMPORTANCE As mother to child transmission (MTCT) of HIV plays a major part in the persistence of the HIV/AIDS epidemic and bnAb-based passive and active vaccines are a primary strategy for HIV prevention, research in this field is of great importance. While previous MTCT research has investigated the neutralizing antibody activity of HIV-infected women, this is, to our knowledge, the largest study identifying differences in bnAb specificity of maternal plasma between transmitting and nontransmitting women. Here, we show that among HIV-infected women with broad and potent neutralization activity, more postpartum-transmitting women had a mappable plasma broadly neutralizing antibody (bnAb) specificity, compared to that of nontransmitting women, suggesting that the nontransmitting women more often have multispecific bnAb responses or bnAb responses that target uncommon epitopes. Such responses may be required for protection against vertical HIV transmission in the setting of maternal bnAb responses.

Mother-to-child HIV-2 transmission: comparison with HIV-1 and evaluation of factors influencing the rate of transmission. A systematic review

A review and collection of data on HIV-2 mother-to-child transmission (MTCT) is absent in the literature. This systematic review and meta-analysis aims to provide a pooled estimate of the rate of HIV-2 MTCT and to identify factors influencing the rate of transmission. PubMed and EMBASE were used to identify eligible publications using a sensitive search strategy. All publications until February 2021 were considered; 146 full-text articles were assessed. Observational studies describing the rate of HIV-2 MTCT in a defined HIV-2 infected study population were included. Other publication types and studies describing HIV-1 or dually infected populations were excluded. Nine studies consisting of 901 mother-child pairs in West Africa, France and Portugal were included in the meta-analysis. The pooled rate estimate of HIV-2 MTCT for antiretroviral therapy-naïve women was 0.2% (95% CI 0.03 to 1.47%), considerably lower than that for HIV-1. The levels of maternal HIV RNA and CD4 cell count were positively related to the vertical transmission rate. Maternal HIV-2 infection did not significantly affect perinatal mortality. It was concluded that the vertical transmission of HIV-2 is lower than that of HIV-1. Maternal viral load and CD4 cell count appear to influence the rate of HIV-2 MTCT.

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

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

Maternal HIV drug resistance is associated with vertical transmission and is prevalent in infected infants

BACKGROUND

We aimed to assess if maternal HIV drug resistance is associated with an increased risk of HIV vertical transmission and to describe the dynamics of drug resistance in HIV-infected infants.

METHODS

A case-control study of PROMISE study participants. "Cases" were mother-infant pairs with HIV vertical transmission during pregnancy or breastfeeding and "controls" were mother-infant pairs without transmission matched 1:3 by delivery date and clinical site. Genotypic HIV drug resistance analyses were performed on mothers' and their infants' plasma at or near the time of infant HIV diagnosis. Longitudinal analysis of genotypic resistance was assessed in available specimens from infants, from diagnosis and beyond, including ART initiation and last study visits.

RESULTS

Our analyses included 85 cases and 255 matched controls. Maternal HIV drug resistance, adjusted for plasma HIV RNA load at infant HIV diagnosis, enrollment CD4 count, and antepartum regimens, was not associated with in utero/peripartum HIV transmission. In contrast, both maternal plasma HIV RNA load and HIV drug resistance were independent risk factors associated with vertical transmission during breastfeeding. Furthermore, HIV drug resistance was selected across infected infants during infancy.

CONCLUSIONS

Maternal HIV drug resistance and maternal viral load were independent risk factors for vertical transmission during breastfeeding, suggesting that nevirapine alone may be insufficient infant prophylaxis against drug-resistant variants in maternal breast milk. These findings support efforts to achieve suppression of HIV replication during pregnancy and suggest that breastfeeding infants may benefit from prophylaxis with a greater barrier to drug resistance than nevirapine alone.

Protection of Newborn Macaques by Plant-Derived HIV Broadly Neutralizing Antibodies: a Model for Passive Immunotherapy during Breastfeeding

Preventing human immunodeficiency virus (HIV) infection in newborns by vertical transmission remains an important unmet medical need in resource-poor areas where antiretroviral therapy (ART) is not available and mothers and infants cannot be treated prepartum or during the breastfeeding period. In the present study, the protective efficacy of the potent HIV-neutralizing antibodies PGT121 and VRC07-523, both produced in plants, were assessed in a multiple-SHIV (simian-human immunodeficiency virus)-challenge breastfeeding macaque model. Newborn macaques received either six weekly subcutaneous injections with PGT121 alone or as a cocktail of PGT121-LS plus VRC07-523-LS injected three times every 2 weeks. Viral challenge with SHIVSF162P3 was twice weekly over 5.5 weeks using 11 exposures. Despite the transient presence of plasma viral RNA either immediately after the first challenge or as single-point blips, the antibodies prevented a productive infection in all babies with no sustained plasma viremia, compared to viral loads ranging from 103 to 5 × 108 virions/ml in four untreated controls. No virus was detected in peripheral blood mononuclear cells (PBMCs), and only 3 of 159 tissue samples were weakly positive in the treated babies. Newborn macaques proved to be immunocompetent, producing transient anti-Env antibodies and anti-drug antibody (ADA), which were maintained in the circulation after passive broadly neutralizing antibody clearance. ADA responses were directed to the IgG1 Fc CH2-CH3 domains, which has not been observed to date in adult monkeys passively treated with PGT121 or VRC01. In addition, high levels of VRC07-523 anti-idiotypic antibodies in the circulation of one newborn was concomitant with the rapid elimination of VRC07. Plant-expressed antibodies show promise as passive immunoprophylaxis in a breastfeeding model in newborns. IMPORTANCE Plant-produced human neutralizing antibody prophylaxis is highly effective in preventing infection in newborn monkeys during repeated oral exposure, modeling virus in breastmilk, and offers advantages in cost of production and safety. These findings raise the possibility that anti-Env antibodies may contribute to the control of viral replication in this newborn model and that the observed immune responsiveness may be driven by the long-lived presence of immune complexes.

Healthcare Workers' Knowledge of HIV-Exposed Infant Feeding Options and Infant Feeding Counseling Practice in Northern Nigeria

BACKGROUND

Despite the existence of evidence-based HIV-exposed infant feeding guidelines, infants in Africa still acquire HIV through inappropriate feeding practices.

OBJECTIVE

To identify predictors of HIV-exposed infant feeding knowledge and counseling practice among health care workers (HCW) in Nigeria.

METHODS

Structured, pretested questionnaires were administered to HCW (n=262) in a tertiary health facility in Kano, Nigeria. Multivariate logistic regression was used to determine predictors of HIV-exposed infant feeding knowledge and counseling practice.

RESULTS

Of 262 respondents, (58.0%, n=152) had good knowledge of recommended feeding options. Respondents listed exclusive breastfeeding (57.6%, n=151), human milk substitutes (45.4%, n=119), HIV-negative wet-nursing (37.0%, n=97), heated expressed human milk (20.6%, n=54) and mixed feeding (13.4%, n=35) as appropriate feeding choices. Over half (57.3%, n=150) of the respondents have ever counseled a HIV-positive mother on infant feeding. Knowledge was predicted by female sex (Adjusted Odds Ratio (AOR)=2.47, 95% Confidence Interval (CI):1.35-4.52), profession (physician vs. laboratory scientist, AOR=4.00, 95%CI:1.25-12.87; nurse/midwife vs. laboratory scientist, AOR=2.75, 95%CI:1.17-9.28), infant feeding counseling training (AOR=3.27, 95%CI:1.87-5.71), and number of children (2-4 vs. 0, AOR=1.75, 95%CI:1.23-3.92). Infant feeding counseling was predicted by female sex (AOR=2.85, 95%CI:1.39-5.85), age (>40 vs. <30 years, AOR=3.87, 95%CI:1.27-15.65), knowledge of infant feeding options (good vs. fair/poor, AOR=3.96, 95%CI:2.07-7.59), training (AOR=2.60, 95%CI:1.42-5.32), and profession (physician vs. laboratory scientist, AOR=10.7, 95%CI:2.85-40.54; nurse/midwife vs. laboratory scientist, AOR=4.8, 95%CI:1.26-18.02).

CONCLUSION

The practice of infant feeding counseling among HCW in Nigeria is associated with sex, knowledge, and profession. Our findings may inform the development of targeted training programs for HCW in similar settings.

Newly diagnosed HIV positive children: a unique index case to improve HIV diagnosis and linkage to care of parents

Newly diagnosed HIV positive children may be unique index cases to identify undiagnosed parents. Data was used from the Pediatric Urgent Start of HAART (NCT02063880) trial, which enrolled hospitalized, ART-naïve, HIV positive children ages 0-12 years in Kenya. Exact McNemar's tests were used to compare proportions of mothers and fathers tested for HIV, linked to care, and on ART at baseline and 6 months. This analysis included 87 newly diagnosed children with HIV who completed 6 months of follow-up. Among 83 children with living mothers, there were improvements in maternal linkage to care and treatment comparing baseline to 6 months (36% vs. 78%; p < 0.0001 and 22% vs. 52%; p < 0.0001). Among 80 children with living fathers, there were increases from baseline to 6 months in the number of fathers who knew the child's HIV status (34% vs. 78%; p < 0.0001), fathers ever tested for HIV (43% vs. 65%; p < 0.0001), fathers ever tested HIV positive (21% vs. 43%; p < 0.0001), fathers ever linked to care (15% vs. 35%; p < 0.0001), and fathers ever initiated on ART (11% vs. 23%; p = 0.0039). Newly diagnosed HIV positive children can be important index cases to identify parents with undiagnosed HIV or poor engagement in care.

Engagement of National Stakeholders and Communities on Health-Care Quality Improvement: Experience from the Implementation of the Partnership for HIV-Free Survival in Tanzania

The Partnership for HIV-Free Survival initiative in Tanzania integrated postnatal nutrition and mother-to-child transmission (MTCT) cascades to reduce vertical HIV transmission. Quality improvement (QI) was implemented in 30 health facilities. Net positive gain resulted in overall improvement in all indicators (above 80%) by the end of the reporting period. Retention in postnatal care (mean = 49.8, standard deviation [SD] = 27.6) and in monthly HIV services (mean = 65.4, SD = 29.5) had the lowest average but showed consecutive and significant (P ≤ .001) gains except for significant decreases in 1 of 6 periods assessed. Average antiretroviral therapy uptake among women (mean = 81.7, SD = 29.5) was highest, with an initial positive gain of 78.9% (P ≤ .001). DNA/polymerase chain reaction for HIV-exposed infants (mean = 71.8, SD = 20.9) and nutrition counseling (mean = 71.2, SD = 26.3) showed similar average performance, with the latter being the only indicator with significant equal periods of gain and decreases. The collaborative QI approach improved process indicators for reducing MTCT in resource-constrained health systems.

The changing profile of paediatric HIV infection: An experience from the Middle East

OBJECTIVE

To describe the clinical and epidemiological profiles of HIV-infected Omani children before and after the implementation of the prevention of mother-to-child transmission of HIV (PMTCT) programme.

METHODS

A retrospective review of HIV-infected children seen at a national paediatric HIV unit between 1992 and 2015 was performed.

RESULTS

Ninety-one HIV-infected children were identified; 59 (65%) were ≤5 years of age at diagnosis, with 28 (47.5%) of these being <1 year old. The average annual incidence of infection per million children (≤14 years old) was 5.7, and the highest (11.6) was in 2010. At diagnosis, 48 (60%) patients had a CD4 count of ˂200cells/mm³. The median HIV viral load was 81600copies/ml at diagnosis and 5911copies/ml at 12 months after HIV treatment (p=0.015). The median CD4 count was 586cells/mm³ at diagnosis and 800cells/mm³ at 12 months after therapy (p=0.004). Compared to those diagnosed before 2009 (n=68), HIV-infected children diagnosed after 2009 (n=22) were more likely to be asymptomatic at the time of HIV diagnosis (23.5% (16/68) vs. 59.1% (13/22); p=0.002) and to have a favourable clinical outcome (42.6% (29/68) vs. 86.4% (19/22); p<0001).

CONCLUSIONS

The number of HIV-infected children in Oman has decreased substantially since the introduction of the PMTCT programme. Furthermore, the HIV-infected children diagnosed after 2009 had higher proportions of asymptomatic HIV infections at diagnosis and favourable clinical outcomes, in comparison to those diagnosed before 2009.

An Overview of Antiretroviral Agents for Treating HIV Infection in Paediatric Population

Paediatric Acquired ImmunoDeficiency Syndrome (AIDS) is a life-threatening and infectious disease in which the Human Immunodeficiency Virus (HIV) is mainly transmitted through Mother-To- Child Transmission (MTCT) during pregnancy, labour and delivery, or breastfeeding. This review provides an overview of the distinct therapeutic alternatives to abolish the systemic viral replication in paediatric HIV-1 infection. Numerous classes of antiretroviral agents have emerged as therapeutic tools for downregulation of different steps in the HIV replication process. These classes encompass Non- Nucleoside Analogue Reverse Transcriptase Inhibitors (NNRTIs), Nucleoside/Nucleotide Analogue Reverse Transcriptase Inhibitors (NRTIs/NtRTIs), INtegrase Inhibitors (INIs), Protease Inhibitors (PIs), and Entry Inhibitors (EIs). Co-administration of certain antiretroviral drugs with Pharmacokinetic Enhancers (PEs) may boost the effectiveness of the primary therapeutic agent. The combination of multiple antiretroviral drug regimens (Highly Active AntiRetroviral Therapy - HAART) is currently the standard therapeutic approach for HIV infection. So far, the use of HAART offers the best opportunity for prolonged and maximal viral suppression, and preservation of the immune system upon HIV infection. Still, the frequent administration of high doses of multiple drugs, their inefficient ability to reach the viral reservoirs in adequate doses, the development of drug resistance, and the lack of patient compliance compromise the complete HIV elimination. The development of nanotechnology-based drug delivery systems may enable targeted delivery of antiretroviral agents to inaccessible viral reservoir sites at therapeutic concentrations. In addition, the application of Computer-Aided Drug Design (CADD) approaches has provided valuable tools for the development of anti-HIV drug candidates with favourable pharmacodynamics and pharmacokinetic properties.

Minimizing the Risk of Perinatal Human Immunodeficiency Virus Transmission

Importance

There are approximately 284,500 adolescent and adult women living with human immunodeficiency virus (HIV) in the United States. It is estimated that approximately 8500 of these women give birth annually. While the rate of perinatal transmission in the United States has decreased by more than 90% since the early 1990s, potentially preventable HIV transmission events still occur and cause significant morbidity and mortality.

Objective

The aim of this review was to summarize the current data regarding perinatal HIV transmission timing and risk factors, current management recommendations, and implications of timing of transmission on patient management.

Evidence Acquisition

Literature review.

Results

This review reiterates that the risk of perinatal HIV transmission can be reduced to very low levels by following current recommendations for screening for HIV in all pregnant women and properly treating HIV-infected mothers, as well as using evidence-based labor management practices.

Conclusions and Relevance

Familiarity with the pathogenesis of HIV transmission is important for obstetric care providers to appropriately manage HIV-infected women in pregnancy, intrapartum, and the postpartum period.

Why is mother to child transmission (MTCT) of HIV a continual threat to new-borns in sub-Saharan Africa (SSA)

Sub-Saharan Africa (SSA) accounts for more than two thirds of the world's HIV infection. Despite scaled-up prevention of mother-to-child transmission of HIV (PMTCT) programmes, mother to child transmission of HIV (MTCT) continues to escalate. We describe the challenges faced by PMTCT in MTCT in SSA. The study reviewed articles and reports published online. The most common barriers and challenges were non-disclosure of HIV status, late initiation of ARVs treatment/adherence, STIs screening, long clinics waiting time, non-involvement of men in ANC/PMTCT, infant feeding methods and sensitization of community members on ANC/PMTCT programmes. The study highlights the need to expand PMTCT coverage and the implementation of the 90-90-90 programme toward MTCT elimination in SSA. That is " ≥90% of pregnant and breast-feeding mothers must know their HIV status; ≥90% of those that are positive are enrolled on ARVs treatment and care; ≥90% of those on ARVs treatment and care are virally suppressed.

A systematic review and meta-analysis of vertical transmission route of HIV in Ethiopia

BACKGROUND

The burden of mother-to-child transmission rate of HIV is high and risk factors are common in Ethiopia. This systematic review and meta-analysis intended to provide the pooled estimation of mother-to-child transmission rate and its risk factors in Ethiopia.

METHODS

We searched PubMed, Google Scholar, EMBASE and Web of Science electronic databases for all available references. We included observational studies including case-control, cohort, and cross-sectional studies. The search was further limited to studies conducted in Ethiopia and publish in English. Heterogeneity was checked using the I² statistic. Egger's test and the funnel plot were used to assess publication bias. A meta-analysis using a weighted inverse variance random-effects model was performed.

RESULTS

A total of 18 studies with 6253 individuals were included in this systematic review and meta-analysis. Of these, 14 studies with 4624 individuals were used to estimate the prevalence. The estimated pooled prevalence of mother-to-child transmission of HIV was 11.4% (95% CI = 9.1-13.7). The pooled adjusted odds ratio (AOR) of mother-to-child transmission of HIV for the infants from rural area was 3.8 (95% CI = 1.4 to 6.3), infants delivered at home was 3.2 (95% CI = 1.2 to 5.2), infant didn't take antiretroviral prophylaxis was 5.8 (95% CI = 1.5 to 10.3), mother didn't take antiretroviral prophylaxis was 6.1 (95% CI = 2.5 to 9.6), mothers didn't receive PMTCT intervention was 5.1 (95% CI = 1.6, 8.6), and on mixed feeding was 4.3 (95% CI = 1.8 to 6.7).

CONCLUSIONS

This systematic review and meta-analysis showed that mother-to-child transmission rate of HIV was high in Ethiopia. Being from the rural residence, home delivery, not taking antiretroviral prophylaxis, the absence of PMTCT intervention, and mixed infant feeding practices increased the risk of HIV transmission.

TRIAL REGISTRATION

It is registered in the Prospero database: (PROSPERO 2017: CRD42017078232 ).

Darunavir for use in pregnant women with HIV

INTRODUCTION

Combination antiretroviral therapy is recommended during pregnancy to decrease the rate of HIV transmission to the baby and reduce morbidity in the mother. More than 50% of women are prescribed a protease inhibitor-based regimen during pregnancy. Darunavir was recently reclassified as a first-line protease inhibitor for use in pregnancy in the US Department of Health and Human Services Perinatal Guidelines. Areas covered: This is a brief review of the use of protease inhibitor therapy during pregnancy, and a discussion of darunavir's utility in this area. Clinical pharmacology and trial data are reviewed, and the safety, efficacy and dosing of darunavir during pregnancy is discussed. Expert commentary: Darunavir has become an important option in the management of HIV during pregnancy. Both once-daily dosing and twice-daily dosing regimens have shown efficacy in clinical studies. Although a significant reduction in total (protein bound and unbound) plasma concentrations of darunavir has been noted during pregnancy, antiviral activity appears to be maintained with standard dosing. This is likely due to diminished changes in unbound drug concentrations. Preterm delivery and low birth weight have been noted for pregnancies of women on darunavir-containg regimens, but a causal relationship has not yet been demonstrated.

HIV pre-exposure prophylaxis for women and infants prevents vaginal and oral HIV transmission in a preclinical model of HIV infection

BACKGROUND

Approximately 1.5 million HIV-positive women become pregnant annually. Without treatment, up to 45% will transmit HIV to their infants, primarily through breastfeeding. These numbers highlight that HIV acquisition is a major health concern for women and children globally. They also emphasize the urgent need for novel approaches to prevent HIV acquisition that are safe, effective and convenient to use by women and children in places where they are most needed.

METHODS

4'-Ethynyl-2-fluoro-2'-deoxyadenosine, a potent NRTI with low cytotoxicity, was administered orally to NOD/SCID/γc-/- mice and to bone marrow/liver/thymus (BLT) humanized mice, a preclinical model of HIV infection. HIV inhibitory activity in serum, cervicovaginal secretions and saliva was evaluated 4 h after administration. 4'-Ethynyl-2-fluoro-2'-deoxyadenosine's ability to prevent vaginal and oral HIV transmission was evaluated using highly relevant transmitted/founder viruses in BLT mice.

RESULTS

Strong HIV inhibitory activity in serum, cervicovaginal secretions and saliva obtained from animals after a single oral dose of 4'-ethynyl-2-fluoro-2'-deoxyadenosine (10 mg/kg) demonstrated efficient drug penetration into relevant mucosal sites. A single daily oral dose of 4'-ethynyl-2-fluoro-2'-deoxyadenosine resulted in efficient prevention of vaginal and oral HIV transmission after multiple high-dose exposures to transmitted/founder viruses in BLT humanized mice.

CONCLUSIONS

Our data demonstrated that 4'-ethynyl-2-fluoro-2'-deoxyadenosine efficiently prevents both vaginal and oral HIV transmission. Together with 4'-ethynyl-2-fluoro-2'-deoxyadenosine's relatively low toxicity and high potency against drug-resistant HIV strains, these data support further clinical development of 4'-ethynyl-2-fluoro-2'-deoxyadenosine as a potential pre-exposure prophylaxis agent to prevent HIV transmission in women and their infants.

The Immune System of HIV-Exposed Uninfected Infants

Infants born to human immunodeficiency virus (HIV) infected women are HIV-exposed but the majority remains uninfected [i.e., HIV-exposed uninfected (HEU)]. HEU infants suffer greater morbidity and mortality from infections compared to HIV-unexposed (HU) peers. The reason(s) for these worse outcomes are uncertain, but could be related to an altered immune system state. This review comprehensively summarizes the current literature investigating the adaptive and innate immune system of HEU infants. HEU infants have altered cell-mediated immunity, including impaired T-cell maturation with documented hypo- as well as hyper-responsiveness to T-cell activation. And although prevaccination vaccine-specific antibody levels are often lower in HEU than HU, most HEU infants mount adequate humoral immune response following primary vaccination with diphtheria toxoid, haemophilus influenzae type b, whole cell pertussis, measles, hepatitis B, tetanus toxoid, and pneumococcal conjugate vaccines. However, HEU infants are often found to have lower absolute neutrophil counts as compared to HU infants. On the other hand, an increase of innate immune cytokine production and expression of co-stimulatory markers has been noted in HEU infants, but this increase appears to be restricted to the first few weeks of life. The immune system of HEU children beyond infancy remains largely unexplored.

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

OBJECTIVE

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

DESIGN

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

METHODS

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

RESULTS

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

CONCLUSION

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

Genetic Analyses of HIV-1 Strains Transmitted from Mother to Child in Northern Vietnam

We previously reported mother-to-child transmission of HIV-1 in nine (6.7%) of 135 children on nevirapine prophylaxis in Vietnam. In the current study, we investigated the appearance and profile of antiretroviral drug (ARV) resistance mutations, the predicted coreceptor usage, and the genetic diversity of HIV-1 strains isolated from the eight pairs of HIV-1-infected mothers and their children, who were followed up to 12 months after birth. Portions of the pol and env C2V3 regions of the HIV-1 strains were analyzed genetically. HIV-1 CRF01_AE RNA was detected in four (50%) children at delivery. Y181C, a nevirapine resistance mutation, appeared in two (25%) children 1 and 3 months after birth, respectively. No ARV resistance mutation was detected in the mothers, though three mothers were on ARV prophylaxis. Five mothers and their children harbored CCR5-tropic (R5) viruses. Two mothers harbored both R5 and CXCR4-tropic (X4) viruses, but their children harbored only R5 viruses even though the X4 viruses were dominant in the mothers. In the remaining one mother, HIV-1 RNA was not amplified and her child harbored both R5 and X4 viruses at birth, but only X4 virus 12 months after delivery. The infants' viruses were more homogeneous than their mothers' viruses (mean distance: 0.5% vs. 1.1%, respectively). This is the first molecular epidemiological study of vertical HIV-1 infections in Vietnam. These findings may provide useful knowledge for the prevention of mother-to-child transmission of HIV-1 and the antiretroviral treatment of children in Vietnam.

Magnetic resonance imaging in viral and prion diseases of the central nervous system

The early detection and specific diagnosis of viral infections of the central nervous system are important because many of these diseases are potentially treatable. However, clinical symptoms and physical examination are often nonspecific, and rapid diagnostic tests are available for some, but not all, viruses. Neuroimaging, in conjunction with clinical history and laboratory tests, plays an important role in narrowing the differential diagnoses. In this article, we review the clinical features, imaging characteristics, diagnosis, and treatment of the more common viral infections and prions that involve the central nervous system.

Viral invasion of the amniotic cavity (VIAC) in the midtrimester of pregnancy

INTRODUCTION

The prevalence of viral infections in the amniotic fluid (AF) has not yet been ascertained. The aim of this study was to determine the prevalence of specific viral nucleic acids in the AF and its relationship to pregnancy outcome.

STUDY DESIGN

From a cohort of 847 consecutive women undergoing midtrimester amniocentesis, 729 cases were included in this study after exclusion of documented fetal anomalies, chromosomal abnormalities, unavailability of AF specimens and clinical outcomes. AF specimens were tested by quantitative real-time PCR for the presence of genome sequences of the following viruses: adenoviruses, herpes simplex virus (HSV), varicella zoster virus (VZV), human herpesvirus 6 (HHV6), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), parvovirus B19 and enteroviruses. Viral nucleic acid testing was also performed in maternal blood and cord blood in the population of women in whom AF was positive for viruses and in a control group of 29 women with AF negative for viral nucleic acids. The relationship between the presence of viruses and pregnancy and neonatal outcome was examined. The correlation between the presence of nucleic acids of viruses in the AF and the concentration of the cytokine interleukin-6 (IL-6) and the T cell chemokine CXCL-10 (or IP-10) in AF and maternal blood were analyzed.

RESULTS

Viral genome sequences were found in 16 of 729 (2.2%) AF samples. HHV6 was the most commonly detected virus (7 cases, 1.0%), followed by HCMV (6 cases, 0.8%), parvovirus B19 (2 cases, 0.3%) and EBV (1 case, 0.1%), while HSV, VZV, enteroviruses and adenoviruses were not found in this cohort. Corresponding viral DNA was also detected in maternal blood of six out of seven women with HHV6-positive AF and in the umbilical cord plasma, which was available in one case. In contrast, viral DNA was not detected in maternal blood of women with AF positive for parvovirus B19, HCMV, EBV or of women with AF negative for viruses. HHV6 genome copy number in AF and maternal blood was consistent with genomic integration of viral DNA and genetic infection in all women. There was no significant difference in the AF concentration of IL-6 and IP-10 between patients with and without VIAC. However, for HCMV, there was a significant relationship between viral copy number and IP-10 concentration in maternal blood and AF. The group of women with AF positive for viral DNA delivered at term healthy neonates without complications in 14 out of 16 cases. In one case of HHV6 infection in the AF, the patient developed gestational hypertension at term, and in another case of HHV6 infection in the AF, the patient delivered at 33 weeks after preterm premature rupture of membranes (PPROM).

CONCLUSION

Viral nucleic acids are detectable in 2.2% of AF samples obtained from asymptomatic women in the midtrimester. HHV6 was the most frequently detected virus in AF. Adenoviruses were not detected. Vertical transmission of HHV6 was demonstrated in one case.

Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Antiretroviral drugs reduce viral replication and can reduce mother-to-child transmission of HIV either by lowering plasma viral load in pregnant women or through post-exposure prophylaxis in their newborns. In rich countries, highly active antiretroviral therapy (HAART) which usually comprises three drugs, has reduced the mother-to-child transmission rates to around 1-2%, but HAART is not always available in low- and middle-income countries. In these countries, various simpler and less costly antiretroviral regimens have been offered to pregnant women or to their newborn babies, or to both.

OBJECTIVES

To determine whether, and to what extent, antiretroviral regimens aimed at decreasing the risk of mother-to-child transmission of HIV infection achieve a clinically useful decrease in transmission risk, and what effect these interventions have on maternal and infant mortality and morbidity.

SEARCH STRATEGY

We sought to identify all relevant studies regardless of language or publication status by searching the Cochrane HIV/AIDS Review Group Trials Register, The Cochrane Library, MEDLINE, EMBASE and AIDSearch and relevant conference abstracts. We also contacted research organizations and experts in the field for unpublished and ongoing studies. The original review search strategy was conducted in 2002 and updated in 2006 and again in 2009.

SELECTION CRITERIA

Randomised controlled trials of any antiretroviral regimen aimed at decreasing the risk of mother-to-child transmission of HIV infection compared with placebo or no treatment, or compared with another antiretroviral regimen.

DATA COLLECTION AND ANALYSIS

Two authors independently selected relevant studies, extracted data and assessed trial quality. For the primary outcomes, we used survival analysis to estimate the probability of infants being infected with HIV (the observed proportion) at various specific time-points and calculated efficacy at a specific time as the relative reduction in the proportion infected. Efficacy, at a specific time, is defined as the preventive fraction in the exposed group compared to the reference group, which is the relative reduction in the proportion infected: 1-(Re/Rf). For those studies where efficacy and hence confidence intervals were not calculated, we calculated the approximate confidence intervals for the efficacy using recommended methods. For analysis of results that are not based on survival analyses we present the relative risk for each trial outcome based on the number randomised. No meta-analysis was conducted as no trial assessed identical drug regimens.

MAIN RESULTS

Twenty-five trials including 18,901 participants with a median trial sample size of 627 ranging from 50 to 1,844 participants were included in this update. Twenty-two trials randomised mothers (18 pre-natally and four in labour) and followed up their infants, and three trials randomised infants. The first trial began in April 1991 and assessed zidovudine (ZDV) versus placebo and since then, the type, dosage and duration of drugs to be compared has been modified in each subsequent trial. We present the results stratified by regimen and type of feeding.Antiretrovirals versus placebo In breastfeeding populations, three trials found that:ZDV given to mothers from 36 to 38 weeks gestation, during labour and for 7 days after delivery significantly reduced HIV infection at 4-8 weeks (Efficacy 32.00%; 95% CI 1.50 to 62.50), 3 to 4 months (Efficacy 33.07%; 95% CI 5.57 to 60.57), 6 months (Efficacy 34.55%; 95% CI 9.05 to 60.05), 12 months (Efficacy 34.31%; 95% CI 9.30 to 59.32) and 18 months (Efficacy 29.74%; 95% CI 2.73 to 56.75).ZDV given to mothers from 36 weeks gestation and during labour significantly reduced HIV infection at 4 to 8 weeks (Efficacy 43.78%; 95% CI 8.78 to 78.78) and 3 to 4 months (Efficacy 36.95%; 95% CI 2.94 to 70.96) but not at birth.ZDV plus lamivudine (3TC) given to mothers from 36 weeks gestation, during labour and for 7 days after delivery and to babies for the first 7 days after birth (PETRA 'regimen A') significantly reduced HIV infection (Efficacy 62.75%; 95% CI 40.76 to 84.74) and a combined endpoint of HIV infection or death (Efficacy 62.75 [, ]61.00%; 95% CI 40.76 to 84.74) at 4 to 8 weeks but these effects were not sustained at 18 months.ZDV plus 3TC given to mothers from the start of labour until 7 days after delivery and to babies for the first 7 days after birth (PETRA 'regimen B') significantly reduced HIV infection (Efficacy 41.83%; 95% CI 12.82 to 70.84) and HIV infection or death at 4 to 8 weeks (Efficacy 35.91%; 95% CI 8.41 to 63.41) but the effects were not sustained at 18 months.ZDV plus 3TC given to mothers during labour only (PETRA 'regimen C') with no treatment to babies did not reduce the risk of HIV infection at either 4 to 8 weeks or 18 months.In non-breastfeeding populations, three trials found that:ZDV given to mothers from 14 to 34 weeks gestation and during labour and to babies for the first 6 weeks after birth significantly reduced HIV infection in babies at 18 months (Efficacy 66.22%; 95% CI 33.94 to 98.50).ZDV given to mothers from 36 weeks gestation and during labour with no treatment to babies ('Thai-CDC regimen') significantly reduced HIV infection at 4 to 8 weeks (Efficacy 50.26%; 95% CI 13.80 to 86.72) but not at birthZDV given to mothers from 38 weeks gestation and during labour with no treatment to babies did not influence HIV transmission at 6 months.Longer versus shorter regimens using the same antiretrovirals One trial in a breastfeeding population found that:ZDV given to mothers during labour and to their babies for the first 3 days after birth compared with ZDV given to mothers from 36 weeks and during labour (similar to 'Thai-CDC') resulted in HIV infection rates that were not significantly different at birth, 4-8 weeks, 3 to 4 months, 6 months and 12 months.Three trials in non-breastfeeding populations found that:ZDV given to mothers from 28 weeks gestation during labour and to infants for the first 3 days after birth compared with ZDV given to mothers from 35 weeks gestation through labour and to infants from birth to 6 weeks significantly reduced HIV infection rate at 6 months (Efficacy 45.35 %; 95% CI 1.39 to 89.31) but compared with the same regimen ZDV given to mothers from 28 weeks gestation through labour and to infants from birth to 6 weeks did not result in a statistically significant difference in HIV infection at 6 months. ZDV given to mothers from 35 weeks gestation during labour and to infants for the first 3 days after birth was considered ineffective for reducing transmission rates and this regimen was discontinued.An antenatal/intrapartum course of ZDV used for a median of 76 days compared with an antenatal/intrapartum ZDV regimen used for a median 28 days with no treatment to babies in either group did not result in HIV infection rates that were significantly different at birth and at 3 to 4 months.In a programme where mothers were routinely receiving ZDV in the third trimester of pregnancy and babies were receiving one week of ZDV therapy, a single dose of nevirapine (NVP) given to mothers in labour and to their babies soon after birth compared with a single dose of NVP given to mothers only resulted in HIV infection rates that were not significantly different at birth and 6 months. However the reduction in risk of HIV infection or death at 6 months was marginally significant (Efficacy 45.00%; 95% CI -4.00 to 94.00).Antiretroviral regimens using different drugs and durations of treatmentIn breastfeeding populations, three trials found that:A single dose of NVP given to mothers at the onset of labour plus a single dose of NVP given to their babies immediately after birth ('HIVNET 012 regimen') compared with ZDV given to mothers during labour and to their babies for a week after birth resulted in lower HIV infection rates at 4-8 weeks (Efficacy 41.00%; 95% CI 11.84 to 70.16), 3-4 months (Efficacy 38.91%; 95% CI 11.24 to 66.58), 12 months (Efficacy 35.98 [9.25, 62.71]36.00%; 95% CI 8.56 to 63.44) and 18 months (Efficacy 39.15%; 95% CI 13.81 to 64.49). In addition, the NVP regimen significantly reduced the risk of HIV infection or death at 4-8 weeks (Efficacy 41.74%; 95% CI 14.30 to 69.18), 3 to 4 months (Efficacy 40.00%; 95% CI 14.34 to 65.66), 12 months (Efficacy 32.17%; 95% CI 8.51 to 55.83) and 18 months (Efficacy 32.57 [9.93, 55.21]33.00%; 95% CI 9.93 to 55.21).The 'HIVNET 012 regimen' plus ZDV given to babies for 1 week after birth compared with the 'HIVNET 012 regimen' alone did not result in a statistically significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth plus ZDV given to babies for 1 week after birth compared with a single dose of NVP given to babies only significantly reduced the HIV infection rate at 4 to 8 weeks (Efficacy 36.79%; 95% CI 3.57 to 70.01).Five trials in non-breastfeeding populations found that:In a population in which mothers were receiving 'standard' antiretroviral for HIV infection a single dose of NVP given to mothers in labour plus a single dose of NVP given to babies immediately after birth ('HIVNET 012 regimen') compared with placebo did not result in a statistically significant difference in HIV infection rates at birth and at 4 to 8 weeks.The 'Thai CDC regimen' compared with the 'HIVNET 012 regimen' did not result in a significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth compared to ZDV given to babies for the first 6 weeks after birth did not result in a significant difference in HIV infection rates at 4-8 weeks and 3 to 4 months. (ABSTRACT TRUNCATED)

HIV: prevention of mother-to-child transmission

INTRODUCTION

Over 2 million children are thought to be living with HIV/AIDS worldwide, of whom over 80% live in sub-Saharan Africa. Without antiretroviral treatment, the risk of HIV transmission from infected mothers to their children is 15% to 30% during gestation or labour, with an additional transmission risk of 10% to 20% associated with prolonged breastfeeding. HIV-1 infection accounts for most infections; HIV-2 is rarely transmitted from mother to child. Transmission is more likely in mothers with high viral loads, advanced disease, or both, in the presence of other sexually transmitted diseases, and with increased exposure to maternal blood. Mixed feeding practices (breast milk plus other liquids or solids) and prolonged breastfeeding are also associated with increased risk of mother-to-child transmission of HIV.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of measures to reduce mother-to-child transmission of HIV? We searched: Medline, Embase, The Cochrane Library, and other important databases up to October 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions.

RESULTS

We found 53 systematic reviews, RCTs, or observational studies that met our inclusion criteria.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiretroviral drugs, different methods of infant feeding, elective caesarean section, immunotherapy, micronutrient supplements, vaginal microbicides, and vitamin supplements.

Acute HIV infection among pregnant women in Malawi

There are limited data on acute HIV infection (AHI) prevalence during pregnancy. Malawian pregnant women admitted in the third trimester and meeting eligibility criteria underwent dual HIV rapid antibody testing. AHI prevalence was retrospectively detected through HIV RNA pooling of seronegative plasma. Among 3,825 pregnant women screened, dual HIV rapid testing indicated that 30.2% were HIV positive, 69.7% were HIV negative, and 0.1% were indeterminate. Sensitivity and specificity of dual rapid testing was 99.0% and 98.7%, respectively. Of 2,666 seronegative specimens, 2,327 had samples available for HIV RNA pooling; 5 women (0.21%) (95% confidence interval, 0.03-0.40%) had AHI with a median peripartum viral load of 1,324,766 copies/mL. Pregnant women are at risk for AHI, warranting counseling of all women and their sexual partners about incident HIV during pregnancy. Dual HIV rapid tests have high sensitivity and specificity. HIV testing should be repeated in the third trimester and/or at delivery.

HIV-1 Tat-based vaccines: an overview and perspectives in the field of HIV/AIDS vaccine development

The HIV epidemic continues to represent one of the major problems worldwide, particularly in the Asia and Sub-Saharan regions of the world, with social and economical devastating effects. Although antiretroviral drugs have had a dramatically beneficial impact on HIV-infected individuals that have access to treatment, it has had a negligible impact on the global epidemic. Hence, the inexorable spreading of the HIV pandemic and the increasing deaths from AIDS, especially in developing countries, underscore the urgency for an effective vaccine against HIV/AIDS. However, the generation of such a vaccine has turned out to be extremely challenging. Here we provide an overview on the rationale for the use of non-structural HIV proteins, such as the Tat protein, alone or in combination with other HIV early and late structural HIV antigens, as novel, promising preventative and therapeutic HIV/AIDS vaccine strategies.

Characteristics of HIV type 1 (HIV-1) glycoprotein 120 env sequences in mother-infant pairs infected with HIV-1 subtype CRF01_AE

We analyzed the characteristics of the envelope genes of human immunodeficiency virus type 1 in 17 mother-infant pairs infected with variants of the CRF01_AE clade. A total of 353 sequences covering almost the entire glycoprotein (gp) 120 region were available for analysis. We found that, even if the virus population in the mother was complex, only viruses of a restricted subset were transmitted to her infant, independently of whether transmission occurred in utero or during the intrapartum period. We did not find that shorter gp120 regions or fewer potential N-glycosylation sites (PNGS) were characteristic of viruses transmitted from mother to infant. However, our data suggest that a limited number of PNGS that seem to be conserved in all variants in infants but are not uniformly present in variants in mothers may confer an advantage for transmission of the virus, thereby highlighting the potentially important role of the "glycan shield." This finding was particularly significant for the PNGS at positions N301 and N384.

Acute HIV infection among Kenyan infants

BACKGROUND

Clinical signs and symptoms of acute human immunodeficiency virus (HIV) infection in infants are not well characterized.

METHODS

Serial clinical assessments and HIV PCR assays were conducted in a cohort of children born to HIV-seropositive mothers from birth to 2 years of age. Acute HIV infection visits were defined as those up to 3 months prior to and including the visit at which HIV DNA was first detected. Noninfection visits included all visits at which the child had test results negative for HIV, including the last visit at which a test result negative for HIV DNA was obtained in children who later acquired HIV infection. Differences in the prevalence of symptoms at acute infection versus noninfection visits were determined overall and were stratified by age at infection (<2 months vs. >or=2 months). HIV RNA was measured serially in infected infants and was compared between infants with and infants without symptoms of acute HIV infection.

RESULTS

There were 125 acute infection visits (among 56 infants) and 3491 noninfection visits (among 306 infants). Acute HIV infection was associated with rash (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-2.8), failure to thrive (OR, 1.9; 95% CI, 1.0-3.5), and lymphadenopathy (OR, 2.5; 95% CI, 1.4-4.8). Acute HIV infection was associated with lymphadenopathy (OR, 2.6; 95% CI, 1.3-5.0) in infants <2 months of age and with pneumonia (OR, 3.2; 95% CI, 1.1-9.3) and dehydration (OR, 6.0; 95% CI, 1.9-18.5) in infants >or=2 months of age. Infant peak viral load and mortality were not associated with symptoms of acute HIV infection. However, infants with symptoms had higher viral levels later in the course of infection than did those without symptoms (P=.05).

CONCLUSIONS

Infants may manifest symptoms early during the course of HIV infection, and symptoms of acute HIV infection may correlate with poor viral control. Rash, failure to thrive, lymphadenopathy, pneumonia, and dehydration may signify acute HIV infection in infants.

HIV: mother-to-child transmission

INTRODUCTION

Over 2 million children are thought to be living with HIV/AIDS worldwide, of whom over 80% live in sub-Saharan Africa. Without anti-retroviral treatment, the risk of HIV transmission from infected mothers to their children is 15-30% during gestation or labour, and 15-20% during breast feeding. HIV-1 infection accounts for most infections; HIV-2 is rarely transmitted from mother to child. Transmission is more likely in mothers with high viral loads and/or advanced disease, in the presence of other sexually transmitted diseases, and with increased exposure to maternal blood.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of measures to reduce mother to child transmission of HIV? We searched: Medline, Embase, The Cochrane Library and other important databases up to January 2007 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions.

RESULTS

We found 18 systematic reviews, RCTs, or observational studies that met our inclusion criteria.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiretroviral drugs, different methods of infant feeding, elective caesarean section, immunotherapy, vaginal microbicides, and vitamin supplements.

The missing link: documentation of recognized maternal human immunodeficiency virus infection in exposed infant birth records, 24 United States jurisdictions, 1999-2003

Despite substantial improvements, perinatal human immunodeficiency virus (HIV) transmission has not been eliminated in the United States. We examined the extent and contribution of missed communication opportunities between obstetric and pediatric providers who cared for HIV-infected women and their infants. This was a retrospective review of HIV-exposed infants whose data were reported to the Centers for Disease Control and Prevention Enhanced Perinatal Surveillance System from 1999-2003 (n = 8115). For approximately 4% of the HIV-exposed infants whose data were reported to the Enhanced Perinatal Surveillance System between 1999 and 2003, recognized maternal HIV infection was not documented in the exposed infants' birth records. Such infants were at higher risk of not receiving appropriate neonatal antiretroviral prophylaxis (adjusted odds ratio, 37.3; 95% CI, 24.6-56.4) and had increased odds of HIV infection (adjusted odds ratio, 1.7; 95% CI, 1.1-2.6). Enhanced communication between pediatric and obstetric and gynecologic providers to eliminate this missed opportunity for prevention would improve HIV infection outcomes for HIV-exposed infants and improve care for their mothers.

Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Antiretroviral drugs (ARV) reduce viral replication and can reduce mother-to-child transmission of HIV either by lowing plasma viral load in pregnant women or through post-exposure prophylaxis in their newborns. In rich countries, highly active antiretroviral therapy (HAART) has reduced the vertical transmission rates to around 1-2%, but HAART is not yet widely available in low and middle income countries. In these countries, various simpler and less costly antiretroviral regimens have been offered to pregnant women or to their newborn babies, or to both.

OBJECTIVES

To determine whether, and to what extent, antiretroviral regimens aimed at decreasing the risk of mother-to-child transmission of HIV infection achieve a clinically useful decrease in transmission risk, and what effect these interventions have on maternal and infant mortality and morbidity.

SEARCH STRATEGY

We sought to identify all relevant studies regardless of language or publication status by searching the Cochrane HIV/AIDS Review Group Trials Register, The Cochrane Library, Medline, EMBASE and AIDSearch and relevant conference abstracts. We also contacted research organizations and experts in the field for unpublished and ongoing studies. The original review search strategy was updated in 2006.

SELECTION CRITERIA

Randomised controlled trials of any antiretroviral regimen aimed at decreasing the risk of mother-to-child transmission of HIV infection compared with placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently selected relevant studies, extracted data and assessed trial quality. For the primary outcomes, we used survival analysis to estimate the probability of infants being infected with HIV (the observed proportion) at various specific time-points and calculated efficacy at a specific time as the relative reduction in the proportion infected. Efficacy, at a specific time, is defined as the preventive fraction in the exposed group compared to the reference group, which is the relative reduction in the proportion infected: 1-(Re/Rf). For those studies where efficacy and hence confidence intervals were not calculated, we calculated the approximate confidence intervals for the efficacy using recommended methods. For analysis of results that are not based on survival analyses we present the relative risk for each trial outcome based on the number randomised. No meta-analysis was conducted as no trial assessed the identical drug regimens.

MAIN RESULTS

Eighteen trials including 14,398 participants conducted in 16 countries were eligible for inclusion in the review. The first trial began in April 1991 and assessed zidovudine (ZDV) versus placebo and since then, the type, dosage and duration of drugs to be compared has been modified in each subsequent trial. Antiretrovirals versus placebo In breastfeeding populations, three trials found that:ZDV given to mothers from 36 to 38 weeks gestation, during labour and for 7 days after delivery significantly reduced HIV infection at 4-8 weeks (Efficacy 32.00%; 95% CI 0.64 to 63.36), 3 to 4 months (Efficacy 34.00%; 95% CI 6.56 to 61.44), 6 months (Efficacy 35.00%; 95% CI 9.52 to 60.48), 12 months (Efficacy 34.00%; 95% CI 8.52 to 59.48) and 18 months (Efficacy 30.00%; 95% CI 2.56 to 57.44).ZDV given to mothers from 36 weeks gestation and during labour significantly reduced HIV infection at 4 to 8 weeks (Efficacy 44.00%; 95% CI 8.72 to 79.28) and 3 to 4 months (Efficacy 37.00%; 95% CI 3.68 to 70.32) but not at birth.ZDV plus lamivudine (3TC) given to mothers from 36 weeks gestation, during labour and for 7 days after delivery and to babies for the first 7 days of life (PETRA 'regimen A') significantly reduced HIV infection (Efficacy 63.00%; 95% CI 41.44 to 84.56) and a combined endpoint of HIV infection or death (Efficacy 61.00%; 95% CI 41.40 to 80.60) at 4 to 8 weeks but these effects were not sustained at 18 months.ZDV plus 3TC given to mothers from the start of labour until 7 days after delivery and to babies for the first 7 days of life (PETRA 'regimen B') significantly reduced HIV infection (Efficacy 42.00%; 95% CI 12.60 to 71.40) and HIV infection or death at 4 to 8 weeks (Efficacy 36.00%; 95% CI 8.56 to 63.44) but the effects were not sustained at 18 months.ZDV plus 3TC given to mothers during labour only (PETRA 'regimen C') with no treatment to babies did not reduce the risk of HIV infection at either 4 to 8 weeks or 18 months. In non-breastfeeding populations, three trials found that:ZDV given to mothers from 14 to 34 weeks gestation and during labour and to babies for the first 6 weeks of life significantly reduced HIV infection in babies at 18 months (Efficacy 66.00%; 95% CI 34.64 to 97.36).ZDV given to mothers from 36 weeks gestation and during labour with no treatment to babies ('Thai-CDC regimen') significantly reduced HIV infection at 4 to 8 weeks (Efficacy 50.00%; 95% CI 12.76 to 87.24) but not at birthZDV given to mothers from 38 weeks gestation and during labour with no treatment to babies did not influence HIV transmission at 6 months. Longer versus shorter regimens using the same antiretrovirals One trial in a breastfeeding population found that:ZDV given to mothers during labour and to their babies for the first 3 days of life compared with ZDV given to mothers from 36 weeks and during labour (similar to 'Thai-CDC') resulted in HIV infection rates that were not significantly different at birth, 4-8 weeks, 3 to 4 months, 6 months and 12 months. Three trials in non-breastfeeding populations found that:ZDV given to mothers from 28 weeks gestation during labour and to infants for the first 3 days after birth compared with ZDV given to mothers from 35 weeks gestation through labour and to infants from birth to 6 weeks significantly reduced HIV infection rate at 6 months (Efficacy 45.00%; 95% CI 1.88 to 88.12) but compared with the same regimen ZDV given to mothers from 28 weeks gestation through labour and to infants from birth to 6 weeks did not result in a statistically significant difference in HIV infection at 6 months. ZDV given to mothers from 35 weeks gestation during labour and to infants for the first 3 days after birth was considered ineffective for reducing transmission rates and this regimen was discontinued.An antenatal/intrapartum course of ZDV used for a median of 76 days compared with an antenatal/intrapartum ZDV regimen used for a median 28 days with no treatment to babies in either group did not result in HIV infection rates that were significantly different at birth and at 3 to 4 months. In a programme where mothers were routinely receiving ZDV in the third trimester of pregnancy and babies were receiving one week of ZDV therapy, a single dose of nevirapine (NVP) given to mothers in labour and to their babies soon after birth compared with a single dose of NVP given to mothers only resulted in HIV infection rates that were not significantly different at birth and 6 months. However the reduction in risk of HIV infection or death at 6 months was marginally significant (Efficacy 45.00%; 95% CI -4.00 to 94.00). Antiretroviral regimens using different drugs and durations of treatment In breastfeeding populations, three trials found that:A single dose of NVP given to mothers at the onset of labour plus a single dose of NVP given to their babies immediately after birth ('HIVNET 012 regimen') compared with ZDV given to mothers during labour and to their babies for a week after birth resulted in lower HIV infection rates at 4-8 weeks (Efficacy 41.00%; 95% CI 11.60 to 70.40), 3-4 months (Efficacy 39.00%; 95% CI 11.56 to 66.44), 12 months (Efficacy 36.00%; 95% CI 8.56 to 63.44) and 18 months (Efficacy 39.00%; 95% CI 13.52 to 64.48). In addition, the NVP regimen significantly reduced the risk of HIV infection or death at 4-8 weeks (Efficacy 42.00%; 95% CI 14.56 to 69.44), 3 to 4 months (Efficacy 40.00%; 95% CI 14.52 to 65.48), 12 months (Efficacy 32.00%; 95% CI 8.48 to 55.52) and 18 months (Efficacy 33.00%; 95% CI 9.48 to 56.52). The 'HIVNET 012 regimen' plus ZDV given to babies for 1 week after birth compared with the 'HIVNET 012 regimen' alone did not result in a statistically significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth plus ZDV given to babies for 1 week after birth compared with a single dose of NVP given to babies only significantly reduced the HIV infection rate at 4 to 8 weeks (Efficacy 37.00%; 95% CI 3.68 to 70.32). Five trials in non-breastfeeding populations found that:In a population in which mothers were receiving 'standard' ARV for HIV infection a single dose of NVP given to mothers in labour plus a single dose of NVP given to babies immediately after birth ('HIVNET 012 regimen') compared with placebo did not result in a statistically significant difference in HIV infection rates at birth and at 4 to 8 weeks. The 'Thai CDC regimen' compared with the 'HIVNET 012 regimen' did not result in a significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth compared to ZDV given to babies for the first 6 weeks of life did not result in a significant difference in HIV infection rates at 4-8 weeks and 3 to 4 months.ZDV plus 3TC given to mothers in labour and for a week after delivery and to their infants for a week after birth (similar to 'PETRA regimen B') compared with NVP given to mothers in labour and immediately after delivery plus a single dose of NVP to their babies immediately after birth (similar to 'HIVNET 012 regimen') did not result in a significant difference in the HIV infection rate at 4 to 8 weeks. (ABSTRACT TRUNCATED)

Biological mechanisms of vertical human immunodeficiency virus (HIV-1) transmission

In the absence of interventions, 30-45% of exposed infants acquire human immunodeficiency virus type 1 (HIV-1) through mother-to-child transmission. It remains unclear why some infants become infected while others do not, despite significant exposure to HIV-1 in utero, during delivery and while breastfeeding. Here we discuss the correlates of vertical transmission with an emphasis on factors that increase maternal HIV-1 levels, either systemically or locally in genital secretions and breast milk. Immune responses may influence maternal viral load, and data suggest that maternal neutralising antibodies reduce infection rates. In addition, infants may be capable of mounting HIV-specific cellular immune responses. We propose that both humoral and cellular responses are necessary to reduce infection because cell-free as well as cell-associated virus appears to play a role in vertical transmission. These distinct forms of the virus may be targeted most effectively by different components of the immune system. We also discuss the use of antiretrovirals to reduce transmission, focusing on the mechanisms of action of regimens currently used in developing country settings. We conclude that prevention relies not only on reducing maternal HIV-1 levels within blood, genital tract and breast milk, but also on pre- and/or post-exposure prophylaxis to the infant. However, HIV-1 has the capacity to mutate under drug pressure and rapidly acquires mutations conferring antiretroviral resistance. This review concludes with data on persistence of low-level resistance after delivery as well as recent guidelines for maternal and infant regimens designed to limit resistance.

Efficient mother-to-child transfer of antiretroviral immunity in the context of preclinical monoclonal antibody-based immunotherapy

When mice under the age of 5 to 6 days are infected, the FrCas(E) retrovirus induces a neurodegenerative disease leading to death within 1 to 2 months. We have recently reported that transient treatment with a neutralizing monoclonal antibody (MAb) shortly after infection, in addition to an expected immediate decrease in the viral load, also favors the development of a strong protective immune response that persists long after the MAb has been cleared. This observation may have important therapeutic consequences, as it suggests that MAbs might be used, not only as direct neutralizing agents, but also as immunomodulatory agents enabling patients to mount their own antiviral immune responses. We have investigated whether immunoglobulins from mothers who displayed a strong anti-FrCas(E) humoral response induced upon MAb treatment could affect both viremia and the immune systems of FrCas(E)-infected pups till adult age upon placental and/or breastfeeding transfer. The strongest effects, i.e., reduction in the viral load and induction of protective humoral antiviral responses, were observed upon breastfeeding alone and breastfeeding plus placental immunity transfer. However, placental transfer of anti-FrCas(E) antibodies was sufficient to both protect neonatally infected animals and help them initiate a neutralizing anti-FrCas(E) response. Also, administration of a neutralizing MAb to naive mothers during late gestation and breastfeeding could generate similar effects. Taken together, our data support the concept that passive immunotherapies during late gestation and/or breastfeeding might help retrovirally infected neonates prime their own protective immune responses, in addition to exerting an immediate antiviral effect.

Oral transmission of HIV, reality or fiction? An update

Human immunodeficiency virus (HIV) and many other viruses can be isolated in blood and body fluids, including saliva, and can be transmitted by genital-genital and especially anal-genital sexual activity. The risk of transmission of HIV via oral sexual practices is very low. Unlike other mucosal areas of the body, the oral cavity appears to be an extremely uncommon transmission route for HIV. We present a review of available evidence on the oral-genital transmission of HIV and analyse the factors that act to protect oral tissues from infection, thereby reducing the risk of HIV transmission by oral sex. Among these factors we highlight the levels of HIV RNA in saliva, presence of fewer CD4+ target cells, presence of IgA antibodies in saliva, presence of other infections in the oral cavity and the endogenous salivary antiviral factors lysozyme, defensins, thrombospondin and secretory leucocyte protease inhibitor (SLPI).

Neutralization escape variants of human immunodeficiency virus type 1 are transmitted from mother to infant

Maternal passive immunity typically plays a critical role in protecting infants from new infections; however, the specific contribution of neutralizing antibodies in limiting mother-to-child transmission of human immunodeficiency virus type 1 is unclear. By examining cloned envelope variants from 12 transmission pairs, we found that vertically transmitted variants were more resistant to neutralization by maternal plasma than were maternal viral variants near the time of transmission. The vertically transmitted envelope variants were poorly neutralized by monoclonal antibodies b12 [corrected] 2G12, 2F5, and 4E10 individually or in combination. Despite the fact that the infant viruses were among the most neutralization resistant in the mother, they had relatively few glycosylation sites. Moreover, the transmitted variants elicited de novo neutralizing antibodies in the infants, indicating that they were not inherently difficult to neutralize. The neutralization resistance of vertically transmitted viruses is in contrast to the relative neutralization sensitivity of viruses sexually transmitted within discordant couples, suggesting that the antigenic properties of viruses that are favored for transmission may differ depending upon mode of transmission.

Pharmacokinetics of antivirals in neonate

BACKGROUND

About 1000 neonates with HIV infection are born every day worldwide. The antiviral therapy for newborn infants is a real necessity. Pharmacokinetics is an important contribution to therapy and no review has been published on the pharmacokinetics of antivirals in neonates up to now.

AIMS

This article provides a review on the pharmacokinetics of antivirals in the neonate. The pharmacokinetic parameters in the neonate are compared with those of the adult, and when possible, the pharmacokinetic parameters were compared in neonates of different ages.

RESULTS

Zidovudine is the antiviral with the largest amount of information on its pharmacokinetics. The clearance (Cl; l/h/kg) of zidovudine is 0.15 (premature), 0.34 (1 day), 0.69 (7 days), 0.65 (< or =14 days), 1.14 (>14 days) and 1.56 (adult). t(1/2) (h) of zidovudine is 7.2 (premature), 4.2 (1 day), 4.0 (7 days), 3.1 (< or =14 days), 1.9 (>14 days) and 1.1 (adult). Zidovudine is mainly eliminated by conjugation with glucuronic acid and glucuronosyl transferase develops postnatally. Cl of lamivudine is 0.19 (1 day), 0.32 (7 days) and 0.30 (adult) and the Cl (l/h/m2) of didanosine is 65 (1 day) and 271 (7 days). A greater volume of distribution (Vd) has been observed in the neonate compared with the adult for nelfinavir, nevirapine and pleconaril.

CONCLUSIONS

The pharmacokinetic parameters of antivirals differ in the neonate and in the adult. The Cl is reduced and t(1/2) is increased in the neonate compared with the adult for zidovudine, lamivudine and ganciclovir. t(max) is generally greater in the neonate than in the adult due to reduced absorption rate in the neonate. The Vd of nelfinavir, nevirapine and pleconaril is greater in the newborn than in the adult. The neonate is a developing organism and the pharmacokinetic parameters of antivirals vary during the first weeks of life.

Transfer of antivirals across the human placenta

BACKGROUND

Viruses cross the placenta and infect the fetus. Antivirals are administered to pregnant women to protect them and the fetus against the viruses. It is necessary to know which antivirals cross the placenta and reach the fetal circulation in pharmacologically significant concentrations in order to plan antiviral therapy.

AIMS

This article reviews the literature on the placental transfer of antivirals against HIV. The review considers also the placental transfer of acyclovir and ganciclovir, which are used against the herpes simplex virus and the cytomegalovirus, respectively.

STUDY DESIGN

Firstly, a medline was performed with the following key words "placental transfer of antivirals". Secondly, a medline was performed with the key words "placenta transfer of..." followed by the name of a single antiviral and it was repeated for 20 antivirals. Thirdly, another medline was performed using the following key words "pharmacokinetics of antiviral in newborn" in order to collect those articles which describe in vivo transfer of antivirals. The literature was critically read and a written note was produced.

RESULTS

The literature on the placental transfer of antivirals includes studies in vitro perfusing the human placenta and studies performed in vivo in which the cord and maternal antiviral plasma concentrations are compared. Both the results obtained in vitro and in vivo show that the protease inhibitors poorly transfer the placenta because of their great molecular weight. With the exception of didanosine, the nucleoside reverse transcriptase inhibitors and nelfinavir, a non-nucleoside reverse transcriptase inhibitor, cross the placenta and the cord, and maternal plasma concentrations equilibrate.

CONCLUSIONS

In vitro and in vivo results are consistent with the view that the nucleoside reverse transcriptase inhibitors cross the human placenta and produce significant pharmacological concentrations in the fetal circulation. Nevirapine, the only studied non-nucleoside reverse transcriptase inhibitor, reach the equilibrium between the fetal and maternal concentration, whereas the protease inhibitors have a poor transfer across the human placenta.

HIV detection in amniotic fluid samples. Amniocentesis can be performed in HIV pregnant women?

OBJECTIVES

To assess amniotic fluid (AF) HIV contamination as a marker of intrauterine HIV infection and to evaluate amniocentesis as a risk factor for vertical HIV transmission when the mother was under antiretroviral treatment.

STUDY DESIGN

Three hundred and sixty-six HIV pregnant women were included in the study. AF was obtained from three groups of patients: (a) genetic amniocentesis before 1997 (n=11); (b) amniocentesis a few days before the delivery day (n=18); and (c) AF collected on delivery (n=38). An univariate study was conducted to analyze amniocentesis as a risk factor of HIV transmission (groups a and b). Groups b and c were recruited after 1997; these patients were under combined antiretroviral treatment, they were studied to relate AF HIV contamination with fetal infection and maternal blood viral load at delivery (n=56).

RESULTS

From 1984 to 1996, before antiretroviral therapy use in HIV pregnant women, transmission rate was 17%. In the group of patients who underwent genetic amniocentesis (group a) it was 30% (3/10) versus 16.2% (40/247) for patients without amniocentesis. Between 1997 and 2000 transmission rate was 3%. In group b it was 0% (0/18) when amniocentesis was done versus 3.7% (3/81) if no amniocentesis was done (no statistical differences). AF virus was undetectable in all samples (n=56) and no newborn infection was observed after the follow up.

CONCLUSIONS

Amniotic fluid virus load was undetectable when maternal antiretroviral therapy was used, even if the virus was detectable in maternal blood samples. This finding raises the possibility to perform amniocentesis, when it is indicated, to provide the mother with an adequate antiretroviral treatment.

Salivary secretory leukocyte protease inhibitor is associated with reduced transmission of human immunodeficiency virus type 1 through breast milk

Secretory leukocyte protease inhibitor (SLPI), a protein found in saliva, breast milk, and genital secretions, is capable of inhibiting human immunodeficiency virus (HIV) type 1 in vitro. The aim of this study was to determine whether SLPI in infant saliva provides protection against mother-to-child HIV-1 transmission. In total, 602 saliva specimens were collected from 188 infants at birth and at ages 1, 3, and 6 months. Infants' median salivary SLPI concentrations were higher at birth than at 6 months (341 vs. 219 ng/mL; P=.001). There was no association between SLPI concentration and HIV-1 transmission overall. However, among 122 breast-fed infants who were HIV-1 uninfected at 1 month, higher salivary SLPI levels were associated with a decreased risk of HIV-1 transmission through breast milk (hazard ratio, 0.5; 95% confidence interval, 0.3-0.9; P=.03). These results suggest that SLPI plays an important role in reducing HIV-1 transmission through breast milk.

Interactions between malaria and HIV infection-an emerging public health problem?

Recent evidence demonstrates interactions between malaria and HIV infection. HIV-infected people are more likely to experience clinical malaria, and acute malaria can up-regulate HIV replication, leading to higher plasma viral loads. This is most serious in pregnant women, where HIV infection increases the risk of placental malaria, leading to increased infant morbidity and mortality.

Preventing vertical HIV transmission in the year 2000: progress and prospects--a review

In the USA, progress in the ability to eliminate vertical HIV-1 transmission that was unthinkable just a few years ago has been virtually achieved with fewer than 200 new cases of infant HIV infection reported in 1999. Nevertheless, critical research questions as well as public health challenges remain. New infant HIV infections continue to occur among women who did not obtain prenatal care or who were not offered HIV testing during pregnancy and innovative approaches are needed to address these barriers. The CDC-funded Mother-Infant Rapid Intervention At Delivery (MIRIAD) Study in five US metropolitan areas is one such approach that will test the feasibility of offering rapid testing to women presenting late in pregnancy or at delivery with undocumented HIV status. In addition, further research addressing the role of the placenta in preventing or enhancing in utero HIV transmission is needed. Internationally, new clinical trial findings provide hope that a short course of antiretrovirals can substantially reduce vertical HIV-1 transmission in resource-poor settings in the developing world where most paediatric HIV infections occur. Future research will focus on the role of post-perinatal exposure prophylaxis with antiretrovirals administered to the infant and on the prevention of postnatal transmission of HIV-1 through breast milk while maintaining adequate nutrition. A major challenge is to translate trial results into a coordinated public health implementation plan in order to maximally reduce mother-to-child HIV-1 transmission worldwide.

Diversity of the HIV-1 long terminal repeat following mother-to-child transmission

A study of the human immunodeficiency virus Type 1 (HIV-1) 5' long terminal repeat (LTR) was performed to determine the extent of variation found within the LTR from 19 mother-infant pairs in Tanzania and to assess whether the LTR is useful in distinguishing maternal sequences that were transmitted to infants. HIV-1 subtypes A, C, and D as well as intersubtype recombinant LTR sequences were detected in mothers and infants. The LTR subtype was 100% concordant between mothers and their infants. Diversity calculations showed a significant reduction in LTR variation in infants compared to their mothers. However, the overall magnitude of LTR variation was less than that found in the env gene from the same individuals. These data suggest a selective constraint active upon the 5' long terminal repeat that is distinct from immune selective pressure(s) directed against HIV-1 structural genes. Detection of maternal LTR variants that were transmitted to infants may yield important information concerning nonstructural determinants of HIV-1 transmission from mother to infant.