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Author(s): Osorio, Luiz Eduardo; Boechat, Maria Ines; Mirochnick, Mark; Kumwenda, Newton; Kreitchmann, Regis; Emel, Lynda; Pinto, Jorge; Joao, Esau; Santos, Breno; Swenson, Molly; George, Kathleen; Sato, Paul; Mofenson, Lynne; Nielsen-Saines, Karin; HIV Prevention Trials Network (HPTN) 057 Protocol Team | Abstract: BackgroundTenofovir disoproxil fumarate (TDF) use during pregnancy has been increasing, and studies linking bone toxicity with exposure to TDF have raised concern for its use in infants.MethodsHand/wrist and spine radiographs were obtained at 3 days and 12 weeks of age in infants born to HIV-infected pregnant women enrolled in the HIV Prevention Trials Network 057 pharmacokinetic study of TDF conducted in Malawi and Brazil assigned to 3 TDF dosing cohorts. In cohort 1, mothers received 600 mg of TDF during labor. In cohort 2, infants received 4 mg/kg dose on days 0, 3 and 5. In cohort 3, a 900 mg maternal dose was given during labor, followed by a 6 mg/kg infant dose on days 0, 3 and 5 of life.ResultsAcross all 3 cohorts, 89 infants had radiographs performed at either time point, and 85 had radiographs performed at both time points. Metaphyseal lucency was present in 1 case in Brazil and 2 in Malawi. Fifteen percent of infants from Brazil and 9% of infants from Malawi presented bone age discrepancies. No other abnormalities were identified in Brazil, whereas in Malawi, there were 7 more cases of wrist osteopenia, 2 of spine osteopenia and 3 other abnormalities.ConclusionBone abnormalities were not uncommon in the overall cohort of HIV-exposed infants. Because of very limited study drug exposure at the time of birth, it is unlikely that TDF was associated with these findings. Untreated maternal HIV disease and/or maternal nutritional status could potentially be related to fetal bone development. This association should be explored in future cohort studies.

This study examined HIV superinfection in HIV-infected women postpartum, and its association with mother-to-child transmission (MTCT).Plasma samples were obtained from HIV-infected women who transmitted HIV to their infants after 6 weeks of age (transmitters, n = 91) and HIV-infected women who did not transmit HIV to their infants (nontransmitters, n = 91). These women were originally enrolled in a randomized trial for prevention of MTCT of HIV in Malawi (Post-Exposure Prophylaxis of Infants trial in Malawi).Two HIV genomic regions (p24 and gp41) were analyzed by next-generation sequencing for HIV superinfection. HIV superinfection was established if the follow-up sample contained a new, phylogenetically distinct viral population. HIV superinfection and transmission risk were examined by multiple logistic regression, adjusted for Post-Exposure Prophylaxis of Infants study arm, baseline viral load, baseline CD4 cell count, time to resumption of sex, and breastfeeding duration.Transmitters had lower baseline CD4 cell counts (P = 0.001) and higher viral loads (P 0.0001) compared with nontransmitters. There were five cases of superinfection among transmitters (rate of superinfection = 4.7/100 person-years) compared with five cases among the nontransmitters (rate of superinfection = 4.4/100 person-years; P = 0.78). HIV superinfection was not associated with increased risk of postnatal MTCT of HIV after controlling for maternal age, baseline viral load, and CD4 cell count (adjusted odds ratio = 2.32, P = 0.30). Longer breastfeeding duration was independently associated with a lower risk of HIV superinfection after controlling for study arm and baseline viral load (P = 0.05).There was a significant level of HIV superinfection in women postpartum, but this was not associated with an increased risk of MTCT via breastfeeding.

Analysis of blood samples collected over 20 years suggests substantial underestimation of this virus in this country., Data on prevalence of hepatitis E virus (HEV) in Malawi is limited. We tested blood samples from HIV-uninfected and -infected populations of women and men enrolled in research studies in Malawi during 1989–2008 to determine the seroprevalence of HEV, hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV). Samples were tested for IgG against HEV, total antibodies against HAV and HCV, and presence of HBV surface antigens. Of 800 samples tested, 16.5% were positive for HEV IgG, 99.6% were positive for HAV antibodies, 7.5% were positive for HBV surface antigen, and 7.1% were positive for HCV antibodies. No clear trends over time were observed in the seroprevalence of HEV, and HIV status was not associated with hepatitis seroprevalence. These preliminary data suggest that the seroprevalence of HEV is high in Malawi; the clinical effects may be unrecognized or routinely misclassified.

Higher HIV diversity has been associated with virologic outcomes in children on antiretroviral treatment (ART). We examined the association of HIV diversity with virologic outcomes in adults from the HPTN 052 trial who initiated ART at CD4 cell counts of 350-550 cells/mm3. A high resolution melting (HRM) assay was used to analyze baseline (pre-treatment) HIV diversity in six regions in the HIV genome (two in gag, one in pol, and three in env) from 95 participants who failed ART. We analyzed the association of HIV diversity in each genomic region with baseline (pre-treatment) factors and three clinical outcomes: time to virologic suppression after ART initiation, time to ART failure, and emergence of HIV drug resistance at ART failure. After correcting for multiple comparisons, we did not find any association of baseline HIV diversity with demographic, laboratory, or clinical characteristics. For the 18 analyses performed for clinical outcomes evaluated, there was only one significant association: higher baseline HIV diversity in one of the three HIV env regions was associated with longer time to ART failure (p = 0.008). The HRM diversity assay may be useful in future studies exploring the relationship between HIV diversity and clinical outcomes in individuals with HIV infection.

Objectives Highly active antiretroviral therapy (HAART) provision to eligible HIV-infected pregnant and post-partum women is critical for optimizing maternal health. We assessed the impact of maternal HAART on HIV-free survival of breastfed infants in Malawi. Methods The post-exposure prophylaxis of infants-Malawi trial (2004–2009) enrolled mothers/infants during labor or immediately post-partum to evaluate 14-week extended infant antiretroviral prophylaxis for preventing HIV transmission through breastfeeding. Mothers meeting national HAART guidelines were referred for therapy. Child HIV-free survival—survival without HIV infection—was compared by maternal HAART status. Results Overall, 3022 mother-infant pairs contributed 4214 infant/person-years (PY) at-risk for HIV infection or death, with 532 events (incidence 12.6/100 PY, 95 % confidence interval [CI] 11.6–13.7). During follow-up, 349 mothers were HAART initiated; 581 remained HAART naive with CD4 cell counts

Background. Combination antiretroviral therapy (cART) reduces genital tract human immunodeficiency virus type 1 (HIV-1) load and reduces the risk of sexual transmission, but little is known about the efficacy of cART for decreasing genital tract viral load (GTVL) and differences in sex or HIV-1 subtype. Methods. HIV-1 RNA from blood plasma, seminal plasma, or cervical wicks was quantified at baseline and at weeks 48 and 96 after entry in a randomized clinical trial of 3 cART regimens. Results. One hundred fifty-eight men and 170 women from 7 countries were studied (men: 55% subtype B and 45% subtype C; women: 24% subtype B and 76% subtype C). Despite similar baseline CD4+ cell counts and blood plasma viral loads, women with subtype C had the highest GTVL (median, 5.1 log10 copies/mL) compared to women with subtype B and men with subtype C or B (4.0, 4.0, and 3.8 log10 copies/mL, respectively; P < .001). The proportion of participants with a GTVL below the lower limit of quantification (LLQ) at week 48 (90%) and week 96 (90%) was increased compared to baseline (16%; P < .001 at both times). Women were significantly less likely to have GTVL below the LLQ compared to men (84% vs 94% at week 48, P = .006; 84% vs 97% at week 96, P = .002), despite a more sensitive assay for seminal plasma than for cervical wicks. No difference in GTVL response across the 3 cART regimens was detected. Conclusions. The female genital tract may serve as a reservoir of persistent HIV-1 replication during cART and affect the use of cART to prevent sexual and perinatal transmission of HIV-1.

We measured longitudinal levels of vitamin D in unsupplemented Malawian infants at 0 (birth), 2, 12, 15, 18 and 24 months of age. Matched maternal plasma and breast milk vitamin D(2) and D(3) levels were also measured at delivery and 2 months postpartum. Vitamin D was measured using isotope-dilution liquid chromatography tandem-mass spectrometry. Vitamin D(3) levels in children were 36% of adult levels at birth, 60% of adult levels at age 2 months, and at par with adult levels by 12 months of age. This adult-equivalent level is subsequently maintained through age 24 months and consisted of a 98% molar ratio of vitamin D(3). Vitamin D levels in breast milk were below the limit of detection, 0.1 ng/ml. Breast milk of unsupplemented Malawian mothers is a poor source of vitamin D.

INTRODUCTION: Continuous evaluation of child survival is needed in sub-Saharan Africa where HIV prevalence among women of reproductive age continues to be high. We examined mortality levels and trends over a period of approximately 20 years among HIV-unexposed and -exposed children in Blantyre Malawi. METHODS: Data from 5 prospective cohort studies conducted at a single research site from 1989 to 2009 were analyzed. In these studies children born to HIV-infected and -uninfected mothers were enrolled at birth and followed longitudinally for at least 2 years. Information on sociodemographic HIV infection status survival and associated risk factors was collected in all studies. Mortality rates were estimated using birth-cohort analyses stratified by maternal and infant HIV status. Multivariate Cox regression models were used to determine risk factors associated with mortality. RESULTS: The analysis included 8286 children. From 1989 to 1995 overall mortality rates (per 100 person-years) in these clinic-based cohorts remained comparable among HIV-uninfected children born to HIV-uninfected mothers (range 3.3-6.9) or to HIV-infected mothers (range 2.5-7.5). From 1989 to 2009 overall mortality remained high among all children born to HIV-infected mothers (range 6.3-19.3) and among children who themselves became infected (range 15.6-57.4 1994-2009). Only lower birth weight was consistently and significantly (P < 0.05) associated with higher child mortality. CONCLUSIONS: HIV infection among mothers and children contributed to high levels of child mortality in the African setting in the pretreatment era. In addition to services that prevent mother-to-child transmission of HIV other programs are needed to improve child survival by lowering HIV-unrelated mortality through innovative interventions that strengthen health infrastructure.

Background. In resource-limited settings, mothers infected with human immunodeficiency virus type 1 (HIV-1) face a difficult choice: breastfeed their infants but risk transmitting HIV-1 or not breastfeed their infants and risk the infants dying of other infectious diseases or malnutrition. Recent results from observational studies and randomized clinical trials indicate daily administration of nevirapine to the infant can prevent breast-milk HIV-1 transmission. Methods. Data from 5396 mother-infant pairs who participated in 5 randomized trials where the infant was HIV-1 negative at birth were pooled to estimate the efficacy of infant nevirapine prophylaxis to prevent breast-milk HIV-1 transmission. Four daily regimens were compared: nevirapine for 6 weeks, 14 weeks, or 28 weeks, or nevirapine plus zidovudine for 14 weeks. Results. The estimated 28-week risk of HIV-1 transmission was 5.8% (95% confidence interval [CI], 4.3%–7.9%) for the 6-week nevirapine regimen, 3.7% (95% CI, 2.5%–5.4%) for the 14-week nevirapine regimen, 4.8% (95% CI, 3.5%–6.7%) for the 14-week nevirapine plus zidovudine regimen, and 1.8% (95% CI, 1.0%–3.1%) for the 28-week nevirapine regimen (log-rank test for trend, P

First-line antiretroviral treatment regimens in resource-limited settings used in breastfeeding mothers often include stavudine (d4T). Limited data describing d4T concentrations in breast milk are available. We analyzed d4T concentrations in 52 mother-infant pairs using ultra-performance liquid chromatography-tandem mass spectrometry (lower limit of quantification: 5 ng/mL in plasma, 20 ng/mL in breast milk). Median (interquartile range) d4T concentrations were 86 (36-191) ng/mL in maternal plasma, 151 (48-259) ng/mL in whole milk, 190 (58-296) ng/mL in skim milk, and5 (5 to5) ng/mL in infant plasma. Although d4T is concentrated in breast milk relative to maternal plasma, the infant d4T dose received from breast milk is very small and not clinically significant.

Optimizing the survival of HIV-uninfected infants born to HIV-infected mothers (ie, HIV-exposed infants) is a major challenge in sub-Saharan Africa, where prevalence of HIV infection remains high among reproductive-age women [1]. The detrimental effects of early weaning to prevent HIV transmission have been shown in multiple studies from Malawi, Uganda, and Botswana [2–5]. In these studies, the risk of severe gastroenteritis and mortality associated with gastroenteritis were higher among HIV-exposed but uninfected infants who were weaned early (at 4–6 months of age), compared with those who breastfed (BF) for longer periods. Additional adverse effects of nonbreastfeeding (NBF) or early weaning among HIV-uninfected African children include acute malnutrition, such as marasmus and kwashiorkor [5], and growth faltering [6, 7]. Infants who stopped BF also did not show increases in HIV-free survival (ie, both remaining alive and free of HIV infection) [8, 9]. How to balance the risks and benefits of BF of HIV-uninfected children of HIV-infected mothers in resource-constrained settings of sub-Saharan Africa where BF alternatives are not safe has been extensively discussed [10–12]. The recent World Health Organization (WHO) recommendations on infant feeding and HIV emphasize infant HIV-free survival [13]. Despite the evidence that NBF increases infant morbidity and mortality in resource-constrained settings, our understanding of the timing of these adverse events is limited. For clinical management and program planning, it will be valuable to know immediate and long-term effects of weaning whenever this practice is initiated. We hypothesize that cessation of BF to prevent transmission of HIV leads to early acute morbidity that occurs during the process of weaning or immediately after weaning. However, infant mortality associated with weaning is a late effect and occurs after the weaning process is completed. The aim of this study was to determine, among HIV-exposed, uninfected Malawian infants, morbidity rates in short follow-up intervals (∼3 months) that encompass weaning and to assess cumulative rates of mortality over time. These infants were originally enrolled in the extended antiretroviral Post-exposure Prophylaxis of Infants in Malawi (PEPI-Malawi) trial.

The expanding services of antiretroviral treatment (ART) in sub-Saharan Africa provide unique opportunities to reduce HIV/AIDS-related morbidity and mortality. In these settings, HIV prevalence among antenatal women remains high and treating eligible pregnant or breastfeeding women with antiretrovirals can substantially reduce transmission of HIV from the mother to her infant. However, identification of women eligible for treatment and ensuring access to ART services is challenging. In this analysis, we used data from a large clinical trial (the PEPI-Malawi study, 2004–09) to prevent mother-to-child transmission of HIV through extended antiretroviral prophylaxis of infants to examine barriers for wider coverage with highly active antiretroviral treatment (HAART) of postpartum women. Maternal HAART was not part of the original PEPI-Malawi clinical trial but became available through a government programme during the course of the study. Therefore, eligible women (CD4 cell count

BACKGROUND: In the Post-Exposure Prophylaxis of Infants (PEPI)-Malawi trial most women received single-dose nevirapine (NVP) at delivery and infants in the extended study arms received single-dose NVP along with 1 week of daily zidovudine (ZDV) followed by either extended daily NVP or extended daily NVP and ZDV up to 14 weeks of age. Although extended NVP prophylaxis reduces the risk of postnatal HIV transmission it may increase the risk of NVP resistance among infants who are HIV-infected despite prophylaxis. METHODS: We analyzed 88 infants in the PEPI-Malawi trial who were HIV-infected in utero and who received prophylaxis for a median of 6 weeks prior to HIV diagnosis. HIV genotyping was performed using the ViroSeq HIV Genotyping System. RESULTS: At 14 weeks of age the proportion of infants with NVP resistance was lower in the extended NVP and ZDV arm than in the extended NVP arm (28/45 62.2% vs. 37/43 86.0%; P = 0.015). None of the infants had ZDV resistance. Addition of extended ZDV to extended NVP was associated with reduced risk of NVP resistance at 14 weeks if prophylaxis was stopped by 6 weeks (54.5 vs. 85.7% P = 0.007) but not if prophylaxis was continued beyond 6 weeks (83.3 vs. 87.5% P = 1.00). CONCLUSION: Addition of extended ZDV to extended NVP prophylaxis significantly reduced the risk of NVP resistance at 14 weeks in infants who were HIV-infected in utero provided that HIV infection was diagnosed and the prophylaxis was stopped by 6 weeks of age.

BACKGROUND: The association between postnatal human immunodeficiency virus type 1 (HIV-1) transmission and maternal highly active antiretroviral therapy (HAART) after infant extended antiretroviral prophylaxis was assessed. METHODS: A follow-up study was conducted for the Post-Exposure Prophylaxis of Infants trial in Blantyre Malawi (PEPI-Malawi). In PEPI-Malawi breast-feeding infants of HIV-infected women were randomized at birth to receive a either control regimen (single-dose nevirapine plus 1 week of zidovudine); the control regimen plus nevirapine to age 14 weeks; or the control regimen plus nevirapine and zidovudine to age 14 weeks. Infant HIV infection maternal CD4 cell count and HAART use were determined. Maternal HAART use was categorized as HAART eligible but untreated (CD4 cell count of

article i nfo Objective: To determine the factors associated with resumption of sexual activity and regular menses after childbirth among women infected with HIV-1. Methods: Information on sociodemographic, behavioral, and clinical factors was obtained from 2 HIV perinatal studies (NVAZ and PEPI trials) conducted in Malawi, 2000- 2009. Factors associated with resumption of sexual activity and menses were analyzed using Cox proportional hazard models. Results: A total of 1838 women from the NVAZ study and 2982 women from the PEPI study were included in the analysis. Resumption of sexual activity was primarily associated with sociodemographic factors (e.g. in the PEPI study, marital status (adjusted hazard ratio (aHR) 0.56, P

This study aimed to determine changes in fertility intentions of HIV-1 infected and uninfected reproductive age women in Blantyre, Malawi. Participants were asked about their fertility intentions at baseline and at 3-month visits for 1 year. Time-to-event statistical models were used to determine factors associated with changes in fertility intentions. Overall, 842 HIV uninfected and 844 HIV infected women were enrolled. The hazard of changing from wanting no more children at baseline to wanting more children at follow-up was 61% lower among HIV infected women compared to HIV uninfected women (P0.01) after adjusting for other factors, while HIV infected women were approximately 3 times more likely to change to wanting no more children. The overall pregnancy rate after 12 months was 14.9 per 100 person-years and did not differ among 102 HIV uninfected and 100 infected women who became pregnant. HIV infection is a significant predictor of fertility intentions over time.

We compared the ability of the LigAmp assay and an ASPCR assay to detect and quantify K103N-containing HIV variants in samples from 63 women who received single-dose nevirapine in a clinical trial. Samples were first analyzed with the ViroSeq HIV Genotyping system, and ViroSeq PCR products were used as templates for the LigAmp and ASPCR assays. A cutoff of 0.5% K103N for detection of K103N was used for both assays. Results for the percentage K103N were similar for the two assays (R(2) = 0.92). Forty-six samples (73.0%) were positive for K103N by both assays and 13 samples (20.6%) were negative by both assays. Four samples (6.3%) were positive by ASPCR only. No samples were positive by LigAmp only. Eight discordant samples were analyzed in more detail. Sequence polymorphisms near oligonucleotide binding sites provided a possible explanation for the discordance in four of eight samples. The percentage K103N was also determined by analyzing 40 HIV clones from each of these eight samples, using a combined amplification/sequencing method (AmpliSeq). The percentage K103N determined by clonal analysis was consistent with the LigAmp result for five of eight samples, and was consistent with the ASPCR result for three of eight samples. Among 320 clones analyzed, we identified eight different codons at position 103 (mean = 3.8 codons/sample), which encoded six different amino acids, illustrating the extensive genetic diversity in HIV. Further studies are needed to compare performance of assays for detection and quantification of HIV drug resistance mutations in clinical samples.

The objective was to study temporal changes in HIV-1 seroreversion (change in reactivity of HIV serology from positive to negative) in uninfected infants born to HIV-1-infected mothers. Secondary analysis of data from 3 cohort studies conducted in Malawi among infants born 1989 through 1991 (International Collaborative AIDS Research [ICAR]) 1993 through 1996 (HIV Network for Prevention Trials [HIVNET]) and 2000 through 2003 (nevirapine/zidovudine [NVAZ]). The proportion of children HIV seroreverting at ages 15 18 and 21 months and the relative odds for seroreversion comparing infants born before 1997 to those born after 1999 were calculated. Included in this analysis were 635 infants from ICAR 459 from HIVNET and 1020 from NVAZ. During the study there was a consistent trend of decrease in proportion of children seroreverting over time: highest during 1989 through 1991 intermediate during 1993 through 1996 and lowest during 2000 through 2003. Additionally there was a strong association between seroreversion and year of birth (before 1997 vs. after 1999): adjusted relative odds 5.1 at 15 months 8.2 at 18 months and 11.2 at 21 months. Age of seroreversion in HIV-1-exposed uninfected infants increased over time. Persistence of maternal HIV-1 antibodies could have implications on timing of infant HIV-1 diagnosis using serological diagnostic methods. (authors)

BACKGROUND The present study was undertaken to determine the risk and timing of late postnatal transmission (LPT) of human immunodeficiency virus type 1 (HIV-1). METHODS Breast-fed infants previously enrolled in 2 trials of antiretroviral prophylaxis were monitored in Malawi. Kaplan-Meier and proportional hazard models assessed cumulative incidence and association of factors with LPT. RESULTS Overall, 98 infants were HIV infected, and 1158 were uninfected. The cumulative risk of LPT at age 24 months was 9.68% (95% confidence interval, 7.80%-11.56%). The interval hazards at 1.5-6, 6-12, 12-18, and 18-24 months were 1.22%, 4.05%, 3.48%, and 1.27%, respectively. CONCLUSIONS The risk of LPT beyond 6 months is substantial. Weaning at 6 months could prevent >85% of LPT.

K103N is frequently detected in HIV-infected women after single dose (SD) nevirapine (NVP). K103N-containing variants were detected more frequently by the ViroSeq HIV-1 Genotyping System in women with subtype C (69.2%) than subtypes A (19.4%, p < 0.0001) or D (36.1%, p < 0.0001). K103N-containing variants were also detected more frequently and at higher levels in women with subtype C by the LigAmp assay. In this report, we analyzed samples collected prior to or within hours after SD NVP administration from antiretroviral drug-naive African women with subtypes A, C, and D. Only 1/254 samples had an NVP resistance mutation detected with the ViroSeq system, and only 4/236 samples had K103N detected at < 0.5% with the LigAmp assay [2/110 (1.8%) with subtype A, 1/46 (2.2%) with subtype C, and 1/80 (1.3%) with subtype D] (p = 0.92). We did not detect significant differences in the pre-NVP frequency of NVP resistance mutations or the pre-NVP levels of K103N-containing variants in women with subtypes A, C, and D ...

We used a sensitive point mutation assay, LigAmp, to detect and quantify K103N-containing variants in African women who received single-dose nevirapine (NVP) to prevent mother-to-child HIV-1 transmission.Plasma for testing was collected 6 to 8 weeks postpartum from 301 women (144 subtype A, 63 subtype C, and 94 subtype D).The portion of women with 0.5% or more K103N-containing variants was lowest for subtype A (60/144, 41.7%) and highest for subtype C (44/63, 69.8%; P0.0001). K103N was rarely detected in pre-NVP samples. In a multivariate model, K103N detection was associated with HIV-1 subtype (CA), after adjusting for log10 delivery viral load, the number of days between NVP dosing and sample collection, age, and parity. Among women with K103N detected: (1) the median %K103N was lower for subtype A (2.2%) than C (11.7%, P = 0.0001) or D (5.5%, P = 0.04), and (2) in a multivariate linear model, higher log10 (%K103N) was associated with HIV subtype (CA, P = 0.0001; DA, P = 0.01; and C vs D, no difference), but not other factors.After administration of single-dose NVP, K103N was detected more frequently and at higher levels in women with subtypes C and D than A. Further studies are needed to evaluate the clinical significance of NVP-resistant variants in this setting.

The HIVNET 012 trial in Uganda showed that mother-to-child transmission (MTCT) of HIV-1 can be prevented by providing pregnant women and their infants with a single dose (SD) of the antiretroviral drug nevirapine (NVP). Safety and efficacy of 1- or 2-dose NVP prophylaxis for prevention of MTCT have been documented in other studies. We have shown that NVP resistance emerges in some women after SD NVP prophylaxis and that the portion of women with NVP resistance is influenced by HIV-1 subtype. At 6 to 8 weeks after SD NVP NVP resistance was more common in women with subtype C (69.2%) than in women with subtype D (36.1% P < 0.0001) or subtype A (19.4% P < 0.0001).4 Selection of NVP-resistant HIV-1 variants in women after NVP dosing could theoretically lower the efficacy of NVP prophylaxis for prevention of HIV transmission by breast-feeding in the first few weeks after birth. In the HIVNET 012 trial most women were infected with HIV-1 subtype A or D. Risk of MTCT was slightly (but not statistically) higher in women with subtype D. In this report we combined data from the HIVNET 012 and NVAZ trials to compare the risk of MTCT in women with subtype C to the risk of MTCT in women with subtypes A and D in the setting of SD NVP prophylaxis. (excerpt)

Replication capacity and transmission of human immunodeficiency virus (HIV)-1 in antiretroviral drug-naive Malawian women who had subtype C infection were investigated. Infant children of these women received either 1 dose of nevirapine or 1 dose of nevirapine plus 1 week of daily doses of zidovudine. PhenoSense HIV was used to determine replication capacity in 49 women whose infants were infected with HIV-1 and in 47 women whose infants were uninfected by 6-8 weeks of age. Mean replication capacity was higher in transmitters than in nontransmitters (P=.01). In a multivariate model, higher replication capacity was associated with transmission (odds ratio, 1.45 for each 10% increase in replication capacity [95% confidence interval, 1.11-1.90]; P = .0063), after adjustment for maternal HIV-1 load and other factors.

This study analyzed mother-to-child HIV transmission rates by sex and exposure time for babies born to HIV-infected untreated African women. Data were analyzed from 2 independent studies done in Malawi during the 1990s. Infections were established by polymerase chain reaction on blood samples. Odds ratios (ORs) for transmission were examined by period at risk: in utero (infected in umbilical cord blood) perinatal (infected in 1st postnatal blood = 4 weeks) and postnatal (later postnatal infection). Among 1394 singleton births girls were more likely to become infected than boys. For in utero transmission the OR was 1.4 (95% CI: 0.9 to 2.2). For transmission during early life (umbilical cord blood not available) the OR was 2.7 (95% CI: 1.5 to 4.9). However transmission risks in the perinatal and postnatal infection periods did not differ in boys and girls. Among 303 tested twin-birth pairs girls were at higher risk than boys for in utero (OR: 2.6; 95% CI: 1.2 to 5.8) and perinatal (OR: 1.9; 95% CI: 1.0 to 3.7) infection. Recognized mother-to-child transmission risk factors did not explain the higher risk of infection in girls. Girls were at higher risk of early (in utero and perinatal) HIV infection than boys. It is proposed that minor histocompatibility reactions between maternal lymphocytes and infant Y chromosome-derived antigens reduce the risk of HIV transmission in boys. (authors)

Although subclinical mastitis is associated with increased HIV load in breast milk, it is not known whether empirical treatment with antibiotics will reduce breast milk HIV load. We examined the effect of antibiotic treatment for subclinical mastitis on HIV load in breast milk. Seventy-five HIV-infected post-partum women in Malawi with subclinical mastitis were treated with oral amoxicillin/clavulanic acid and were followed between 1 and 24 weeks later. Breastmilk HIV-1 load and sodium concentration were measured and microbiological studies were performed at presentation. At 1 week (n = 34), the proportion of women with elevated breast milk leukocyte counts decreased significantly to 41.2% (p < 0.0001) and there was a nonsignificant increase in breast milk HIV-1 RNA load (p = 0.9264) and sodium concentration (p = 0.08) in the affected breast. At 4 to 12 weeks (n = 63), breast milk HIV-1 RNA load and sodium concentration decreased significantly (p < 0.05) and 17.5% had elevated breast milk leukocyte counts. Treatment with amoxicillin/clavulanic acid was associated with a significant decrease in inflammation of the breast, but breast milk HIV load remained elevated despite a significant decrease from baseline. These findings have important implications regarding how mothers should be counselled on safety of resuming breastfeeding after resolution of subclinical mastitis.

Objective. In the Human Immunodeficiency Virus (HIV) Network for Prevention Trials (HIVNET) 012 trial in Uganda, 6-8 weeks after single-dose nevirapine (SD-NVP), NVP resistance mutations were detected at a higher rate in women with HIV-1 subtype D than in women with subtype A. Here, we evaluate the rate of NVP resistance mutations in women with subtype C. Methods. NVP resistance mutations were detected using the ViroSeq HIV-1 Genotyping System. Results. The portion of women with any NVP resistance mutation was higher in those with subtype C (45/ 65 [69.2%] in the NVP and zidovudine trial, Malawi) than in those in the HIVNET 012 trial with either subtype A (28/144 [19.4%]; P

Innovative, low-cost, and acceptable measures are needed to reduce sexually transmitted infections (STIs) including HIV. Use of a topical microbicide wipe for penile cleaning before and after sex might be effective in preventing STIs. However, evaluation of this simple method has not been done. Two studies were conducted in Malawi to determine the safety, acceptability, and potential efficacy of a benzalkonium chloride topical penile microbicide wipe. The first study was a phase 1 dose-escalating clinical trial among low-risk circumcised or uncircumcised HIV-negative men. The second study was a pilot before-after efficacy study among uncircumcised HIV-negative or -positive men. In the first study 24 circumcised and 27 uncircumcised men were enrolled. During the entire study period, 18 adverse events (AEs) were reported, and 3 AEs were confirmed by physical examination. Acceptability concerns did not increase with dose escalation, and adherence to use of the wipe ranged from 89%-95%. In the second study, 27 men were enrolled. Gram stain and culture tests showed significant reductions in frequency of several organisms after use of the wipe, including STI-associated bacteria. This penile wipe is safe, acceptable, and can decrease the frequency of penile colonization with microorganisms. The clinical relevance remains to be determined in larger clinical trials.

Defining viral dynamics in natural infection is prognostic of disease progression and could prove to be important for vaccine trial design as viremia may be a likely secondary end point in phase III HIV efficacy trials. There are limited data available on the early course of plasma viral load in subtype C HIV-1 infection in Africa. Plasma viral load and CD4+ T cell counts were monitored in 51 recently infected subjects for 9 months. Individuals were recruited from four southern African countries: Zambia, Malawi, Zimbabwe, and South Africa and the median estimated time from seroconversion was 8.9 months (interquartile range, 5.7–14 months). All were infected with subtype C HIV-1 and median viral loads, measured using branched DNA, ranged from 3.82–4.02 log10 RNA copies/ml from 2–24 months after seroconversion. Viral loads significantly correlated with CD4+ cell counts (r = –0.5, p < 0.0001; range, 376–364 cells/mm3) and mathematical modeling defined a median set point of 4.08 log10 (12 143 RNA copies/ml), ...

The epidemiology and microbiology of subclinical mastitis, a risk factor for perinatal HIV transmission, have not been well characterized. In all, 250 HIV-infected women were followed from two weeks to 12 months postpartum in Blantyre, Malawi, and subclinical mastitis was assessed by breast milk leukocyte counts. The point prevalence of subclinical mastitis at 2, 4, 6, 10, and 14 weeks, and 6, 9, and 12 months was 12.2%, 7.8%, 6.8%, 3.7%, 10.6%, 5.1%, 4.9%, and 1.9%, respectively ( P = 0.002), and 27.2% of women had at least one episode of subclinical mastitis. There was no significant relationship between maternal plasma HIV load or parity and subclinical mastitis. Staphylococcus aureus was isolated in 30% of women with subclinical mastitis, and the proportion of women with positive cultures decreased during follow-up ( P = 0.02). Subclinical mastitis is prevalent among breastfeeding mothers and further studies are needed to characterize the differences between infectious and non-infectious subclinical mastitis.

The acute phase response and inflammation are associated with lower plasma retinol concentrations, but their effect on breast milk retinol concentrations is unclear. We measured plasma retinol concentrations, acute phase proteins, and breast milk retinol concentrations in 237 breast-feeding women at 2 wk postpartum in Blantyre, Malawi; 16.5% of the women had plasma retinol0.70 micromol/L and 14.8% had breast milk retinol1.05 micromol/L. Among women with and without inflammation [alpha(1)-acid glycoprotein (AGP)1 g/L and/or C-reactive protein (CRP)5 mg/L], geometric mean (95% CI) plasma retinol was 0.89 (0.84, 0.94) and 1.05 (1.01, 1.17) mumol/L, respectively (P0.0001). Among women with and without inflammation, geometric mean (95% CI) breast milk retinol was 2.12 (1.89, 2.36) and 2.05 (1.75, 2.39) micromol/L, respectively (P = 0.74). In multiple linear regression models adjusting for age, parity, education, BMI, and days postpartum, plasma retinol concentrations were associated with plasma AGP and CRP concentrations (P0.0001 and P = 0.01, respectively), whereas breast milk retinol concentrations were unaffected by plasma AGP and CRP concentrations (P = 0.22 and P = 0.86, respectively). These findings suggest that breast milk retinol concentrations are not affected by systemic inflammation.

We assessed the safety of short-term antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV by monitoring haematological changes in children up to the age of 18 months. Babies of HIV-infected women were randomised at birth to receive a single dose of nevirapine (NVP) alone or with zidovudine (ZDV) twice daily for a week. Based on the time of presentation to the labour ward, mothers of these babies might or might not have received intrapartum NVP. Complete blood counts were performed at birth and at 1.5, 3, 6, 9, 12, 15 and 18 months. Babies' HIV status was determined by HIV-1 RNA testing. A total of 1755 babies were included in the study. Age-specific mean haemoglobin levels and prevalence of anaemia (haemoglobin < 10 g/dL) were not significantly different in cases where only the babies received a single dose of NVP and cases where NVP was given to mother/infant pairs or additional ZDV to the baby. Among HIV-infected children compared with uninfected children, the age-specific frequency of anaemia was significantly greater, anaemia started earlier and recovery to normal levels was slower and prolonged. A reversible granulocytopenia was observed in all children between 1.5 and 3 months of age. HIV infection significantly increased the children's risk of death. Antiretroviral prophylaxis appeared to protect against anaemia and child death. Short regimens of antiretrovirals to prevent MTCT of HIV are not associated with long-term adverse haematological changes.

The objectives were to evaluate the safety of 100 mg nonoxynol-9 (N-9) gel a vaginal microbicide on the genital mucosa of women from Malawi and Zimbabwe in preparation for a phase III efficacy study. HIV-uninfected women (180) were enrolled and randomized to either N-9 or placebo gel and instructed to insert gel into the vagina twice daily for 14 days. Follow up examinations were conducted at 7 and 14 days. The number of adverse events in the N-9 gel group was higher than in the placebo group (40% versus 13%; P < 0.01). Reported number of any genital symptoms was significantly higher in the N-9 group (38% N-9 13% placebo; P = 0.01). The number of total epithelial disruptions was higher in the N-9 group (20% versus 3%; P < 0.01); however the number of genital ulcers and abrasions in the N-9 group was low (2% and 3% respectively) and not different from that in the placebo group (1% and 2% respectively). N-9 gel 100 mg caused a significant increase in the rate of genital symptoms and epithelial disruptions compared with placebo. The clinical significance of these epithelial disruptions is unknown. Although these findings alone were not sufficient to cancel the planned phase III study when considered together with the negative results from the COL-1492 effectiveness trial of 52.5 mg N-9 gel the decision was made to cancel the planned phase III trial of 100 mg N-9 gel. (authors)

Characterization of optimal CTL epitopes in Gag can provide crucial information for evaluation of candidate vaccines in populations at the epicenter of the HIV-1 epidemic. We screened 38 individuals with recent subtype C HIV-1 infection using overlapping consensus C Gag peptides and hypothesized that unique HLA-restricting alleles in the southern African population would determine novel epitope identity. Seventy-four percent of individuals recognized at least one Gag peptide pool. Ten epitopic regions were identified across p17, p24, and p2p7p1p6, and greater than two-thirds of targeted regions were directed at: TGTEELRSLYNTVATLY (p17, 35%); GPKEPFRDYVDRFFKTLRAEQATQDV (p24, 19%); and RGGKLDKWEKIRLRPGGKKHYMLKHL (p17, 15%). After alignment of these epitopic regions with consensus M and a consensus subtype C sequence from the cohort, it was evident that the regions targeted were highly conserved. Fine epitope mapping revealed that five of nine identified optimal Gag epitopes were novel: HLVWASREL, LVWASRELERF, LYNTVATLY, PFRDYVDRFF, and TLRAEQATQD, and were restricted by unique HLA-Cw*08, HLA-A*30/B*57, HLA-A*29/B*44, and HLA-Cw*03 alleles, respectively. Notably, three of the mapped epitopes were restricted by more than one HLA allele. Although these epitopes were novel and restricted by unique HLA, they overlapped or were embedded within previously described CTL epitopes from subtype B HIV-1 infection. These data emphasize the promiscuous nature of epitope binding and support our hypothesis that HLA diversity between populations can shape fine epitope identity, but may not represent a constraint for universal recognition of Gag in highly conserved domains.

An understanding of the relationship between the breadth and magnitude of T-cell epitope responses and viral loads is important for the design of effective vaccines. For this study, we screened a cohort of 46 subtype C human immunodeficiency virus type 1 (HIV-1)-infected individuals for T-cell responses against a panel of peptides corresponding to the complete subtype C genome. We used a gamma interferon ELISPOT assay to explore the hypothesis that patterns of T-cell responses across the expressed HIV-1 genome correlate with viral control. The estimated median time from seroconversion to response for the cohort was 13 months, and the order of cumulative T-cell responses against HIV proteins was as follows: Nef > Gag > Pol > Env > Vif > Rev > Vpr > Tat > Vpu. Nef was the most intensely targeted protein, with 97.5% of the epitopes being clustered within 119 amino acids, constituting almost one-third of the responses across the expressed genome. The second most targeted region was p24, comprising 17% of the responses. There was no correlation between viral load and the breadth of responses, but there was a weak positive correlation (r= 0.297;P= 0.034) between viral load and the total magnitude of responses, implying that the magnitude of T-cell recognition did not contribute to viral control. When hierarchical patterns of recognition were correlated with the viral load, preferential targeting of Gag was significantly (r= 0.445;P= 0.0025) associated with viral control. These data suggest that preferential targeting of Gag epitopes, rather than the breadth or magnitude of the response across the genome, may be an important marker of immune efficacy. These data have significance for the design of vaccines and for interpretation of vaccine-induced responses.

We examined birth order and delivery route as risk factors for mother-to-child transmission of human immunodeficiency virus (HIV)-1 in 315 twin pairs born in Malawi during 1994-1998. No antiretroviral drugs were administered to these subjects. Infections were detected by polymerase chain reaction and were stratified as having occurred either in utero, perinatally, or postnatally. Risk of in utero infection for 630 infants (39 infections) did not differ by birth order (first born, 6.3%; second born, 6.0%). Similarly, in 260 vaginally delivered infants evaluated for perinatal infection (45 infections), risk did not differ by birth order (first born, 15.9%; second born, 18.7%); risk of perinatal infection was significantly lower in cesarean-delivered infants (odds ratio, 0.19 [95% confidence interval, 0.02-0.78]). There was no effect on postnatal transmission rates. Thus, in contrast to the authors of earlier studies, we did not find birth order to be an important risk factor for infection in twins. These findings indicate that birth-canal exposure is not a major contributor to a newborn's risk of HIV-1 infection.

Objective. To compare the effectiveness of methods for assessing the quality of pediatric outpatient health provider performance in developing countries. Design. Exit interviews, record reviews, and provider interview results were compared with those of direct observation of pediatric patient care. Thirty health care providers in 14 facilities in Lilongwe District, Malawi were interviewed and observed, treating 436 children in August 1994. Caretakers for 426 of the patients were interviewed, and 362 pediatric outpatient entries in the health center patient register were located and reviewed. Main measures. Kappa statistics measuring the level of agreement on the same sample were used for three methods (record reviews, provider interviews, and exit interviews) in comparison with the fourth method, direct observation. Results. All three methods had strengths and weaknesses. Exit interviews with caretakers provided reliable responses for many history-taking tasks, easily discernible physical exam tasks, and many counseling tasks. Record review took little time, but provided limited information: however, the results were reliable for treatments. Provider interviews had much lower reliability, but were usable for assessing more rare events (treating severely ill children). Conclusions. Although exit interviews and direct observation provide the ‘best’ data, they are most resource-intensive. Depending on the purpose of the assessment, various combinations of methods might be more effective.

Vitamin A is essential for immunity and growth. A controlled clinical that involved 697 human immunodeficiency virus (HIV)-infected pregnant women was conducted to determine whether vitamin A prevents anemia, low birth weight, growth failure, HIV transmission, and mortality. Women received daily doses of iron and folate, either alone or combined with vitamin A (3 mg retinol equivalent), from 18-28 weeks' gestation until delivery. In the vitamin A and control groups, respectively, the mean (± SE) birth weights were 2895 ± 31 g and 2805 ± 32 g (P = .05), the proportions of low-birth-weight infants were 14.0% and 21.1% (P = .03), the proportions of anemic infants at 6 weeks postpartum were 23.4% and 40.6% (P

Host genetic factors may influence the course of human immunodeficiency virus (HIV) infection. In Blantyre, Malawi, polymerase chain reaction was used to identify twin pairs who were concordantly HIV-1-infected in utero or perinatally and then to examine strain divergence or virus levels in identical and fraternal twin pairs. Among 315 twin pairs, both infants in 14 fraternal and 5 identical pairs were found to be infected at the same visit. Among 10 pairs, HIV-1 sequences were determined for both infants at >or=1 time point. HIV levels had a common profile in both fraternal and identical twin pairs. Identical twins were not always infected by the same quasi species, indicating that their mothers had multiple quasi species capable of infecting their infants. Subsequent viral divergence appears to depend on quasi-species stability rather than on genetically controlled host immune responses. Thus, given infection, factors intrinsic to HIV-1 are more important than host genetics in viral evolution.

Background: HIV-1 surveys in defined populations identify underlying risks and trends useful to mount interventions. Goal: The goal of the study was to determine HIV-1 prevalence and risk factors among men working at a Malawian sugar estate. Study Design: Three independent surveys were conducted in 1994, 1997, and 1998. Procedures included obtaining informed consent, interviewing, and drawing blood for HIV and syphilis testing. Analyses determined prevalence of HIV and associated risk factors. Results: HIV prevalence was 24.3% in 1994 (n = 1691), 22.8% in 1997 (n = 615), and 20.9% in 1998 (n = 1354; P < 0.03). From 1994 to 1998, the percentage of subjects with a history of sexually transmitted disease (STD) decreased from 43.6% to 29.5% (P < 0.0001), accompanied by a substantial rise in STDs confirmed by physical examination (from 7.5% to 16.8%; P < 0.0001) and by laboratory testing for syphilis (from 6.5% to 10.4%; P < 0.0001). The percentage with multiple sex partners declined (from 62.0% to 35.2%; P < 0.0001), and condom use rose (from 10.9% to 18.9%; P < 0.0001). STDs were significantly associated with prevalent HIV infection each year. Conclusions: The prevalence of HIV has remained relatively stable and high in this cohort.

Objective: To measure hepatic and hematological parameters among neonates randomized to receive ultra-short antiretroviral regimens. Design: As part of an on-going clinical trial in Malawi infants born to women who received (early presenters) or did not receive (late presenters) standard intrapartum nevirapine (NVP) dosing were randomized to receive orally either single dose NVP alone or NVP plus zidovudine (twice daily for 1 week). An additional group of untreated infants (born to HIV-uninfected women) was enrolled as a control. Methods: Laboratory measurements were performed at birth and repeated at 6 weeks of age. Serum alanine aminotransferase (ALT) was measured on approximately 200 infants consecutively enrolled and randomized at the start of the trial. Complete blood count (CBC) was performed on approximately 800 infants at birth and 600 infants at 6 weeks of age. ALT and CBC were also determined on approximately 200 control infants. Results: At birth there were no differences in ALT values between the groups of children. At 6 weeks of age ALT levels were significantly higher among the treated groups compared with control group (geometric mean of 11.5 U/l for controls and 16.2±19.1 U/l for treated groups; P

INTRODUCTION Although studies suggest that vitamin A or its metabolites influence the synthesis of erythropoietin in vitro and in animal models, it is unclear whether vitamin A supplementation increases plasma erythropoietin concentrations in humans. OBJECTIVE To determine whether daily vitamin A supplementation increases plasma erythropoietin concentrations in pregnant women with a high prevalence of anaemia. METHODS A randomized, double-blind, controlled clinical trial was conducted to examine the effect of daily vitamin A (3000 microg retinol equivalent), iron (30 mg), and folate (400 microg) versus iron (30 mg) and folate (400 microg) (control) on haemoglobin and plasma erythropoietin concentrations in 203 pregnant women in Malawi, Africa. RESULTS Mean gestational age at enrollment was 23 wk, at which time 50% of the women were anaemic (haemoglobin

Background: Although anemia is highly prevalent during pregnancy and is common during human immunodeficiency virus (HIV) infection, anemia and iron status have not been well characterized in HIV-infected pregnant women. Objective: To gain insight into iron status in HIV-infected pregnant women using plasma transferrin receptor and related indicators of anemia. Study design: Plasma transferrin receptor, ferritin, α1-acid glycoprotein, C-reactive protein and hemoglobin concentrations were measured in pregnant women, gestational age 18–28 weeks, seen in an urban antenatal clinic in Blantyre, Malawi. Results: The prevalence of anemia among 662 HIV-positive and 190 HIV-negative pregnant women was 73.1% and 50.0%, respectively (P

Human milk contains important immunological factors that protect the breast from infection and are thought to protect infants from infection, including human immunodeficiency virus (HIV) infection. Human milk immunological factors have not been well characterized in HIV infected lactating women. Lysozyme, secretory leukocyte protease inhibitor (SLPI), sodium (an indicator of mastitis), and HIV were measured in breast milk of 334 HIV-infected women at 6 weeks postpartum. Women with mastitis, as indicated by elevated breast milk sodium concentrations, had higher median levels lysozyme (290 vs 221 mg/L,p2) and higher maternal HIV load (p6) by quartile were risk factors for mastitis. Mastitis, as indicated by elevated breast milk sodium levels, is associated with high concentrations of immunological factors and higher HIV load in breast milk.

In developed areas, human immunodeficiency virus (HIV)-infected infants have high virus levels and rapidly progress to death. HIV levels were assessed in 1994-1997 in untreated infants in Malawi by analysis of dried blood spots tested by nucleic acid silica-bound amplification. Of 24 umbilical cord blood (CB)-positive samples, 83% had >10,000 copies/mL. The median virus level was 78,000 copies/mL. First positive sample median levels were 355,000 copieslmL among 52 perinatally infected infants and 130,000 copies/mL among 43 infants infected by breast-feeding. Virus levels were stable, and initial levels predicted levels 1 year after infection (P =.005), at which time levels did not significantly differ among in utero, perinatally, or postnatally infected infants. Thus, neither age at infection nor route of infection significantly influenced HIV levels measured 1 year after infection. Most (87%) CB-positive infants were infected before labor onset, since virus levels greatly exceeded those expected in their mothers.

HIV-infected and uninfected children who survived their first year of life were prospectively followed in Malawi to assess levels of mortality and related risk factors during the second and third years of life.Children with known HIV status from an earlier perinatal intervention trial were enrolled. These children [HIV-infected (Group A); HIV-uninfected but born to HIV-seropositive mothers (Group B); and children born to HIV-seronegative mothers (Group C)] were followed every 3 months until age 36 months. Mortality data were collected at each visit. Immunologic data (CD4+ percent) were collected at or immediately after enrollment.Overall 702 children were enrolled and 83 children died during follow-up. The mortality rate per 1000 person years of observation was 339.3 among Group A children, 46.3 among Group B children and 35.7 among Group C children. Among HIV-infected children the cumulative proportion surviving to age 24 months was 70% and those surviving to age 36 months was 55%. By age 32 months none of the severely immunosuppressed (CD4%15%) children had survived. The mortality differentials between HIV-infected and uninfected children persisted after adjusting for several risk factors. The major causes of death among infected children (n = 52) were wasting and respiratory conditions.Although all HIV-infected children had received childhood immunizations, mortality was high. Management of these children should include aggressive antimicrobial treatment, and evaluation of prophylactic regimens should be considered.

Human immunodeficiency virus (HIV) type 1 load in breast milk and mastitis were examined as risk factors for vertical transmission of HIV-1. Six weeks after delivery, HIV-1 load and sodium (an indicator of mastitis) were measured in breast milk from 334 HIV-1-infected women in Malawi. Median breast milk HIV-1 load was 700 copies/mL among women with HIV-1-infected infants versus undetectable (

Breast milk transmission of HIV-1 continues to present enormous challenges for prevention of infant HIV-1 infection. Breast milk confers a variety of benefits to infants but can also be a vehicle for HIV- 1 transmission. Determining the amount of risk due to breast-feeding duration of risk and cofactors for risk is useful for designing efficient interventions to decrease the incidence of infant HIV-1 infection. In this issue of the Journal Taha et al. evaluated late postnatal transmission in cohorts of Malawian mother-infant pairs who participated in 2 previously published clinical trials of antiretrovirals to prevent mother-to-child transmission (the nevirapine-zidovudine studies). Overall 1256 infants without HIV-1 infection at 1.5 months were monitored for 24 months to determine the risk of late postnatal transmission. The risk of HIV-1 acquisition in this group was 9.7% and the vast majority (87.4%) of late infections occurred after 6 months of age. The study was large yielded a fairly precise risk estimate and included a 2-year follow-up which enabled comparison of risk estimates for serial intervals of ~6 months. Interestingly the 1.5-6-month age interval was the one with the lowest risk of HIV-1 transmission (1.22%). Finally utilizing the cohorts size and long follow-up period the authors were also able to identify several significant correlates of late postnatal transmission. (excerpt)

To examine rates of HIV-1 and sexually transmitted disease (STD) among pregnant and postpartum women in urban Malawi, Africa.Serial cross-sectional surveys and a prospective study.Three major surveys were conducted in 1990, 1993 and 1994/1995. Consecutive first-visit antenatal women and women giving birth at the Queen Elizabeth Central Hospital were tested for HIV and STD after counseling and obtaining informed consent. Unlinked, anonymous HIV testing was also conducted on smaller samples of antenatal women in the same hospital to provide annual prevalence data. HIV-seronegative postpartum women from the 1990 and 1993 surveys were enrolled in a prospective study to determine HIV incidence.HIV seroprevalence rose from 2.0% in 1985 to 32.8% in 1996, a 16-fold increase. The highest age-specific HIV prevalence was in the following age-groups: 20-24 years during 1990, 25-29 years during 1993, and 30-34 years during 1996. Among 1173 women followed for a median of 30.9 months, HIV incidence was 5.98 per 100 person-years in women aged20 years and declined steadily in older women. The prevalence of STD significantly declined among both HIV-positive and negative women. This decline in STD prevalence, however, was not accompanied by increased condom use over time.Among urban childbearing women in Malawi, incidence of HIV is highest among young women while, currently, prevalence is highest among older women. Recent declines in STD prevalence suggest that HIV prevention programs are having an impact either through improved STD diagnosis and treatment or reduced risk behaviors. Sequential cross-sectional STD prevalence measures may be useful in monitoring effectiveness of STD and HIV prevention activities.Prevalence rates of HIV-1 and other sexually transmitted diseases (STDs) among pregnant and postpartum women were investigated in sequential, cross-sectional studies (1990, 1993, and 1994-95) conducted at Queen Elizabeth Central Hospital in Blantyre, Malawi. Annual anonymous, unlinked testing revealed a linear increase in HIV-1 prevalence among antenatal patients from 2.0% in 1985 to 32.8% in 1996. Analysis of demographic attributes of women enrolled in the 1990 and 1993 surveys of consecutive, first-visit antenatal women (n = 6603 and 2161, respectively) and the 1994-95 study of all women giving birth at the hospital during a 6-month period (n = 6964) indicated that HIV-infected women were most likely to be young, with fewer pregnancies, and be more educated. The highest age-specific HIV prevalence shifted from 20-24 years in 1990 to 30-34 years in 1996, indicating an aging cohort of women who became infected at a younger age. Reported lifetime use of condoms increased from 5.6% in 1990 to 17.5% in 1993, then declined to 4.9% in 1995; condom use was consistently higher among HIV-positive than HIV-negative women. The prevalence of all STDs (syphilis, trichomoniasis, gonorrhea, and genital warts and ulcers) declined significantly during 1990-96, with the most consistent decreases recorded among HIV-positive women. In a follow-up study of 1173 HIV-seronegative, postpartum women evaluated for 2302 person-years (average duration, 30.9 months), 97 seroconverted (4.21/100 person-years). The seroconversion rate declined steadily from 21.26/100 person-years in 1990 to 1.11/100 person-years in 1994-95. These findings are consistent with those from other sub-Saharan African countries, indicating a rapid increase in HIV prevalence followed by stabilization within about 10 years of the onset of the epidemic. The large decline in STD prevalence in the antenatal population suggests that Malawi's national AIDS prevention program is having an impact, either through improved STD diagnosis and treatment or reduced risk behaviors.

The US Food and Drug Administration-cleared ViroSeq HIV-1 Genotyping System (ViroSeq) and other population sequencing-based human immunodeficiency virus type 1 (HIV-1) genotyping methods detect antiretroviral drug resistance mutations present in the major viral population of a test sample. These assays also detect some mutations in viral variants that are present as mixtures. We compared detection of the K103N nevirapine resistance mutation using ViroSeq and a sensitive, quantitative point mutation assay, LigAmp. The LigAmp assay measured the percentage of K103N-containing variants in the viral population (percentage of K103N). We analyzed 305 samples with HIV-1 subtypes A, C, and D collected from African women after nevirapine administration. ViroSeq detected K103N in 100% of samples with >20% K103N, 77.8% of samples with 10 to 20% K103N, 71.4% of samples with 5 to 10% K103N, and 16.9% of samples with 1 to 5% K103N. The sensitivity of ViroSeq for detection of K103N was similar for subtypes A, C, and D. These data indicate that the ViroSeq system reliably detects the K103N mutation at levels above 20% and frequently detects the mutation at lower levels. Further studies are needed to compare the sensitivity of different assays for detection of HIV-1 drug resistance mutations and to determine the clinical relevance of HIV-1 minority variants.

The administration of single-dose nevirapine to women in labor and their infants can prevent HIV-1 mother-to-child transmission. We examined nevirapine resistance in infants who were HIV-1 infected despite single-dose nevirapine prophylaxis, including 18 Ugandan infants (HIVNET 012 trial, nine subtype A and nine subtype D) and 23 Malawian infants (NVAZ trial, all subtype C). Nevirapine resistance was more frequent in infants with subtype C than with subtypes A and D (87 versus 50%, P = 0.016).