Caroline C. King

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

BACKGROUND In resource-limited settings where no safe alternative to breastfeeding exists, WHO recommends that antiretroviral prophylaxis be given to either HIV-infected mothers or infants throughout breastfeeding. We assessed the effect of 28 weeks of maternal or infant antiretroviral prophylaxis on postnatal HIV infection at 48 weeks. METHODS The Breastfeeding, Antiretrovirals, and Nutrition (BAN) Study was undertaken in Lilongwe, Malawi, between April 21, 2004, and Jan 28, 2010. 2369 HIV-infected breastfeeding mothers with a CD4 count of 250 cells per μL or more and their newborn babies were randomly assigned with a variable-block design to one of three, 28-week regimens: maternal triple antiretroviral (n=849); daily infant nevirapine (n=852); or control (n=668). Patients and local clinical staff were not masked to treatment allocation, but other study investigators were. All mothers and infants received one dose of nevirapine (mother 200 mg; infant 2 mg/kg) and 7 days of zidovudine (mother 300 mg; infants 2 mg/kg) and lamivudine (mothers 150 mg; infants 4 mg/kg) twice a day. Mothers were advised to wean between 24 weeks and 28 weeks after birth. The primary endpoint was HIV infection by 48 weeks in infants who were not infected at 2 weeks and in all infants randomly assigned with censoring at loss to follow-up. This trial is registered with ClinicalTrials.gov, number NCT00164736. FINDINGS 676 mother-infant pairs completed follow-up to 48 weeks or reached an endpoint in the maternal-antiretroviral group, 680 in the infant-nevirapine group, and 542 in the control group. By 32 weeks post partum, 96% of women in the intervention groups and 88% of those in the control group reported no breastfeeding since their 28-week visit. 30 infants in the maternal-antiretroviral group, 25 in the infant-nevirapine group, and 38 in the control group became HIV infected between 2 weeks and 48 weeks of life; 28 (30%) infections occurred after 28 weeks (nine in maternal-antiretroviral, 13 in infant-nevirapine, and six in control groups). The cumulative risk of HIV-1 transmission by 48 weeks was significantly higher in the control group (7%, 95% CI 5-9) than in the maternal-antiretroviral (4%, 3-6; p=0·0273) or the infant-nevirapine (4%, 2-5; p=0·0027) groups. The rate of serious adverse events in infants was significantly higher during 29-48 weeks than during the intervention phase (1·1 [95% CI 1·0-1·2] vs 0·7 [0·7-0·8] per 100 person-weeks; p<0·0001), with increased risk of diarrhoea, malaria, growth faltering, tuberculosis, and death. Nine women died between 2 weeks and 48 weeks post partum (one in maternal-antiretroviral group, two in infant-nevirapine group, six in control group). INTERPRETATION In resource-limited settings where no suitable alternative to breastfeeding is available, antiretroviral prophylaxis given to mothers or infants might decrease HIV transmission. Weaning at 6 months might increase infant morbidity. FUNDING US Centers for Disease Control and Prevention.

Bacterial Vaginosis and the Natural History of Human Papillomavirus

Objective. To evaluate associations between common vaginal infections and human papillomavirus (HPV). Study Design. Data from up to 15 visits on 756 HIV-infected women and 380 high-risk HIV-uninfected women enrolled in the HIV Epidemiology Research Study (HERS) were evaluated for associations of bacterial vaginosis, trichomoniasis, and vaginal Candida colonization with prevalent HPV, incident HPV, and clearance of HPV in multivariate analysis. Results. Bacterial vaginosis (BV) was associated with increased odds for prevalent (aOR = 1.14, 95% CI: 1.04, 1.26) and incident (aOR = 1.24, 95% CI: 1.04, 1.47) HPV and with delayed clearance of infection (aHR = 0.84, 95% CI: 0.72, 0.97). Whereas BV at the preceding or current visit was associated with incident HPV, in an alternate model for the outcome of incident BV, HPV at the current, but not preceding, visit was associated with incident BV. Conclusion. These findings underscore the importance of prevention and successful treatment of bacterial vaginosis.

A lipid-based nutrient supplement mitigates weight loss among HIV-infected women in a factorial randomized trial to prevent mother-to-child transmission during exclusive breastfeeding

BACKGROUND Breastfeeding increases metabolic demands on the mother, and excessive postnatal weight loss increases maternal mortality. OBJECTIVE We evaluated the efficacy of a lipid-based nutrient supplement (LNS) for prevention of excess weight loss in breastfeeding, HIV-infected women. DESIGN The BAN (Breastfeeding, Antiretrovirals, and Nutrition) Study was a randomized controlled trial in Lilongwe, Malawi. At delivery, HIV-infected mothers and their infants were randomly assigned according to a 2-arm (with and without LNS) by 3-arm (maternal triple-antiretroviral prophylaxis, infant-nevirapine prophylaxis, or neither) factorial design. The 28-wk LNS intervention provided daily energy (700 kcal), protein (20 g), and micronutrients (except for vitamin A) to meet lactation needs. Women were counseled to breastfeed exclusively for 24 wk and to wean by 28 wk. Weight change (0-28 wk) was tested in an intent-to-treat analysis by using 2-factor ANOVA and with longitudinal mixed-effects models. RESULTS At delivery, the LNS (n = 1184) and control (n = 1185) groups had similar mean weights and BMIs. Women receiving the LNS had less 0-28-wk weight loss (-1.97 compared with -2.56 kg, P = 0.003). This difference remained significant after adjustment for maternal antiretroviral drug therapy and baseline BMI. Women receiving antiretroviral drugs had more weight loss than did those not receiving antiretroviral drugs (-2.93 compared with -1.90 kg, P < 0.001). The benefit of the LNS for reducing weight loss was observed both in those receiving antiretroviral drugs (-2.56 compared with -3.32 kg, P = 0.019) and in those not receiving antiretroviral drugs (-1.63 compared with -2.16 kg, P = 0.034). CONCLUSIONS The LNS reduced weight loss among HIV-infected, breastfeeding women, both in those taking maternal antiretroviral prophylaxis to prevent postnatal HIV transmission and in those not receiving antiretroviral prophylaxis. Provision of an LNS may benefit HIV-infected, breastfeeding women in resource-limited settings. This trial was registered at clinicaltrials.gov as NCT00164762.

Validation Data-Based Adjustments for Outcome Misclassification in Logistic Regression:An Illustration

Misclassification of binary outcome variables is a known source of potentially serious bias when estimating adjusted odds ratios. Although researchers have described frequentist and Bayesian methods for dealing with the problem, these methods have seldom fully bridged the gap between statistical research and epidemiologic practice. In particular, there have been few real-world applications of readily grasped and computationally accessible methods that make direct use of internal validation data to adjust for differential outcome misclassification in logistic regression. In this paper, we illustrate likelihood-based methods for this purpose that can be implemented using standard statistical software. Using main study and internal validation data from the HIV Epidemiology Research Study, we demonstrate how misclassification rates can depend on the values of subject-specific covariates, and we illustrate the importance of accounting for this dependence. Simulation studies confirm the effectiveness of the maximum likelihood approach. We emphasize clear exposition of the likelihood function itself, to permit the reader to easily assimilate appended computer code that facilitates sensitivity analyses as well as the efficient handling of main/external and main/internal validation-study data. These methods are readily applicable under random cross-sectional sampling, and we discuss the extent to which the main/internal analysis remains appropriate under outcome-dependent (case-control) sampling.

Role of Intestinal Mucosal Integrity in HIV Transmission to Infants Through Breast-feeding: The BAN Study

BACKGROUND Increased intestinal permeability may be one of the mechanisms of transmission of human immunodeficiency virus (HIV) to infants through breast-feeding. Intestinal permeability correlates with microbial translocation, which can be measured through quantification of bacterial lipopolysaccharide (LPS). METHODS We evaluated levels of plasma LPS (by the Limulus amebocyte lysate assay) and immune activation markers in serial specimens from infants exposed to but uninfected with HIV and infants infected with HIV from the Breastfeeding, Antiretrovirals, and Nutrition (BAN) study. RESULTS Plasma LPS levels increased after infants in the BAN study were weaned from the breast, at 24 weeks of age. Cotrimoxazole prophylaxis was associated with higher plasma LPS levels (P = .004). Infants with HIV infection had higher LPS levels, compared with uninfected infants (P = .004). Higher preinfection plasma LPS levels were a significant predictor of infant HIV infection through breast-feeding (hazard ratio = 1.60 for every unit increase in plasma LPS level; P = .01) and of lower infant length-for-age z scores (P = .02). CONCLUSIONS These findings suggest that disruption in intestinal integrity is a mechanism of HIV transmission to infants through breast-feeding. Weaning from breast milk and use of antibiotic prophylaxis was associated with increased levels of microbial translocation, which could facilitate HIV entry through the intestine. Complementary approaches to enhance intestinal mucosal integrity in the infant may further reduce breast-feeding transmission of HIV.

Hepatitis B virus infection among HIV-infected pregnant women in Malawi and transmission to infants

BACKGROUND & AIMS The extent of HBV infection to infants of HBV/HIV-coinfected pregnant women in sub-Saharan Africa is unknown. The aim of this study was to assess prevalence of HBV infection among antiretroviral-naïve, HIV-infected pregnant women in Malawi and examine HBV transmission to their infants. METHODS Plasma from 2048 HIV-infected, Malawian women and their infants were tested for markers of HBV infection. Study participants were provided standard-of-care health services, which included administration of pentavalent vaccine to infants at 6, 10, and 14 weeks of age. RESULTS One-hundred and three women (5%) were HBsAg-positive; 70 of these HBsAg-positive women were also HBV-DNA-positive. Sixteen women (0.8%) were HBV-DNA-positive but HBsAg-negative. Five of 51 infants (9.8%) born to HBsAg-positive and/or HBV-DNA-positive women were HBV-DNA-positive by 48 weeks of age.HBV DNA concentrations of two infants of mothers who received extended lamivudine-containing anti-HIV prophylaxis were <4 log10 IU/ml compared to ⩾ 8 log10 IU/ml in three infants of mothers who did not. CONCLUSIONS HBV DNA was detected in nearly 10% of infants born to HBV/HIV-coinfected women. Antenatal testing for HIV and HBV, if instituted, can facilitate implementation of prophylactic measures against infant infection by both viruses.

Association of HIV-1 Envelope-Specific Breast Milk IgA Responses with Reduced Risk of Postnatal Mother-to-Child Transmission of HIV-1

ABSTRACT Infants born to HIV-1-infected mothers in resource-limited areas where replacement feeding is unsafe and impractical are repeatedly exposed to HIV-1 throughout breastfeeding. Despite this, the majority of infants do not contract HIV-1 postnatally, even in the absence of maternal antiretroviral therapy. This suggests that immune factors in breast milk of HIV-1-infected mothers help to limit vertical transmission. We compared the HIV-1 envelope-specific breast milk and plasma antibody responses of clade C HIV-1-infected postnatally transmitting and nontransmitting mothers in the control arm of the Malawi-based Breastfeeding Antiretrovirals and Nutrition Study using multivariable logistic regression modeling. We found no association between milk or plasma neutralization activity, antibody-dependent cell-mediated cytotoxicity, or HIV-1 envelope-specific IgG responses and postnatal transmission risk. While the envelope-specific breast milk and plasma IgA responses also did not reach significance in predicting postnatal transmission risk in the primary model after correction for multiple comparisons, subsequent exploratory analysis using two distinct assay methodologies demonstrated that the magnitudes of breast milk total and secretory IgA responses against a consensus HIV-1 envelope gp140 (B.con env03) were associated with reduced postnatal transmission risk. These results suggest a protective role for mucosal HIV-1 envelope-specific IgA responses in the context of postnatal virus transmission. This finding supports further investigations into the mechanisms by which mucosal IgA reduces risk of HIV-1 transmission via breast milk and into immune interventions aimed at enhancing this response. IMPORTANCE Infants born to HIV-1-infected mothers are repeatedly exposed to the virus in breast milk. Remarkably, the transmission rate is low, suggesting that immune factors in the breast milk of HIV-1-infected mothers help to limit transmission. We compared the antibody responses in plasma and breast milk of HIV-1-transmitting and -nontransmitting mothers to identify responses that correlated with reduced risk of postnatal HIV-1 transmission. We found that neither plasma nor breast milk IgG antibody responses were associated with risk of HIV-1 transmission. In contrast, the magnitudes of the breast milk IgA and secretory IgA responses against HIV-1 envelope proteins were associated with reduced risk of postnatal HIV-1 transmission. The results of this study support further investigations of the mechanisms by which mucosal IgA may reduce the risk of HIV-1 transmission via breastfeeding and the development of strategies to enhance milk envelope-specific IgA responses to reduce mother-to-child HIV transmission and promote an HIV-free generation.

Contraceptive Methods and Risk of HIV Acquisition or Female-to-Male Transmission

Effective family planning with modern contraception is an important intervention to prevent unintended pregnancies which also provides personal, familial, and societal benefits. Contraception is also the most cost-effective strategy to reduce the burden of mother-to-child HIV transmission for women living with HIV who wish to prevent pregnancy. There are concerns, however, that certain contraceptive methods, in particular the injectable contraceptive depot medroxyprogesterone acetate (DMPA), may increase a woman’s risk of acquiring HIV or transmitting it to uninfected males. These concerns, if confirmed, could potentially have large public health implications. This paper briefly reviews the literature on use of contraception among women living with HIV or at high risk of HIV infection. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommendations place no restrictions on the use of hormonal contraceptive methods by women with or at high risk of HIV infection, although a clarification recommends that, given uncertainty in the current literature, women at high risk of HIV who choose progestogen-only injectable contraceptives should be informed that it may or may not increase their risk of HIV acquisition and should also be informed about and have access to HIV preventive measures, including male or female condoms.

Effects of cotrimoxazole prophylactic treatment on adverse health outcomes among HIV-exposed, uninfected infants.

Background: The World Health Organization guidelines recommend cotrimoxazole prophylactic treatment (CPT) for all HIV-exposed infants from age 6 weeks to the cessation of breastfeeding and the exclusion of HIV infection. There are limited data on the effects of CPT among this population of infants. We examined the effects of CPT on adverse health outcomes among HIV-exposed infants during the first 36 weeks of life using data from the Breastfeeding, Antiretrovirals and Nutrition study, a large clinical trial of antiretroviral drugs given to the mother or infant for the prevention of HIV transmission during breastfeeding. Methods: For the analysis, we assigned a status of CPT-exposed to infants who were participating in the study after the CPT program started. We estimated unadjusted and adjusted hazard ratios for the effect of CPT status on time to incident malaria, severe illness or death, anemia, and weight-for-age Z score < −2.0. Participation in the study was limited to focus exclusively on HIV-exposed, uninfected infants. Results: The hazard ratio for the effect of CPT on incident malaria was 0.35 (95% confidence interval: 0.21, 0.57) during the first 10 weeks of CPT exposure and 0.93 (95% confidence interval: 0.67, 1.29) for the remaining 20 weeks. CPT was not associated with the other outcomes examined. Conclusions: CPT offered temporary protection against malaria among HIV-exposed, uninfected infants. However, CPT offered no protection against anemia, low weight for age or the collapsed outcome of severe illness or death.

Prevalence of hepatitis C virus infection among human immunodeficiency virus-1-infected pregnant women in Malawi: The BAN study

BACKGROUND In Sub-Saharan Africa, prevalence estimates of hepatitis C virus (HCV) vary widely. OBJECTIVES To assess the prevalence of HCV infection among HIV-infected, pregnant women screened for a large clinical trial in Lilongwe, Malawi. STUDY DESIGN Plasma from 2041 HIV-infected, pregnant women was screened for anti-HCV IgG using a chemiluminiscent immunometric assay (CIA). Specimens with a signal-cut-off ratio≥1.00 were considered reactive and those with S/Co ratio<1.00 non-reactive. All CIA-reactive specimens were tested by a recombinant immunoblot assay (RIBA) for anti-HCV and by PCR for HCV RNA. RESULTS Of 2041 specimens, 110 (5.3%, 95% CI: 4.5-6.5%) were CIA reactive. Of the 109 CIA reactive specimens available for RIBA testing, 2 (1.8%) were positive, 28 (25.7%) were indeterminate, and 79 (72.5%) were negative. All CIA-reactive specimens were HCV RNA negative (n=110). The estimated HCV prevalence based on the screening assay alone was 5.3%; based on supplemental RIBA testing, the status of HCV infection remained indeterminate in 1.4% (28/2040, 95% CI: 0.1-2.0) and the prevalence of confirmed HCV infections was 0.1% (2/2040, 95% CI: 0-0.4%). CONCLUSIONS HCV seroprevalence among HIV-infected, pregnant women in Malawi confirmed by supplemental RIBA HCV 3.0 is low (0.1%); CIA showed a high false-reactivity rate in this population.