The social dynamics of HIV transmission as reflected through discordant couples in rural Uganda

Frequency of HIV serodifferent couples within TB-affected households in a setting with a high burden of HIV-associated TB

INTRODUCTION

Strong epidemiological links between human immunodeficiency virus (HIV) and tuberculosis (TB) may make household TB contact investigation an efficient strategy for HIV screening and finding individuals in serodifferent partnerships at risk of HIV and linking them to HIV prevention services. We aimed to compare the proportions of HIV serodifferent couples in TB-affected households and in the general population of Kampala, Uganda.

METHODS

We included data from a cross-sectional trial of HIV counselling and testing (HCT) in the context of home-based TB evaluation in Kampala, Uganda in 2016-2017. After obtaining consent, community health workers visited the homes of participants with TB to screen contacts for TB and offer HCT to household members ≥ 15 years. We defined index participants and their spouses or parents as couples. Couples were classified as serodifferent if confirmed by self-reported HIV status or by HIV testing results. We used a two-sample test of proportions to compare the frequency of HIV serodifference among couples in the study to its prevalence among couples in Kampala in the 2011 Uganda AIDS Indicator Survey (UAIS).

RESULTS

We included 323 index TB participants and 507 household contacts aged ≥ 18 years. Most index participants (55%) were male, while most (68%) adult contacts were female. There was ≥ 1 couple in 115/323 (35.6%) households, with most couples (98/115, 85.2%) including the index participant and spouse. The proportion of households with HIV-serodifferent couples was 18/323 (5.6%), giving a number-needed-to-screen of 18 households. The proportion of HIV serodifference among couples identified in the trial was significantly higher than among couples in the UAIS (15.7% vs. 8%, p = 0.039). The 18 serodifferent couples included 14 (77.8%) where the index participant was living with HIV and the spouse was HIV-negative, and 4 (22.2%) where the index partner was HIV-negative, while the spouse was living with HIV.

CONCLUSIONS

The frequency of HIV serodifference among couples identified in TB-affected households was higher than in the general population. TB household contact investigation may be an efficient strategy for identifying people with substantial exposure to HIV and linking them to HIV prevention services.

Cost-effectiveness of couples' voluntary HIV counselling and testing in six African countries: a modelling study guided by an HIV prevention cascade framework

INTRODUCTION

Couples' voluntary HIV counselling and testing (CVCT) is a high-impact HIV prevention intervention in Rwanda and Zambia. Our objective was to model the cost-per-HIV infection averted by CVCT in six African countries guided by an HIV prevention cascade framework. The HIV prevention cascade as yet to be applied to evaluating CVCT effectiveness or cost-effectiveness.

METHODS

We defined a priority population for CVCT in Africa as heterosexual adults in stable couples. Based on our previous experience nationalizing CVCT in Rwanda and scaling-up CVCT in 73 clinics in Zambia, we estimated HIV prevention cascade domains of motivation for use, access and effectiveness of CVCT as model parameters. Costs-per-couple tested were also estimated based on our previous studies. We used these parameters as well as country-specific inputs to model the impact of CVCT over a five-year time horizon in a previously developed and tested deterministic compartmental model. We consider six countries across Africa with varied HIV epidemics (South Africa, Zimbabwe, Kenya, Tanzania, Ivory Coast and Sierra Leone). Outcomes of interest were the proportion of HIV infections averted by CVCT, nationwide CVCT implementation costs and costs-per-HIV infection averted by CVCT. We applied 3%/year discounting to costs and outcomes. Univariate and Monte Carlo multivariate sensitivity analyses were conducted.

RESULTS

We estimated that CVCT could avert between 54% (Sierra Leone) and 62% (South Africa) of adult HIV infections. Average costs-per-HIV infection averted were lowest in Zimbabwe ($550) and highest in South Africa ($1272). Nationwide implementations would cost between 7% (Kenya) and 21% (Ivory Coast) of a country's President's Emergency Plan for AIDS Relief (PEPFAR) budget over five years. In sensitivity analyses, model outputs were most sensitive to estimates of cost-per-couple tested; the proportion of adults in heterosexual couples and HIV prevention cascade domains of CVCT motivation and access.

CONCLUSIONS

Our model indicates that nationalized CVCT could prevent over half of adult HIV infections for 7% to 21% of the modelled countries' five-year PEPFAR budgets. While other studies have indicated that CVCT motivation is high given locally relevant promotional and educational efforts, without required indicators, targets and dedicated budgets, access remains low.

Modeling HIV Transmission from Sexually Active Alcohol-Consuming Men in ART Programs to Seronegative Wives

BACKGROUND

The rollout of antiviral therapy in Low and Middle Income Countries (LMICs) has reduced HIV transmission rates at the potential risk of resistant HIV transmission. We sought to predict the risk of wild type and antiviral resistance transmissions in these settings.

METHODS

A predictive model utilizing viral load, ART adherence, genital ulcer disease, condom use, and sexual event histories was developed to predict risks of HIV transmission to wives of 233 HIV+ men in 4 antiretroviral treatment centers in Maharashtra, India.

RESULTS

ARV Therapy predicted a 5.71-fold reduction in transmissions compared to a model of using condoms alone, with 79.9%, of remaining transmissions resulting in primary ART-resistance.

CONCLUSIONS

ART programs reduce transmission of HIV to susceptible partners at a substantial increased risk for transmission of resistant virus. Enhanced vigilance in monitoring adherence, use of barrier protections, and viral load may reduce risks of resistant HIV transmissions in LMIC settings.

Near Full-length Genomic Sequencing and Molecular Analysis of HIV-Infected Individuals in a Network-based Intervention (TRIP) in Athens, Greece: Evidence that Transmissions Occur More Frequently from those with High HIV-RNA

Background:

TRIP (Transmission Reduction Intervention Project) was a network-based, contact tracing approach to locate and link to care, mostly people who inject drugs (PWID) with recent HIV infection.

Objective:

We investigated whether sequences from HIV-infected participants with high viral load cluster together more frequently than what is expected by chance.

Methods:

Paired end reads were generated for 104 samples using Illumina MiSeq next-generation se-quencing.

Results:

63 sequences belonged to previously identified local transmission networks of PWID (LTNs) of an HIV outbreak in Athens, Greece. For two HIV-RNA cut-offs (105 and 106 IU/mL), HIV transmissions were more likely between PWID with similar levels of HIV-RNA (p<0.001). 10 of the 14 sequences (71.4%) from PWID with HIV-RNA >106 IU/mL were clustered in 5 pairs. For 4 of these clusters (80%), there was in each one of them at least one sequence from a recently HIV-infected PWID.

Conclusion:

We showed that transmissions are more likely among PWID with high viremia.

HIV testing and counselling couples together for affordable HIV prevention in Africa

BACKGROUND

The impact and cost-effectiveness of couples' voluntary HIV counselling and testing (CVCT) has not been quantified in real-world settings. We quantify cost-per-HIV-infection averted by CVCT in Zambia from the donor's perspective.

METHODS

From 2010 to 2016, CVCT was established in 73 Zambian government clinics. The cost-per-HIV-infection averted (CHIA) of CVCT was calculated using observed expenditures and effectiveness over longitudinal follow-up. These observed measures parameterized hypothetical 5-year nationwide implementations of: 'CVCT'; 'treatment-as-prevention (TasP) for discordant couples' identified by CVCT; and 'population TasP' for all HIV+ cohabiting persons identified by individual testing.

RESULTS

In all, 207 428 couples were tested (US $52/couple). Among discordant couples in which HIV+ partners self-reported antiretroviral therapy (ART), HIV incidence was 8.5/100 person-years before and 1.8/100 person-years after CVCT (79% reduction). Corresponding reductions for non-ART-using discordant and concordant negative couples were 63% and 47%, respectively. CVCT averted an estimated 58% of new infections at US $659 CHIA. In nationwide implementation models, CVCT would prevent 17 times the number of infections vs 'TasP for discordant couples' at 86% of the cost, and nine times the infections vs 'population TasP' at 28% of the cost.

CONCLUSIONS

CVCT is a cost-effective, feasible prevention strategy in Zambia. We demonstrate the novel, added effectiveness of providing CVCT to ART users, for whom ART use alone only partially mitigated transmission risk. Our results indicate a major policy shift (supporting development of CVCT indicators, budgets and targets) and have clinical implications (suggesting promotion of CVCT in ART clinics as a high-impact prevention strategy).

Population HIV transmission risk for serodiscordant couples in Guangxi, Southern China: A cohort study

We evaluated the risk of human immunodeficiency virus (HIV) transmission among serodiscordant couples with low adherence to antiretroviral therapy (ART).Data of heterosexual couples/partners in 2010 were extracted from an Internet-based system. Participants were then followed over the course of a year with 6- and 12-month assessments. Prevalence and density of HIV seroconversion were calculated for spouses/partners who did not have a positive HIV test results at baseline. We calculated the transmission odds ratio (OR) value stratified by personal characteristics and behavioral correlates at 6- and 12-month follow-up, as well as seroconversion in spouses/partners over the year.A total of 5544 HIV/AIDS patients and their spouses/partners were recruited in this cohort. Incidence of HIV seroconversion among HIV-negative spouse/partner was 63.7/100 person years (PYs) (430/674.9) at the 6-month follow-up and 33.2/100PYs (567/1707.1PYs) at 12 months. The OR value of transmission from female to male was 2.1 times higher than from male to females at 6 months and 2.3 times higher at 12 months (P < .001). The 55- to 64-year age group was most likely to transmit HIV to their spouses/partners, 2.2 times greater than the participants who were 65 years and older. Married participants were 2.4 times higher at 6 months and 2.5 times higher at 12 months to transmit HIV than divorced/widowed participants. Lastly, transmission among illiterate participants was 6.7 times higher at 6 months and 2.3 times higher at 12 months than those with an educational attainment of community college or above.High HIV seroconversion was observed in this cohort. Spouses/partners who were male had the highest risk of HIV acquisition; those aged 55 to 64 years, having married status, and are HIV-positive with less education were more likely to transmit HIV.

Gender inequality dynamics in the prevention of a heterosexual HIV epidemic in sub-Saharan Africa

This paper critiques the approach to the elimination of gender inequality as an HIV prevention strategy in the just ended era of the Millennium Development Goals, with the aim of contributing to the formulation of policy guidelines for sub-Saharan Africa in the Sustainable Development Goals. The aim is to underscore the mutual responsibility of women and men in achieving a sustainable HIV response and ending the epidemic. While taking into account the real vulnerability of women, prevention programmes can reflect gender dynamics more accurately so that attention is given to the role of both sexes in propagating - or stemming - a predominantly heterosexual HIV epidemic. More emphasis could be given to the harm caused to both men and women by certain norms related to masculinity and sexuality, and the subsequent need for combined efforts in reducing intimate partner violence and concurrency. The empowerment and engagement of both women and men as agents of change would need to be dealt with more creatively.

Community Cultural Norms, Stigma and Disclosure to Sexual Partners among Women Living with HIV in Thailand, Brazil and Zambia (HPTN 063)

BACKGROUND

Serostatus disclosure may facilitate decreased HIV transmission between serodiscordant partners by raising risk awareness and heightening the need for prevention. For women living with HIV (WLWH), the decision to disclose may be influenced by culturally determined, community-level stigma and norms. Understanding the impact of community HIV stigma and gender norms on disclosure among WLWH in different countries may inform intervention development.

METHODS

HPTN063 was a longitudinal, observational study of sexually active HIV-infected individuals, including heterosexual women, in care in Zambia, Thailand and Brazil. At baseline, a questionnaire measuring community HIV stigma and gender norms, anticipated stigma, demographic, partner/relationship characteristics, and intimate partner violence was administered. Longitudinal HIV disclosure to sexual partners was determined via audio-computer assisted self-interview (ACASI) at the baseline and quarterly during the one year following up. Logistic regression was conducted to identify the predictors of disclosure.

RESULTS

Almost half (45%) of women living with HIV acknowledged perceived community HIV stigma (the belief that in their community HIV infection among women is associated with sex work and multiple sexual partners). Many women (42.9%) also acknowledged perceived community gender norms (the belief that traditional gender norms such as submissiveness to husbands/male sexual partners is necessary and that social status is lost if one does not procreate). HIV disclosure to current sex partners was reported by 67% of women. In multivariate analysis, among all women, those who were older [OR 0.16, 95%CI(0.06,0.48)], reported symptoms of severe depression [OR 0.53, 95%CI(0.31, 0.90)], endorsed anticipated stigma [OR 0.30, 95%CI(0.18, 0.50)], and were unmarried [OR 0.43, 95%CI(0.26,0.71)] were less likely to disclose to current partners. In an analysis stratified by marital status and cohabitation, unmarried [OR 0.41, 95%CI(0.20,0.82)] and non-cohabiting women [OR 0.31, 95%CI(0.13,0.73)] who perceived community HIV stigma were less likely to disclose to their sex partners.

CONCLUSIONS

Perceived community level HIV stigma, along with individual level factors such as anticipated stigma, depressive symptoms, and older age, predict non-disclosure of HIV status to sexual partners among WLWH in diverse geographic settings. Interventions to promote disclosure among women in serodiscordant relationships should incorporate community-level interventions to reduce stigma and promote gender equality.

Effect of Couples Counselling on Reported HIV Risk Behaviour among HIV Serodiscordant Couples by ART Use, HIV Status and Gender in Rural Uganda

Background

We examined several measures of self-reported HIV risk behaviour in mutually disclosed sero-discordant couples over time to see if a couples counselling intervention was associated with changes in these behaviors.

Methods

We analysed data from a prospective cohort study of HIV sero-discordant couples in Jinja, Uganda collected between June 2009 and December 2011. Participants received couples counselling, at 3-monthly intervals. We examined trends in reported condom-use, number of concurrent sexual partners, knowledge of HIV serostatus of concurrent partners and condom use of concurrent partners using Generalized Estimating Equation models, comparing responses at study enrollment with responses at six, 12 18 and 24 months of follow-up.

Results

A total of 586 couples were enrolled and the female member was HIV positive in 255 (44%) of them. The median age for female participants was 35 years and 42 years for men. Reported condom use at last sex with spouse increased over time (p<0.001) with the largest increases found among couples where the positive participant never received ART during the study(an increase from 68.8% at enrollment to 97.1% at 24 months). Male participants reported reductions in the number of concurrent sexual partners (p<0.001), increase in the knowledge of the HIV serostatus of these partners (p = 0.001) and a trend towards improved condom-use among non-primary partners (p = 0.070). Reported reduced risky behaviors did not wane over the study period.

Conclusion

Couples counselling resulted in increased condom use among all participants and among men the intervention resulted in reductions in risk behaviour with concurrent sexual partners. Routine counselling for serodiscordant couples should be integrated in routine ART care programs.

Lay Social Resources for Support of Adherence to Antiretroviral Prophylaxis for HIV Prevention Among Serodiscordant Couples in sub-Saharan Africa: A Qualitative Study

Effectiveness of antiretroviral pre-exposure prophylaxis (PrEP) for HIV prevention will require high adherence. Using qualitative data, this paper identifies potential lay social resources for support of PrEP adherence by HIV serodiscordant couples in Uganda, laying the groundwork for incorporation of these resources into adherence support initiatives as part of implementation. The qualitative analysis characterizes support for PrEP adherence provided by HIV-infected spouses, children, extended family members, and the larger community. Results suggest social resources for support of PrEP adherence in Africa are plentiful outside formal health care settings and health systems and that couples will readily use them. The same shortage of health professionals that impeded scale-up of antiretroviral treatment for HIV/AIDS in Africa promises to challenge delivery of PrEP. Building on the treatment scale-up experience, implementers can address this challenge by examining the value of lay social resources for adherence support in developing strategies for delivery of PrEP.

HIV sexual transmission is predominantly driven by single individuals rather than discordant couples: a model-based approach

Understanding the relative contribution to HIV transmission from different social groups is important for public-health policy. Information about the importance of stable serodiscordant couples (when one partner is infected but not the other) relative to contacts outside of stable partnerships in spreading disease can aid in designing and targeting interventions. However, the overall importance of within-couple transmission, and the determinants and correlates of this importance, are not well understood. Here, we explore how mechanistic factors – like partnership dynamics and rates of extra-couple transmission – affect various routes of transmission, using a compartmental model with parameters based on estimates from Sub-Saharan Africa. Under our assumptions, when sampling model parameters within a realistic range, we find that infection of uncoupled individuals is usually the predominant route (median 0.62, 2.5%–97.5% quantiles: 0.26–0.88), while transmission within discordant couples is usually important, but rarely represents the majority of transmissions (median 0.33, 2.5%–97.5% quantiles: 0.10–0.67). We find a strong correlation between long-term HIV prevalence and the contact rate of uncoupled individuals, implying that this rate may be a key driver of HIV prevalence. For a given level of prevalence, we find a negative correlation between the proportion of discordant couples and the within-couple transmission rate, indicating that low discordance in a population may reflect a relatively high rate of within-couple transmission. Transmission within or outside couples and among uncoupled individuals are all likely to be important in sustaining heterosexual HIV transmission in Sub-Saharan Africa. Hence, intervention policies should be broadly targeted when practical.

Women and HIV in Sub-Saharan Africa

Thirty years since the discovery of HIV, the HIV pandemic in sub-Saharan Africa accounts for more than two thirds of the world's HIV infections. Southern Africa remains the region most severely affected by the epidemic. Women continue to bear the brunt of the epidemic with young women infected almost ten years earlier compared to their male counterparts. Epidemiological evidence suggests unacceptably high HIV prevalence and incidence rates among women. A multitude of factors increase women's vulnerability to HIV acquisition, including, biological, behavioral, socioeconomic, cultural and structural risks. There is no magic bullet and behavior alone is unlikely to change the course of the epidemic. Considerable progress has been made in biomedical, behavioral and structural strategies for HIV prevention with attendant challenges of developing appropriate HIV prevention packages which take into consideration the socioeconomic and cultural context of women in society at large.

The risk of HIV transmission within HIV-1 sero-discordant couples appears to vary across sub-Saharan Africa

BACKGROUND

Representative and precise estimates for the annual risk of HIV transmission (ϕ) from the infected to the uninfected partner in a stable HIV-1 sero-discordant couple (SDC) are not available. Nevertheless, quantifying HIV infectiousness is critical to understanding HIV epidemiology and implementing prevention programs.

MATERIALS AND METHODS

We estimated ϕ and examined its variation across 23 countries in sub-Saharan Africa (SSA) by constructing and analyzing a mathematical model that describes HIV dynamics among SDCs. The model was parameterized using empirical measures such as those of the nationally representative Demographic and Health Surveys. Uncertainty and sensitivity analyses were conducted to assess the robustness of the findings.

RESULTS

We estimated a median ϕ of 11.1 per 100 person-years across SSA. A clustering based on HIV population prevalence was observed with a median ϕ of 7.5 per 100 person-years in low HIV prevalence countries (<5%) compared to 19.5 per 100 person-years in high prevalence countries (>5%). The association with HIV prevalence explained 67% of the variation in ϕ, and suggested an increase of 0.95 per 100 person-years in ϕ for every 1% increase in HIV prevalence.

CONCLUSIONS

Empirical measures from cohort studies appear to underestimate HIV infectiousness in SSA. The risk of HIV transmission among SDCs appears also to vary across SSA, and this may have contributed to the contrasting HIV epidemic trajectories in this continent.

Heterosexual HIV-1 infectiousness and antiretroviral use: systematic review of prospective studies of discordant couples

BACKGROUND

Recent studies have estimated the reduction in HIV-1 infectiousness with antiretroviral therapy (ART), but high-quality studies such as randomized controlled trials, accompanied by rigorous adherence counseling, are likely to overestimate the effectiveness of treatment-as-prevention in real-life settings.

METHODS

We attempted to summarize the effect of ART on HIV transmission by undertaking a systematic review and meta-analysis of HIV-1 infectiousness per heterosexual partnership (incidence rate and cumulative incidence over study follow-up) estimated from prospective studies of discordant couples. We used random-effects Poisson regression models to obtain summary estimates. When possible, the analyses were further stratified by direction of transmission (man-to-woman or woman-to-man) and economic setting (high- or low-income countries). Potential causes of heterogeneity of estimates were explored through subgroup analyses.

RESULTS

Fifty publications were included. Nine allowed comparison between ART and non-ART users within studies (ART-stratified studies), in which summary incidence rates were 3.6/100 person-years (95% confidence interval = 2.0-6.5) and 0.2/100 person-years (0.07-0.7) for non-ART- and ART-using couples, respectively (P < 0.001), constituting a 91% (79-96%) reduction in per-partner HIV-1 incidence rate with ART use. The 41 studies that did not stratify by ART use provided estimates with high levels of heterogeneity (I statistic) and few reported levels of ART use, making interpretation difficult. Nevertheless, estimates tended to be lower with ART use. Infectiousness tended to be higher for low-income than high-income settings, but there was no clear pattern by direction of transmission (man-to-woman and woman-to-man).

CONCLUSIONS

ART substantially reduces HIV-1 infectiousness within discordant couples, based on observational studies, and could play a major part in HIV-1 prevention efforts. However, the non-zero risk from partners receiving ART demonstrates that appropriate counseling and other risk-reduction strategies for discordant couples are still required. Additional estimates of ART effectiveness by adherence level from real-life settings will be important, especially for persons starting treatment early without symptoms.

HIV testing and counseling leads to immediate consistent condom use among South African stable HIV-discordant couples

OBJECTIVE

Effective behavioral HIV prevention is needed for stable HIV-discordant couples at risk for HIV, especially those without access to biomedical prevention. This analysis addressed whether HIV testing and counseling with ongoing counseling and condom distribution lead to reduced unprotected sex in HIV-discordant couples.

METHODS

Partners in Prevention HSV/HIV Transmission Study was a randomized trial conducted from 2004 to 2008 assessing whether acyclovir reduced HIV transmission from HSV-2/HIV-1-coinfected persons to HIV-uninfected sex partners. This analysis relied on self-reported behavioral data from 508 HIV-infected South African participants. The exposure was timing of first HIV testing and counseling: 0-7, 8-14, 15-30, or >30 days before baseline. In each exposure group, predicted probabilities of unprotected sex in the last month were calculated at baseline, month 1, and month 12 using generalized estimating equations with a logit link and exchangeable correlation matrix.

RESULTS

At baseline, participants who knew their HIV status for less time experienced higher predicted probabilities of unprotected sex in the last month: 0-7 days, 0.71; 8-14 days, 0.52; 15-30 days, 0.49; >30 days, 0.26. At month 1, once all participants had been aware of being in HIV-discordant relationships for ≥1 month, predicted probabilities declined: 0-7 days, 0.08; 8-14 days, 0.08; 15-30 days, 0.15; >30 days, 0.14. Lower predicted probabilities were sustained through month 12: 0-7 days, 0.08; 8-14 days, 0.11; 15-30 days, 0.05; >30 days, 0.19.

CONCLUSIONS

Unprotected sex declined after HIV-positive diagnosis and declined further after awareness of HIV discordance. Identifying HIV-discordant couples for behavioral prevention is important for reducing HIV transmission risk.

HIV-1 transmission within marriage in rural Uganda: a longitudinal study

Background

Early initiation of antiretroviral therapy reduces risk of transmission to the uninfected partner in HIV discordant couples, but there are relatively little observational data on HIV transmission within couples from non-trial settings. The aims of this paper are to estimate HIV incidence among HIV discordant couples using longstanding observational data from a rural Ugandan population and to identify factors associated with HIV transmission within couples, including the role of HSV-2 infection.

Methods

Using existing data collected at population-wide annual serological and behavioural surveys in a rural district in southwest Uganda between 1989 and 2007, HIV discordant partners were identified. Stored serum samples were tested for HSV-2 serostatus using the Kalon ELISA test. HIV seroconversion rates and factors association with HIV seroconversion were analysed using Poisson regression.

Results

HIV status of both partners was known in 2465 couples and of these 259 (10.5%) were HIV serodiscordant. At enrolment, HSV-2 prevalence was 87.3% in HIV positive partners and 71.5% in HIV negative partners. Of the 259 discordant couples, 62 converted to HIV (seroconversion rate 7.11/100 PYAR, 95%CI; 5.54, 9.11) with the rate decreasing from 10.89 in 1990–1994 to 4.32 in 2005–2007. Factors independently associated with HIV seroconversion were female sex, non-Muslim religion, greater age difference (man older than woman by more than 15 years), higher viral load in the positive partner and earlier calendar period. HSV-2 was not independently associated with HIV acquisition (HR 1.62, 95%CI; 0.57, 4.55) or transmission (HR 0.61, 95%CI; 0.24, 1.57). No transmissions occurred in the 29 couples where the index partner was on ART during follow up (872 person-years on ART).

Discussion

HIV negative partners in serodiscordant couples have a high incidence of HIV if the index partner is not on antiretroviral therapy and should be provided with interventions such as couple counselling, condoms and antiretroviral treatment.

Genital immunology and HIV susceptibility in young women

Women account for a substantial majority of HIV infections in endemic regions, where women are also infected at a much younger age than men. Part of this epidemiological skewing is due to socio-cultural factors, but it is clear that biological factors enhance the susceptibility of women--particularly young women--to HIV acquisition after sexual exposure. These factors, including important differences in mucosal immunology at the site of genital HIV exposure, are the focus of this concise review. Compared to heterosexual men, women have an increased surface area of mucosal HIV exposure, increased mucosal expression of the HIV co-receptor CCR5 and a greater probability of virus exposure on the rectal mucosa. Differences that are specific to young women include a pro-inflammatory immune environment and a proportionate increase in single-cell, columnar genital epithelium. These important biological reasons for enhanced HIV susceptibility in young women highlight the need for targeted HIV prevention within this vulnerable population.

HIV-1 prevention for HIV-1 serodiscordant couples

A substantial proportion of HIV-1 infected individuals in sub-Saharan Africa are in stable relationships with HIV-1 uninfected partners, and HIV-1 serodiscordant couples thus represent an important target population for HIV-1 prevention. Couple-based HIV-1 testing and counseling facilitates identification of HIV-1 serodiscordant couples, counseling about risk reduction, and referrals to HIV-1 treatment, reproductive health services, and support services. Maximizing HIV-1 prevention for HIV-1 serodiscordant couples requires a combination of strategies, including counseling about condoms, sexual risk, fertility, contraception, and the clinical and prevention benefits of antiretroviral therapy (ART) for the HIV-1-infected partner; provision of clinical care and ART for the HIV-1-infected partner; antenatal care and services to prevent mother-to-child transmission for HIV-1-infected pregnant women; male circumcision for HIV-1-uninfected men; and, pending guidelines and demonstration projects, oral pre-exposure prophylaxis (PrEP) for HIV-1-uninfected partners.

HIV serodiscordant relationships in India: translating science to practice

Over the past 30 years, several interventions have been identified to prevent HIV transmission from HIV-infected persons to uninfected persons in discordant relationships. Yet, transmissions continue to occur. Interventions such as voluntary counselling and testing, condom promotion and risk reduction counselling are very effective in preventing transmission among serodiscordant couples but are underutilized in India despite their widespread availability. New interventions such as pre-risk exposure prophylaxis and universal antiretroviral therapy (irrespective of CD4 count) have been newly identified but face several challenges that impede their widespread implementation in India. Discordant couples in India also face certain unique socio-cultural issues such as marital and fertility pressure. We briefly review the various interventions (existing and novel) available for persons in discordant relationships in India and socio-cultural issues faced by these individuals and make recommendations to maximize their implementation.

Gendered HIV risk patterns among polygynous sero-discordant couples in Uganda

Stable serodiscordant relationships and sexual concurrency are pathways that contribute to the HIV epidemic in sub-Saharan Africa. However whether polygyny imparts the same risks as informal concurrent relationships remains an open research question. Using data collected at enrollment from a cohort study of sero-discordant couples, this analysis investigates how polygynous relationships differ from those involving only a single female spouse and whether men involved in polygynous partnerships are more likely to report HIV-risk behaviour than those in single spouse partnerships. Of 444 enrolled couples, 111 (25%) were polygynous and 333 (75%) were single-spouse partnerships. We found that polygynous men were more likely to report controlling sexual decision-making and to report any unprotected sex with unknown sero-status partner. After controlling for potential confounders, polygynous men were still more likely to report unprotected sex with an unknown sero-status partner. In this sample of sero-discordant couples we found indication of excess HIV-risk behaviour among men involved in polygynous relationships.

Concurrent partnerships and HIV: an inconvenient truth

The strength of the evidence linking concurrency to HIV epidemic severity in southern and eastern Africa led the Joint United Nations Programme on HIV/AIDS and the Southern African Development Community in 2006 to conclude that high rates of concurrent sexual partnerships, combined with low rates of male circumcision and infrequent condom use, are major drivers of the AIDS epidemic in southern Africa. In a recent article in the Journal of the International AIDS Society, Larry Sawers and Eileen Stillwaggon attempt to challenge the evidence for the importance of concurrency and call for an end to research on the topic. However, their "systematic review of the evidence" is not an accurate summary of the research on concurrent partnerships and HIV, and it contains factual errors concerning the measurement and mathematical modelling of concurrency.Practical prevention-oriented research on concurrency is only just beginning. Most interventions to raise awareness about the risks of concurrency are less than two years old; few evaluations and no randomized-controlled trials of these programmes have been conducted. Determining whether these interventions can help people better assess their own risks and take steps to reduce them remains an important task for research. This kind of research is indeed the only way to obtain conclusive evidence on the role of concurrency, the programmes needed for effective prevention, the willingness of people to change behaviour, and the obstacles to change.

Disclosure of HIV results among discordant couples in Rakai, Uganda: a facilitated couple counselling approach

Disclosure of HIV sero-positive results among HIV-discordant couples in sub-Saharan Africa is generally low. We describe a facilitated couple counselling approach to enhance disclosure among HIV-discordant couples. Using unique identifiers, 293 HIV-discordant couples were identified through retrospective linkage of married or cohabiting consenting adults individually enrolled into a cohort study and into two randomised trials of male circumcision in Rakai, Uganda. HIV-discordant couples and a random sample of HIV-infected concordant and HIV-negative concordant couples (to mask HIV status) were invited to sensitisation meetings to discuss the benefits of disclosure and couple counselling. HIV-infected partners were subsequently contacted to encourage HIV disclosure to their HIV-uninfected partners. If the index positive partner agreed, the counsellor facilitated the disclosure of HIV results, and provided ongoing support. The proportion of disclosure was determined. Eighty-one per cent of HIV-positive partners in discordant relationships disclosed their status to their HIV-uninfected partners in the presence of the counsellor. The rates of disclosure were 81.3% in male HIV-positive and 80.2% in female HIV-positive discordant couples. Disclosure did not vary by age, education or occupation. In summary, disclosure of HIV-positive results in discordant couples using facilitated couple counselling approach is high, but requires a stepwise process of sensitisation and agreement by the infected partner.

HIV status in discordant couples in sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Most couples affected by HIV/AIDS in sub-Saharan Africa live in discordant relationships. Men are thought to be the index case in most relationships, and most social marketing and awareness campaigns are focused on men. We investigated serodiscordance in stable relationships to establish the gender balance of index-case infections.

METHODS

We did a systematic review, random-effects meta-analysis, and meta-regression of published and unpublished studies enrolling discordant couples and assessed the proportion of men and women that were index cases. We repeated the analysis with data from demographic and health surveys (DHS) from the 14 countries that have documented the HIV status of couples. Our primary outcome was the total number of HIV discordant couples, including the proportion of HIV-positive women.

FINDINGS

We included data from 27 cohorts of 13,061 couples and DHS data from 14 countries of 1145 couples. The proportion of HIV-positive women in stable heterosexual serodiscordant relationships was 47% (95% CI 43-52), which shows that women are as likely as men to be the index partner in a discordant couple. DHS data (46%, 41-51) and our sensitivity analysis (47%, 43-52) showed similar findings. Meta-regression showed that urban versus rural residence (odds ratio 0.31, 95% CI 0.22-0.39), latitude (β coefficient 0.02, 0.023-0.034), gender equality (β coefficient -0.42, -0.56 to -0.27), HIV prevalence (β coefficient -0.037, -0.04 to -0.030), and older age (β coefficient 0.20, 0.08-0.32) were associated with the proportion of female index cases.

INTERPRETATION

Our study shows the need to focus on both sexes in HIV prevention strategies, such as promotion of condom use and mitigation of risk behaviours.

FUNDING

None.

High uptake of home-based, district-wide, HIV counseling and testing in Uganda

More than 80% of the people infected with HIV in low-income countries of sub-Saharan Africa do not know their HIV serostatus. Innovative measures of increasing access to HIV counseling and testing (HCT) are urgently needed so as to improve care and prevention. We implemented a home-based HCT program in Bushenyi District from September 2004 to March 2007, in Uganda where approximately 90% of people aged older than 14 years had never tested for HIV to gauge whether it was acceptable and increased uptake of HCT. Twenty-nine teams comprising a counselor and a laboratory assistant systematically visited homes offering HCT for all people older than 14 years of age and at-risk children (mother deceased or HIV infected) using a rapid HIV testing three-test algorithm. HIV-infected people received cotrimoxazole prophylaxis, were supplied with long-lasting insecticide-treated bed nets and equipment for treatment of drinking water at home, and were referred for assessment for antiretroviral therapy. The program reached 92,984 (63%) of all the homes in the district. Of these, 32,3621 people were eligible for HCT, and 28,2857 (87%) were present at home and were offered pretest counseling. A total of 264,966 (94%) accepted testing and received their results, of whom 11,359 (4.3%) were HIV-infected. Ninety percent of those testing had never tested before. The cost of testing was $7.83 per previously untested client. Ninety-seven percent of HIV-infected people initiated cotrimoxazole prophylaxis, 74% received bed nets, 70% received water treatment equipment, and 11% began antiretroviral therapy. Forty-four percent of people who were in an HIV-discordant relationship were infected. These results demonstrate that home-based HCT was well-accepted, feasible, and effective in identifying HIV-infected individuals who did not know their HIV status in rural Uganda.

Prevalence of child and adult sexual abuse and risk taking practices among HIV serodiscordant African-American couples

This study reports the prevalence of child (CSA) and adult (ASA) sexual abuse among 535 African American HIV serodiscordant couples from four major United State cities, and its relationship to personal and couple related vulnerabilities and HIV risk factors. As part of a randomized, clinical trial, CSA and ASA histories were obtained through face-to-face interviews. Results indicate that HIV positive women were significantly more likely to report one kind of abuse (32.32%), either before or since age 18 or both (32.6%). HIV-positive men (34.9%) were significantly more likely to report CSA than HIV-negative men (22.0%). Overall, 72% of couples reported that one or both had CSA histories. These findings underscore the heightened emotional vulnerability, and STI and HIV transmission risk taking practices, associated with sexual abuse. Sexual abuse histories among couples should be assessed to better understand how these histories may contribute to couples dynamics and risk-taking practices.

Rethinking gender, heterosexual men, and women's vulnerability to HIV/AIDS

Most HIV prevention literature portrays women as especially vulnerable to HIV infection because of biological susceptibility and men's sexual power and privilege. Conversely, heterosexual men are perceived as active transmitters of HIV but not active agents in prevention. Although the women's vulnerability paradigm was a radical revision of earlier views of women in the epidemic, mounting challenges undermine its current usefulness. We review the etiology and successes of the paradigm as well as its accruing limitations. We also call for an expanded model that acknowledges biology, gender inequality, and gendered power relations but also directly examines social structure, gender, and HIV risk for heterosexual women and men.

Strategies for harm reduction among HIV-affected couples who want to conceive

As effective HIV treatments become more widespread, HIV-infected individuals are living longer, healthier lives. Many HIV-affected couples (sero-discordant and sero-concordant) are considering options for safer reproduction. A large body of evidence suggests that reproductive technologies can help HIV-affected couples to safely conceive with minimal risk of HIV transmission to their partner. However, for most couples such technologies are neither geographically nor economically accessible. This paper addresses the options for safer procreation among HIV-affected couples who cannot access reproductive technologies.

Fitting the HIV epidemic in Zambia: a two-sex micro-simulation model

BACKGROUND

In describing and understanding how the HIV epidemic spreads in African countries, previous studies have not taken into account the detailed periods at risk. This study is based on a micro-simulation model (individual-based) of the spread of the HIV epidemic in the population of Zambia, where women tend to marry early and where divorces are not frequent. The main target of the model was to fit the HIV seroprevalence profiles by age and sex observed at the Demographic and Health Survey conducted in 2001.

METHODS AND FINDINGS

A two-sex micro-simulation model of HIV transmission was developed. Particular attention was paid to precise age-specific estimates of exposure to risk through the modelling of the formation and dissolution of relationships: marriage (stable union), casual partnership, and commercial sex. HIV transmission was exclusively heterosexual for adults or vertical (mother-to-child) for children. Three stages of HIV infection were taken into account. All parameters were derived from empirical population-based data. Results show that basic parameters could not explain the dynamics of the HIV epidemic in Zambia. In order to fit the age and sex patterns, several assumptions were made: differential susceptibility of young women to HIV infection, differential susceptibility or larger number of encounters for male clients of commercial sex workers, and higher transmission rate. The model allowed to quantify the role of each type of relationship in HIV transmission, the proportion of infections occurring at each stage of disease progression, and the net reproduction rate of the epidemic (R(0) = 1.95).

CONCLUSIONS

The simulation model reproduced the dynamics of the HIV epidemic in Zambia, and fitted the age and sex pattern of HIV seroprevalence in 2001. The same model could be used to measure the effect of changing behaviour in the future.

What the better half is thinking: A comparison of men's and women's responses and agreement between spouses regarding reported sexual and reproductive behaviors in Rwanda

Objective

To compare responses to a sexual behavioral survey of spouses in cohabiting heterosexual relationships in Kigali, Rwanda.

Design

Cross-sectional survey.

Methods

Husbands and wives in 779 cohabiting couples were interviewed separately with parallel questionnaires. Participants were recruited from a three-year old cohort of 1458 antenatal clinic attendees enrolled in a prospective study in 1988. Analyses compared responses at the gender- and couple-level for agreement and disagreement.

Results

Couples were in disagreement more than agreement. Women reported occasionally refusing sex, suggesting condom use, and believing married men were unfaithful. Men reported being in a faithful relationship, greater condom use, and being understanding when wives refused sex. Agreement included relationship characteristics, safety of condoms, and whether condoms had ever been used in the relationship. Disagreement included the preferred timing of next pregnancy, desire for more children, and whether a birth control method was currently used and type of method.

Conclusions

Rwandan husbands and wives differed in sexual behavior and reproductive-related topics. Couple-level reporting provides the most reliable measure for relationship aspects as couples’ agreement cannot be assumed among cohabiting partnerships. Furthermore, HIV prevention programs for couples should incorporate communication skills to encourage couple agreement of HIV-related issues.

HIV-1 infection of human penile explant tissue and protection by candidate microbicides

OBJECTIVE

Factors governing events between exposure of male genital mucosa surfaces and the establishment of infection are poorly understood. Furthermore, little is known about the safety and efficacy of microbicides on male genital mucosa.

DESIGN

Here we present a novel penile tissue explant model to characterize the mechanisms of HIV-1 infection of male genital tissue and evaluate candidate microbicides.

METHODS

Mucosal explant culture conditions were determined for glans, urethra and foreskin obtained from gender reassignment and circumcision. Density and distribution of CD4 and CD1a cells were visualized by microscopy. In vitro HIV-1 infection was determined by measuring p24 release, whereas microbicide biocompatibility and efficacy were assessed by measurement of tissue viability, cytokine expression and p24 production.

RESULTS

Cultured glans and foreskin showed comparable epithelial thickness but some differences in CD4 and CD1a cell density. All tissue sites examined (foreskin, glans, meatus, urethra) were equally susceptible to R5 HIV-1 infection, which was productively disseminated by migratory cells emigrating from tissue. In contrast, X4 HIV-1 failed to infect mucosal tissue and dissemination by migratory cells was less efficient. The three candidate microbicides poly(methyl 2-propionamidoacrylate), PRO 2000 and Cyanovirin-N, showed good tissue compatibility and efficient prevention of HIV-1 infection, causing only minor changes in tissue cytokine profile.

CONCLUSION

The described model provides a useful model to study the determinants of HIV-1 infection of male genital tissue and is likely to be an important tool for the future development of microbicide candidates and concepts.

Support Groups, Marriage, and the Management of Ambiguity among HIV-Positive Women in Northern Nigeria

In the context of the African HIV epidemic, support groups are not simply spaces for discussions of social and health well-being; neither are they institutions functioning solely to cultivate self-responsible and economically empowered patients. HIV-positive women in northern Nigeria have appropriated a support group to facilitate their marriage arrangements. In this group, women negotiate the threats of stigma and the promises of respectable marriage through what I call the management of ambiguity surrounding their HIV status. I further argue that the practice of support group matchmaking reveals the local political economic dynamics that shape social and illness trajectories in resource-poor settings.

‘This is where we buried our sons’: people of advanced old age coping with the impact of the AIDS epidemic in a resource-poor setting in rural Uganda

Much research on the impact of HIV and AIDS on older people fails to differentiate between age groups, and treats those aged from 50 years to the highest ages as homogeneous. The ‘oldest old’ or those aged over 75 years may be particularly vulnerable through declining health and independence as a result of the AIDS epidemic, which has forced some to take on roles that younger relatives would have performed had they lived. In this paper we describe the past and current experience of eight people in advanced old age living in rural Uganda who were informants for an ethnographic study of the impact of HIV and AIDS on households during 1991–92 and again in 2006–07. The aim of the study was to understand how they had coped with the impacts of the epidemic. From the eight case studies, it is concluded that family size, socio-economic status and some measure of good fortune in sustained good health enabled these people to live to an advanced age. While we recommend that targeted social protection is important in helping the poorest among the oldest, we suggest that sustaining respect for age and experience, and ensuring that older people do not feel discarded by family and society are as important as meeting their practical needs.

The impact of project closure on HIV incidence and mortality in a cohort of couples in Lusaka, Zambia

The objective of this study was to assess the impact of temporary closure of an HIV research clinic on the health of study participants. Primary data were collected quarterly from couples enrolled in research studies at an established HIV study site. There were 632 participating couples enrolled when the project closed, 475 of whom returned when it re-opened six months later. HIV sero-incidence, mortality rates and risk-taking behaviours were compared before and during the closure. Perceived impact of the closure was measured in returning participants. Demographic data collected at the last pre-closure study visit were used to look at the differences between returning and non-returning study participants. Serologic data from those who returned were compared pre- and post-closure to examine changes in HIV incidence. Mortality rates were estimated from reported deaths, and were compared pre- and during project closure. Perceptions of the impact of the closure among returning participants were examined through an interviewer administered questionnaire. It was found that couples who returned were not demographically different from couples who did not return. Most participants reported no problems with finding alternate sources of condoms and the incidence of HIV did not change significantly during the closure. Eighty-four percent respondents reported that the closure had a negative impact on them, 87% of whom rated loss of medical care as the main impact. The mortality rate among HIV-positive participants doubled from 6.7/100 person years to 12.4/100 person years during the closure (p=0.01). Results indicate that couples voluntary counselling and testing (CVCT) established durable risk-reduction behaviours that persisted during project closure. ThIn ae loss of healthcare was perceived as the most negative impact on participants, reflected in increased mortality rates. Research projects should make transition plans and budget for mechanisms to reduce the negative impact on participants of project closures.

Evolution of couples' voluntary counseling and testing for HIV in Lusaka, Zambia

BACKGROUND

: We describe promotional strategies for couples' voluntary HIV counseling and testing (CVCT) and demographic risk factors for couples in Lusaka, Zambia, where an estimated two thirds of new infections occur in cohabiting couples.

PRINCIPAL FINDINGS

: CVCT attendance as a function of promotional strategies is described over a 6-year period. Cross-sectional analyses of risk factors associated with HIV in men, women, and couples are presented. Community workers (CWs) recruited from couples seeking CVCT promoted testing in their communities. Attendance dropped when CW outreach ended, despite continued mass media advertisements. In Lusaka, 51% of 8500 cohabiting couples who sought HIV testing were concordant negative for HIV (MF) and 26% concordant positive (MF); 23% had 1 HIV-positive partner and one HIV-negative partner, with 11% HIV-positive man/HIV-negative woman (MF) and 12% HIV-negative man/HIV-positive woman (FM). HIV infection was associated with men's age 30 to 39, women's age 25 to 34, duration of union <3 years, and number of children <2. Even among couples with either 1 or 2 or no risk factors, HIV prevalence was 45% and 29%, respectively.

CONCLUSIONS

: Many married African adults do not have high-risk profiles, nor realize that only 1 may be HIV positive. Active and sustained promotion is needed to encourage all couples to be jointly tested and counseled.

Enrollment and retention of HIV discordant couples in Lusaka, Zambia

BACKGROUND

Biased enrollment and attrition compromise the power of clinical trials and limit generalizability of findings. We identify predictors of enrollment and retention for HIV-discordant couples enrolled in prospective studies in Zambia.

PRINCIPAL FINDINGS

A total of 1995 discordant couples were invited to enroll. Predictors of nonenrollment, loss to follow-up, and missed appointments were evaluated using multivariate models. MF couples were more likely to be eligible and to enroll and less likely to be lost to follow-up than FM couples. Substantial losses to follow-up occurred between testing and enrollment (21.3% of MF and 28.1% of FM) and between enrollment and the first follow-up visit (24.9% of MF and 30.5% of FM). Among MF and FM couples, residence far from the clinic, younger age, and women's age at first intercourse </=17 years were predictive of attrition. No income, </=2 lifetime sex partners, no history of sexually transmitted infection in women, and recent extramarital contact in their male partners predicted attrition in FM couples.

CONCLUSIONS

Discordant couples are critical to observational studies and clinical trials to prevent male-to-female and female-to-male transmission. Retention biases must be taken into account during analysis. Run-in designs that delay randomization may improve retention in clinical trials.

Moving from preventing HIV/AIDS in its infancy to preventing family illness and death (PFID)

In April 2007, UNAIDS released Securing the future--advocating for children, a call for the global community to recognize that "children still remain largely absent from national and international political responses to the AIDS pandemic". Most efforts to date to protect children from HIV have focused on prevention of mother-to-child transmission (PMTCT) programs. Though expanding PMTCT programs, particularly in sub-Saharan Africa, are crucial, even widespread PMTCT programs would still be grossly inadequate for achieving the goal of protecting children from HIV/AIDS. The global community needs to fundamentally reframe its approach to HIV prevention to fully address the health of families, otherwise the future for at-risk children is likely to remain bleak. After identifying challenges with current approaches, we review recent research that provides insights into ways prevention programs may be adapted to better protect families and children from the devastating consequences of HIV/AIDS. Only by protecting families from HIV/AIDS will we be able to achieve the goal of an AIDS-free generation.

The HIV transmission gradient: relationship patterns of protection

We describe a gradient of potential HIV transmission from HIV-infected persons to their partners and thence to uninfected populations. The effect of this newly discovered transmission gradient is to limit the spread of HIV. We roughly estimate a 2% long-term transmission probability for sex and 14% for drug injection for two-step transmission. Then we test theories to account for this pattern on a network sample of 267 inner city drug users and nonusers. Although HIV positive persons engaged in a high level of risk with one another, they engaged in less risk with HIV negative partners, and these partners engaged in even lower levels of risk with other HIV negative persons. Analyses suggest that the primary motivation for sexual risk reduction is partner protection, while emotional closeness is the major barrier. Hypotheses accounting for risk in terms of self protection, social norms, gender power, and drug use were weakly supported or unsupported.

Potential Impact of Antiretroviral Therapy on HIV-1 Transmission and AIDS Mortality in Resource-Limited Settings

OBJECTIVE

To estimate the potential impact of antiretroviral therapy on the heterosexual spread of HIV-1 infection and AIDS mortality in resource-limited settings.

METHODS

A mathematic model of HIV-1 disease progression and transmission was used to assess epidemiologic outcomes under different scenarios of antiretroviral therapy, including implementation of World Health Organization guidelines.

RESULTS

Implementing antiretroviral therapy at 5% HIV-1 prevalence and administering it to 100% of AIDS cases are predicted to decrease new HIV-1 infections and cumulative deaths from AIDS after 10 years by 11.2% (inter-quartile range [IQR]: 1.8%-21.4%) and 33.4% (IQR: 26%-42.8%), respectively. Later implementation of therapy at endemic equilibrium (40% prevalence) is predicted to be less effective, decreasing new HIV-1 infections and cumulative deaths from AIDS by 10.5% (IQR: 2.6%-19.3%) and 27.6% (IQR: 20.8%-36.8%), respectively. Therapy is predicted to benefit the infected individual and the uninfected community by decreasing transmission and AIDS deaths. The community benefit is greater than the individual benefit after 25 years of treatment and increases with the proportion of AIDS cases treated.

CONCLUSIONS

Antiretroviral therapy is predicted to have individual and public health benefits that increase with time and the proportion of infected persons treated. The impact of therapy is greater when introduced earlier in an epidemic, but the benefit can be lost by residual infectivity or disease progression on treatment and by sexual disinhibition of the general population.

The incidence and prevalence of orphanhood associated with parental HIV infection: a population-based study in Rakai, Uganda

BACKGROUND

There are limited empirical data on the prevalence and incidence of orphanhood due to parental HIV infection.

OBJECTIVE

To assess the prevalence and incidence of orphanhood, and the population attributable fraction (PAF) of incident orphanhood associated with parental HIV infection, in a rural population with a 14.8% adult HIV prevalence.

METHODS

The data are derived from a community cohort in Rakai District, Uganda. Census data were collected on all resident members in 10,657 households, including survival of parents of resident children in 1996/1997. Consenting adults were interviewed, provided blood for HIV testing, and were followed up 10 months later to determine parental death and incident orphanhood. The incidence rate ratio (IRR) of orphanhood associated with parental HIV-infection was estimated by Poisson multivariate regression.

RESULTS

A total of 22,712 children aged 0-14 years were enumerated in 1996/1997. The overall prevalence of orphanhood was higher among children of HIV-infected parents (22.7%) compared with children of uninfected parents, 7.9%. The annual incidence of orphanhood was 8.2% if at least one parent was HIV positive, and 0.5% if both parents were HIV negative (adjusted IRR = 18.93). Older age of children, and older maternal age were significantly associated with an increased risk of orphanhood. The PAF of incident orphanhood due to parental HIV infection was 37.3%, and was highest among younger children (adjusted PAF = 50.6% for 0-4 year olds), and children with younger mothers aged < 25 years (adjusted PAF = 75.7%).

CONCLUSIONS

Parental HIV infection markedly increased the incidence of orphanhood, especially among younger children and the children of younger mothers.

Methods to estimate the number of orphans as a result of AIDS and other causes in Sub-Saharan Africa

OBJECTIVE

To derive methods to estimate and project the fraction of children orphaned by AIDS and other causes.

METHODS

HIV/AIDS affects orphan numbers through increased adult and child mortality and reduced fertility of HIV-positive women. We extend an epidemiologic and demographic model used previously to estimate maternal orphans to paternal orphans. We account for the impact of HIV/AIDS on child survival by modeling the HIV status of the partners of men who die of AIDS or other causes based on data on the concordance of heterosexual partners. Subsequently, the proportion of orphans whose parents have both died is predicted by a regression model fitted to orphanhood data from 34 national demographic and health surveys (DHSs). The approach is illustrated with an application to Tanzania and compared with DHS estimates for the years 1992 and 1999.

RESULTS

Projections of the number and age distribution of orphans using these methods agree with survey data for Tanzania. They show the rise in orphanhood over the last decade that has resulted from the HIV epidemic.

CONCLUSIONS

The methods allow estimation of the numbers of children whose mother, father, or both parents have died for countries with generalized heterosexual HIV epidemics. These methods have been used to produce orphan estimates for high-prevalence countries published by Joint United Nations Program on HIV/AIDS, World Health Organization, United Nations Children's Fund, and US Agency for International Development in 2002 and 2004.

Determinants and consequences of sexual networks as they affect the spread of sexually transmitted infections

Because pathogens spread only within the unique context of a sexual union between people when one person is infectious, the other is susceptible to new infection, and condoms are not used to prevent transmission, the epidemiological study of sexually transmitted infections (STIs) is particularly challenging. Social network analysis entails the study of ties among people and how the structure and quality of such ties affect individuals and overall group dynamics. Although ascertaining complete sexual networks is difficult, application of this approach has provided unique insights into the spread of STIs that traditional individual-based epidemiological methods do not capture. This article provides a brief background on the design and assessments of studies of social networks, to illustrate how these methods have been applied to understanding the distribution of STIs, to inform the development of interventions for STI control.

Management of vaginal discharge syndrome: how effective is our strategy?

Although syndromic management of sexually transmitted diseases in highly endemic areas provides a short-term benefit to the individuals treated, it has no impact on decreasing prevalence rates. The numerous factors that contribute to this are discussed. Rapid reinfection from a large pool of infected symptomatic and asymptomatic individuals as well as the non-specific nature of presenting symptoms in women with vaginal discharge syndrome are major causes.

HIV status and union dissolution in sub-Saharan Africa: the case of Rakai, Uganda

Little is known about the impact of HIV infection on the disruption of families through separation, divorce, and widowhood. Using life tables and multinomial logistic regression, this research examined the influence of HIV status on the risk of separation or divorce and widowhood among women in Rakai, Uganda. The multivariate results revealed that dissolution is more common among HIV-infected women and that infected women in HIV-discordant couples are especially likely to face separation or divorce than women in other HIV-status couples. These results highlight women's vulnerability to the social impact of HIV infection and the importance of dyadic studies of the disruption of unions.

Factors affecting HIV concordancy in married couples in four African cities

OBJECTIVE

To determine risk factors for HIV transmission within married couples in four urban populations in sub-Saharan Africa.

METHODS

Data from a cross-sectional population-based study were used. Representative random samples approximating 1000 men and 1000 women in each of four cities of Kisumu (Kenya), Ndola (Zambia), Cotonou (Benin), and Yaoundé (Cameroon), were interviewed and tested for sexually transmitted infections (STI). Married couples were identified as concordant negative, discordant, or concordant positive for each STI. After excluding concordant HIV negative couples, analysis of behavioural and STI risk factors for HIV positive concordancy was undertaken across the four cities and in each city separately where sample size allowed.

RESULTS

Among 221 couples in which at least one member was HIV positive, we found that the only significant risk factor for positive HIV concordancy was herpes simplex type 2 (HSV-2) status. After adjusting for age and city of residence the odds ratio for HIV concordancy compared to couples with neither spouse HSV-2 positive was 3.4 (95% confidence interval, 0.62-18.4) for couples with one partner HSV-2 positive and 8.6 (95% confidence interval, 1.6-45.0) for couples with both partners HSV-2 positive. The same trends were seen in Kisumu and Ndola when they were analysed separately (numbers were small in the other cities).

CONCLUSIONS

Although cross-sectional studies are not ideal for delineating the sequence of transmission events, this study adds to the evidence that HSV-2 is a key risk factor in promoting HIV transmission.

Who infects whom? HIV-1 concordance and discordance among migrant and non-migrant couples in South Africa

OBJECTIVES

To measure HIV-1 discordance among migrant and non-migrant men and their rural partners, and to estimate the relative risk of infection from inside versus outside primary relationships.

DESIGN

A cross-sectional behavioural and HIV-1 seroprevalence survey among 168 couples in which the male partner either a migrant, or not.

METHODS

A detailed questionnaire was administered and blood was collected for laboratory analysis. A mathematical model was developed to estimate the relative risk of infection from inside versus from outside regular relationships.

RESULTS

A total of 70% (117 of 168) of couples were negatively concordant for HIV, 9% (16 of 168) were positively concordant and 21% (35 of 168) were discordant. Migrant couples were more likely than non-migrant couples to have one or both partners infected [35 versus 19%; P = 0.026; odds ratio (OR) = 2.28] and to be HIV-1 discordant (27 versus 15%; P = 0.066; OR = 2.06). In 71.4% of discordant couples, the male was the infected partner; this did not differ by migration status. In the mathematical model, migrant men were 26 times more likely to be infected from outside their regular relationships than from inside [relative risk (RR) = 26.3; P = 0.000]; non-migrant men were 10 times more likely to be infected from outside their regular relationships than inside (RR = 10.5; P = 0.00003).

CONCLUSIONS

Migration continues to play an important role in the spread of HIV-1 in South Africa. The direction of spread of the epidemic is not only from returning migrant men to their rural partners, but also from women to their migrant partners. Prevention efforts will need to target both migrant men and women who remain at home.

HIV risk in relation to marriage in areas with high prevalence of HIV infection

In sub-Saharan Africa, the prevalence of HIV infection among young women is much higher than that among young men. Many women enter marriage HIV-infected, suggesting that men may be predominantly infected by their wives. Using data from cross-sectional surveys in Kisumu, Kenya, and Ndola, Zambia, in 1997, the prevalence of HIV infection at marriage was estimated from age at marriage and age- and sex-specific prevalence of HIV infection among unmarried individuals. Using a deterministic model, this prevalence was compared with measured concordance of HIV infection among recently married couples to estimate transmission probabilities within marriage and extramarital incidence of HIV infection. Over a wide range of assumptions, we estimated that at least one quarter of cases of HIV infection in recently married men were acquired from extramarital partnerships, and for both men and women, less than one half of cases of HIV infection were acquired from their spouse. In these sites, many infections in married men, even in those with HIV-infected wives, may be acquired from outside the marriage.