A phase III clinical trial of antibiotics to reduce chorioamnionitis-related perinatal HIV-1 transmission

Placental pathology in women with HIV

Recognizing the importance of placental features and their unique functions can provide insight into maternal health, the uterine environment during the course of pregnancy, birth outcomes and neonatal health. In the context of HIV and antiretroviral therapy (ART), there have been great strides in the prevention of mother to child transmission of HIV. However, there is still paucity of data on the impact of HIV/ART exposure on placental pathology and studies available only examine specific patterns of placental injury, further justifying the need for a more defined and comprehensive approach to the differential diagnoses of HIV/ART-exposed placentae. The purpose of this review is to consolidate findings from individual studies that have been reported on patterns of placental injury in the context of HIV/ART exposure. In both the pre- and post-ART eras HIV and/or ART has been associated with placental injury including maternal vascular malperfusion as well as acute and chronic inflammation. These patterns of injury are further associated with adverse birth outcomes including preterm birth and current evidence suggests an association between poor placental function and compromised fetal development. With the ever increasing number of pregnant women with HIV on ART, there is a compelling need for full incorporation of placental diagnoses into obstetric disease classification. It is also important to take into account key elements of maternal clinical history. Lastly, there is a need to standardize the reporting of placental pathology in order to glean additional insight into the elucidation of HIV/ART associated placental injury.

Biomarkers for a histological chorioamnionitis diagnosis in pregnant women with or without group B streptococcus infection: a case-control study

Background

Chorioamnionitis may cause serious perinatal and neonatal adverse outcomes, and group B streptococcus (GBS) is one of the most common bacteria isolated from human chorioamnionitis. The present study analyzed the impact of GBS infection and histological chorioamnionitis (HCA) on pregnancy outcomes and the diagnostic value of various biomarkers.

Methods

Pregnant women were grouped according to GBS infection and HCA detection. Perinatal and neonatal adverse outcomes were recorded with a follow-up period of 6 weeks. The white blood cell count (WBC), neutrophil ratio, and C-reactive protein (CRP) level from peripheral blood and soluble intercellular adhesion molecule-1 (sICAM-1), interleukin 8 (IL-8), and tumor necrosis factor α (TNF-α) levels from cord blood were assessed.

Results

A total of 371 pregnant women were included. Pregnant women with GBS infection or HCA had a higher risk of pathological jaundice and premature rupture of membranes and higher levels of sICAM-1, IL-8, and TNF-α in umbilical cord blood. Univariate and multivariate regression analysis revealed that sICMA-1, IL-8, TNF-α, WBC, and CRP were significantly related to an increased HCA risk. For all included pregnant women, TNF-α had the largest receiver operating characteristic (ROC) area (area: 0.841; 95% CI: 0.778–0.904) of the biomarkers analyzed. TNF-α still had the largest area under the ROC curve (area: 0.898; 95% CI: 0.814–0.982) for non-GBS-infected pregnant women, who also exhibited a higher neutrophil ratio (area: 0.815; 95% CI: 0.645–0.985) and WBC (area: 0.849; 95% CI: 0.72–0.978), but all biomarkers had lower value in the diagnosis of HCA in GBS-infected pregnant women.

Conclusion

GBS infection and HCA correlated with several perinatal and neonatal adverse outcomes. TNF-α in cord blood and WBCs in peripheral blood had diagnostic value for HCA in non-GBS-infected pregnant women but not GBS-infected pregnant women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03731-7.

Combined evaluation of sexually transmitted infections in HIV-infected pregnant women and infant HIV transmission

Background

Sexually transmitted infections (STIs) including Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Treponema pallidum (TP), and cytomegalovirus (CMV) may lead to adverse pregnancy and infant outcomes. The role of combined maternal STIs in HIV mother-to-child transmission (MTCT) was evaluated in mother-infant pairs from NICHD HPTN 040.

Methodology

Urine samples from HIV-infected pregnant women during labor were tested by polymerase chain reaction (PCR) for CT, NG, and CMV. Infant HIV infection was determined by serial HIV DNA PCR testing. Maternal syphilis was tested by VDRL and confirmatory treponemal antibodies.

Results

A total of 899 mother-infant pairs were evaluated. Over 30% had at least one of the following infections (TP, CT, NG, and/or CMV) detected at the time of delivery. High rates of TP (8.7%), CT (17.8%), NG (4%), and CMV (6.3%) were observed. HIV MTCT was 9.1% (n = 82 infants). HIV MTCT was 12.5%, 10.3%, 11.1%, and 26.3% among infants born to women with CT, TP, NG or CMV respectively. Forty-two percent of HIV-infected infants were born to women with at least one of these 4 infections. Women with these infections were nearly twice as likely to have an HIV-infected infant (aOR 1.9, 95% CI 1.1–3.0), particularly those with 2 STIs (aOR 3.4, 95% CI 1.5–7.7). Individually, maternal CMV (aOR 4.4 1.5–13.0) and infant congenital CMV (OR 4.1, 95% CI 2.2–7.8) but not other STIs (TP, CT, or NG) were associated with an increased risk of HIV MTCT.

Conclusion

HIV-infected pregnant women identified during labor are at high risk for STIs. Co-infection with STIs including CMV nearly doubles HIV MTCT risk. CMV infection appears to confer the largest risk of HIV MTCT.

Trial registration

NCT00099359.

Chlamydia and Gonorrhea in HIV-Infected Pregnant Women and Infant HIV Transmission

BACKGROUND

Sexually transmitted infections (STIs) such as Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) can lead to adverse pregnancy and neonatal outcomes. The prevalence of STIs and its association with HIV mother-to-child transmission (MTCT) were evaluated in a substudy analysis from a randomized, multicenter clinical trial.

METHODOLOGY

Urine samples from HIV-infected pregnant women collected at the time of labor and delivery were tested using polymerase chain reaction testing for the detection of CT and NG (Xpert CT/NG; Cepheid, Sunnyvale, CA). Infant HIV infection was determined by HIV DNA polymerase chain reaction at 3 months.

RESULTS

Of the 1373 urine specimens, 249 (18.1%) were positive for CT and 63 (4.6%) for NG; 35 (2.5%) had both CT and NG detected. Among 117 cases of HIV MTCT (8.5% transmission), the lowest transmission rate occurred among infants born to CT- and NG-uninfected mothers (8.1%) as compared with those infected with only CT (10.7%) and both CT and NG (14.3%; P = 0.04). Infants born to CT-infected mothers had almost a 1.5-fold increased risk for HIV acquisition (odds ratio, 1.47; 95% confidence interval, 0.9-2.3; P = 0.09).

CONCLUSIONS

This cohort of HIV-infected pregnant women is at high risk for infection with CT and NG. Analysis suggests that STIs may predispose to an increased HIV MTCT risk in this high-risk cohort of HIV-infected women.

Chlamydia trachomatis Infection in Pregnancy: The Global Challenge of Preventing Adverse Pregnancy and Infant Outcomes in Sub-Saharan Africa and Asia

Screening and treatment of sexually transmitted infections (STIs) in pregnancy represents an overlooked opportunity to improve the health outcomes of women and infants worldwide. Although Chlamydia trachomatis is the most common treatable bacterial STI, few countries have routine pregnancy screening and treatment programs. We reviewed the current literature surrounding Chlamydia trachomatis in pregnancy, particularly focusing on countries in sub-Saharan Africa and Asia. We discuss possible chlamydial adverse pregnancy and infant health outcomes (miscarriage, stillbirth, ectopic pregnancy, preterm birth, neonatal conjunctivitis, neonatal pneumonia, and other potential effects including HIV perinatal transmission) and review studies of chlamydial screening and treatment in pregnancy, while simultaneously highlighting research from resource-limited countries in sub-Saharan Africa and Asia.

Antibiotic prophylaxis during the second and third trimester to reduce adverse pregnancy outcomes and morbidity

BACKGROUND

Several studies have suggested that prophylactic antibiotics given during pregnancy improved maternal and perinatal outcomes, while others have shown no benefit and some have reported adverse effects.

OBJECTIVES

To determine the effect of prophylactic antibiotics on maternal and perinatal outcomes during the second and third trimester of pregnancy for all women or women at risk of preterm delivery.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2015) and reference lists of retrieved articles.

SELECTION CRITERIA

Randomised controlled trials comparing prophylactic antibiotic treatment with placebo or no treatment for women in the second or third trimester of pregnancy before labour.

DATA COLLECTION AND ANALYSIS

We assessed trial quality and extracted data.

MAIN RESULTS

The review included eight randomised controlled trials. Approximately 4300 women were recruited to detect the effect of prophylactic antibiotic administration on pregnancy outcomes. Primary outcomesAntibiotic prophylaxis did not reduce the risk of preterm prelabour rupture of membranes (risk ratio (RR) 0.31; 95% confidence interval (CI) 0.06 to 1.49 (one trial, 229 women), low quality evidence) or preterm delivery (RR 0.88; 95% CI 0.72 to 1.09 (six trials, 3663 women), highquality evidence). However, preterm delivery was reduced in the subgroup of pregnant women with a previous preterm birth who had bacterial vaginosis (BV) during the current pregnancy (RR 0.64; 95% CI 0.47 to 0.88 (one trial, 258 women)), but there was no reduction in the subgroup of pregnant women with previous preterm birth without BV during the pregnancy (RR 1.08; 95% CI 0.66 to 1.77 (two trials, 500 women)). A reduction in the risk of postpartum endometritis (RR 0.55; 95% CI 0.33 to 0.92 (one trial, 196 women)) was observed in high-risk pregnant women (women with a history of preterm birth, low birthweight, stillbirth or early perinatal death) and in all women (RR 0.53; 95% CI 0.35 to 0.82 (three trials, 627 women), moderate quality evidence). There was no difference in low birthweight (RR 0.86; 95% CI 0.53 to 1.39 (four trials; 978 women)) or neonatal sepsis (RR 11.31; 95% CI 0.64 to 200.79) (one trial, 142 women)); and blood culture confirming sepsis was not reported in any of the studies. Secondary outcomesAntibiotic prophylaxis reduced the risk of prelabour rupture of membranes (RR 0.34; 95% CI 0.15 to 0.78 (one trial, 229 women), low quality evidence) and gonococcal infection (RR 0.35; 95% CI 0.13 to 0.94 (one trial, 204 women)). There were no differences observed in other secondary outcomes (congenital abnormality; small-for-gestational age; perinatal mortality), whilst many other secondary outcomes (e.g. intrapartum fever needing treatment with antibiotics) were not reported in included trials.Regarding the route of antibiotic administration, vaginal antibiotic prophylaxis during pregnancy did not prevent infectious pregnancy outcomes. The overall risk of bias was low, except that incomplete outcome data produced high risk of bias in some studies. The quality of the evidence using GRADE was assessed as low for preterm prelabour rupture of membranes, high for preterm delivery, moderate for postpartum endometritis, low for prelabour rupture of membranes, and very low for chorioamnionitis. Intrapartum fever needing treatment with antibiotics was not reported in any of the included studies.

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis did not reduce the risk of preterm prelabour rupture of membranes or preterm delivery (apart from in the subgroup of women with a previous preterm birth who had bacterial vaginosis). Antibiotic prophylaxis given during the second or third trimester of pregnancy reduced the risk of postpartum endometritis, term pregnancy with pre-labour rupture of membranes and gonococcal infection when given routinely to all pregnant women. Substantial bias possibly exists in the review's results because of a high rate of loss to follow-up and the small numbers of studies included in each of our analyses. There is also insufficient evidence on possible harmful effects on the baby. Therefore, we conclude that there is not enough evidence to support the use of routine antibiotics during pregnancy to prevent infectious adverse effects on pregnancy outcomes.

Strategies for the prevention of mother to child transmission in Western countries: an update

BACKGROUND

During the last decades remarkable scientific advances have been made toward the prevention of HIV mother-to-child transmission, in particular in developed nations. The aim of this review was to analyze the latest findings and available international recommendations on the prevention of HIV mother-to-child transmission in high-income countries.

METHODS

We performed a literature search of the Cochrane Library, MEDLINE by PubMed and EMBASE from database inception through June 2014, using the following terms: HIV, mother-to-child transmission and mother-to-child-transmission prevention. All types of articles in the English language were included. US and available European guidelines were searched and included in the analysis.

RESULTS

One hundred fifty articles were selected for inclusion in this review.

CONCLUSIONS

Global epidemiology of HIV infection is rapidly evolving, in particular in high-resource countries. The interpretation of clinical and epidemiological studies is crucial for the development of evidence-based recommendations to guide the management of HIV mother-to-child transmission. Although significant progress has been made, heterogeneity between countries in specific interventions still exists, which may address future research.

Chorioamnionitis in pregnancy: a comparative study of HIV-positive and HIV-negative parturients

Chorioamnionitis is an important risk factor for vertical transmission of HIV/AIDS. We compared the prevalence and correlates of histologic chorioamnionitis (HCA) in HIV-positive and HIV-negative pregnant women. HIV-positive and -negative parturients were interviewed, examined and had their placentas examined histologically for chorioamnionitis. Data regarding HIV were also retrieved from their hospital records. A total of 298 parturients (150 HIV positive and 148 HIV negative) were enrolled. The two groups were similar in socio-demographic and obstetric parameters except for age. The prevalence of HCA was 57.1% in HIV-positive women and 61.6% in HIV-negative women (p = 0.43). HCA staging was associated with the number of intrapartum vaginal examinations in HIV-positive subjects and nulliparity in HIV-negative subjects. The number of intrapartum vaginal examinations and coitus in the week prior to delivery significantly affected the grade of HCA in HIV-negative subjects. The prevalence of HCA in both HIV-positive and HIV-negative is high. Most variables did not affect the occurrence of HCA in both groups studied except number of intrapartum examinations, coitus in the preceding one week and nulliparity, which were related to severity of the disease.

Antibiotic prophylaxis during the second and third trimester to reduce adverse pregnancy outcomes and morbidity

BACKGROUND

Several studies have suggested that prophylactic antibiotics given during pregnancy improved maternal and perinatal outcomes, while others have shown no benefit and some have reported adverse effects.

OBJECTIVES

To determine the effect of prophylactic antibiotics on maternal and perinatal outcomes during the second and third trimester of pregnancy for all women or women at risk of preterm delivery.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2014) and reference lists of retrieved articles.

SELECTION CRITERIA

Randomised controlled trials comparing prophylactic antibiotic treatment with placebo or no treatment for women in the second or third trimester of pregnancy before labour.

DATA COLLECTION AND ANALYSIS

We assessed trial quality and extracted data.

MAIN RESULTS

The review included seven randomised controlled trials. Approximately 2100 women were recruited to detect the effect of prophylactic antibiotic administration on pregnancy outcomes. Primary outcomesAntibiotic prophylaxis did not reduce the risk of preterm prelabour rupture of membranes (risk ratio (RR) 0.31; 95% confidence interval (CI) 0.06 to 1.49 (one trial, 229 women) low quality evidence) or preterm delivery (RR 0.85; 95% CI 0.64 to 1.14 (five trials, 1480 women) low quality evidence). However, preterm delivery was reduced in the subgroup of pregnant women with a previous preterm birth who had bacterial vaginosis (BV) during the current pregnancy (RR 0.64; 95% CI 0.47 to 0.88 (one trial, 258 women), but there was no reduction in the subgroup of pregnant women with previous preterm birth without BV during the pregnancy (RR 1.08; 95% CI 0.66 to 1.77 (two trials, 500 women)). A reduction in the risk of postpartum endometritis (RR 0.55; 95% CI 0.33 to 0.92 (one trial, 196 women)) was observed in high-risk pregnant women (women with a history of preterm birth, low birthweight, stillbirth or early perinatal death) and in all women (RR 0.53; 95% CI 0.35 to 0.82 (three trials, 627 women) moderate quality evidence). There was no difference in low birth weight (RR 0.86; 95% CI 0.53 to 1.39 (four trials; 978 women) or neonatal sepsis (RR 11.31; 95% CI 0.64 to 200.79); and blood culture confirming sepsis was not reported in any of the studies. Secondary outcomesAntibiotic prophylaxis reduced the risk of prelabour rupture of membranes (RR 0.34; 95% CI 0.15 to 0.78 (one trial, 229 women) low quality evidence) and gonococcal infection (RR 0.35; 95% CI 0.13 to 0.94 (one trial, 204 women)). There were no differences observed in other secondary outcomes (congenital abnormality; small-for-gestational age; perinatal mortality), whilst many other secondary outcomes (e.g. intrapartum fever needing treatment with antibiotics) were not reported in included trials.Regarding the route of antibiotic administration, vaginal antibiotic prophylaxis during pregnancy did not prevent infectious pregnancy outcomes. The overall risk of bias was low except that incomplete outcome data produced high risk of bias in some studies. The quality of the evidence using GRADE was assessed as low for preterm prelabour rupture of membranes, low for preterm delivery, moderate for postpartum endometritis, low for prelabour rupture of membranes, and very low for chorioamnionitis. Intrapartum fever needing treatment with antibiotics was not reported in any of the included studies.

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis did not reduce the risk of preterm prelabour rupture of membranes or preterm delivery (apart from in the subgroup of women with a previous preterm birth who had bacterial vaginosis). Antibiotic prophylaxis given during the second or third trimester of pregnancy reduced the risk of postpartum endometritis, preterm rupture of membranes and gonococcal infection when given routinely to all pregnant women. Substantial bias possibly exists in the review's results because of a high rate of loss to follow-up and the small numbers of studies included in each of our analyses. There is also insufficient evidence on possible harmful effects on the baby. Therefore, we conclude that there is not enough evidence to recommend the use of routine antibiotics during pregnancy to prevent infectious adverse effects on pregnancy outcomes.

Adjusting for time-dependent sensitivity in an illness-death model, with application to mother-to-child transmission of HIV

In mother-to-child transmission of HIV, identifying infected infants relies on a diagnostic test with imperfect sensitivity that is administered at scheduled visits. Under this scenario, a participant's true state may be unknown at the start and end times of the study, and the detection of transitions into illness may be delayed or missed altogether. This could lead to biased estimates of the risk of transmission and covariate associations. When a test has imperfect sensitivity, but perfect specificity, the additional uncertainty can be captured as a random variable measuring delay in detection. The cumulative distribution then defines a time-dependent sensitivity function that increases over time. We present a maximum likelihood based illness-death model that accounts for imperfect sensitivity by including the delay as an exponential distribution. We specify transition rates as penalized B-splines to allow for nonhomogeneity of risk and discuss the model under Markov and semi-Markov assumptions. We apply this method to our motivating data set, a study of 1499 mother and infant pairs at three sites in Africa.

Cost-effectiveness of a package of interventions for expedited antiretroviral therapy initiation during pregnancy in Cape Town, South Africa

Initiating antiretroviral therapy (ART) early in pregnancy is an important component of effective interventions to prevent the mother-to-child transmission of HIV (PMTCT). The rapid initiation of ART in pregnancy(RAP) program was a package of interventions to expedite ART initiation in pregnant women in Cape Town, South Africa. Retrospective cost-effectiveness, sensitivity and threshold analyses were conducted of the RAP program to determine the cost-utility thresholds for rapid initiation of ART in pregnancy. Costs were drawn from a detailed micro-costing of the program. The overall programmatic cost was US$880 per woman and the base case cost-effectiveness ratio was US$1,160 per quality-adjusted lifeyear (QALY) saved. In threshold analyses, the RAP program remained cost-effective if mother-to-child transmission was reduced by C0.33 %; if C1.76 QALY were saved with each averted perinatal infection; or if RAP-related costs were under US$4,020 per woman. The package of rapid initiation services was very cost-effective, as compared to standard services in this setting. Threshold analyses demonstrated that the intervention required minimal reductions in perinatal infections in order to be cost-effective. Interventions for the rapid initiation of ART in pregnancy hold considerable potential as a cost-effective use of limited resources for PMTCT in sub-Saharan Africa.

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.

Mother-to-child transmission of HIV: the pre-rapid advice experience of the university of Nigeria teaching hospital Ituku/Ozalla, Enugu, South-east Nigeria

Background

Mother-to-child transmission of human immune deficiency virus (HIV) is the most common route of HIV transmission in the pediatric age group. A number of risk factors contribute to the rate of this transmission. Such risk factors include advance maternal HIV disease, lack of anti-viral prophylaxis in the mother and child, mixing of maternal and infant blood during delivery and breastfeeding. This study aims to determine the cumulative HIV infection rate by 18 months and the associated risk factors at the University of Nigeria Teaching Hospital, Enugu.

Results

A retrospective study, involving HIV exposed infants seen at the pediatric HIV clinic of UNTH between March 2006 and September 2008. Relevant data were retrieved from their medical records. The overall rate of mother to child transmission of HIV in this study was 3.9% (95% CI 1.1%- 6.7%). However, in children breastfed for 3 months or less, the rate of transmission was 10% (95% CI −2.5%-22.5%), compared to 3.5% (95% CI 0.5%-6.5%) in children that had exclusive replacement feeding.

Conclusions

This retrospective observational study shows a 3.9% cumulative rate of mother-to-child transmission of HIV by 18 months of age in Enugu. Holistic but cost effective preventive interventions help in reducing the rate of mother-to-child transmission of HIV even in economically-developing settings like Nigeria.

The HIV Epidemic: High-Income Countries

The HIV epidemic in higher-income nations is driven by receptive anal intercourse, injection drug use through needle/syringe sharing, and, less efficiently, vaginal intercourse. Alcohol and noninjecting drug use increase sexual HIV vulnerability. Appropriate diagnostic screening has nearly eliminated blood/blood product-related transmissions and, with antiretroviral therapy, has reduced mother-to-child transmission radically. Affected subgroups have changed over time (e.g., increasing numbers of Black and minority ethnic men who have sex with men). Molecular phylogenetic approaches have established historical links between HIV strains from central Africa to those in the United States and thence to Europe. However, Europe did not just receive virus from the United States, as it was also imported from Africa directly. Initial introductions led to epidemics in different risk groups in Western Europe distinguished by viral clades/sequences, and likewise, more recent explosive epidemics linked to injection drug use in Eastern Europe are associated with specific strains. Recent developments in phylodynamic approaches have made it possible to obtain estimates of sequence evolution rates and network parameters for epidemics.

Trends in birth weight and gestational age for infants born to HIV-infected, antiretroviral treatment-naive women in Malawi

BACKGROUND

We analyzed birth outcomes among infants of treatment-naive, HIV-infected women from a series of mother-to-child transmission of HIV studies in Blantyre, Malawi.

METHODS

Data from 6 prospective studies at 1 research site were analyzed. Mean birth weight (BW) and gestational age (GA), and frequency of low birth weight (LBW; <2500 g) and preterm (PT) birth (GA < 37 weeks) were estimated. We assessed risk factors for LBW and PT birth using mixed-effects logistic regression. Adjusted odds ratios (AOR) and 95% confidence intervals from earlier studies (1989-1994) and later studies (2000-2007) are presented separately.

RESULTS

The analysis included 8874 HIV-exposed infants. Mean BW and GA ranged from 2793 to 3079 g, and from 37.8 to 39.0 weeks. Greater maternal age was consistently (during both the early and late periods) associated with lower odds of LBW and PT birth; AOR (95% confidence intervals) for both outcomes in the early and late periods, respectively, were 0.98 (0.96-1.00) and 0.97 (0.95-0.99). Female infant gender was consistently associated with higher odds of PT birth during both periods and with higher odds of LBW during the later period. During the early period, higher maternal education was associated with lower odds of LBW (AOR 0.67 [0.48-0.95]) and PT birth (AOR 0.70 [0.51-0.95]), and later birth year was associated with lower odds of PT birth (AOR 0.35 [0.19-0.70]).

CONCLUSIONS

BW and GA remained stable within each time period. This analysis provides important baseline information for monitoring HIV treatment effects on birth outcomes. Modifiable factors affecting BW and GA should continue to be explored.

Host factors that influence mother-to-child transmission of HIV-1: genetics, coinfections, behavior and nutrition

Mother-to-child transmission (MTCT) is the most important mode of HIV-1 acquisition among infants and children and it can occur in utero, intrapartum and postnatally through breastfeeding. Great progress has been made in preventing MTCT through use of antiretroviral regimens during gestation, labor/delivery and breastfeeding. The mechanisms of MTCT, however, are multifactorial and remain incompletely understood. This review focuses on select host factors affecting MTCT, in particular genetic factors, coexisting infections, behavioral factors and nutrition. Whereas much emphasis has been placed on decreasing maternal HIV-1 viral load, an important determinant of MTCT, through use of antiretroviral agents, complementary focus on overall maternal health is often neglected. By addressing coinfections in mothers and infants, improving the mother's nutritional status and modifying risky behaviors and practices, not only is maternal and child health improved, but a direct benefit in reducing MTCT can be derived. The study of genetic variations in susceptibility to HIV-1 infection is rapidly evolving, and the future is likely to bring revolutionary changes in HIV-1 prevention by enhancing natural resistance to infection and by individually tailoring pharmacologic regimens.

Evaluating the incremental value of new biomarkers with integrated discrimination improvement

The integrated discrimination improvement (IDI) index is a popular tool for evaluating the capacity of a marker to predict a binary outcome of interest. Recent reports have proposed that the IDI is more sensitive than other metrics for identifying useful predictive markers. In this article, the authors use simulated data sets and theoretical analysis to investigate the statistical properties of the IDI. The authors consider the common situation in which a risk model is fitted to a data set with and without the new, candidate predictor(s). Results demonstrate that the published method of estimating the standard error of an IDI estimate tends to underestimate the error. The z test proposed in the literature for IDI-based testing of a new biomarker is not valid, because the null distribution of the test statistic is not standard normal, even in large samples. If a test for the incremental value of a marker is desired, the authors recommend the test based on the model. For investigators who find the IDI to be a useful measure, bootstrap methods may offer a reasonable option for inference when evaluating new predictors, as long as the added predictive capacity is large.

Bayesian estimation of the time-varying sensitivity of a diagnostic test with application to mother-to-child transmission of HIV

We present a Bayesian model to estimate the time-varying sensitivity of a diagnostic assay when the assay is given repeatedly over time, disease status is changing, and the gold standard is only partially observed. The model relies on parametric assumptions for the distribution of the latent time of disease onset and the time-varying sensitivity. Additionally, we illustrate the incorporation of historical data for constructing prior distributions. We apply the new methods to data collected in a study of mother-to-child transmission of HIV and include a covariate for sensitivity to assess whether two different assays have different sensitivity profiles.

Immune-based approaches to the prevention of mother-to-child transmission of HIV-1: active and passive immunization

Despite more than 2 decades of research, an effective vaccine that can prevent HIV-1 infection in populations exposed to the virus remains elusive. In the pursuit of an HIV-1 vaccine, does prevention of exposure to maternal HIV-1 in utero, at birth or in early life through breast milk require special consideration? This article reviews what is known about the immune mechanisms of susceptibility and resistance to mother-to-child transmission (MTCT) of HIV-1 and summarizes studies that have used passive or active immunization strategies to interrupt MTCT of HIV-1. Potentially modifiable infectious cofactors that may enhance transmission and/or disease progression (especially in the developing world) are described. An effective prophylactic vaccine against HIV-1 infection needs to be deployed as part of the Extended Program of Immunization recommended by the World Health Organization for use in developing countries, so it is important to understand how the infant immune system responds to HIV-1 antigens, both in natural infection and presented by candidate vaccines.

Mother-to-child transmission of HIV: pathogenesis, mechanisms and pathways

More than 400,000 children were infected with (HIV-1) worldwide in 2008, or more than 1000 children per day. Mother-to-child transmission (MTCT) of HIV-1 is the most important mode of HIV acquisition in infants and children. MTCT of HIV-1 can occur in utero, intrapartum, and postnatally through breastfeeding. Great progress has been made in preventing such transmission, through the use of antiretroviral prophylactic regimens to the mother during gestation and labor and delivery and to either mother or infant during breast feeding. The timing and mechanisms of transmission, however, are multifactorial and remain incompletely understood. This article summarizes what is known about the pathogenetic mechanisms and routes of MTCT of HIV-1, and includes virologic, immunologic, genetic, and mucosal aspects of 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.

Illness during pregnancy and bacterial vaginosis are associated with in-utero HIV-1 transmission

HIV-1 transmission in utero accounts for 20-30% of vertical transmission events in breast-feeding populations. In a prospective study of 463 HIV-1-infected mothers and infants, illness during pregnancy was associated with 2.6-fold increased risk of in-utero HIV-1 transmission [95% confidence interval (CI) 1.2-5.8] and bacterial vaginosis with a three-fold increase (95% CI 1.0-7.0) after adjusting for maternal HIV-1 viral load. Interventions targeting these novel risk factors could lead to more effective prevention of transmission during pregnancy.

The APPLe study: a randomized, community-based, placebo-controlled trial of azithromycin for the prevention of preterm birth, with meta-analysis

BACKGROUND

Premature birth is the major cause of perinatal mortality and morbidity in both high- and low-income countries. The causes of preterm labour are multiple but infection is important. We have previously described an unusually high incidence of preterm birth (20%) in an ultrasound-dated, rural, pregnant population in Southern Malawi with high burdens of infective morbidity. We have now studied the impact of routine prophylaxis with azithromycin as directly observed, single-dose therapy at two gestational windows to try to decrease the incidence of preterm birth.

METHODS AND FINDINGS

We randomized 2,297 pregnant women attending three rural and one peri-urban health centres in Southern Malawi to a placebo-controlled trial of oral azithromycin (1 g) given at 16-24 and 28-32 wk gestation. Gestational age was determined by ultrasound before 24 wk. Women and their infants were followed up until 6 wk post delivery. The primary outcome was incidence of preterm delivery, defined as <37 wk. Secondary outcomes were mean gestational age at delivery, perinatal mortality, birthweight, maternal malaria, and anaemia. Analysis was by intention to treat. There were no significant differences in outcome between the azithromycin group (n = 1,096) and the placebo group (n = 1,087) in respect of preterm birth (16.8% versus 17.4%), odds ratio (OR) 0.96, 95% confidence interval (0.76-1.21); mean gestational age at delivery (38.5 versus 38.4 weeks), mean difference 0.16 (-0.08 to 0.40); mean birthweight (3.03 versus 2.99 kg), mean difference 0.04 (-0.005 to 0.08); perinatal deaths (4.3% versus 5.0%), OR 0.85 (0.53-1.38); or maternal malarial parasitaemia (11.5% versus 10.1%), OR 1.11 (0.84-1.49) and anaemia (44.1% versus 41.3%) at 28-32 weeks, OR 1.07 (0.88-1.30). Meta-analysis of the primary outcome results with seven other studies of routine antibiotic prophylaxis in pregnancy (>6,200 pregnancies) shows no effect on preterm birth (relative risk 1.02, 95% confidence interval 0.86-1.22).

CONCLUSIONS

This study provides no support for the use of antibiotics as routine prophylaxis to prevent preterm birth in high risk populations; prevention of preterm birth requires alternative strategies.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN84023116

Neisseria gonorrhoeae antimicrobial susceptibility in Lilongwe, Malawi, 2007

BACKGROUND

Malawi adopted syndromic management of sexually transmitted infections in 1993. Based on clinical efficacy and cost, gentamicin 240 mg intramuscularly, and doxycycline 100 mg twice daily x 7 days was selected as the first line regimen to treat urethritis. We sought to establish current laboratory-based Neisseria gonorrhoeae antibiotic susceptibility patterns for Malawi and describe the pattern of susceptibility since syndromic management began.

METHODS

Between May 15 and August 10, 2007, 126 men with urethritis attending the STD clinic at Kamuzu Central Hospital in Lilongwe had history, genital exam, and urethral swabs taken. All were treated with gentamicin and doxycycline in accordance with Malawi guidelines. Gonorrhea was diagnosed by Gram stain and culture. Antimicrobial susceptibility patterns in gonococcal isolates were determined by disk diffusion and E-test minimum inhibitory concentration (MIC) determination and agar dilution MIC determination.

RESULTS

One hundred six isolates were cultured, and MICs were determined for 100. High levels of resistance to tetracycline and penicillin were observed, but isolates were uniformly susceptible to both gentamicin and ciprofloxacin. Susceptibility patterns identified by the agar dilution MIC and E-test MIC agreed.

CONCLUSIONS

The most recent study continues the trend of high susceptibility of gonococcal isolates to gentamicin in Malawi after 14 years of use and suggests agar dilution MICs may be substituted with the simpler E-test methods in future susceptibility testing. However because of the lack of susceptibility criteria for aminoglycosides for N. gonorrhoeae and the difficulty obtaining clinical/in vitro correlates in this setting, caution should be exercised in using these data for modifying treatment regimens.

Effect of prenatal and perinatal antibiotics on maternal health in Malawi, Tanzania, and Zambia

OBJECTIVE

We assessed the effect of prenatal and peripartum antibiotics on maternal morbidity and mortality among HIV-infected and uninfected women.

METHODS

A multicenter trial was conducted at clinical sites in 4 Sub-Saharan African cities: Blantyre and Lilongwe, Malawi; Dar es Salaam, Tanzania; and Lusaka, Zambia. A total of 1558 HIV-infected and 271 uninfected pregnant women who were eligible to receive both the prenatal and peripartum antibiotic/placebo regimens were enrolled. Pregnant women were interviewed at 20-24 weeks of gestation and a physical examination was performed. Women were randomized to receive either antibiotics or placebo. At the 26-30 week visit, participants were given antibiotics or placebo to be taken every 4 hours beginning at the onset of labor and continuing after delivery 3 times a day until a 1-week course was completed. Logistic regression and Cox proportional hazards models were used.

RESULTS

There were no significant differences between the antibiotic and placebo groups for medical conditions, obstetric complications, physical examination findings, puerperal sepsis, and death in either the HIV-infected or the uninfected cohort.

CONCLUSION

Administration of study antibiotics during pregnancy had no effect on maternal morbidity and mortality among HIV-infected and uninfected pregnant women.

Selected hematologic and biochemical measurements in African HIV-infected and uninfected pregnant women and their infants: the HIV Prevention Trials Network 024 protocol

Background

Reference values for hematological and biochemical assays in pregnant women and in newborn infants are based primarily on Caucasian populations. Normative data are limited for populations in sub-Saharan Africa, especially comparing women with and without HIV infection, and comparing infants with and without HIV infection or HIV exposure.

Methods

We determined HIV status and selected hematological and biochemical measurements in women at 20–24 weeks and at 36 weeks gestation, and in infants at birth and 4–6 weeks of age. All were recruited within a randomized clinical trial of antibiotics to prevent chorioamnionitis-associated mother-to-child transmission of HIV (HPTN024). We report nearly complete laboratory data on 2,292 HIV-infected and 367 HIV-uninfected pregnant African women who were representative of the public clinics from which the women were recruited. Nearly all the HIV-infected mothers received nevirapine prophylaxis at the time of labor, as did their infants after birth (always within 72 hours of birth, but typically within just a few hours at the four study sites in Malawi (2 sites), Tanzania, and Zambia.

Results

HIV-infected pregnant women had lower red blood cell counts, hemoglobin, hematocrit, and white blood cell counts than HIV-uninfected women. Platelet and monocyte counts were higher among HIV-infected women at both time points. At the 4–6-week visit, HIV-infected infants had lower hemoglobin, hematocrit and white blood cell counts than uninfected infants. Platelet counts were lower in HIV-infected infants than HIV-uninfected infants, both at birth and at 4–6 weeks of age. At 4–6 weeks, HIV-infected infants had higher alanine aminotransferase measures than uninfected infants.

Conclusion

Normative data in pregnant African women and their newborn infants are needed to guide the large-scale HIV care and treatment programs being scaled up throughout the continent. These laboratory measures will help interpret clinical data and assist in patient monitoring in a sub-Saharan Africa context.

Trial Registration

nicalTrials.gov Identifier NCT00021671.

Primary HIV-1 infection among infants in sub-Saharan Africa: HPTN 024

OBJECTIVES

Our objectives were to assess clinical signs and diagnoses associated with primary HIV-1 infection among infants.

METHODS

We analyzed data from a clinical trial (HIV Prevention Trials Network Protocol 024) in sub-Saharan Africa. Study visits were conducted at birth, at 4-6 weeks, and at 3, 6, 9, and 12 months. The study population comprised live born, singleton, first-born infants of HIV-1-infected women with negative HIV-1 RNA assays who were still breastfeeding at 4-6 weeks.

RESULTS

Of 1317 HIV-1-exposed infants, 84 became HIV-1 infected after 4-6 weeks and 1233 remained uninfected. There were 102 primary and 5650 nonprimary infection visits. The most common signs were cough and diarrhea, and the most common diagnoses were malaria and pneumonia. Primary infection was associated with significantly increased odds of diarrhea [odds ratio (OR) = 2.4], pneumonia (OR = 3.5), otitis media (OR = 3.1), and oral thrush (OR = 2.9). For the clinical signs and diagnoses evaluated, sensitivity was low (1%-16.7%) and specificity was high (88.2%-99%). Positive predictive values ranged from 0.1%-1.4%. Negative predictive values ranged from 28.0%-51.1%.

CONCLUSIONS

Certain clinical signs and diagnoses, although more common during primary HIV-1 infection, had low sensitivity and high specificity. Efforts to expand access to laboratory assays for the diagnosis of primary HIV-1 infection among infants of HIV-1-infected women should be emphasized.

Intrapartum antibiotic exposure and early neonatal, morbidity, and mortality in Africa

BACKGROUND

Infants born to women who receive intrapartum antibiotics may have higher rates of infectious morbidity and mortality than unexposed infants.

OBJECTIVE

Our goal was to determine the association of maternal intrapartum antibiotics and early neonatal morbidity and mortality.

METHODS

We performed secondary analysis of data from a multisite randomized, placebo-controlled clinical trial of antibiotics to prevent chorioamnionitis-associated mother-to-child transmission of HIV-1 and preterm birth in sub-Saharan Africa. Early neonatal morbidity and mortality were analyzed. In an intention-to-treat (ITT) analysis, infants born to women randomly assigned to antibiotics or placebo were compared. In addition, non-ITT analysis was performed because some women received nonstudy antibiotics for various clinical indications.

RESULTS

Overall, 2659 pregnant women were randomly assigned. Of these, 2466 HIV-1-infected and HIV-1-uninfected women delivered 2413 live born and 84 stillborn infants. In the ITT analysis, there were no significant associations between exposure to antibiotics and early neonatal outcomes. Non-ITT analyses showed more illness at birth (11.2% vs 8.6%, P = .03) and more admissions to the special care infant unit (12.6% vs 9.8%, P = .04) among infants exposed to maternal intrapartum antibiotics than among unexposed infants. Additional analyses revealed greater early neonatal morbidity and mortality among infants of mothers who received nonstudy antibiotics than of mothers who received study antibiotics.

CONCLUSIONS

There is no association between intrapartum exposure to antibiotics and early neonatal morbidity or mortality. The associations observed in non-ITT analyses are most likely the result of women with peripartum illnesses being more likely to receive nonstudy antibiotics.

Genital tract infections among HIV-infected pregnant women in Malawi, Tanzania and Zambia

SUMMARY

The aim of this study was to compare the prevalence and factors associated with genital tract infections among HIV-infected pregnant women from African sites. Participants were recruited from Blantyre and Lilongwe, Malawi; Dar es Salaam, Tanzania; and Lusaka, Zambia. Genital tract infections were assessed at baseline. Of 2627 eligible women enrolled, 2292 were HIV-infected. Of these, 47.8% had bacterial vaginosis (BV), 22.4% had vaginal candidiasis, 18.8% had trichomoniasis, 8.5% had genital warts, 2.6% had chlamydia infection, 2.2% had genital ulcers and 1.7% had gonorrhoea. The main factors associated with genital tract infections included genital warts (adjusted odds ratio [AOR] 1.8, 95% CI 1.2-2.7), genital ulcers (AOR 2.4, 95% CI 1.2-5.1) and abnormal vaginal discharge (AOR 2.5, 95% CI 1.9-3.3) for trichomoniasis. BV was the most common genital tract infection followed by candidiasis and trichomoniasis. Differences in burdens and risk factors call for enhanced interventions for identification of genital tract infections among HIV-infected women.

Determining an optimal testing strategy for infants at risk for mother-to-child transmission of HIV-1 during the late postnatal period

OBJECTIVES

To determine the optimal time for a second HIV-1 nucleic acid amplification assay to detect late postnatal transmission of HIV-1 (first negative test at 4-8 weeks of age) in resource-limited settings.

DESIGN

A longitudinal analysis of data from HIV Prevention Trial Network trial 024.

METHODS

Children born to HIV-1-infected mothers enrolled in the HIV Prevention Trial Network trial 024 were tested for HIV-1 infection at six intervals within the first year of life. Mothers and infants received nevirapine prophylaxis. We estimated the probability of being alive and having a positive test in each interval after 4-8 weeks and at 30 days after weaning, conditional on having acquired HIV during the late postnatal period. The interval with the highest probability was taken to be the optimal visit interval.

RESULTS

A total of 1609 infants from HIV Prevention Trial Network trial 024 had at least one HIV-1 diagnostic test and were included in the analysis. We found that testing at 1 month after weaning or 12 months of age (whichever comes first) identified 81% of those infected during the late postnatal period (after 4-8 weeks) through breastfeeding. In total, 93% (95% confidence interval 89, 98) of all infected infants would be detected if tests were performed at these two time points.

CONCLUSION

In resource-limited settings, HIV-1 PCR testing at 4-8 weeks followed by a second test at 1 month after weaning or at 1 year of age (whichever comes first), led to the identification of the vast majority of HIV-1-infected infants.

Morbidity and mortality among a cohort of human immunodeficiency virus type 1-infected and uninfected pregnant women and their infants from Malawi, Zambia, and Tanzania

BACKGROUND

Morbidity and mortality patterns among pregnant women and their infants (before antiretroviral therapy was widely available) determines HIV-1 diagnostic, monitoring, and care interventions.

METHODS

Data from mothers and their infants enrolled in a trial of antibiotics to reduce mother-to-child-transmission of HIV-1 at 4 sub-Saharan African sites were analyzed. Women were enrolled during pregnancy and follow-up continued until the infants reached 12 months of age. We describe maternal and infant morbidity and mortality in a cohort of HIV-1-infected and HIV-1-uninfected mothers. Maternal and infant factors associated with mortality risk in the infants were assessed using Cox proportional hazard modeling.

RESULTS

Among 2292 HIV-1-infected mothers, 166 (7.2%) had a serious adverse event (SAE) and 42 (1.8%) died, whereas no deaths occurred among the 331 HIV-1 uninfected mothers. Four hundred twenty-four (17.8%) of 2383 infants had an SAE and 349 (16.4%) died before the end of follow-up. Infants with early HIV-1 infection (birth to 4-6 weeks) had the highest mortality. Among infants born to HIV-1-infected women, maternal morbidity and mortality (P = 0.0001), baseline CD4 count (P = 0.0002), and baseline plasma HIV-1 RNA concentration (P < 0.0001) were significant predictors of infant mortality in multivariate analyses.

CONCLUSIONS

The high mortality among infants with early HIV-1 infection supports access to HIV-1 diagnostics and appropriate early treatment for all infants of HIV-1-infected mothers. The significant association between stage of maternal HIV-1 infection and infant mortality supports routine CD4 counts at the time of prenatal HIV-1 testing.

A coarsened multinomial regression model for perinatal mother to child transmission of HIV

Background

In trials designed to estimate rates of perinatal mother to child transmission of HIV, HIV assays are scheduled at multiple points in time. Still, infection status for some infants at some time points may be unknown, particularly when interim analyses are conducted.

Methods

Logistic regression models are commonly used to estimate covariate-adjusted transmission rates, but their methods for handling missing data may be inadequate. Here we propose using coarsened multinomial regression models to estimate cumulative and conditional rates of HIV transmission. Through simulation, we compare the proposed models to standard logistic models in terms of bias, mean squared error, coverage probability, and power. We consider a range of treatment effect and visit process scenarios, while including imperfect sensitivity of the assay and contamination of the endpoint due to early breastfeeding transmission. We illustrate the approach through analysis of data from a clinical trial designed to prevent perinatal transmission.

Results

The proposed cumulative and conditional models performed well when compared to their logistic counterparts. Performance of the proposed cumulative model was particularly strong under scenarios where treatment was assumed to increase the risk of in utero transmission but decrease the risk of intrapartum and overall perinatal transmission and under scenarios designed to represent interim analyses. Power to estimate intrapartum and perinatal transmission was consistently higher for the proposed models.

Conclusion

Coarsened multinomial regression models are preferred to standard logistic models for estimation of perinatal mother to child transmission of HIV, particularly when assays are missing or occur off-schedule for some infants.

Nutritional indicators of adverse pregnancy outcomes and mother-to-child transmission of HIV among HIV-infected women

BACKGROUND

Poor nutrition may be associated with mother-to-child transmission (MTCT) of HIV and other adverse pregnancy outcomes.

OBJECTIVE

The objective was to examine the relation of nutritional indicators with adverse pregnancy outcomes among HIV-infected women in Tanzania, Zambia, and Malawi.

DESIGN

Body mass index (BMI; in kg/m(2)) and hemoglobin concentrations at enrollment and weight change during pregnancy were prospectively related to fetal loss, neonatal death, low birth weight, preterm birth, and MTCT of HIV.

RESULTS

In a multivariate analysis, having a BMI < 21.8 was significantly associated with preterm birth [odds ratio (OR): 1.82; 95% CI: 1.34, 2.46] and low birth weight (OR: 2.09; 95% CI: 1.41, 3.08). A U-shaped relation between weight change during pregnancy and preterm birth was observed. Severe anemia was significantly associated with fetal loss or stillbirth (OR: 3.67; 95% CI: 1.16, 11.66), preterm birth (OR: 2.08; 95% CI: 1.39, 3.10), low birth weight (OR: 1.76; 95% CI: 1.07, 2.90), and MTCT of HIV by the time of birth (OR: 2.26; 95% CI: 1.18, 4.34) and by 4-6 wk among those negative at birth (OR: 2.33; 95% CI: 1.15, 4.73).

CONCLUSIONS

Anemia, poor weight gain during pregnancy, and low BMI in HIV-infected pregnant women are associated with increased risks of adverse infant outcomes and MTCT of HIV. Interventions that reduce the risk of wasting or anemia during pregnancy should be evaluated to determine their possible effect on the incidence of adverse pregnancy outcomes and MTCT of HIV.

Risk factors for late postnatal transmission of human immunodeficiency virus type 1 in sub-Saharan Africa

BACKGROUND

We conducted secondary data analyses of a clinical trial (HIVNET 024) to assess risk factors for late postnatal transmission (LPT) of human immunodeficiency virus type 1 (HIV-1) through breast-feeding.

METHODS

Data regarding live born, singleton infants of HIV-1-infected mothers were analyzed. The timing of HIV-1 transmission through 12 months after birth was defined as: in utero (positive HIV-1 RNA results at birth), perinatal/early postnatal (negative results at birth, positive at 4-6 week visit), or LPT (negative results through the 4-6 week visit, but positive assays thereafter through the 12-month visit). HIV-1-uninfected infants were those with negative HIV-1 enzyme immunoassay results at 12 months of age, or infants with negative HIV-1 RNA results throughout follow-up.

RESULTS

Of 2292 HIV-1-infected enrolled women, 2052 mother/infant pairs met inclusion criteria. Of 1979 infants with HIV-1 tests, 404 were HIV-1-infected, and 382 had known timing of infection (LPT represented 22% of transmissions). Further analyses of LPT included infants who were breast-feeding at the 4-6 week visit (with negative HIV-1 results at that visit) revealed 6.9% of 1317 infants acquired HIV-1 infection through LPT by 12 months of age. More advanced maternal HIV-1 disease at enrollment (lower CD4 counts, higher plasma viral loads) were the factors associated with LPT in adjusted analyses.

CONCLUSIONS

In this breast-feeding population, 6.9% of infants uninfected at 6 weeks of age acquired HIV-1 infection by 12 months. Making interventions to decrease the risk of LPT of HIV-1 available and continuing research regarding the mechanisms of LPT (so as to develop improved interventions to reduce such transmission) remain essential.

Prevention of mother-to-child transmission: program changes and the effect on uptake of the HIVNET 012 regimen in Malawi

OBJECTIVE(S)

To evaluate uptake of HIV testing in a prevention of mother-to-child transmission program (PMTCT) in Lilongwe, Malawi from April 2002 until December 2006.

DESIGN

Retrospective analysis of monthly reports from the beginning of the program.

SETTING

Four antenatal clinics in Lilongwe, Malawi.

METHODS

Pregnant women attending urban antenatal clinics in Lilongwe were invited to participate in a PMTCT program. Women were given information and education on antenatal care and PMTCT in groups of 8 to 12. Written informed consent for HIV testing was obtained privately. Women returned for the test result 1-2 weeks later. Mothers and infants were given the HIVNET 012 regimen. Rapid HIV testing and 'opt-out' testing were instituted in July 2003 and April 2005, respectively. Infants were tested using HIV DNA PCR and, if HIV positive, a CD4 cell percentage was obtained and the infants were referred for further medical evaluation and treatment.

RESULTS

The program reached 20 000 pregnant women in the first 12 months. Acceptance of HIV testing increased from 45% to 73% (P < 0.001) when rapid, same day testing was instituted. When opt-out testing was instituted, 99% of the mothers agreed to testing. Of the infants tested, 15.5% were HIV positive.

CONCLUSION

Rapid HIV testing using the opt-out method increased acceptance of HIV testing in the PMTCT program to 99% in urban Lilongwe, Malawi.

Predictors of stillbirth in sub-saharan Africa

OBJECTIVE

To describe the incidence and predictors of stillbirth in a predominantly human immunodeficiency virus (HIV)-infected African cohort.

METHODS

Human Immunodeficiency Virus (HIV) Prevention Trials Network (HPTN) 024 was a randomized controlled trial of empiric antibiotics to reduce chorioamnionitis-related perinatal HIV transmission. A proportion of HIV-uninfected individuals were enrolled to reduce community-based stigma surrounding the trial. For this analysis, only women who gave birth to singleton infants were included.

RESULTS

Of 2,659 women enrolled, 2,434 (92%) mother- child pairs met inclusion criteria. Of these, 2,099 (86%) infants were born to HIV-infected women, and 335 (14%) were born to HIV-uninfected women. The overall stillbirth rate was 32.9 per 1,000 deliveries (95% confidence interval [CI] 26.1-40.7). In univariable analyses, predictors for stillbirth included previous stillbirth (odds ratio [OR] 2.3, 95% CI 1.2-4.3), antenatal hemorrhage (OR 14.4, 95% CI 4.3-47.9), clinical chorioamnionitis (OR 20.9, 95% CI 5.1-86.2), and marked polymorphonuclear infiltration on placental histology (OR 2.9, 95% CI 1.7-5.2). When compared with pregnancies longer than 37 weeks, those at 34-37 weeks (OR 1.7, 95% CI 0.8-3.4) and those at less than 34 weeks (OR 22.8, 95% CI 13.6-38.2) appeared more likely to result in stillborn delivery. Human immunodeficiency virus infection was not associated with a greater risk for stillbirth in either univariable (OR 1.5, 95% CI 0.7-3.0) or multivariable (adjusted OR 1.11, 95% CI 0.38-3.26) analysis. Among HIV-infected women, however, decreasing CD4 cell count was inversely related to stillbirth risk (P=.009).

CONCLUSION

In this large cohort, HIV infection was not associated with increased stillbirth risk. Further work is needed to elucidate the relationship between chorioamnionitis and stillbirth in African populations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00021671

LEVEL OF EVIDENCE

II.

Time to undetectable viral load after highly active antiretroviral therapy initiation among HIV-infected pregnant women

BACKGROUND

There have been no clinical trials in resource-rich regions that have addressed the question of which highly active antiretroviral therapy (HAART) regimens are more effective for optimal viral response in antiretroviral-naive, human immunodeficiency virus (HIV)-infected pregnant women.

METHODS

Data on 240 HIV-1-infected women starting HAART during pregnancy who were enrolled in the prospective European Collaborative Study from 1997 through 2004 were analyzed. An interval-censored survival model was used to assess whether factors, including type of HAART regimen, race, region of birth, and baseline immunological and virological status, were associated with the duration of time necessary to suppress viral load below undetectable levels before delivery of a newborn.

RESULTS

Protease inhibitor-based HAART was initiated in 156 women (65%), 125 (80%) of whom received nelfinavir, and a nevirapine-based regimen was initiated in the remaining 84 women (35%). Undetectable viral loads were achieved by 73% of the women by the time of delivery. Relative hazards of time to achieving viral suppression were 1.54 (95% confidence interval, 1.05-2.26) for nevirapine-based HAART versus PI-based regimens and 1.90 (95% confidence interval, 1.16-3.12) for western African versus non-African women. The median duration of time from HAART initiation to achievement of an undetectable viral load was estimated to be 1.4 times greater in women receiving PI-based HAART, compared with women receiving nevirapine-based HAART. Baseline HIV RNA load was also a significant predictor of the rapidity of achieving viral suppression by delivery, but baseline immune status was not.

CONCLUSIONS

In this study, nevirapine-based HAART (compared with PI [mainly nelfinavir]-based HAART), western African origin, and lower baseline viral load were associated with shorter time to achieving viral suppression.