Gerald Tegha

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.

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.

Measures of viral load using Abbott RealTime HIV-1 Assay on venous and fingerstick dried blood spots from provider-collected specimens in Malawian District Hospitals

BACKGROUND Viral suppression is a key indicator of antiretroviral therapy (ART) response among HIV-infected patients. Dried blood spots (DBS) are an appealing alternative to conventional plasma-based virologic testing, improving access to monitoring in resource-limited settings. However, validity of DBS obtained from fingerstick in field settings remains unknown. OBJECTIVES Investigate feasibility and accuracy of DBS vs plasma collected by healthcare workers in real-world settings of remote hospitals in Malawi. Compare venous DBS to fingerstick DBS for identifying treatment failure. STUDY DESIGN We recruited patients from ART clinics at two district hospitals in Malawi, collecting plasma, venous DBS (vDBS), and fingerstick DBS (fsDBS) cards for the first 149 patients, and vDBS and fsDBS only for the subsequent 398 patients. Specimens were tested using Abbott RealTime HIV-1 Assay (lower detection limit 40 copies/ml (plasma) and 550 copies/ml (DBS)). RESULTS 21/149 (14.1%) had detectable viremia (>1.6 log copies/ml), 13 of which were detectable for plasma, vDBS, and fsDBS. Linear regression demonstrated high correlation for plasma vs. DBS (vDBS: β=1.19, R(2)=0.93 (p<0.0001); fsDBS β=1.20, R(2)=0.90 (p<0.0001)) and vDBS vs. fsDBS (β=0.88, R(2)=0.73, (p<0.0001)). Mean difference between plasma and vDBS was 1.1 log copies/ml [SD: 0.27] and plasma and fsDBS 1.1 log copies/ml [SD: 0.31]. At 5000 copies/ml, sensitivity was 100%, and specificity was 98.6% and 97.8% for vDBS and fsDBS, respectively, compared to plasma. CONCLUSIONS DBS from venipuncture and fingerstick perform well at the failure threshold of 5000 copies/ml. Fingerstick specimen source may improve access to virologic treatment monitoring in resource-limited settings given task-shifting in high-volume, low-resource facilities.

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.

Addition of 7 days of zidovudine plus lamivudine to peripartum single-dose nevirapine effectively reduces nevirapine resistance postpartum in HIV-infected mothers in Malawi

Background:We assessed whether 7 days of zidovudine + lamivudine postpartum with single-dose nevirapine at labor decreases nevirapine resistance in HIV-infected women in Malawi. Methods:HIV-infected pregnant women receiving intrapartum single-dose nevirapine and 7 days of zidovudine + lamivudine (n = 132) and women receiving intrapartum single-dose nevirapine alone (n = 66) were followed from an antenatal visit through 6 weeks postpartum. Plasma specimens at 2 and 6 weeks postpartum were tested for genotypic resistance to nevirapine by population sequencing and sensitive real-time polymerase chain reaction. Poisson regression was used to determine predictors of postpartum nevirapine resistance. Results:Median HIV RNA was similar at entry (4.27 log vs. 4.35 log, P = 0.87), differed at 2 weeks postpartum (2.67 log vs. 3.58 log, P < 0.0001) but not at 6 weeks postpartum (4.49 log vs. 4.40 log, P = 0.79), between single-dose nevirapine/zidovudine + lamivudine and single-dose nevirapine groups, respectively. Nevirapine resistance, measured by population sequencing and sensitive real-time polymerase chain reaction, was significantly less common in those receiving single-dose nevirapine/zidovudine + lamivudine compared with single-dose nevirapine, respectively, at 2 weeks [10% (4 of 40) vs. 74% (31 of 42), P < 0.0001] and 6 weeks postpartum [10% (11 of 115) vs. 64% (41 of 64), P < 0.0001; adjusted relative risk = 0.18, 95% confidence interval (0.10 to 0.34)]. Conclusions:The significant decrease in nevirapine resistance conferred by 1 week of zidovudine + lamivudine should help policymakers optimize peripartum HIV prophylaxis recommendations.

Effect of cytomegalovirus infection on breastfeeding transmission of HIV and on the health of infants born to HIV-infected mothers

Background:Cytomegalovirus (CMV) infection can be acquired in utero or postnatally through horizontal transmission and breastfeeding. The effect of postnatal CMV infection on postnatal HIV transmission is unknown. Methods:The Breastfeeding, Antiretrovirals and Nutrition study, conducted in Malawi, randomized 2369 mothers and their infants to three antiretroviral prophylaxis arms – mother (triple regimen), infant (nevirapine), or neither – for 28 weeks of breastfeeding, followed by weaning. Stored plasma and peripheral blood mononuclear cell specimens were available for 492 infants at 24 weeks and were tested with CMV PCR. Available samples from infants who were CMV PCR-positive at 24 weeks were also tested at birth (N = 242), and from infants PCR-negative at 24 weeks were tested at 48 weeks (N = 96). Cox proportional-hazards models were used to determine if CMV infection was associated with infant morbidity, mortality, or postnatal HIV acquisition. Results:At 24 weeks of age, CMV DNA was detected in 345/492 infants (70.1%); the estimated congenital CMV infection rate was 2.3%, and the estimated rate of CMV infection at 48 weeks was 78.5%. CMV infection at 24 weeks was associated with subsequent HIV acquisition through breastfeeding or infant death between 24 and 48 weeks of age (hazard ratio 4.27, P = 0.05). Conclusion:Most breastfed infants of HIV-infected mothers in this resource-limited setting are infected with CMV by 24 weeks of age. Early CMV infection may be a risk factor for subsequent infant HIV infection through breastfeeding, pointing to the need for comprehensive approaches in order to achieve elimination of breastfeeding transmission of HIV.

Antiretroviral therapy provided to HIV-infected Malawian women in a randomized trial diminishes the positive effects of lipid-based nutrient supplements on breast-milk B vitamins

BACKGROUND Little information is available on B vitamin concentrations in human milk or on how they are affected by maternal B vitamin deficiencies, antiretroviral therapy, or maternal supplementation. OBJECTIVE The objective was to evaluate the effects of antiretroviral therapy and/or lipid-based nutrient supplements (LNSs) on B vitamin concentrations in breast milk from HIV-infected women in Malawi. DESIGN Breast milk was collected from 537 women recruited within the Breastfeeding, Antiretrovirals, and Nutrition study at 2 or 6 wk and 24 wk postpartum. Women were assigned to receive antiretrovirals and LNSs, antiretrovirals only, LNSs only, or a control. Antiretrovirals and LNSs were given to the mothers from weeks 0 to 28. The antiretrovirals were zidovudine/lamivudine and nelfinavir or lopinavir/ritonavir. LNSs provided 93-118% of the Recommended Dietary Allowances of thiamin, riboflavin, niacin, pyridoxine, and vitamin B-12. Infants were exclusively breastfed. RESULTS LNSs increased milk concentrations of all vitamins except thiamin, whereas antiretrovirals lowered concentrations of nicotinamide, pyridoxal, and vitamin B-12. Although antiretrovirals alone had no significant effect on riboflavin concentrations, they negatively affected the LNS-induced increase in this vitamin. Thiamin was not influenced by the study interventions. Concentrations of all B vitamins were much lower than usually accepted values. CONCLUSIONS All B vitamins were low in milk, and all but thiamin were increased by maternal supplementation with LNSs. Antiretrovirals alone decreased concentrations of some B vitamins in milk. When LNS was given in addition to antiretrovirals, the negative effect of antiretrovirals offset the positive effect of LNSs for all vitamins except thiamin. This trial was registered at clinicaltrials.gov as NCT00164762.

Low Absolute Neutrophil Counts in African Infants

Infants of African origin have a lower normal range of absolute neutrophil counts than white infants; this fact, however, remains under appreciated by clinical researchers in the United States. During the initial stages of a clinical trial in Malawi, the authors noted an unexpectedly high number of infants with absolute neutrophil counts that would be classifiable as neutropenic using the National Institutes of Health’s Division of AIDS toxicity tables. The authors argue that the relevant Division of AIDS table does not take into account the available evidence of low absolute neutrophil counts in African infants and that a systematic collection of data from many African settings might help establish the absolute neutrophil count cutpoints to be used for defining neutropenia in African populations.

Impact of Daily Cotrimoxazole on Clinical Malaria and Asymptomatic Parasitemias in HIV-Exposed, Uninfected Infants

BACKGROUND Cotrimoxazole preventive therapy (CPT) is recommended for all human immunodeficiency virus (HIV)-exposed infants to avoid opportunistic infections. Cotrimoxazole has antimalarial effects and appears to reduce clinical malaria infections, but the impact on asymptomatic malaria infections is unknown. METHODS We conducted an observational cohort study using data and dried blood spots (DBSs) from the Breastfeeding, Antiretrovirals and Nutrition study to evaluate the impact of CPT on malaria infection during peak malaria season in Lilongwe, Malawi. We compared malaria incidence 1 year before and after CPT implementation (292 and 682 CPT-unexposed and CPT-exposed infants, respectively), including only infants who remained HIV negative by 36 weeks of age. Malaria was defined as clinical, asymptomatic (using DBSs at 12, 24, and 36 weeks), or a composite outcome of clinical or asymptomatic. Linear and binomial regression with generalized estimating equations were used to estimate the association between CPT and malaria. Differences in characteristics of parasitemias and drug resistance polymorphisms by CPT status were also assessed in the asymptomatic infections. RESULTS CPT was associated with a 70% (95% confidence interval, 53%-81%) relative reduction in the risk of asymptomatic infection between 6 and 36 weeks of age. CPT appeared to provide temporary protection against clinical malaria and more sustained protection against asymptomatic infections, with no difference in parasitemia characteristics. CONCLUSIONS CPT appears to reduce overall malaria infections, with more prolonged impacts on asymptomatic infections. Asymptomatic infections are potentially important reservoirs for malaria transmission. Therefore, CPT prophylaxis may have important individual and public health benefits.

Plasma and breast-milk selenium in HIV-infected Malawian mothers are positively associated with infant selenium status but are not associated with maternal supplementation: results of the Breastfeeding, Antiretrovirals, and Nutrition study

BACKGROUND Selenium is found in soils and is essential for human antioxidant defense and immune function. In Malawi, low soil selenium and dietary intakes coupled with low plasma selenium concentrations in HIV infection could have negative consequences for the health of HIV-infected mothers and their exclusively breastfed infants. OBJECTIVE We tested the effects of lipid-based nutrient supplements (LNS) that contained 1.3 times the Recommended Dietary Allowance of sodium selenite and antiretroviral drugs (ARV) on maternal plasma and breast-milk selenium concentrations. DESIGN HIV-infected Malawian mothers in the Breastfeeding, Antiretrovirals, and Nutrition study were randomly assigned at delivery to receive: LNS, ARV, LNS and ARV, or a control. In a subsample of 526 mothers and their uninfected infants, we measured plasma and breast-milk selenium concentrations at 2 or 6 (depending on the availability of infant samples) and 24 wk postpartum. RESULTS Overall, mean (± SD) maternal (range: 81.2 ± 20.4 to 86.2 ± 19.9 μg/L) and infant (55.6 ± 16.3 to 61.0 ± 15.4 μg/L) plasma selenium concentrations increased, whereas breast-milk selenium concentrations declined (14.3 ± 11.5 to 9.8 ± 7.3 μg/L) from 2 or 6 to 24 wk postpartum (all P < 0.001). Compared with the highest baseline selenium tertile, low and middle tertiles were positively associated with a change in maternal plasma or breast-milk selenium from 2 or 6 to 24 wk postpartum (both P < 0.001). With the use of linear regression, we showed that LNS that contained selenium and ARV were not associated with changes in maternal plasma and breast-milk selenium, but maternal selenium concentrations were positively associated with infant plasma selenium at 2 or 6 and 24 wk postpartum (P < 0.001) regardless of the study arm. CONCLUSIONS Selenite supplementation of HIV-infected Malawian women was not associated with a change in their plasma or breast-milk selenium concentrations. Future research should examine effects of more readily incorporated forms of selenium (ie, selenomethionine) in HIV-infected breastfeeding women.