Maternal viral load and timing of mother-to-child HIV transmission, Bangkok, Thailand. Bangkok Collaborative Perinatal HIV Transmission Study Group

"PrEP Gives the Woman the Control": Healthcare Worker Perspectives on Using pre-Exposure Prophylaxis (PrEP) During Pregnancy and Postpartum in Kenya

Background: Pregnant and postpartum women in high HIV prevalent regions are at increased HIV risk. Oral pre-exposure prophylaxis (PrEP) can decrease HIV incidence reducing infant HIV infections. Understanding healthcare worker (HCW) beliefs about PrEP prior to national roll-out is critical to supporting PrEP scale-up. Methods: We conducted 45 semi-structured interviews among a range of HCW cadres with and without PrEP provision experience purposively recruited from four clinics in Kenya to compare their views on prescribing PrEP during pregnancy and postpartum. Interviews were analysed using a conventional content analysis approach to identify key influences on PrEP acceptability and feasibility. Results: All HCWs perceived PrEP as an acceptable and feasible HIV prevention strategy for pregnant and postpartum women. They believed PrEP meets women’s needs as an on-demand, female-controlled prevention strategy that empowers women to take control of their HIV risk. HCWs highlighted their role in PrEP delivery success while acknowledging how their knowledge gaps, concerns and perceived PrEP implementation challenges may hinder optimal PrEP delivery. Conclusion: HCWs supported PrEP provision to pregnant and postpartum women. However, counseling tools to address risk perceptions in this population and strategies to reduce HCW knowledge gaps, concerns and perceived implementation barriers are required.

Maternal natural killer cells at the intersection between reproduction and mucosal immunity

Many maternal immune cells populate the decidua, which is the mucosal lining of the uterus transformed during pregnancy. Here, abundant natural killer (NK) cells and macrophages help the uterine vasculature adapt to fetal demands for gas and nutrients, thereby supporting fetal growth. Fetal trophoblast cells budding off the forming placenta and invading deep into maternal tissues come into contact with these and other immune cells. Besides their homeostatic functions, decidual NK cells can respond to pathogens during infection, but in doing so, they may become conflicted between destroying the invader and sustaining fetoplacental growth. We review how maternal NK cells balance their double duty both in the local microenvironment of the uterus and systemically, during toxoplasmosis, influenza, cytomegalovirus, malaria and other infections that threat pregnancy. We also discuss recent developments in the understanding of NK-cell responses to SARS-Cov-2 infection and the possible dangers of COVID-19 during pregnancy.

HIV in Neonates and Infants

Advances in perinatal HIV management have averted a significant number of infections in neonates and have made the possibility of elimination of mother-to-child transmission a reality; however, significant gaps in implementation of early testing programs as well as the expansion of therapeutic strategies to neonates are hindering prevention efforts and access to safer, more effective and easier to administer treatment. This article provides insights on the current state of perinatal HIV, recent advances, and future needs.

Mini review: Prevention of mother-child transmission of HIV: 25 years of continuous progress toward the eradication of pediatric AIDS?

Prevention of mother-to-child transmission with antiretrovirals is extraordinarily effective. When medically well followed, a mother living with human immunodeficiency virus can now expect to avoid transmitting the virus to her child. Despite the immense difficulties inherent in the global implementation of this treatment, the virtual disappearance of pediatric AIDS can be considered in the long term.

Mother-to-Child HIV Transmission With In Utero Dolutegravir vs. Efavirenz in Botswana

BACKGROUND

A large-scale evaluation of mother-to-child transmission (MTCT) with dolutegravir (DTG)-based antiretroviral treatment (ART) has not been conducted previously.

SETTING

Botswana was the first African country to change from efavirenz (EFV)/tenofovir (TDF)/emtricitabine (FTC) to DTG/TDF/FTC first-line ART.

METHODS

From April 2015 to July 2018, the Early Infant Treatment Study offered HIV DNA testing at <96 hours of life. Maternal ART regimen was available for screened infants who could be linked to the separate Tsepamo surveillance study database. We evaluated characteristics of HIV-positive infants, and compared MTCT rates by ART regimen for linked infants.

RESULTS

Of 10,622 HIV-exposed infants screened, 42 (0.40%) were HIV-positive. In total, 5064 screened infants could be linked to the surveillance database, including 1235 (24.4%) exposed to DTG/TDF/FTC and 2411 (47.6%) exposed to EFV/TDF/FTC. MTCT was rare when either regimen was started before conception: 0/213 [0.00%, 95% confidence interval (CI): 0.00% to 1.72%] on DTG, 1/1497 (0.07%, 95% CI: 0.00% to 0.37%) on EFV. MTCT was similar for women starting each ART regimen in pregnancy: 8/999 (0.80%, 95% CI: 0.35% to 1.57%) for DTG and 8/883 (0.91%, 95% CI: 0.39% to 1.78%) for EFV (risk difference 0.11%, 95% CI: -0.79% to 1.06%). Most MTCT events (4/8 with DTG, 6/9 with EFV) occurred when ART was started <90 days before delivery. Infants exposed to DTG in utero had lower baseline HIV RNA compared with other HIV-infected infants.

CONCLUSION

In utero MTCT in Botswana remains rare in the DTG era. No significant MTCT differences were observed between DTG/TDF/FTC and EFV/TDF/FTC. Risk was highest for both groups when ART was started in the third trimester.

Evaluation of HIV-1 neutralizing and binding antibodies in maternal-infant transmission in Thailand

Despite anti-retroviral therapy (ART) interventions for HIV+ pregnant mothers, over 43,000 perinatal infections occur yearly. Understanding risk factors that lead to mother-to-child transmission (MTCT) of HIV are critical. We evaluated maternal and infant plasma binding and neutralizing antibody responses in a drug-naïve, CRF01_AE infected MTCT cohort from Thailand to determine associations with transmission risk. Env V3-specific IgG and neutralizing antibody responses were significantly higher in HIV- infants, as compared to HIV+ infants. In fact, infant plasma neutralizing antibodies significantly associated with non-transmission. Conversely, increased maternal Env V3-specific IgG and neutralizing antibody responses were significantly associated with increased transmission risk, after controlling for maternal viral load. Our results highlight the importance of evaluating both maternal and infant humoral immune responses to better understand mechanisms of protection, as selective placental antibody transport may have a role in MTCT. This study further emphasizes the complex role of Env-specific antibodies in MTCT of CRF01_AE HIV.

HIV drug resistance patterns in pregnant women using next generation sequence in Mozambique

Background

Few data on HIV resistance in pregnancy are available from Mozambique, one of the countries with the highest HIV toll worldwide. Understanding the patterns of HIV drug resistance in pregnant women might help in tailoring optimal regimens for prevention of mother to child transmission of HIV (pMTCT) and antenatal care.

Objectives

To describe the frequency and characteristics of HIV drug resistance mutations (HIVDRM) in pregnant women with virological failure at delivery, despite pMTCT or antiretroviral therapy (ART).

Methods

Samples from HIV-infected pregnant women from a rural area in southern Mozambique were analysed. Only women with HIV-1 RNA >400c/mL at delivery were included in the analysis. HIVDRM were determined using MiSeq® (detection threshold 1%) at the first antenatal care (ANC) visit and at the time of delivery.

Results

Ninety and 60 samples were available at the first ANC visit and delivery, respectively. At first ANC, 97% of the women had HIV-1 RNA>400c/mL, 39% had CD4+ counts <350 c/mm³ and 30% were previously not on ART. Thirteen women (14%) had at least one HIVDRM of whom 70% were not on previous ART. Eight women (13%) had at least one HIVDRM at delivery. Out of 37 women with data available from the two time points, 8 (21%) developed at least one new HIVDRM during pMTCT or ART. Twenty seven per cent (53/191), 32% (44/138) and 100% (5/5) of the mutations that were present at enrolment, delivery and that emerged during pregnancy, respectively, were minority mutations (frequency <20%).

Conclusions

Even with ultrasensitive HIV-1 genotyping, less than 20% of women with detectable viremia at delivery had HIVDRM before initiating pMTCT or ART. This suggests that factors other than pre-existing resistance, such as lack of adherence or interruptions of the ANC chain, are also relevant to explain lack of virological suppression at the time of delivery in women receiving antiretrovirals drugs during pregnancy.

HIV Transmission to Premature Very Low Birth Weight Infants

There is sparse literature about HIV transmission in preterm infants. Eighty-two HIV-exposed preterm infants received birth polymerase chain reactions (PCRs). Five (6.1%) were HIV positive with all 5 mothers receiving inadequate antiretrovirals. Of the PCR-negative infants, 9 died and 87% of the survivors received further PCR testing which remained negative. With correct care, intrapartum transmission of HIV can virtually be eliminated.

HIV viral load: a concept analysis and critique

In this article, we examine the concept of HIV viral load and how it has evolved over time (1995-2013) in the field of HIV/AIDS. Although the term viral load is used extensively in this field, few efforts have been directed toward the conceptualization of HIV viral load, which is often left unquestioned, undertheorized, and portrayed as a neutral and objective laboratory value that has remained relatively stable over time--with the exception of progressive advancements in technology, techniques, and sensitivity. The purpose of this article is to apply the evolutionary concept analysis method developed by Rodgers (1989, 2000a) to the concept of HIV viral load. To set the stage, we establish the need for a concept analysis of HIV viral load and provide an overview of the evolutionary view. Then, drawing on the steps proposed by Rodgers (2000a), we outline the process of data collection, management, and analysis. We then offer an in-depth discussion of the findings (attributes, antecedents, and consequences) informed by Wuest's (2000) critical approach to concept analysis. We conclude by highlighting the implications of this analysis for clinical practice, research, and theory.

Duration of ruptured membranes and mother-to-child HIV transmission: a prospective population-based surveillance study

OBJECTIVE

To investigate the association between duration of rupture of membranes (ROM) and mother-to-child HIV transmission (MTCT) rates in the era of combination antiretroviral therapy (cART).

DESIGN

The National Study of HIV in Pregnancy and Childhood (NSHPC) undertakes comprehensive population-based surveillance of HIV in pregnant women and children.

SETTING

UK and Ireland.

POPULATION

A cohort of 2398 singleton pregnancies delivered vaginally, or by emergency caesarean section, in women on cART in pregnancy during the period 2007-2012 with information on duration of ROM; HIV infection status was available for 1898 infants.

METHODS

Descriptive analysis of NSHPC data.

MAIN OUTCOME MEASURES

Rates of MTCT.

RESULTS

In 2116 pregnancies delivered at term, the median duration of ROM was 3 hours 30 minutes (interquartile range, IQR 1-8 hours). The overall MTCT rate for women delivering at term with duration of ROM ≥4 hours was 0.64% compared with 0.34% for ROM <4 hours, with no significant difference between the groups (OR 1.90, 95% CI 0.45-7.97). In women delivering at term with a viral load of <50 copies/ml, there was no evidence of a difference in MTCT rates with duration of ROM ≥4 hours, compared with <4 hours (0.14% for ≥4 hours versus 0.12% for <4 hour; OR 1.14, 95% CI 0.07-18.27). Among infants born preterm with infection status available, there were no transmissions in 163 deliveries where the maternal viral load was <50 copies/ml.

CONCLUSIONS

No association was found between duration of ROM and MTCT in women taking cART.

TWEETABLE ABSTRACT

Rupture of membranes of more than 4 hours is not associated with MTCT of HIV in women on effective ART delivering at term.

Antiretroviral therapy and mother-to-child transmission of HIV-1

The advent of highly active antiretroviral therapy has facilitated the virtual elimination of mother-to-child transmission of HIV infection in developed countries, reducing transmission rates to approximately 1 to 2%. In these settings, highly active antiretroviral therapy has also transformed pediatric HIV infection into a chronic disease; although there are associated costs in terms of side effects and the heavy pill burden. In less developed settings, easier-to-use adaptations of antiretroviral therapy regimens, such as short-course and single-dose antiretroviral strategies or neonatal postexposure prophylaxis can also substantially prevent mother-to-child transmission, although to a lesser degree than highly active antiretroviral therapy. However, postnatal transmission of infection through breastfeeding significantly reduces the longer-term efficacy of these strategies. Ongoing research is focusing on the use of antiretroviral therapy in the breastfeeding period.

The management of HIV-infected pregnant women

PURPOSE OF REVIEW

The purpose of this article is to update the current practice in the management of HIV-infected pregnant women and present evidence-based recommendations for the reduction of mother-to-child transmission.

RECENT FINDINGS

Early and sustained control of HIV viral replication is associated with decreasing residual risk of transmission and favors initiating antiretroviral drugs sufficiently early in naive women to suppress viral replication by the third trimester; however, this potential benefit must be balanced against the unknown long-term outcome of first-trimester drug exposure. Efavirenz should whenever possible be avoided in the first trimester of gestation, but its use seems well tolerated for 39 days after last menstrual period when the neural tube closes. Raltegravir may be considered in special circumstances in pregnancy.

SUMMARY

The HIV viral load and the risk factors for prematurity must be considered when deciding when to start antiretroviral treatment in each individual pregnant woman. A ritonavir-boosted protease inhibitor combined with two nucleoside reverse transcriptase inhibitors is currently the most widely used regimen. Among protease inhibitors, lopinavir combined with ritonavir is the most frequently used; however, atazanavir combined with ritonavir is a good alternative. Elective cesarean section is the best delivery mode for pregnant women with viral loads more than 50  copies/ml.

Frequency and factors associated with adherence to and completion of combination antiretroviral therapy for prevention of mother to child transmission in western Kenya

Introduction

The objective of this analysis was to identify points of disruption within the prevention of mother-to-child transmission (PMTCT) continuum from combination antiretroviral therapy (CART) initiation until delivery.

Methods

To address this objective, the electronic medical records of all antiretroviral-naïve adult pregnant women who were initiating CART for PMTCT between January 2006 and February 2009 within the Academic Model Providing Access To Healthcare (AMPATH), western Kenya, were reviewed. Outcomes of interest were clinician-initiated change or stop in regimen, disengagement from programme (any, early, late) and self-reported medication adherence. Disengagement was categorized as early disengagement (any interval of greater than 30 days between visits but returning to care prior to delivery) or late disengagement (no visit within 30 days prior to the date of delivery). The association between covariates and the outcomes of interest were assessed using bivariate (Kruskal-Wallis test for continuous variables and the Chi-square test for categorical variables) and multivariate logistic regression analysis.

Results

A total of 4284 antiretroviral-naïve pregnant women initiated CART between January 2006 and February 2009. The majority of women (89%) reported taking all of their medication at every visit. There were 18 (0.4%) deaths reported. Clinicians discontinued CART in 10 patients (0.7%) while 1367 (31.9%) women disengaged from care. Of those disengaging, 404 (29.6%) disengaged early and 963 (70.4%) late. In the multivariate model, the odds of disengagement decreased with increasing age (odds ratio [OR] 0.982; confidence interval [CI] 0.966–0.998) and increasing gestational age at CART initiation (OR 0.925; CI 0.909–0.941). Women receiving care at a district hospital (OR 0.794; CI 0.644–0.980) or tuberculosis medication (OR 0.457; CI 0.202–0.935) were less likely to disengage. The odds of disengagement were higher in married women (OR 1.277; CI 1.034–1.584). The odds of early disengagement decreased with increasing age at CART initiation (OR 0.902; CI 0.881–0.924). The odds of late disengagement decreased with increasing age at CART initiation (OR 0.936; CI 0.917–0.956). While they increased with higher CD4 counts at CART-initiation (OR 1.001; CI 1.000–1001) and in married women (OR 1.297; CI 1.000–1.695)

Conclusions

In a PMTCT programme embedded in an antiretroviral treatment programme with an active outreach department, the majority (67.4%) of women remained engaged and received uninterrupted prenatal CART.

The role of co-infections in mother-to-child transmission of HIV

In HIV-infected women, co-infections that target the placenta, fetal membranes, genital tract, and breast tissue, as well as systemic maternal and infant infections, have been shown to increase the risk for mother-to-child transmission of HIV (MTCT). Active co-infection stimulates the release of cytokines and inflammatory agents that enhance HIV replication locally or systemically and increase tissue permeability, which weakens natural defenses to MTCT. Many maternal or infant co-infections can affect MTCT of HIV, and particular ones, such as genital tract infection with herpes simplex virus, or systemic infections such as hepatitis B, can have substantial epidemiologic impact on MTCT. Screening and treatment for co-infections that can make infants susceptible to MTCT in utero, peripartum, or postpartum can help reduce the incidence of HIV infection among infants and improve the health of mothers and infants worldwide.

Maternal mid-upper arm circumference is associated with birth weight among HIV-infected Malawians

The authors examined the relationship of maternal anthropometry to fetal growth and birth weight among 1005 human immunodeficiency virus (HIV)-infected women in Lilongwe, Malawi, who consented to enrollment in the Breastfeeding, Antiretrovirals, and Nutrition Study (www.thebanstudy.org). Anthropometric assessments of mid-upper arm circumference (MUAC), arm muscle area (AMA), and arm fat area (AFA) were collected at the baseline visit between 12 and 30 weeks' gestation and in up to 4 follow-up prenatal visits. In longitudinal analysis, fundal height increased monotonically at an estimated rate of 0.92 cm/wk and was positively and negatively associated with AMA and AFA, respectively. These latter relationships varied over weeks of follow-up. Baseline MUAC, AMA, and AFA were positively associated with birth weight (MUAC: 31.84 g/cm(2), 95% confidence interval [CI], 22.18-41.49 [P < .01]; AMA: 6.88 g/cm(2), 95% CI, 2.51-11.26 [P < .01]; AFA: 6.97 g/cm(2), 95% CI, 3.53-10.41 [P < .01]). In addition, MUAC and AMA were both associated with decreased odds for low birth weight (LBW; <2500 g) (MUAC: odds ratio [OR] = 0.85, 95% CI, 0.77-0.94 [P < .01]; AMA: OR = 0.95, 95% CI, 0.91-0.99 [P < .05]). These findings support the use of MUAC as an efficient, cost-effective screening tool for LBW in HIV-infected women, as in HIV-uninfected women.

In utero and intra-partum HIV-1 transmission and acute HIV-1 infection during pregnancy: using the BED capture enzyme-immunoassay as a surrogate marker for acute infection

OBJECTIVE

The BED assay was developed to estimate the proportion of recent HIV infections in a population. We used the BED assay as a proxy for acute infection to quantify the associated risk of mother-to-child-transmission (MTCT) during pregnancy and delivery. Design A total of 3773 HIV-1 sero-positive women were tested within 96 h of delivery using the BED assay, and CD4 cell count measurements were taken. Mothers were classified according to their likelihood of having recently seroconverted.

METHODS

The risk of MTCT in utero and intra-partum was assessed comparing different groups defined by BED and CD4 cell count, adjusting for background factors using multinomial logistic models.

RESULTS

Compared with women with BED ≥ 0.8/CD4 ≥ 350 (typical of HIV-1 chronic patients) there was insufficient evidence to conclude that women presenting with BED < 0.8/CD4 ≥ 350 (typical of recent infections) were more likely to transmit in utero [adjusted odds ratio (aOR) = 1.37, 96% confidence interval (CI) 0.90-2.08, P = 0.14], whereas women with BED < 0.8/CD4 200-349 (possibly recently infected patients) had a 2.57 (95% CI 1.39-4.77, P-value < 0.01) odds of transmitting in utero. Women who had BED < 0.8/CD4 < 200 were most likely to transmit in utero (aOR 3.73, 95% CI 1.27-10.96, P = 0.02). BED and CD4 cell count were not predictive of intra-partum infections.

CONCLUSIONS

These data provide evidence that in utero transmission of HIV might be higher among women who seroconvert during pregnancy.

Prevention of vertical transmission of HIV-1 in resource-limited settings

One of the most exciting areas of HIV research is that of prevention of vertical transmission from mother to child, since it accounts for 90% of childhood HIV infections, and therefore prevention in this context has an enormous potential impact on the spread of HIV among children. Focused research has yielded highly successful strategies for reducing infant infection rates, particularly in the developed world, and much work is underway to implement appropriate strategies in resource-limited settings, although this is not without challenges. Although transmission rates in some settings have been reduced to approximately 1%, scale-up and widespread implementation and application of strategic interventions for prevention of mother-to-child transmission of HIV during pregnancy, delivery and breastfeeding are needed in the developing world.

The clinical care of the HIV-1-infected infant

Despite well-established strategies to decrease the mother-to-child transmission of HIV-1, new perinatal infections continue to occur globally, reflecting marked disparities in access to health care. Once HIV-1 infection has been established in an infant, the combination of early initiation of antiretroviral therapy and prophylaxis against Pneumocystis jiroveci pneumonia is paramount to reducing disease progression. This article reviews the recommendations and evidence for the treatment of HIV-1-infected infants.

The role of transplacental microtransfusions of maternal lymphocytes in in utero HIV transmission

BACKGROUND

The mechanisms of HIV transmission from mothers to infants are poorly understood. A possible mechanism of in utero transmission is transplacental transfer of HIV-infected maternal leukocytes into the fetal circulation during pregnancy.

OBJECTIVE

To determine if the frequency of in utero HIV infection correlates with presence or levels of maternal cells (MCs) in placenta-derived cord blood.

METHODS

DNA was extracted from dried cord blood spots (DBS) from newborns born to HIV+ mothers and corresponding maternal DBS specimens. Paired mother-infant samples were probed to identify unique maternal sequences targeted by 24 allele-specific real-time polymerase chain reaction assays. Infant DBS-derived DNA was then probed in replicate analyses for noninherited maternal allelic sequences. Rates of detection and levels of MCs in DBS samples of HIV(+) and HIV(-) newborns were compared.

RESULTS

Of 114 mother-infant pairs with informative alleles, 38 newborns were HIV(+) and 76 HIV(-), based on detection of HIV DNA/RNA at birth. MC were detected in 23 of 38 HIV(+) newborns (60.5%) and in 47 of 76 HIV(-) newborns (61.8%). The mean and median concentrations of nucleated MCs in DBS for the HIV(+)/MC(+) newborns (n = 23) were 0.33% and 0.27%, respectively, compared with 0.09% and 0.10% for the HIV(-)/MC(+) newborns (n = 47) (2-sample T test for means: P = 0.78).

CONCLUSIONS

There was no significant difference in rates of detection or concentrations of MC in DBS between HIV(+) and HIV(-) newborns. Therefore, we could not demonstrate a correlation between MC in DBS, assumed to reflect levels of in utero maternal-fetal cell trafficking, and the risk of in utero HIV transmission.

Population attributable fractions for late postnatal mother-to-child transmission of HIV-1 in Sub-Saharan Africa

OBJECTIVES

Assess population attributable fractions (PAFs) for late postnatal transmission (LPT) of HIV-1 in a cohort of HIV-1-exposed infants.

METHODS

We used data established from a risk factor analysis of LPT (negative HIV-1 results through the 4-6 week visit, but positive assays thereafter through the 12-month visit) from a perinatal clinical trial conducted in 3 sub-Saharan countries. PAFs were calculated as the proportions of excess LPTs attributed to identified risk factors.

RESULTS

For the cohort of 1317 infants, 206 (15.6%) had only low maternal CD4 counts (<200 cells/mm), 332 (25.2%) had only high maternal plasma viral loads (VLs) (>50,000 copies/mL), and 81 (6.2%) had both low CD4 counts and high VLs. Their PAFs were 26.0% [95% confidence interval (CI): 12.0% to 36.0%], 37.0% (95% CI: 22.0% to 51.0%), and 16.0% (95% CI: 6.0% to 25.0%), respectively.

CONCLUSIONS

Our PAF analysis illustrates the public health impact of the substantial proportion of LPTs accounted for by high-risk women with both low CD4 counts and high VLs. In light of these results, access to and use of antiretroviral therapy by high-risk HIV-1-infected pregnant women is essential. Additional strategies to reduce LPT for those not meeting criteria for antiretroviral therapy should be implemented.

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 vertical transmission in Rio Grande, Southern Brazil

The aim of this study was to determine the rate and risk factors of HIV-1 mother-to-child transmission (MTCT), the timing of transmission and the transmitted subtype in a population where subtypes B and C co-circulate. One hundred and forty-four babies born to HIV-1-infected mothers were studied. Subtype and timing of transmission were determined by a nested polymerase chain reaction of the gp41 gene. Seven children were infected (4.9%): four were infected intrautero and one intrapartum. The higher frequency of intrautero transmission was statistically significant ( P = 0.001). Use of antiretrovirals (ARVs) in the three stages of gestation was a protective risk factor for MTCT (PR = 0.42; CI: 0.21–0.83; P = 0.013). A higher HIV viral load at delivery was the only independent risk factor for MTCT. Early and universal access to ARVs during pregnancy are the most important measures to decrease vertical HIV-1 transmission even in areas where HIV clade distribution differs.

Breastfeeding in HIV-positive women: What can be recommended?

Breastfeeding remains a common practice in parts of the world where the burden of HIV is highest and the fewest alternative feeding options exist. The impossible dilemma faced by HIV-positive mothers is whether to breastfeed their infants in keeping with cultural norms but in doing so risk transmitting the virus through breast milk, or to pursue formula feeding, which comes with its own set of risks, including a higher rate of infant mortality from diarrheal illnesses, while reducing transmission of HIV. Treatment of mothers and/or their infants with antiretroviral drugs is a strategy that has been employed for several decades to reduce HIV transmission through pregnancy and delivery, but the effect of these agents when taken during breastfeeding is a newer field of study. In this article we evaluate the latest clinical research, from trials that encourage exclusive breastfeeding to trials of antiretroviral therapy (ART) for either the mother or infant, in an attempt to prevent transmission of HIV through breast milk. Additionally, we discuss research that is in progress, with results anticipated in the next few years that will further shape clinical guidelines and practice. Exclusive breastfeeding is much safer than mixed feeding (the supplementation of breastfeeding with other foods), and should be encouraged even in settings where ART for either the mother or infant is not readily available. The research published regarding maternal treatment with highly active antiretroviral therapy (HAART) during pregnancy and the breastfeeding period has all been non-randomized with relatively little statistical power, but suggests maternal HAART can drastically reduce the risk of transmission of HIV. Infant prophylaxis has been intensively studied in several trials and has been shown to be as effective as maternal treatment with antiretrovirals, reducing the transmission rate after 6 weeks to as low as 1.2%. Research that is in progress will provide us with more answers about the relative contribution of maternal treatment and infant prophylaxis in preventing transmission, and the results of such research may be expected as early as this year through 2013. There is hope that perinatal HIV transmission may be greatly reduced in breastfeeding populations worldwide through a combination of behavioral interventions that encourage exclusive breastfeeding and pharmacologic interventions with antiretrovirals for mothers and/or their infants.

Differential expression and interaction of host factors augment HIV-1 gene expression in neonatal mononuclear cells

We have previously shown a higher level of HIV-1 replication and gene expression in neonatal (cord) blood mononuclear cells (CBMC) compared with adult blood cells (PBMC), which could be due to differential expression of host factors. We performed the gene expression profile of CBMC and PBMC and found that 8013 genes were expressed at higher levels in CBMC than PBMC and 8028 genes in PBMC than CBMC, including 1181 and 1414 genes upregulated after HIV-1 infection in CBMC and PBMC, respectively. Several transcription factors (NF-kappaB, E2F, HAT-1, TFIIE, Cdk9, Cyclin T1), signal transducers (STAT3, STAT5A) and cytokines (IL-1beta, IL-6, IL-10) were upregulated in CBMC than PBMC, which are known to influence HIV-1 replication. In addition, a repressor of HIV-1 transcription, YY1, was down regulated in CBMC than PBMC and several matrix metalloproteinase (MMP-7, -12, -14) were significantly upregulated in HIV-1 infected CBMC than PBMC. Furthermore, we show that CBMC nuclear extracts interacted with a higher extent to HIV-1 LTR cis-acting sequences, including NF-kappaB, NFAT, AP1 and NF-IL6 compared with PBMC nuclear extracts and retroviral based short hairpin RNA (shRNA) for STAT3 and IL-6 down regulated their own and HIV-1 gene expression, signifying that these factors influenced differential HIV-1 gene expression in CBMC than PBMC.

A forensic nursing protocol for initiating human immunodeficiency virus post-exposure prophylaxis following sexual assault

The use of human immunodeficiency virus post-exposure prophylaxis (HIV PEP) should be considered in the care of sexual assault patient populations. In order to effectively implement HIV PEP following sexual assault, healthcare providers need to have a working knowledge of HIV transmission risk factors following a sexual exposure and protocols for initiating HIV PEP. Being able to implement evidence-based practices that address each of these factors is paramount to successful prevention of HIV transmission following a sexual assault exposure. Most healthcare practitioners, however, lack the specialized knowledge needed to address these issues in the expeditious manner necessitated by a potential HIV exposure.

IMPLICATIONS

This paper is designed to provide healthcare providers with a basic understanding of HIV transmission risk factors and the knowledge and skills needed to effectively implement HIV PEP following a sexual assault exposure.

Risk factors of preterm delivery in HIV-infected pregnant women receiving zidovudine for the prevention of perinatal HIV

AIM

Several studies have shown that preterm delivery, a primary cause of perinatal mortality and morbidity, is more frequent in HIV-positive women. This study aimed to determine factors associated with prematurity in HIV-infected women and identify risks for which specific interventions could be targeted.

METHODS

Data were prospectively collected in a clinical trial assessing the efficacy of different zidovudine prophylaxis durations for the prevention of perinatal HIV transmission in Thailand. Characteristics associated with prematurity - delivery before 37 weeks--were assessed using univariate and multivariate logistic regression and were subsequently used to identify subgroups of women at risk.

RESULTS

Among 979 women, independent prematurity risk factors were: viral load <3.5 or >4.5 log copies/mL; hemoglobin > 11.5 g/dL; weight gain <0.25 kg/week; and body mass index <20 kg/m2. These factors allowed us to define four subgroups with an expected probability of prematurity increasing from 3% to 30%. The two subgroups with the highest expected probability of prematurity were considered to be 'at risk' as opposed to the two lowest (odds ratio = 2.6, 95% confidence interval: 1.7-4.0) and the sensitivity and specificity of the prediction were 51% and 71%, respectively.

CONCLUSION

In this study, four risk factors of preterm delivery were identified allowing the identification of subgroups at increasing risk of prematurity. Adequate nutrition and the provision of highly active antiretroviral therapy during pregnancy as recommended by the World Health Organization for the prevention of perinatal transmission for immunocompromised women in resource-constrained countries may reduce the risk of premature delivery.

Mother to child transmission of HIV-1 in a Thai population: role of virus characteristics and maternal humoral immune response

The objective of this study was to investigate factors influencing mother to child transmission of HIV-1 in Thailand, where HIV-1 CRF01_AE, the major subtype in Southeast Asia, predominates. Samples from 84 HIV-1 infected, anti-retroviral treatment-naïve, non-breast feeding mothers, 28 who transmitted HIV-1 to their babies (transmitters) and 56 who did not (non-transmitters), were studied for maternal humoral immune response and virus characteristics. Maternal humoral immune response was measured by lymphocyte phenotyping; neutralizing antibodies to laboratory HIV-1 MN strain and two clinical isolates; peptide binding antibody to gp41 and V3 from strains CRF01_AE, B, and MN; autologous antibodies; and quasispecies diversity. Virus characteristics studied were viral load, co-receptor usage, and viral replication capacity. No significant difference between transmitters and non-transmitters was found for any parameter of maternal humoral immune response. However, viral load and viral replication capacity were significantly higher in transmitters versus non-transmitters and were not correlated with each other. This suggests that viral replication capacity may be a transmission factor independent of viral load, which is already well established as a risk factor for transmission of HIV-1. All except four viral isolates used the CCR5 co-receptor. This is one of few studies of vertical transmission in a population where HIV-1 CRF01_AE predominates. The data suggest that in this population the maternal humoral immune response was not important in preventing transmission at parturition, but that virus characteristics were key factors, and that viral replication capacity may contribute to birth-associated mother to child transmission of HIV-1.

Population analysis of the pregnancy-related modifications in lopinavir pharmacokinetics and their possible consequences for dose adjustment

OBJECTIVES

To investigate the possible necessity of an increase in lopinavir dose during pregnancy in order to achieve the concentrations previously defined as predictive of virological efficacy.

PATIENTS AND METHODS

Lopinavir pharmacokinetics were investigated by a population approach performed on 145 HIV-infected women, including 74 pregnant women. The final model was used to determine the probability of achievement of the target trough concentrations by Monte Carlo simulations.

RESULTS

The typical population estimates (inter-individual variability %) of apparent clearance (CL/F) and volume of distribution were 4.38 L/h (24%) and 58.4 L (59%), respectively. Pregnancy associated with a gestational age >15 weeks and delivery were found to increase lopinavir CL/F by 39% and 58%, respectively. With the standard 400 mg twice-a-day regimen, the probability of reaching the 1 mg/L target trough concentration for protease inhibitor (PI)-naive patients was 99% and 96% for non-pregnant and pregnant women, respectively. An important decrease in the probability of achieving the 5.7 mg/L target trough concentration for salvage therapy was observed for non-pregnant women (55%), this decrease being even greater for pregnant women (21%). Raising the lopinavir dose to 600 mg twice daily increased these probabilities to 87% and 53% for non-pregnant and pregnant women, respectively.

CONCLUSIONS

Modification of the lopinavir dose is unlikely to be required for PI-naive pregnant women; however, in pregnant women who have previously received a PI, therapeutic drug monitoring and/or empirical increasing of the dose should be considered.

The role of transplacental microtransfusions of maternal lymphocytes in HIV transmission to newborns

BACKGROUND

Perinatal HIV transmission could occur via microtransfused maternal blood during delivery. If so, detecting maternal cells in umbilical cord blood should correlate with infection risk.

OBJECTIVE

To develop sensitive assays for maternal DNA in infant's blood stored as dried blood spots (DBS) and examine the correlation between microtransfusion and perinatal HIV infection risk.

METHODS

Blood-in-blood serial dilutions were prepared as DBS. Extracted DNA was amplified for unique minor-population sequences using 24 allele-specific polymerase chain reaction assays. Using newborns born to HIV+ mothers, paired mother-infant samples were similarly examined to identify unique maternal sequences targeted by allele-specific polymerase chain reaction of DNA extracted from cord blood DBS. Cord-blood PCR-negative infants were categorized as uninfected or perinatally infected by HIV PCR on samples collected 4-8 weeks after birth.

RESULTS

Sequences from added cells were detected at less than 1: 1000 dilutions in 19 of 20 aliquots, and less than 1: 10 000 dilutions in seven of 20 aliquots; the median limit of detection (probit analysis) was one added genomic sequence in 9500 background sequences of amplifiable DNA. Maternal sequences were detected in cord-blood DBS of 50% of infected infants (N = 18) and 44% of uninfected infants (N = 43). Infection did not correlate with more frequent detection of maternal sequences.

CONCLUSION

This semiquantitative assay reliably detected maternal DNA sequences in DBS at levels of less than 1: 1000 cells. Maternal sequences were frequently detected but did not correlate infection risk with detection or level of maternal DNA in umbilical cord blood. Therefore, we could not demonstrate that microtransfusions at parturition were responsible for perinatal HIV transmission.

Pharmacokinetics and therapeutic drug monitoring of antiretrovirals in pregnant women

Highly active antiretroviral therapy is recommended for HIV-infected pregnant women to prevent mother-to-child transmission. The specific physiological background induced by pregnancy leads to significant changes in maternal pharmacokinetics, suggesting potential variability in plasma concentrations of antiretrovirals during gestation. Therapeutic drug monitoring (TDM) of protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) is recommended in certain situations, including pregnancy, but its systematic use in HIV-infected pregnant women remains controversial. This review provides an update of the pharmacokinetic data available for PIs and NNRTIs in pregnant women and highlights the clinical interest of systematic TDM of certain antiretroviral drugs during pregnancy, including nevirapine, nelfinavir, saquinavir, indinavir and lopinavir.

Trends in perinatal HIV prevention in New York City, 1994-2003

OBJECTIVES

We examined trends in perinatal HIV prevention interventions in New York City implemented during 1994 to 2003 to ascertain the success of the interventions in reducing perinatal transmission.

METHODS

We used data obtained from infant records at 22 hospitals. We used multiple logistic regression to analyze factors associated with prenatal care and perinatal HIV transmission.

RESULTS

We analyzed data for 4729 perinatally HIV-exposed singleton births. Of mothers with prenatal care data, 92% had prenatal care. The overall proportion who received prenatal care and were diagnosed with HIV before delivery was 86% in 1994 to 1996 and 90% in 1997 to 2003. Use of prenatal antiretrovirals among mothers who received prenatal care was 63% in 1994 to 1996 and 82% in 1997 to 2003. From 1994 to 2003, cesarean births among the entire sample increased from 15% to 55%. During 1997 to 2003, the perinatal HIV transmission rate among the entire sample was 7%; 45% of mothers of infected infants had missed opportunities for perinatal HIV prevention. During 1997 to 2003, maternal illicit drug use was significantly associated with lack of prenatal care. Lack of prenatal, intrapartum, and neonatal antiretrovirals; maternal illicit drug use; and low birthweight were significantly associated with perinatal HIV transmission.

CONCLUSIONS

Interventions for perinatal HIV prevention can successfully decrease HIV transmission rates. Ongoing perinatal HIV surveillance allows for monitoring the implementation of guidelines to prevent mother-to-child transmission of HIV and determining factors that may contribute to perinatal HIV transmission.

Risk factors for in utero or intrapartum mother-to-child transmission of human immunodeficiency virus type 1 in Thailand

BACKGROUND

The identification of risk factors for in utero and intrapartum transmission of human immunodeficiency virus type 1 (HIV-1) is crucial to the design and understanding of preventive interventions.

METHODS

The randomized Perinatal HIV Prevention Trial-1 enrolled 1437 pregnant women and their non-breast-fed infants, to compare the efficacy of various durations of zidovudine prophylaxis. Using univariate and multivariate logistic regression analyses, we studied the role that factors known or occurring at various times during gestation or delivery play in in utero and intrapartum transmission.

RESULTS

Variables independently associated with in utero transmission were HIV-1 load >35,000 copies/mL (adjusted odds ratio [AOR], 4.2) and delayed initiation of maternal zidovudine prophylaxis until >31.4 weeks gestation (AOR, 3.0). Variables associated with intrapartum transmission were HIV-1 load >10,000 copies/mL (AOR, 3.8 for 10,000-35,000 copies/mL and 7.1 for >35,000 copies/mL), induction of labor (AOR, 2.6), and premature labor with tocolysis (AOR, 15.1).

CONCLUSIONS

With the exception of very high HIV-1 load, risk factors for in utero transmission were different from those for intrapartum transmission. Optimal prophylactic interventions must address each of the major risk factors, with appropriate timing.

Approaches for scaling up human immunodeficiency virus testing and counseling in prevention of mother-to-child human immunodeficiency virus transmission settings in resource-limited countries

Prevention of mother-to-child human immunodeficiency virus (HIV) transmission (PMTCT) programs have nearly eliminated mother-to-child transmission of HIV in developed countries, but progress in resource-limited countries has been slow. A key factor limiting the scale-up of PMTCT programs is lack of knowledge of HIV serostatus. Increasing the availability and acceptability of HIV testing and counseling services will encourage more women to learn their status, providing a gateway to PMTCT interventions. Key factors contributing to the scale-up of testing and counseling include a policy of provider-initiated testing and counseling with right to refuse (opt-out); group pretest counseling; rapid HIV testing; innovative staffing strategies; and community and male involvement. Integration of testing and counseling within the community and all maternal and child health settings are critical for scaling-up and for linking women and their families to care and treatment services. This paper will review best practices needed for expansion of testing and counseling in PMTCT settings in resource-limited countries.

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.

Antiretroviral therapy 2006: Pharmacology, applications, and special situations

As we approach the completion of the first 25 years of the human immunodeficiency virus (HIV) epidemic, there have been dramatic improvements in the care of patients with HIV infection. These have prolonged life and decreased morbidity. There are twenty currently available antiretrovirals approved in the United States for the treatment of this infection. The medications, including their pharmacokinetic properties, side effects, and dosing are reviewed. In addition, the current approach to the use of these medicines is discussed. We have included a section addressing common comorbid conditions including hepatitis B and C along with tuberculosis.

Gene-expression profiling of HIV-1 infection and perinatal transmission in Botswana

Perinatal transmission of human immunodeficiency virus (HIV)-1 represents a major problem in many regions of the world, especially Southern Africa. With the exception of viral and proviral load, the role for maternal cofactors in perinatal transmission outcome is largely unknown. In this study, an assessment was made of peripheral blood mononuclear cells (PBMC) gene-expression profiles to better understand transcriptional changes associated with HIV-1 infection and perinatal transmission among young adult mothers with infants in Botswana. Peripheral blood mononuclear cells specimens were used from 25 HIV+ drug naive and 20 HIV- healthy mothers, similar in age and location, collected in 1999-2000 and 2003, and processed with the exact same methods, as previously described. Expression profiling of 22 277 microarray gene probes implicated a broad initiation of innate response gene-sets, including toll-like receptor, interferon-stimulated and antiviral RNA response pathways in association with maternal HIV-1 infection. Maternal transmission status was further associated with host genes that influence RNA processing and splicing patterns. In addition to real-time polymerase chain reaction validation of specific genes, enriched category validation of PBMC profiles was conducted using two independent data sets for either HIV-1 infection or an unrelated RNA virus, severe acute respiratory virus infection. HIV-1 pathogen-specific host profiles should prove a useful tool in infection and transmission intervention efforts worldwide.

Effectiveness of Short-Term and Long-Term Zidovudine Prophylaxis on Detection of HIV-1 Subtype E in Human Placenta and Vertical Transmission

Antiretroviral treatment with zidovudine (ZDV) from the 14th week until the end of pregnancy has markedly reduced the vertical transmission rate of HIV-1 in Europe and North America. A shorter duration of treatment has reduced this rate in Africa and Southeast Asia to a lesser degree. In Southeast Asia, subtype E is the major subtype rather than subtype B as in Western countries. The goals of this study were to determine the optimal duration of ZDV prophylaxis for subtype E and to confirm its effectiveness at the histologic level. Fifty pregnant women seropositive for HIV-1 subtype E were given ZDV prophylaxis consisting of 300 mg administered twice daily, switching to 300 mg administered every 3 hours from the onset of labor until delivery. Twenty-seven received "short-term" ZDV lasting 14 to 35 days before delivery, whereas the other 23 received "long-term" ZDV lasting 62 to 92 days. The effectiveness of ZDV prophylaxis was assessed by detection of HIV-1 in the placenta using in situ polymerase chain reaction (PCR). All babies in this study were tested up to one year of age. Three were not positive until after one month of age, but one was positive as a neonate. Four neonates were positive for HIV-1 as detected by PCR on peripheral blood, including one in the neonatal period. All cases were from the short-term prophylaxis group. Decidual glandular epithelial cells were the only cell type in the placenta that expressed HIV proviral DNA under ZDV prophylaxis. Sixty-seven percent of placentas in the short-term ZDV group showed more than occasional positive cells compared with 22% in the group receiving long-term ZDV prophylaxis (P < 0.02). This is first study to compare the effectiveness of short-term and long-term ZDV prophylaxis with respect to the presence of HIV in the placenta. Our study shows that longer (at least 60 days) prophylaxis is more effective in reducing HIV expression in the placenta and is associated with reduced transmission to neonates.

Vaginal disinfection for preventing mother-to-child transmission of HIV infection

BACKGROUND

Mother-to-child transmission (MTCT) of HIV infection is one of the most tragic consequences of the HIV epidemic, especially in resource-limited countries, resulting in about 650 000 new paediatric HIV infections each year worldwide. The paediatric HIV epidemic threatens to seriously undermine decade-old child survival programmes.

OBJECTIVES

To estimate the effect of vaginal disinfection on the risk of MTCT of HIV and infant and maternal mortality and morbidity, as well as tolerability of vaginal disinfection in HIV-infected women.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register, Cochrane Pregnancy and Childbirth Register, PubMed, EMBASE, AIDSLINE, LILACS, AIDSTRIALS, and AIDSDRUGS, using standardised methodological filters for identifying trials. We also searched reference lists of identified articles, relevant editorials, expert opinions and letters to journal editors, and abstracts and proceedings of relevant conferences, and contacted subject experts and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Randomised trials or clinical trials comparing vaginal disinfection during labour with placebo or no treatment, in known HIV-infected pregnant women. Trials had to include an estimate of the effect of vaginal disinfection on MTCT of HIV and or infant and maternal mortality and morbidity.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trial eligibility and quality, and extracted data. Meta-analysis was performed using the Yusuf-Peto modification of Mantel-Haenszel's fixed effect method.

MAIN RESULTS

Only two trials that included 708 patients met the inclusion criteria. The effect of vaginal disinfection on the risk of MTCT of HIV (OR 0.93, 95% CI 0.65 to 1.33), neonatal death (OR 1.38, 95% CI 0.30 to 6.33), and death after the neonatal period (OR 1.45, 95% CI 0.47 to 4.45) is uncertain. There was no evidence that vaginal disinfection increased adverse effects in mothers (OR 1.15, 95% CI 0.41 to 3.22), and evidence from one trial showed that adverse effects decreased in neonates (OR 0.14, 95% CI 0.07 to 0.31).

AUTHORS' CONCLUSIONS

Currently, there is no evidence of an effect of vaginal disinfection on the risk of MTCT of HIV. Given its simplicity and low cost, there is need for a large well-designed and well-conducted randomised controlled trial to assess the additive effect of vaginal disinfection on the risk of MTCT of HIV in antiretroviral treated women.

Chorioamnionitis is associated with placental transmission of human immunodeficiency virus-1 subtype E in the early gestational period

The frequency and the cellular basis for HIV-1 transmission from mother to child in the early gestational period are poorly understood. We compared the placentas of 24 women seropositive for HIV-1 subtype E and who had not received any antiretroviral drugs, to placentas of 25 seronegative women. All placentas were obtained during therapeutic abortion at 6-23 weeks gestation. Placentas and fetal organs were examined by routine light microscopy, immunostaining for p24 capsid protein, and in situ PCR to localize which cells were infected with HIV-1 subtype E. The number of previous abortions was not a factor in placental HIV infection since this number was higher in seronegative women (P < 0.01). There were no significant differences between the placentas of the two groups with respect to presence of chorioamnionitis, villitis, villous stromal fibrosis, infarction, abnormal villous maturation, deciduitis or decidual necrosis. HIV-1 subtype E was detected in up to 83% of placentas, either by immunostaining or in situ PCR, in trophoblast, villous stromal cells, Hofbauer cells, decidual and decidual glandular epithelium. Fetal organs were positive for HIV in 30% (6/20) of cases. There was a significant association between transmission of HIV to the fetus and the histologic findings of chorioamnionitis, plasmacellular deciduitis and decidual cell necrosis. This is the first report showing an association of chorioamnionitis with early in utero transmission of HIV-1 subtype E. This may help explain the cases of in utero transmission that persist despite antiretroviral prophylaxis, given that therapy is started in the late gestational period.

Management of breech presentation in areas with high prevalence of HIV infection

OBJECTIVE

To provide recommendations for the management of breech presentation in areas of high prevalence of human immunodeficiency virus (HIV) infection.

METHOD

Review of relevant literature.

RESULTS

Studies show that elective cesarean section (CS) is safer than vaginal delivery for breech presentation, external cephalic version (ECV) at term increases the chance of vaginal cephalic delivery. Although there are no studies of the risk of mother-to-child transmission of HIV from ECV, indirect evidence suggests that any increased risk is likely to be very small.

RECOMMENDATIONS

Where CS is available and safe, HIV-positive women, or women who might be at risk of HIV, with a fetus at term with breech presentation, should be offered elective CS to reduce the risks of both vaginal breech delivery and mother-to-child HIV infection. HIV-negative women can be offered ECV at term to try to avoid CS. Where women do not have access to a safe CS, or prefer vaginal delivery, the benefit for both mother and child of attempting ECV at term is likely to outweigh the theoretical, very small, risk of facilitating HIV transmission.

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.

Risk factors for in utero and intrapartum transmission of HIV

OBJECTIVE

To identify predictors of in utero and intrapartum HIV-1 transmission in infants born in the Women and Infants Transmission Study between 1990 and 2000.

METHODS

In utero HIV-1 infection was defined as an infant with the first positive HIV-1 peripheral blood mononuclear cell culture and/or DNA polymerase chain reaction assay at 7 days of age or younger; intrapartum infection was defined as having a negative HIV-1 culture and/or DNA polymerase chain reaction assay at 7 days of age or younger and the first positive assay after 7 days of age.

RESULTS

Of 1709 first-born singleton children with defined HIV-1 infection status, 166 (9.7%) were found to be HIV-1 infected; transmission decreased from 18.1% in 1990-1992 to 1.6% in 1999-2000. Presumed in utero infection was observed in 34% of infected children, and presumed intrapartum infection, in 66%. Among infected children, the proportion with in utero infection increased over time from 27% in 1990-1992 to 80% (4 of 5) in 1999-2000 (P = 0.072). Maternal antenatal viral load and antiretroviral therapy were associated with risk of both in utero and intrapartum transmission. Controlling for maternal antenatal viral load and antiretroviral therapy, low birth weight was significantly associated with in utero transmission, while age, antenatal CD4 cell percentage, year, birth weight, and duration of membrane rupture were associated with intrapartum transmission.

CONCLUSION

Although there have been significant declines in perinatal HIV-1 infection over time, there has been an increase in the proportion of infections transmitted in utero.

Gender differences in perinatal HIV acquisition among African infants

OBJECTIVE

We investigated gender-specific risks of mother-to-child transmission (MTCT) at birth and at 6 to 8 weeks among infants born to HIV-infected African women.

DESIGN

Follow-up study of infants enrolled in 2 randomized, phase III, clinical trials to prevent MTCT, conducted in Blantyre, Malawi, in southeast Africa.

METHODS

Infants were enrolled at birth and monitored postnatally, and their HIV status was assessed at birth and at 6 to 8 weeks (assessment beyond 6-8 weeks is ongoing). Statistical analyses were stratified according to gender, and comparisons were made with descriptive, univariate, and multivariate statistical tests. MTCT was estimated at birth and at 6 to 8 weeks among infants who were not infected at birth.

RESULTS

Overall, 966 boys and 998 girls were enrolled. The rate of HIV transmission at birth was 9.5% (187 of 1964 infants). However, at birth significantly more girls (12.6%) than boys (6.3%) were infected with HIV. This association remained significant after controlling for maternal viral load and other factors. Among infants who were uninfected at birth, 8.7% (135 of 1554 infants) acquired HIV by 6 to 8 weeks; of these infants, more girls acquired HIV (10.0%), compared with boys (7.4%).

CONCLUSIONS

Female infants may be more susceptible to HIV infection before birth and continuing after birth. Alternatively, in utero mortality rates of HIV-infected male infants may be disproportionately higher and thus more HIV-infected female infants are born. In areas of sub-Saharan Africa, where HIV infection rates are high among women of reproductive age, the magnitude of the gender transmission differences observed in this study could have clinical, preventive, and demographic implications.

The effect of Plasmodium falciparum malaria on peripheral and placental HIV-1 RNA concentrations in pregnant Malawian women

OBJECTIVE

To investigate the effect of placental Plasmodium falciparum malaria infection on peripheral and/or placental HIV-1 viral load.

DESIGN

A cross-sectional study of HIV-infected pregnant women, with and without placental malaria, delivering at Queen Elizabeth Central Hospital in Malawi.

METHODS

Peripheral blood samples were collected from consenting women and tested for HIV. HIV-infected women received nevirapine at the onset of labor. At delivery, placental blood and tissue specimens were collected. HIV-1 RNA concentrations were measured in peripheral and placental plasma samples, and malaria infection was determined by placental histopathology.

RESULTS

Of the 480 HIV-infected women enrolled, 304 had placental histopathology performed, of whom 74 (24.3%) had placental malaria. Compared with women without placental malaria, those with placental malaria had a 2.5-fold higher geometric mean peripheral HIV-1 RNA concentration (62,359 versus 24 814 copies/ml; P = 0.0007) and a 2.4-fold higher geometric mean placental HIV-1 RNA concentration (11,733 versus 4919 copies/ml; P = 0.008). In multivariate analyses, after adjusting for CD4 cell count and other covariates, placental malaria was associated with a 1.7-fold increase in geometric mean peripheral HIV-1 RNA concentration (47,747 versus 27,317 copies/ml; P = 0.02) and a 2.0-fold increase in geometric mean placental HIV-1 RNA concentration (9670 versus 4874 copies/ml; P = 0.03).

CONCLUSION

Placental malaria infection is associated with an increase in peripheral and placental HIV-1 viral load, which might increase the risk of mother-to-child transmission of HIV.