Risk of heterosexual HIV transmission attributable to sexually transmitted infections and non-specific genital inflammation in Zambian discordant couples, 1994-2012

Background

Studies have demonstrated the role of ulcerative and non-ulcerative sexually transmitted infections (STI) in HIV transmission/acquisition risk; less is understood about the role of non-specific inflammatory genital abnormalities.

Methods

HIV-discordant heterosexual Zambian couples were enrolled into longitudinal follow-up (1994-2012). Multivariable models estimated the effect of genital ulcers and inflammation in both partners on time-to-HIV transmission within the couple. Population-attributable fractions (PAFs) were calculated.

Results

A total of 207 linked infections in women occurred over 2756 couple-years (7.5/100 CY) and 171 in men over 3216 CY (5.3/100 CY). Incident HIV among women was associated with a woman's non-STI genital inflammation (adjusted hazard ratio (aHR) = 1.55; PAF = 8%), bilateral inguinal adenopathy (BIA; aHR = 2.33; PAF = 8%), genital ulceration (aHR = 2.08; PAF = 7%) and the man's STI genital inflammation (aHR = 3.33; PAF = 5%), BIA (aHR = 3.35; PAF = 33%) and genital ulceration (aHR = 1.49; PAF = 9%). Infection among men was associated with a man's BIA (aHR = 4.11; PAF = 22%) and genital ulceration (aHR = 3.44; PAF = 15%) as well as with the woman's non-STI genital inflammation (aHR = 1.92; PAF = 13%) and BIA (aHR = 2.76; PAF = 14%). In HIV-M+F- couples, the man being uncircumcised. with foreskin smegma. was associated with the woman's seroconversion (aHR = 3.16) relative to being circumcised. In F+M- couples, uncircumcised men with BIA had an increased hazard of seroconversion (aHR = 13.03 with smegma and 4.95 without) relative to being circumcised. Self-reporting of symptoms was low for ulcerative and non-ulcerative STIs.

Conclusions

Our findings confirm the role of STIs and highlight the contribution of non-specific genital inflammation to both male-to-female and female-to-male HIV transmission/acquisition risk. Studies are needed to characterize pathogenesis of non-specific inflammation including inguinal adenopathy. A better understanding of genital practices could inform interventions.

Sustained effect of couples' HIV counselling and testing on risk reduction among Zambian HIV serodiscordant couples

Background

We present temporal trends in self-reported and biological markers of unprotected sex and sex with concurrent partners in discordant couples receiving couples' voluntary HIV counselling and testing (CVCT).

Methods

Heterosexual Zambian HIV-serodiscordant couples were enrolled into longitudinal follow-up in an open cohort (1994–2012). Multivariable Anderson-Gill models explored predictors of self-report and biological indicators of unprotected sex within (including sperm on a vaginal swab, incident pregnancy or incident linked HIV infection) and outside (including self-report, STI and unlinked HIV infection) the union. Measures of secular trends in baseline measures were also examined.

Results

At enrolment of 3049 couples, men were 35 years old on average, women were 29 years, and couples had been together for an average of 7 years. M+F− couples reported an average of 16.6 unprotected sex acts in the 3 months prior to enrolment (pre-CVCT), dropping to 5.3 in the >0–3 month interval, and 2.0 in >6 month intervals (p-trend <0.001). Corresponding values for M−F+ couples were 22.4 unprotected sex acts in the 3 months prior enrolment, dropping to 5.2 in the >0–3 month interval, and 3.1 in >6 month intervals (p-trend <0.001). Significant reductions in self-report and biological markers of outside partners were also noted. Predictors of unprotected sex between study partners after CVCT included prevalent pregnancy (adjusted HR, aHR=1.6–1.9); HIV+ men being circumcised (aHR=1.2); and HIV− women reporting sex with outside partners (aHR=1.3), alcohol (aHR=1.2), injectable (aHR=1.4) or oral (aHR=1.4) contraception use. Fertility intentions were also predictive of unprotected sex (aHR=1.2–1.4). Secular trends indicated steady declines in reported outside partners and STIs.

Conclusion

Reductions in self-reported unprotected sex after CVCT were substantial and sustained. Reinforced risk-reduction counselling in pregnant couples, couples desiring children and couples with HIV− women having outside partners or using alcohol or injectable or oral contraception are indicated.

Contraceptive discontinuation and switching among couples receiving integrated HIV and family planning services in Lusaka, Zambia

OBJECTIVE

To describe predictors of contraceptive method discontinuation and switching behaviours among HIV-positive couples receiving couples' voluntary HIV counselling and testing services in Lusaka, Zambia.

DESIGN

Couples were randomized in a factorial design to two-family planning educational intervention videos, received comprehensive family planning services and were assessed every 3 months for contraceptive initiation, discontinuation and switching.

METHODS

We modelled factors associated with contraceptive method upgrading and downgrading via multivariate Andersen-Gill models.

RESULTS

Most women continued the initial method selected after randomization. The highest rates of discontinuation/switching were observed for injectable contraceptive and intrauterine device users. Time to discontinuing the more effective contraceptive methods or downgrading to oral contraceptives or condoms was associated with the women's younger age, desire for more children within the next year, heavy menstrual bleeding, bleeding between periods and cystitis/dysuria. Health concerns among women about contraceptive implants and male partners not wanting more children were associated with upgrading from oral contraceptives or condoms. HIV status of the woman or the couple was not predictive of switching or stopping.

CONCLUSION

We found complicated patterns of contraceptive use. The predictors of contraception switching indicate that interventions targeted to younger couples that address common contraception-related misconceptions could improve effective family planning utilization. We recommend these findings be used to increase the uptake and continuation of contraception, especially long-acting reversible contraceptive (LARC) methods, and that fertility goal based, LARC-focused family planning be offered as an integral part of HIV prevention services.

Unintended pregnancy among HIV positive couples receiving integrated HIV counseling, testing, and family planning services in Zambia

Objective

We describe rates of unintended pregnancy among HIV positive couples in Lusaka, Zambia. We also identify factors associated with unintended pregnancy among oral contraceptive pill (OCP) using couples in this cohort.

Design

Data were analyzed from couples randomized in a factorial design to two family planning intervention videos.

Methods

Rates of unintended pregnancy were stratified by contraceptive method used at time of pregnancy. Predictors of time to unintended pregnancy among OCP users were determined via multivariate Cox modeling.

Results

The highest rates of unintended pregnancy were observed among couples requesting condoms only (26.4/100CY) or OCPs (20.7/100CY); these rates were not significantly different. OCP users accounted for 37% of the couple-years (CY) observed and 87% of unintended pregnancies. Rates of unintended pregnancy for injectable (0.7/100CY) and intrauterine device (1.6/100CY) users were significantly lower relative to condom only users. No pregnancies occurred among contraceptive implant users or after tubal ligation. Factors associated (p<0.05) with time to unintended pregnancy among OCP users in multivariate analysis included the man wanting more children, the woman being HIV negative versus having stage IV HIV disease, and the woman reporting: younger age, no previous OCP use, missed OCPs, or sex without a condom.

Conclusions

Long-acting reversible contraceptive methods were effective in the context of integrated couples HIV prevention and contraceptive services. Injectable methods were also effective in this context. Given the high user failure rate of OCPs, family planning efforts should promote longer-acting methods among OCP users wishing to avoid pregnancy. Where other methods are not available or acceptable, OCP adherence counseling is needed, especially among younger and new OCP users.

Trial registration

ClinicalTrials.gov NCT00067522

Impact of long-term contraceptive promotion on incident pregnancy: a randomized controlled trial among HIV-positive couples in Lusaka, Zambia

OBJECTIVES

To evaluate the impact of family planning promotion on incident pregnancy in a combined effort to address Prongs 1 and 2 of prevention of mother-to-child transmission of HIV.

DESIGN

We conducted a factorial randomized controlled trial of 2 video-based interventions.

METHODS

"Methods" and "Motivational" messages promoted long-term contraceptive use among 1060 couples with HIV in Lusaka, Zambia.

RESULTS

Among couples not using contraception before randomization (n = 782), the video interventions had no impact on incident pregnancy. Among baseline contraceptive users, viewing the "Methods video" which focused on the intrauterine device and contraceptive implant was associated with a significantly lower pregnancy incidence [hazard ratio (HR) = 0.38; 95% confidence interval (CI): 0.19 to 0.75] relative to those viewing control and/or motivational videos. The effect was strongest in concordant positive couples (HR = 0.22; 95% CI: 0.08 to 0.58) and couples with HIV-positive women (HR = 0.23; 95% CI: 0.09 to 0.55).

CONCLUSIONS

The "Methods video" intervention was previously shown to increase uptake of long-acting contraception and to prompt a shift from daily oral contraceptives to quarterly injectables and long-acting methods such as the intrauterine device and implant. Follow-up confirms sustained intervention impact on pregnancy incidence among baseline contraceptive users, in particular couples with HIV-positive women. Further work is needed to identify effective interventions to promote long-acting contraception among couples who have not yet adopted modern methods.

A gp41-based heteroduplex mobility assay provides rapid and accurate assessment of intrasubtype epidemiological linkage in HIV type 1 heterosexual transmission Pairs

A critical step in HIV-1 transmission studies is the rapid and accurate identification of epidemiologically linked transmission pairs. To date, this has been accomplished by comparison of polymerase chain reaction (PCR)-amplified nucleotide sequences from potential transmission pairs, which can be cost-prohibitive for use in resource-limited settings. Here we describe a rapid, cost-effective approach to determine transmission linkage based on the heteroduplex mobility assay (HMA), and validate this approach by comparison to nucleotide sequencing. A total of 102 HIV-1-infected Zambian and Rwandan couples, with known linkage, were analyzed by gp41-HMA. A 400-base pair fragment within the envelope gp41 region of the HIV proviral genome was PCR amplified and HMA was applied to both partners' amplicons separately (autologous) and as a mixture (heterologous). If the diversity between gp41 sequences was low (<5%), a homoduplex was observed upon gel electrophoresis and the transmission was characterized as having occurred between partners (linked). If a new heteroduplex formed, within the heterologous migration, the transmission was determined to be unlinked. Initial blind validation of gp-41 HMA demonstrated 90% concordance between HMA and sequencing with 100% concordance in the case of linked transmissions. Following validation, 25 newly infected partners in Kigali and 12 in Lusaka were evaluated prospectively using both HMA and nucleotide sequences. Concordant results were obtained in all but one case (97.3%). The gp41-HMA technique is a reliable and feasible tool to detect linked transmissions in the field. All identified unlinked results should be confirmed by sequence analyses.

Promotion of couples' voluntary HIV counselling and testing in Lusaka, Zambia by influence network leaders and agents

OBJECTIVES

Hypothesising that couples' voluntary counselling and testing (CVCT) promotions can increase CVCT uptake, this study identified predictors of successful CVCT promotion in Lusaka, Zambia.

DESIGN

Cohort study.

SETTING

Lusaka, Zambia.

PARTICIPANTS

68 influential network leaders (INLs) identified 320 agents (INAs) who delivered 29 119 CVCT invitations to heterosexual couples.

INTERVENTION

The CVCT promotional model used INLs who identified INAs, who in turn conducted community-based promotion and distribution of CVCT invitations in two neighbourhoods over 18 months, with a mobile unit in one neighbourhood crossing over to the other mid-way through.

PRIMARY OUTCOME

The primary outcome of interest was couple testing (yes/no) after receipt of a CVCT invitation. INA, couple and invitation characteristics predictive of couples' testing were evaluated accounting for two-level clustering.

RESULTS

INAs delivered invitations resulting in 1727 couples testing (6% success rate). In multivariate analyses, INA characteristics significantly predictive of CVCT uptake included promoting in community-based (adjusted OR (aOR)=1.3; 95% CI 1.0 to 1.8) or health (aOR=1.5; 95% CI 1.2 to 2.0) networks versus private networks; being employed in the sales/service industry (aOR=1.5; 95% CI 1.0 to 2.1) versus unskilled manual labour; owning a home (aOR=0.7; 95% CI 0.6 to 0.9) versus not; and having tested for HIV with a partner (aOR=1.4; 95% CI 1.1 to 1.7) or alone (aOR=1.3; 95% CI 1.0 to 1.6) versus never having tested. Cohabiting couples were more likely to test (aOR=1.4; 95% CI 1.2 to 1.6) than non-cohabiting couples. Context characteristics predictive of CVCT uptake included inviting couples (aOR=1.2; 95% CI 1.0 to 1.4) versus individuals; the woman (aOR=1.6; 95% CI 1.2 to 2.2) or couple (aOR=1.4; 95% CI 1.0 to 1.8) initiating contact versus the INA; the couple being socially acquainted with the INA (aOR=1.6; 95% CI 1.4 to 1.9) versus having just met; home invitation delivery (aOR=1.3; 95% CI 1.1 to 1.5) versus elsewhere; and easy invitation delivery (aOR=1.8; 95% CI 1.4 to 2.2) versus difficult as reported by the INA.

CONCLUSIONS

This study demonstrated the ability of influential people to promote CVCT and identified agent, couple and context-level factors associated with CVCT uptake in Lusaka, Zambia. We encourage the development of CVCT promotions in other sub-Saharan African countries to support sustained CVCT dissemination.

A randomized controlled trial to promote long-term contraceptive use among HIV-serodiscordant and concordant positive couples in Zambia

BACKGROUND

Countries facing high HIV prevalence often also experience high levels of fertility and low contraceptive use, suggesting high levels of unmet need for contraceptive services. In particular, the unique needs of couples with one or both partners HIV positive are largely missing from many current family planning efforts, which focus on the prevention of pregnancies in the absence of reduction of the risk of HIV and other sexually transmitted infections (STIs).

METHODS

This article presents an examination of contraceptive method uptake among a cohort of HIV serodiscordant and concordant positive study participants in Zambia.

RESULTS

Baseline contraceptive use was low; however, exposure to a video-based intervention that provided information on contraceptive methods and modeled desirable future planning behaviors dramatically increased the uptake of modern contraceptive methods.

CONCLUSIONS

Including information on family planning in voluntary counseling and testing (VCT) services in addition to tailoring the delivery of family planning information to meet the needs and concerns of HIV-positive women or those with HIV-positive partners is an essential step in the delivery of services and prevention efforts to reduce the transmission of HIV. Family planning and HIV prevention programs should integrate counseling on dual method use, combining condoms for HIV/STI prevention with a long-acting contraceptive for added protection against unplanned pregnancy.

The influence of informed consent content on study participants' contraceptive knowledge and concerns

Little is known about how the information presented in the informed consent process influences study outcomes among participants. This study examines the influence of informed consent content on reported baseline contraceptive knowledge and concerns among two groups of HIV-serodiscordant and seroconcordant HIV-positive couples enrolled in research projects at an HIV research center in Lusaka, Zambia. We found significant differences in the reporting of contraceptive knowledge and concerns between couples viewing consent materials that included detailed information about contraception and those viewing consent materials that lacked the detailed information. We conclude that the design of informed consent materials should strike a balance between ensuring that participants give truly informed consent and educating participants in ways that do not compromise the assessment of the impact of behavioral interventions.

Knowledge, use, and concerns about contraceptive methods among sero-discordant couples in Rwanda and Zambia

OBJECTIVE

The unique needs of sero-discordant couples are largely missing from many current family planning efforts, which focus on the prevention of pregnancies in absence of the reduction of the risk of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). Conversely, HIV testing and programs focus exclusively on condom use without discussion of more effective contraceptive methods. In order to provide information to inform the development of family planning services tailored to the unique needs of sero-discordant couples, this study examined the contraceptive knowledge, use, and concerns among sero-discordant couples in urban Rwanda and Zambia.

METHODS

This article presents a comparison of family planning knowledge, use, and concerns about contraception among two cohorts of HIV sero-discordant study participants in Rwanda and Zambia.

RESULTS

The results reveal an interesting profile of contraceptive knowledge and use among sero-discordant couples; in both settings, despite high levels of knowledge of contraception, use of contraceptive methods remains relatively low. There is a clear gender difference in both the reporting of knowledge and use of contraceptive methods, and there is evidence of clandestine contraceptive use by women.

CONCLUSIONS

Including information on family planning in voluntary counseling and testing (VCT) services in addition to tailoring the delivery of family planning information to meet to needs and concerns of HIV-positive women or those with HIV positive partners is an essential step in the delivery of services and prevention efforts to reduce the transmission of HIV. Family planning and HIV prevention programs should integrate counseling on "dual method use," combining condoms for HIV/STI prevention with a long-acting contraceptive for added protection against unplanned pregnancy.

Effects of early, abrupt weaning on HIV-free survival of children in Zambia

BACKGROUND

In low-resource settings, many programs recommend that women who are infected with the human immunodeficiency virus (HIV) stop breast-feeding early. We conducted a randomized trial to evaluate whether abrupt weaning at 4 months as compared with the standard practice has a net benefit for HIV-free survival of children.

METHODS

We enrolled 958 HIV-infected women and their infants in Lusaka, Zambia. All the women planned to breast-feed exclusively to 4 months; 481 were randomly assigned to a counseling program that encouraged abrupt weaning at 4 months, and 477 to a program that encouraged continued breast-feeding for as long as the women chose. The primary outcome was either HIV infection or death of the child by 24 months.

RESULTS

In the intervention group, 69.0% of the mothers stopped breast-feeding at 5 months or earlier; 68.8% of these women reported the completion of weaning in less than 2 days. In the control group, the median duration of breast-feeding was 16 months. In the overall cohort, there was no significant difference between the groups in the rate of HIV-free survival among the children; 68.4% and 64.0% survived to 24 months without HIV infection in the intervention and control groups, respectively (P=0.13). Among infants who were still being breast-fed and were not infected with HIV at 4 months, there was no significant difference between the groups in HIV-free survival at 24 months (83.9% and 80.7% in the intervention and control groups, respectively; P=0.27). Children who were infected with HIV by 4 months had a higher mortality by 24 months if they had been assigned to the intervention group than if they had been assigned to the control group (73.6% vs. 54.8%, P=0.007).

CONCLUSIONS

Early, abrupt cessation of breast-feeding by HIV-infected women in a low-resource setting, such as Lusaka, Zambia, does not improve the rate of HIV-free survival among children born to HIV-infected mothers and is harmful to HIV-infected infants.(ClinicalTrials.gov number, NCT00310726.)

The relationship between alcohol consumption and unprotected sex among known HIV-discordant couples in Rwanda and Zambia

Although alcohol abuse is highly prevalent in many countries in sub-Saharan Africa, little is known about the relationship between alcohol consumption and risky sexual behavior in these settings. An understanding of this relationship is particularly important given the high prevalence of HIV that exists in many of these countries. This study analyzes data collected from members of cohabiting HIV-discordant couples regarding alcohol consumption and self-reported condom use. After controlling for demographic and socioeconomic co-factors, alcohol use by male partners of HIV-discordant couples was associated with self-reported unprotected sex at follow-up. Counseling about alcohol use should be part of HIV testing and counseling programs, particularly among those found to be HIV-positive.

Modified Kigali combined staging predicts risk of mortality in HIV-infected adults in Lusaka, Zambia

We assessed the utility of the modified Kigali combined (MKC) staging system for predicting survival in HIV-infected Zambian adults in a prospective, longitudinal, open cohort. From 1995 to 2004, HIV-discordant couples (one HIV-infected partner and one HIV-negative partner) were recruited from couples' voluntary counseling and testing centers in Lusaka, Zambia and followed at 3-month intervals. MKC stage, which incorporates clinical stage with erythrocyte sedimentation rate (ESR), hematocrit, and body mass index (BMI), was determined at enrollment. Kaplan-Meier survival and Cox proportional hazard methods were used to calculate median survival and relative hazards. We enrolled 1479 HIV-discordant couples with a combined 7305 person-years of follow-up. Among HIV-infected participants over the 9-year study period, there were 333 confirmed deaths. The time to 50% mortality was 8.5 years with MKC stage 1 and 2 disease compared to 3.7 years with MKC stage 4 disease at enrollment. Survival rates at 3 years were 85% with MKC stage 1 and 2 disease, 74% with MKC stage 3 disease, and 51% with MKC stage 4 disease. A total of 275 HIV-negative partners seroconverted during follow-up. In comparison, survival rates at 3 years were 94% for HIV-negative participants and 92% for participants who seroconverted during follow-up. In multivariate analysis, MKC stage 4 disease (HR = 3.7, 95% CI = 2.7-5.0) remained a strong predictor of mortality. Incorporating ESR, hematocrit, and BMI with clinical staging is a powerful, low-cost tool to identify HIV-infected adults at high risk for mortality.

New heterosexually transmitted HIV infections in married or cohabiting couples in urban Zambia and Rwanda: an analysis of survey and clinical data

BACKGROUND

Sub-Saharan Africa has a high rate of HIV infection, most of which is attributable to heterosexual transmission. Few attempts have been made to assess the extent of HIV transmission within marriages, and HIV-prevention efforts remain focused on abstinence and non-marital sex. We aimed to estimate the proportion of heterosexual transmission of HIV which occurs within married or cohabiting couples in urban Zambia and Rwanda each year.

METHODS

We used population-based data from Demographic and Health Surveys (DHS) on heterosexual behaviour in Zambia in 2001-02 and in Rwanda in 2005. We also used data on the HIV serostatus of married or cohabiting couples and non-cohabiting couples that was collected through a voluntary counselling and testing service for urban couples in Lusaka, in Zambia, and Kigali, in Rwanda. We estimated the probability that an individual would acquire an incident HIV infection from a cohabiting or non-cohabiting sexual partner, and then the proportion of total heterosexual HIV transmission which occurs within married or cohabiting couples in these settings each year.

FINDINGS

We analysed DHS data from 1739 Zambian women, 540 Zambian men, 1176 Rwandan women, and 606 Rwandan men. Under our base model, we estimated that 55.1% to 92.7% of new heterosexually acquired HIV infections among adults in urban Zambia and Rwanda occurred within serodiscordant marital or cohabiting relationships, depending on the sex of the index partner and on location. Under our extended model, which incorporated the higher rates of reported condom use that we found with non-cohabiting partners, we estimated that 60.3% to 94.2% of new heterosexually acquired infections occurred within marriage or cohabitation. We estimated that an intervention for couples which reduced transmission in serodiscordant urban cohabiting couples from 20% to 7% every year could avert 35.7% to 60.3% of heterosexually transmitted HIV infections that would otherwise occur.

INTERPRETATION

Since most heterosexual HIV transmission for both men and women in urban Zambia and Rwanda takes place within marriage or cohabitation, voluntary counselling and testing for couples should be promoted, as should other evidence-based interventions that target heterosexual couples.

High uptake of exclusive breastfeeding and reduced early post-natal HIV transmission

BACKGROUND

Empirical data showing the clear benefits of exclusive breastfeeding (EBF) for HIV prevention are needed to encourage implementation of lactation support programs for HIV-infected women in low resource settings among whom replacement feeding is unsafe. We conducted a prospective, observational study in Lusaka, Zambia, to test the hypothesis that EBF is associated with a lower risk of postnatal HIV transmission than non-EBF.

METHODS AND RESULTS

As part of a randomized trial of early weaning, 958 HIV-infected women and their infants were recruited and all were encouraged to breastfeed exclusively to 4 months. Single-dose nevirapine was provided to prevent transmission. Regular samples were collected from infants to 24 months of age and tested by PCR. Detailed measurements of actual feeding behaviors were collected to examine, in an observational analysis, associations between feeding practices and postnatal HIV transmission. Uptake of EBF was high with 84% of women reporting only EBF cumulatively to 4 months. Post-natal HIV transmission before 4 months was significantly lower (p = 0.004) among EBF (0.040 95% CI: 0.024-0.055) than non-EBF infants (0.102 95% CI: 0.047-0.157); time-dependent Relative Hazard (RH) of transmission due to non-EBF = 3.48 (95% CI: 1.71-7.08). There were no significant differences in the severity of disease between EBF and non-EBF mothers and the association remained significant (RH = 2.68 95% CI: 1.28-5.62) after adjusting for maternal CD4 count, plasma viral load, syphilis screening results and low birth weight.

CONCLUSIONS

Non-EBF more than doubles the risk of early postnatal HIV transmission. Programs to support EBF should be expanded universally in low resource settings. EBF is an affordable, feasible, acceptable, safe and sustainable practice that also reduces HIV transmission providing HIV-infected women with a means to protect their children's lives.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00310726.

Genetic and neutralization properties of subtype C human immunodeficiency virus type 1 molecular env clones from acute and early heterosexually acquired infections in Southern Africa

A standard panel of subtype C human immunodeficiency virus type 1 (HIV-1) Env-pseudotyped viruses was created by cloning, sequencing, and characterizing functional gp160 genes from 18 acute and early heterosexually acquired infections in South Africa and Zambia. In general, the gp120 region of these clones was shorter (most evident in V1 and V4) and less glycosylated compared to newly transmitted subtype B viruses, and it was underglycosylated but no different in length compared to chronic subtype C viruses. The gp120s also exhibited low amino acid sequence variability (12%) in V3 and high variability (39%) immediately downstream of V3, a feature shared with newly transmitted subtype B viruses and chronic viruses of both subtypes. When tested as Env-pseudotyped viruses in a luciferase reporter gene assay, all clones possessed an R5 phenotype and resembled primary isolates in their sensitivity to neutralization by HIV-1-positive plasmas. Results obtained with a multisubtype plasma panel suggested partial subtype preference in the neutralizing antibody response to infection. The clones were typical of subtype C in that all were resistant to 2G12 (associated with loss of N-glycosylation at position 295) and most were resistant to 2F5, but all were sensitive to 4E10 and many were sensitive to immunoglobulin G1b12. Finally, conserved neutralization epitopes in the CD4-induced coreceptor binding domain of gp120 were poorly accessible and were difficult to induce and stabilize with soluble CD4 on Env-pseudotyped viruses. These results illustrate key genetic and antigenic properties of subtype C HIV-1 that might impact the design and testing of candidate vaccines. A subset of these gp160 clones are suitable for use as reference reagents to facilitate standardized assessments of vaccine-elicited neutralizing antibody responses.

Impact of chloroquine on viral load in breast milk

The anti-malarial agent chloroquine has activity against HIV. We compared the effect of chloroquine (n = 18) to an anti-malarial agent without known anti-HIV-activity, sulfadoxine-pyrimethamine (n = 12), on breast milk HIV RNA levels among HIV-infected breastfeeding women in Zambia. After adjusting for CD4 count and plasma viral load, chloroquine was associated with a trend towards lower levels of HIV RNA in breast milk compared with sulfadoxine-pyrimethamine (P = 0.05). Higher breastmilk viral load was also observed among women receiving presumptive treatment for symptomatic malaria compared with asymptomatic controls and among controls reporting fever in the prior week. Further research is needed to determine the potential role of chloroquine in prevention of HIV transmission through breastfeeding.

Predictors of Nonadherence to Single-Dose Nevirapine Therapy for the Prevention of Mother-to-Child HIV Transmission

BACKGROUND

Adequate adherence is required for prevention of mother-to-child transmission of HIV (pMTCT) programs to be effective. We investigated predictors and extent of nonadherence to single-dose nevirapine.

METHODS

Data on nevirapine intake and possible predictors were collected among 760 HIV-positive women with liveborn babies enrolled in a study in Lusaka, Zambia.

RESULTS

Most (94%) women took nevirapine before delivery, and most (91%) newborns received it soon after delivery. Maternal nonadherence was associated with home births (odds ratio [OR]: 3.2; 95% confidence interval [CI]: 1.3 to 7.4), no high school education (OR: 2.4; 95% CI: 1.1 to 5.3), and low newborn birth weight (OR: 4.6; 95% CI: 1.3 to 20.1). Disclosure of HIV status and couples counseling was only associated with adherence among home births. Failure to administer nevirapine to the newborn was associated with birth at the tertiary hospital (OR: 7.2; 95% CI: 3.7 to 13.8), lower 5-minute Apgar scores (OR: 0.5; 95% CI: 0.4 to 0.7), and neonatal death (OR: 5.8; 95% CI: 2.0 to 16.3).

CONCLUSIONS

Excellent adherence to single-dose nevirapine for pMTCT can be achieved. Nonadherence seems to be affected by place of birth and by poor health status of the newborn. Procedures to ensure that viable yet ill neonates receive nevirapine should be part of clinical protocols and training within pMTCT programs.

Prolonged breast-feeding and mortality up to two years post-partum among HIV-positive women in Zambia

BACKGROUND

A previously reported association between prolonged lactation and maternal mortality has generated concern that breast-feeding may be detrimental for HIV-positive women.

METHODS

As part of a trial conducted in Lusaka, Zambia, 653 HIV-positive women were randomly assigned either to a counseling program that encouraged abrupt cessation of breast-feeding at 4 months (group A) or to a program that encouraged prolonged breast-feeding for the duration of the woman's own informed choice (group B). We examined whether mortality up to 2 years post-partum increased with breast-feeding for a longer duration.

RESULTS

There was no difference in mortality 12 months after delivery between 326 HIV-positive women randomly assigned to short breast-feeding [group A: 4.93%; 95% confidence interval (CI), 2.42-7.46] versus 327 women assigned to long breast-feeding (group B: 4.89%; 95% CI, 2.38-7.40). Analysis based on actual practice, rather than random assignment, also demonstrated no increased mortality due to breast-feeding.

CONCLUSIONS

Although HIV-related mortality was high in this cohort of untreated HIV-positive women, prolonged lactation was not associated with increased mortality.

Alpha-defensins in the prevention of HIV transmission among breastfed infants

Alpha-defensins have been observed to have anti-HIV activity but have not been investigated in relation to mother-to-child HIV transmission. We measured the concentration of alpha-defensins in breast milk of HIV-positive mothers and tested whether the concentrations were associated with HIV transmission. A nested case-control study of 32 HIV-positive women who transmitted HIV to their infants and 52 randomly selected HIV-positive women who did not transmit HIV to their infants was conducted in Lusaka, Zambia. alpha-Defensins were detected in most (79%) of the milk samples tested. Concentrations of alpha-defensins increased as breast milk HIV RNA quantity increased, and breast milk HIV RNA quantity was, in turn, a strong and significant predictor of HIV transmission. After adjustment for milk HIV RNA quantity, however, alpha-defensin concentration was significantly associated with a decreased risk of intrapartum and postnatal HIV transmission (odds ratio = 0.3, 95% confidence interval: 0.09-0.93). Our data suggest that there may be a role for alpha-defensins in prevention of HIV transmission to breastfed infants.

Women in couples antenatal HIV counseling and testing are not more likely to report adverse social events

BACKGROUND

Couple counseling has been promoted as a strategy to improve uptake of interventions to prevent mother-to-child HIV transmission (pMTCT) and to minimize adverse social outcomes associated with disclosure of HIV status.

OBJECTIVES

We tested whether women counseled antenatally as part of a couple were more likely to accept HIV testing and nevirapine in a pMTCT program, and whether they would be less likely to experience later adverse social events than women counseled alone.

METHODS

A pMTCT program that included active community education and outreach to encourage couple counseling and testing was implemented in two antenatal clinics in Lusaka, Zambia. A subset of HIV-positive women was asked to report their experience of adverse social events 6 months after delivery. Couple-counseled women were compared with individual-counseled women stratified by whether or not they had disclosed their HIV status to their partners.

RESULTS

Nine percent (868) of 9409 women counseled antenatally were counseled with their husband. Couple-counseled women were more likely to accept HIV testing (96%) than women counseled alone (79%); however uptake of nevirapine was not improved. Six months after delivery, 28% of 324 HIV-positive women reported at least one adverse social event (including physical violence, verbal abuse, divorce or separation). There were no significant differences in reported adverse social events between couple- and individual-counseled women.

CONCLUSIONS

Couple counseling did not increase the risk of adverse social events associated with HIV disclosure. Support services and interventions to improve social situations for people living with HIV need to be further evaluated.

Issues in the design of a clinical trial with a behavioral intervention--the Zambia exclusive breast-feeding study

PURPOSE

We present the rationale and design of the Zambian Exclusive Breast-feeding Study (ZEBS), a randomized trial evaluating the efficacy of short-duration exclusive breast-feeding (EBF) as a strategy to reduce postnatal human immunodeficiency virus (HIV) transmission while preserving the other health benefits of this important mode of infant feeding.

METHODS

One thousand two hundred HIV-positive pregnant women were recruited in Lusaka, Zambia, and followed with their infants for 24 months. In addition to Nevirapine (NVP), all women received intensive and frequent clinic- and home-based counseling to support exclusive breast-feeding. When the infant was 1 week of age, half of the women were randomly assigned to a group encouraged to abruptly (<24 h) cease all breast-feeding at 4 months. The primary outcome of the experimental (randomized) comparison is HIV-free survival at 24 months. The design is also observational and will compare HIV transmission rates between those who do and do not adhere to the counseling intervention promoting exclusive breast-feeding.

CONCLUSION

Our study aims to quantify the benefit-risk ratio of early cessation of exclusive breast-feeding to interrupt mother-to-child transmission of HIV with an intensive behavioral intervention and has both observational and experimental analytic approaches. Our study design assesses efficacy and also has a prominent applied component that if the intervention is effective, it will permit rapid and sustainable adoption within low-resource communities.