Polygyny and the spread of HIV in sub-Saharan Africa: a case of benign concurrency

Sexual partner concurrency: is it a useful concept for HIV prevention? A systematic review of the evidence for intervention effectiveness in low- and middle-income countries

If sexual partner concurrency drives HIV transmission dynamics, shouldn't HIV prevention efforts be addressing this behavior? We systematically reviewed studies evaluating interventions to reduce sexual partner concurrency in low- and middle-income countries using pre/post or multi-arm designs. Only two studies met our inclusion criteria; neither found significant differences by intervention exposure on self-reported concurrency. Overall, very few interventions have specifically targeted concurrency, and those that did have not been rigorously evaluated. In practice, concurrency may be difficult to separate from multiple partnerships more generally.

Factors Contributing to High HIV Prevalence in Majang Zone, Southwest Ethiopia: What Lies Beneath the Tip of the Iceberg?

BACKGROUND

Despite the tremendous efforts made, HIV epidemic has been continuing to be a public health threat and one of the leading causes of death in sub-Saharan African countries. Gambella region is a high prevalence region persistently exhibiting the highest share of HIV cases in Ethiopia. Thus, the objective of this study was to explore factors contributing to high HIV prevalence in the Majang zone of Gambella region, Southwest Ethiopia.

METHODS

A descriptive qualitative study was conducted in the Majang zone of Gambella region, Southwest Ethiopia from March to May 2019. A heterogeneous purposive sampling technique was employed to recruit key informants and focused group discussion participants. Eighteen key informant interviews and 9 focused group discussions were conducted (N = 90) with health professionals, youth, mothers, and community elders. An interview guide developed through an extensive literature review was used to elicit information from the study participants, and data were collected by the investigators themselves with the help of local guides. Data were audio recorded, transcribed, translated, coded, and analyzed thematically, assisted by Atlas.ti 7.5.16 software. Trustworthiness of the data was ensured through data triangulation, prolonged engagement, member checking, and inquiry audit in which findings were audited and verified by qualitative research experts. Ethical clearance was obtained from the Institutional Review Board of Mizan Tepi University, and written signed informed consent was obtained from all the participants prior to conducting the interviews.

RESULTS

A total of 90 individuals have participated in this study. Several factors appear to underlie the sustained high prevalence of HIV in the study area and were organized into five major themes: 1) government-related factors, 2) community perception towards HIV, 3) substance use, 4) socio-cultural factors, and 5) movement of people.

CONCLUSION

Low government attention towards HIV prevention and control activities, low perceived severity of HIV, substance use, socio-cultural factors, and high movement of people appear to inform the understanding of factors contributing to HIV risk in Majang zone. The sociocultural factors include the use of "Tifo Bet" and social support for polygamy. These findings loudly call for the governmental, non-governmental, and private sectors to reconsider and strengthen strategies for the prevention and control of HIV in the study area.

Understanding ethnic variations in HIV prevalence in Kenya: the role of cultural practices

Patterns of HIV prevalence in Kenya suggest that areas where various cultural practices are prevalent bear a disproportionate burden of HIV. This paper examines (i) the contextual effects of cultural practices (polygyny, male circumcision) and related sexual behaviour factors on HIV prevalence and (ii) the extent to which specific cultural practices in a community/county might explain existing ethnic variations in HIV prevalence in Kenya. The analysis applies multilevel logistic regression to data from the 2012/13 Kenya AIDS Indicator Survey. The results reveal striking ethnic variations in HIV prevalence in Kenya. The prevalence of polygyny in a community is positively associated with HIV prevalence, while a higher level of male circumcision in a county is protective for both men and women. The effects of these factors are stronger for men than women at both individual and contextual (community/county) levels. These cultural practices and associated risk factors partly explain existing ethnic differences in HIV prevalence in Kenya, but there remain significant ethnic variations that are not explained by these cultural practices or related sexual behaviour factors. These call for stronger empirical evidence to offer stronger theoretical explanations and inform effective policy and practice to address HIV epidemic in adversely affected communities in Kenya and similar settings in sub-Saharan Africa.

A qualitative study of attitudes towards, typologies, and drivers of concurrent partnerships among people of black Caribbean ethnicity in England and their implications for STI prevention

BACKGROUND

Partner concurrency, (having sexual partnerships overlapping in time), especially when condoms are not used, can facilitate sexually transmitted infections (STI) transmission. In Britain, STI diagnoses rates and the reporting of concurrency are higher among black Caribbeans than other ethnic groups. We explored attitudes towards, drivers, characteristics, and contexts of concurrent partnerships, and their implications for STI risk among black Caribbeans in England.

METHODS

Purposive sampling, by sex and age-groups, was used to recruit participants (overall n = 59) from five sexual health clinics and community settings in London and Birmingham, England. Audio-recorded four focus group discussions (n = 28 participants), and in-depth interviews (n = 31) were conducted (June 2014-December 2015). Transcribed data were thematically analysed using Framework Analysis.

RESULTS

'Main plus' and 'non-main' concurrency were identified in this population. Main plus concurrency involves an individual having a main partner with whom s/he has a "relationship" with, and the individual and/or their partner secretly or explicitly have other non-main partners. In contrast, non-main concurrency entails having multiple, non-committed partners overlapping in time, where concurrency is usually taken as a given, making disclosure to partners irrelevant. While main partnerships were usually long-term, non-main partnerships ranged in duration from a single event through to encounters lasting several months/years. Condomless sex was common with ex/long-term/married/cohabiting partners; whereas condoms were typically used with non-main partners. However, condom use declined with partnership duration and familiarity with partners. Awareness of partners' concurrency facilitated condom use, STI-testing, and partner notification. While unresolved feelings, or sharing children with ex-partners, usually facilitated main plus concurrency; non-main concurrency was common among young, and single people. Gender norms, notions of masculinity, and sexual desires influenced concurrency. Black Caribbean popular music, social media, peer pressure, and relationship norms among black Caribbeans were also perceived to encourage concurrency, especially among men and young people.

CONCLUSIONS

Concurrency among black Caribbeans is shaped by a complex interaction between emotional/psychological, interpersonal, sociocultural, and structural factors. Concurrency type, its duration, and awareness influence sexual health choices, and thus STI risk in this population. Collecting these data during clinic consultations could facilitate offering partner notification methods tailored to concurrency type. Gender- and age-specific, culturally-sensitive interventions addressing STI risks associated with concurrency are needed.

Computational Prediction of Subjective Human Immunodeficiency Virus Status in Malawi Using a Random Forest Approach

An individual's subjective judgment about his or her Human Immunodeficiency Virus status depends on certain factors, behavioral, health, and sociodemographic alike. This paper aims to develop a model with good accuracy for predicting subjective HIV infection status using the random forest approach. A total of 12,796 responses of Malawians over a 12-year period were assessed. Fourteen risk factors including behavioral, health, and sociodemographic information were analysed as potential predictors of subjective Human Immunodeficiency Virus infection status in the general population and thirteen behavioral, health, and sociodemographic information were analysed among males and females. The random forest approach was adopted to build a comprehensive model comprising 14 risk factors in Malawi. It was revealed that age, worries about infection, and health rate were the most significant predictors as compared to use of condoms, marital status, and education which were the least important predictors of subjective Human Immunodeficiency Virus status in Malawi. However, the importance of infidelity on the part of a spouse and marital status as predictors of subjective Human Immunodeficiency Virus status alternated among males and females. The importance of infidelity and marital status was relatively high among females than among males. The model achieved a prediction accuracy of about 97%-99% measured by c-statistic with jack-knife cross validation and verified by Mathews correlation coefficient. As a result, RF based model has great potential to be an effective approach for analysing subjective health status.

The influence of marital status on HIV infection in an HIV hyperendemic area of rural South Africa, 2000-2017

Marital status is one of the factors whose impact on HIV infection has always been studied but contradictory findings have been reported. The drastic changes in marriage patterns in South Africa influences the role of marital status on HIV infection. This study aims to give evidence-based information on the association between marital status and HIV infection in a hyperendemic HIV area in rural South Africa. This study was conducted on longitudinal data collected from the African Health Research Institute (AHRI) based in northern rural KwaZulu-Natal from 2000 to 2017 using multivariable Cox regression. The multivariable Cox regression results found marital status to be a significant factor of HIV infection. Compared to those who were married, the risk of HIV infection was approximately two times in those who were never married while those who were widowed presented as much as twice the risk of HIV infection. In addition, less educated participants were at more risk of HIV infection than those with tertiary education. Furthermore, as expected, the risk of HIV infection increased with age (20-24 HR: 3.05 (2.32-4.02); 25-34 HR: 3.98 (3.12-5.07) and 35-49 HR: 4.36 (3.36-5.67). Women were more susceptible to HIV infection than men were. This study found marital status to be an influential factor of HIV infection together with other socio-economic and demographic factors. This finding will help guide policy makers on empowerment programmes and policies targeting HIV and other health related issues in rural South Africa.

Sexual Concurrency and Contraceptive Use Among Young Adult Women

Leveraging 2.5 years of weekly data from the Relationship Dynamics and Social Life Study, we investigate the relationship between young women's sexual concurrency and their contraceptive behavior. Specifically, we (1) examine whether young women changed their contraceptive use when switching from one to multiple concurrent sexual partners in the same week; (2) explore the uniformity of contraceptive responses to concurrency across relationship context; and (3) compare the contraceptive behaviors of never-concurrent women with those of ever-concurrent women in weeks when they were not concurrent. Nearly one in five sexually active young women had sex with two or more people in the same week. When they were concurrent, these women's odds of using any contraception increased threefold, and their odds of using condoms increased fourfold. This pattern of contraceptive adjustments was the same across relationship characteristics, such as duration and exclusivity. Yet when they were not concurrent, ever-concurrent women were less likely to use any contraception and used condoms less consistently than women who were never concurrent. We discuss these findings in the context of ongoing debates about the role of sexual concurrency in STI transmission dynamics.

Association between substance use and concurrent sexual relationships among urban slum dwellers in Nairobi, Kenya

While the overall incidence and prevalence of HIV/AIDS are declining in Africa, substance use-related HIV/AIDS is on the rise. The main objectives of this study were to elicit the types of commonly used substances and to examine the association between substance use and concurrent sexual relationships among slum dwellers in Kenya. Freelisting elicitation techniques were used to identify the most commonly used substances using 53 key informants. This was followed by a self-administered, structured questionnaire using a convenience sample of 506 participants. Findings from our freelisting analysis produced 27 substances that were used in the community. Analysis of the survey data shows that participants who reported using substances in the past three months were more likely to be involved in concurrent sexual relationships than those who did not (86.2% vs. 74.0%; p = .002). In the multivariable model, the odds of ever having concurrent sexual relationships were higher among participants who used any substance in the past three months (aOR 2.46; 95% CI 1.37-4.42, p < .01). The observed association between substance use and concurrent sexual relationships may be influenced by social and economic factors such as poverty and lack of opportunity among urban slum dwellers.

Greater wealth inequality, less polygyny: rethinking the polygyny threshold model

Monogamy appears to have become the predominant human mating system with the emergence of highly unequal agricultural populations that replaced relatively egalitarian horticultural populations, challenging the conventional idea-based on the polygyny threshold model-that polygyny should be positively associated with wealth inequality. To address this polygyny paradox, we generalize the standard polygyny threshold model to a mutual mate choice model predicting the fraction of women married polygynously. We then demonstrate two conditions that are jointly sufficient to make monogamy the predominant marriage form, even in highly unequal societies. We assess if these conditions are satisfied using individual-level data from 29 human populations. Our analysis shows that with the shift to stratified agricultural economies: (i) the population frequency of relatively poor individuals increased, increasing wealth inequality, but decreasing the frequency of individuals with sufficient wealth to secure polygynous marriage, and (ii) diminishing marginal fitness returns to additional wives prevent extremely wealthy men from obtaining as many wives as their relative wealth would otherwise predict. These conditions jointly lead to a high population-level frequency of monogamy.

Understanding the urban-rural disparity in HIV and poverty nexus: the case of Kenya

Background

The relationship between HIV and poverty is complex and recent studies reveal an urban-rural divide that is not well understood. This paper examines the urban-rural disparity in the relationship between poverty and HIV infection in Kenya, with particular reference to possible explanations relating to social cohesion/capital and other moderating factors.

Methods

Multilevel logistic regression models are applied to nationally-representative samples of 13 094 men and women of reproductive age from recent Kenya Demographic and Health Surveys.

Results

The results confirm a disproportionate higher risk of HIV infection among the urban poor, despite a general negative association between poverty and HIV infection among rural residents. Estimates of intra-community correlations suggest lower social cohesion in urban than rural communities. This, combined with marked socio-economic inequalities in urban areas is likely to result in the urban poor being particularly vulnerable. The results further reveal interesting cultural variations and trends. In particular, recent declines in HIV prevalence among urban residents in Kenya have been predominantly confined to those of higher socio-economic status.

Conclusion

With current rapid urbanization patterns and increasing urban poverty, these trends have important implications for the future of the HIV epidemic in Kenya and similar settings across the sub-Saharan Africa region.

Jaboya ("Sex for Fish"): A Qualitative Analysis of Contextual Risk Factors for Extramarital Partnerships in the Fishing Communities in Western Kenya

Extramarital partnerships exacerbate high HIV prevalence rates in many communities in sub-Saharan Africa. We explored contextual risk factors and suggested interventions to reduce extramarital partnerships among couples in the fishing communities on Lake Victoria, Kenya. We conducted 12 focus group discussions with 9-10 participants each (N = 118) and 16 in-depth interviews (N = 16) with fishermen and their spouses. Couples who participated were consented and separated for simultaneous gender-matched discussions/interviews. Interview topics included courtship and marriage, relationship and sexual satisfaction, extramarital relationships and how to intervene on HIV risks. Coding, analysis, and interpretation of the transcripts followed grounded theory tenets that allow analytical themes to emerge from the participants. Our results showed that extramarital partnerships were perceived to be widespread and were attributed to factors related to sexual satisfaction such as women needing more foreplay before intercourse, discrepancies in sexual desire, and boredom with the current sexual repertoire. Participants also reported that financial and sociophysical factors such as family financial support and physical separation, contributed to the formation of extramarital partnerships. Participants made suggestions for interventions that reduce extramarital partnerships to minimize HIV risks at the community, couple, and individual level. These suggestions emphasized improving community education, spousal communication, and self-evaluation for positive behavior change. Future studies can draw upon these findings as a basis for designing community-owned interventions that seek to reduce community-level HIV risk through a reduction in the number of sexual partners.

'Good culture, bad culture': polygyny, cultural change and structural drivers of HIV in Papua New Guinea

Culture is often problematised as a key structural driver of HIV transmission in Papua New Guinea. Official HIV programmes, as well as church teachings, tend to focus on customary marital practices of polygyny and bride price payments as 'harmful traditions'. This focus can oversimplify the effects of current and historical nuances of cultural, political and economic change on sexual concurrency and gender inequality. Community-based healthcare workers in Southern Highlands Province explain that customary marital practices are now highly reconfigured from their traditional forms. A recent mining boom has financially advantaged local and travelling men, who are driving an increase of sexual concurrency, transactional sex and inflation of bride price payments. Healthcare workers suggest that the erosion of important social relationships and kinship obligations by the expanding cash economy has caused an intensification of individual male power while enhancing the vulnerability of women. Yet without the means to challenge the effects of uneven economic development, healthcare workers are left to target 'culture' as the central influence on individual behaviours. A commitment to address structural inequality by political leadership and in HIV prevention programmes and a careful contextualisation of cultural change is needed.

Islamic Influence on HIV Risk and Protection Among Central Asian Male Migrant Workers in Kazakhstan

HIV incidence is increasing in Central Asia, where migrant workers experience risks for acquiring sexually transmitted HIV. As a social and structural factor that may influence perceptions and behavior, we examine how Islam shapes HIV risk and protection. Phenomenological qualitative interviews examine religion and contexts of HIV risk among 48 male Central Asian migrant workers residing in Almaty, Kazakhstan. Men described nonvaginal sex, alcohol use, premarital sex, and extramarital sex as forbidden or frowned upon. Religious networks were unlikely to discuss HIV risks, and some men viewed religious affiliation or practices as protective. Marital practices including neke (religious marriage), polygyny, and bride kidnapping may be linked to risk. Findings suggest adhering to Islamic ideals may be protective for some men, but for others, assumptions of protection may enhance risk. HIV prevention strategies among Central Asian migrants may be strengthened by attention to religious and cultural understandings of risk and protection.

Partnership duration, concurrency, and HIV in sub-Saharan Africa

A widely accepted explanation for the exceptionally high HIV prevalence in sub-Saharan Africa is the practice of long-term overlapping heterosexual partnering. This article shows that long-duration concurrent partnering can be protective against HIV transmission rather than promoting it. Monogamous partnering prevents sexual transmission to anyone outside the partnership and, in an initially concordant-seronegative partnership, prevents sexual acquisition of HIV by either partner. Those protections against transmission and acquisition last as long as the partnership persists without new outside partnerships. Correspondingly, these two protective effects characterise polygynous partnerships, whether or not the polygyny is formal or informal, until a partner initiates a new partnership. Stable and exclusive unions of any size protect against HIV transmission, and more durable unions provide a longer protective effect. Survey research provides little information on partnership duration in sub-Saharan Africa and sheds no light on the interaction of duration, concurrency, and HIV. This article shows how assumptions about partnership duration in individual-based sexual-network models affect the contours of simulated HIV epidemics. Longer mean partnership duration slows the pace at which simulated epidemics grow. With plausible assumptions about partnership duration and at levels of concurrency found in the region, simulated HIV epidemics grow slowly or not at all. Those results are consistent with the hypothesis that long-duration partnering is protective against HIV and inconsistent with the hypothesis that long-term concurrency drives the HIV epidemics in sub-Saharan Africa.

Gender asymmetry in concurrent partnerships and HIV prevalence

The structure of the sexual network of a population plays an essential role in the transmission of HIV. Concurrent partnerships, i.e. partnerships that overlap in time, are important in determining this network structure. Men and women may differ in their concurrent behavior, e.g. in the case of polygyny where women are monogamous while men may have concurrent partnerships. Polygyny has been shown empirically to be negatively associated with HIV prevalence, but the epidemiological impacts of other forms of gender-asymmetric concurrency have not been formally explored. Here we investigate how gender asymmetry in concurrency, including polygyny, can affect the disease dynamics. We use a model for a dynamic network where individuals may have concurrent partners. The maximum possible number of simultaneous partnerships can differ for men and women, e.g. in the case of polygyny. We control for mean partnership duration, mean lifetime number of partners, mean degree, and sexually active lifespan. We assess the effects of gender asymmetry in concurrency on two epidemic phase quantities (R₀ and the contribution of the acute HIV stage to R₀) and on the endemic HIV prevalence. We find that gender asymmetry in concurrent partnerships is associated with lower levels of all three epidemiological quantities, especially in the polygynous case. This effect on disease transmission can be attributed to changes in network structure, where increasing asymmetry leads to decreasing network connectivity.

Disease dynamics and costly punishment can foster socially imposed monogamy

Socially imposed monogamy in humans is an evolutionary puzzle because it requires costly punishment by those who impose the norm. Moreover, most societies were—and are—polygynous; yet many larger human societies transitioned from polygyny to socially imposed monogamy beginning with the advent of agriculture and larger residential groups. We use a simulation model to explore how interactions between group size, sexually transmitted infection (STI) dynamics and social norms can explain the timing and emergence of socially imposed monogamy. Polygyny dominates when groups are too small to sustain STIs. However, in larger groups, STIs become endemic (especially in concurrent polygynist networks) and have an impact on fertility, thereby mediating multilevel selection. Punishment of polygynists improves monogamist fitness within groups by reducing their STI exposure, and between groups by enabling punishing monogamist groups to outcompete polygynists. This suggests pathways for the emergence of socially imposed monogamy, and enriches our understanding of costly punishment evolution.

Many human societies transitioned from polygyny to socially imposed monogamy as group sizes increased. Using a simulation model, the authors show that sexually transmitted infections impose heavier fitness penalties on polygynists as group size grows, enabling monogamists who punish polygyny to thrive in large groups.

Prevalence and social drivers of HIV among married and cohabitating heterosexual adults in south-eastern Tanzania: analysis of adult health community cohort data

Background

In sub-Saharan Africa, the prevalence of HIV among married and cohabiting couples is substantial. Information about the underlying social drivers of HIV transmission in couples is critical for the development of structural approaches to HIV prevention, but not readily available. We explored the association between social drivers, practices, and HIV status among stable couples in Ifakara, Tanzania.

Design

Using a cross-sectional design, we analyzed data from a sample of 3,988 married or cohabiting individuals, aged 15 years and older from the MZIMA adult health community cohort study of 2013. Sociodemographic factors (sex, income, age, and education), gender norms (perceived acceptability for a wife to ask her partner to use a condom when she knows he is HIV positive), marriage characteristics (being in a monogamous or a polygamous marriage, being remarried), sexual behavior practices (lifetime number of sexual partners and concurrent sexual partners), health system factors (ever used voluntary HIV counseling and testing), and lifestyle patterns (alcohol use) were used to explore the odds of being HIV positive, with 95% confidence intervals.

Results

Prevalence of HIV/AIDS was 6.7% (5.9% males and 7.1% females). Gender norms, that is, perception that a woman is not justified to ask her husband to use a condom even when she knows he has a disease (adjusted odds ratio AOR=1.51, 95% CI 1.06–2.17), marital characteristics, that is, being remarried (AOR=1.49, 95% CI 1.08–2.04), and sexual behavior characteristics, that is, lifetime number of sexual partners (2–4: AOR=1.47, 95% CI 1.02–2.11; 5+: AOR=1.61, 95% CI 1.05–2.47) were the main independent predictors of HIV prevalence.

Conclusions

Among married or cohabiting individuals, the key social drivers/practices that appeared to make people more vulnerable for HIV are gender norms, marriage characteristics (being remarried), and sexual behavior practices (lifetime number of sexual partners). Married and cohabiting couples are an important target group for HIV prevention efforts in Tanzania. In addition to individual interventions, structural interventions are needed to address the gender norms, remarriage, and sexual practices that shape differential vulnerability to HIV in stable couples.

Concurrent partnerships in Cape Town, South Africa: race and sex differences in prevalence and duration of overlap

Introduction

Concurrent partnerships (CPs) have been suggested as a risk factor for transmitting HIV, but their impact on the epidemic depends upon how prevalent they are in populations, the average number of CPs an individual has and the length of time they overlap. However, estimates of prevalence of CPs in Southern Africa vary widely, and the duration of overlap in these relationships is poorly documented. We aim to characterize concurrency in a more accurate and complete manner, using data from three disadvantaged communities of Cape Town, South Africa.

Methods

We conducted a sexual behaviour survey (n=878) from June 2011 to February 2012 in Cape Town, using Audio Computer-Assisted Self-Interviewing to collect sexual relationship histories on partners in the past year. Using the beginning and end dates for the partnerships, we calculated the point prevalence, the cumulative prevalence and the incidence rate of CPs, as well as the duration of overlap for relationships begun in the previous year. Linear and binomial regression models were used to quantify race (black vs. coloured) and sex differences in the duration of overlap and relative risk of having CPs in the past year.

Results

The overall point prevalence of CPs six months before the survey was 8.4%: 13.4% for black men, 1.9% for coloured men, 7.8% black women and 5.6% for coloured women. The median duration of overlap in CPs was 7.5 weeks. Women had less risk of CPs in the previous year than men (RR 0.43; 95% CI: 0.32–0.57) and black participants were more at risk than coloured participants (RR 1.86; 95% CI: 1.17–2.97).

Conclusions

Our results indicate that in this population the prevalence of CPs is relatively high and is characterized by overlaps of long duration, implying there may be opportunities for HIV to be transmitted to concurrent partners.

Synergistic vulnerabilities: antiretroviral treatment among women in Uganda

Despite being an early success story in the reduction of HIV infection rates, Uganda faces myriad challenges in the recent era of accelerated antiretroviral treatment (ARV) scale-up. For those able to access treatment, ongoing vulnerabilities of poverty and violence compound treatment-related costs and concerns. This paper explores experiences of one particularly vulnerable population - women on ARVs who have also experienced intimate partner violence (IPV). Data were collected over 12 months in Uganda. They include ethnographic interviews (n = 40) drawn from a larger sample of women on ARV and semi-structured interviews with policy-makers and service providers (n = 42), examining the intersection of experiences and responses to treatment from multiple perspectives. Women's narratives show that due to treatment, immediate health concerns take on secondary importance, while other forms of vulnerability, including IPV and poverty, can continue to shape treatment experiences and the decision to stay in violent relationships. Providers likewise face difficulties in overburdened clinics, though they recognise women's concerns and the importance of considering other forms of vulnerability in treatment. This analysis makes the case for integrating treatment with other types of social services and demonstrates the importance of understanding the ways in which synergistic and compounding vulnerabilities confound treatment scale-up efforts.

Trends in concurrency, polygyny, and multiple sex partnerships during a decade of declining HIV prevalence in eastern Zimbabwe

Background. Observed declines in the prevalence of human immunodeficiency virus (HIV) infection in Zimbabwe have been attributed to population-level reductions in sexual partnership numbers. However, it remains unknown whether certain types of sex partnerships were more important to this decline. Particular debate surrounds the epidemiologic importance of polygyny (the practice of having multiple wives).

Methods. We analyze changes in reported multiple partnerships, nonmarital concurrency, and polygyny in eastern Zimbabwe during a period of declining HIV prevalence, from 1998 to 2011. Trends are reported for adult men (age, 17–54 years) and women (age, 15–49 years) from 5 survey rounds of the Manicaland HIV/STD Prevention Project, a general-population open cohort study.

Results. At baseline, 34.2% of men reported multiple partnerships, 11.9% reported nonmarital concurrency, and 4.6% reported polygyny. Among women, 4.6% and 1.8% reported multiple partnerships and concurrency, respectively. All 3 partnership indicators declined by similar relative amounts (around 60%–70%) over the period. Polygyny accounted for around 25% of male concurrency. Compared with monogamously married men, polygynous men reported higher levels of subsequent divorce/separation (adjusted relative risk [RR], 2.92; 95% confidence interval [CI], 1.87–4.55) and casual sex partnerships (adjusted RR, 1.63; 95% CI, 1.41–1.88).

Conclusions. No indicator clearly dominated declines in partnerships. Polygyny was surprisingly unstable and, in this population, should not be considered a safe form of concurrency.

Correlates of prevalent HIV infection among adults and adolescents in the Kisumu incidence cohort study, Kisumu, Kenya

We estimated HIV prevalence and identified correlates of HIV infection among 1106 men and women aged 16-34 years residing in Kisumu, Kenya. Demographic, sexual, and other behavioural data were collected using audio computer-assisted self-interview in conjunction with a medical examination, real-time parallel rapid HIV testing, and laboratory testing for pregnancy, gonorrhoea, chlamydia, syphilis, and herpes simplex virus type 2. Multivariate logistic regression was used to identify variables associated with prevalent HIV infection by gender. Overall HIV prevalence was 12.1%. HIV prevalence among women (17.1%) was approximately two-and-one-half times the prevalence among men (6.6%). Odds of HIV infection in men increased with age (aOR associated with one-year increase in age = 1.21, CI = 1.07-1.35) and were greater among those who were uncircumcised (aOR = 4.42, CI = 1.41-13.89) and those who had an herpes simplex virus type 2-positive (aOR = 3.13, CI = 1.12-8.73) test result. Odds of prevalent HIV infection among women also increased with age (aOR associated with one-year increase in age = 1.16, CI = 1.04-1.29). Women who tested herpes simplex virus type 2 positive had more than three times the odds (aOR = 3.85, CI = 1.38-10.46) of prevalent HIV infection compared with those who tested herpes simplex virus type 2 negative. Tailored sexual health interventions and programs may help mitigate HIV age and gender disparities.

A new approach to measuring partnership concurrency and its association with HIV risk in couples

Empirical estimates of the association between concurrent partnerships (CP) and HIV risk are affected by non-sampling errors in survey data on CPs, e.g., because respondents misreport the extent of their CPs. We propose a new approach to measuring CPs in couples, which permits assessing how respondent errors affect estimates of the association between CPs and HIV risk. Each couple member is asked (1) to report whether s/he has engaged in CPs and (2) to assess whether his/her partner has engaged in CPs, since their couple started. Cross-tabulating these data yields multiple classifications (with varying combinations of sensitivity/specificity) of the CPs of each couple member. We then measure the association between CPs and HIV outcomes according to each classification. The resulting range of estimates is an indicator of the uncertainty associated with respondent errors. We tested this approach using data on 520 matched couples drawn from the Likoma Network Study. Results suggest that existing tests of the concurrency hypothesis are affected by significant uncertainty.

Structural and community-level interventions for increasing condom use to prevent the transmission of HIV and other sexually transmitted infections

BACKGROUND

Community interventions to promote condom use are considered to be a valuable tool to reduce the transmission of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). In particular, special emphasis has been placed on implementing such interventions through structural changes, a concept that implies public health actions that aim to improve society's health through modifications in the context wherein health-related risk behavior takes place. This strategy attempts to increase condom use and in turn lower the transmission of HIV and other STIs.

OBJECTIVES

To assess the effects of structural and community-level interventions for increasing condom use in both general and high-risk populations to reduce the incidence of HIV and STI transmission by comparing alternative strategies, or by assessing the effects of a strategy compared with a control.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, from 2007, Issue 1), as well as MEDLINE, EMBASE, AEGIS and ClinicalTrials.gov, from January 1980 to April 2014. We also handsearched proceedings of international acquired immunodeficiency syndrome (AIDS) conferences, as well as major behavioral studies conferences focusing on HIV/AIDS and STIs.

SELECTION CRITERIA

Randomized control trials (RCTs) featuring all of the following.1. Community interventions ('community' defined as a geographical entity, such as cities, counties, villages).2. One or more structural interventions whose objective was to promote condom use. These type of interventions can be defined as those actions improving accessibility, availability and acceptability of any given health program/technology.3. Trials that confirmed biological outcomes using laboratory testing.

DATA COLLECTION AND ANALYSIS

Two authors independently screened and selected relevant studies, and conducted further risk of bias assessment. We assessed the effect of treatment by pooling trials with comparable characteristics and quantified its effect size using risk ratio. The effect of clustering at the community level was addressed through intra-cluster correlation coefficients (ICCs), and sensitivity analysis was carried out with different design effect values.

MAIN RESULTS

We included nine trials (plus one study that was a subanalysis) for quantitative assessment. The studies were conducted in Tanzania, Zimbabwe, South Africa, Uganda, Kenya, Peru, China, India and Russia, comprising 75,891 participants, mostly including the general population (not the high-risk population). The main intervention was condom promotion, or distribution, or both. In general, control groups did not receive any active intervention. The main risk of bias was incomplete outcome data.In the meta-analysis, there was no clear evidence that the intervention had an effect on either HIV seroprevalence or HIV seroincidence when compared to controls: HIV incidence (risk ratio (RR) 0.90, 95% confidence interval (CI) 0.69 to 1.19) and HIV prevalence (RR 1.02, 95% CI 0.79 to 1.32). The estimated effect of the intervention on other outcomes was similarly uncertain: Herpes simplex virus 2 (HSV-2) incidence (RR 0.76, 95% CI 0.55 to 1.04); HSV-2 prevalence (RR 1.01, 95% CI 0.85 to 1.20); syphilis prevalence (RR 0.91, 95% CI 0.71 to 1.17); gonorrhoea prevalence (RR 1.16, 95% CI 0.67 to 2.02); chlamydia prevalence (RR 0.94, 95% CI 0.75 to 1.18); and trichomonas prevalence (RR 1.00, 95% CI 0.77 to 1.30). Reported condom use increased in the experimental arm (RR 1.20, 95% CI 1.03 to 1.40). In the intervention groups, the number of people reporting two or more sexual partners in the past year did not show a clear decrease when compared with control groups (RR 0.90, 95% CI 0.78 to 1.04), but knowledge about HIV and other STIs improved (RR 1.15, 95% CI 1.04 to 1.28, and RR 1.23, 95% CI 1.07 to 1.41, respectively). The quality of the evidence was deemed to be moderate for nearly all key outcomes.

AUTHORS' CONCLUSIONS

There is no clear evidence that structural interventions at the community level to increase condom use prevent the transmission of HIV and other STIs. However, this conclusion should be interpreted with caution since our results have wide confidence intervals and the results for prevalence may be affected by attrition bias. In addition, it was not possible to find RCTs in which extended changes to policies were conducted and the results only apply to general populations in developing nations, particularly to Sub-Saharan Africa, a region which in turn is widely diverse.

SI infection on a dynamic partnership network: characterization of R0

We model the spread of an SI (Susceptible → Infectious) sexually transmitted infection on a dynamic homosexual network. The network consists of individuals with a dynamically varying number of partners. There is demographic turnover due to individuals entering the population at a constant rate and leaving the population after an exponentially distributed time. Infection is transmitted in partnerships between susceptible and infected individuals. We assume that the state of an individual in this structured population is specified by its disease status and its numbers of susceptible and infected partners. Therefore the state of an individual changes through partnership dynamics and transmission of infection. We assume that an individual has precisely n 'sites' at which a partner can be bound, all of which behave independently from one another as far as forming and dissolving partnerships are concerned. The population level dynamics of partnerships and disease transmission can be described by a set of (n +1)(n +2) differential equations. We characterize the basic reproduction ratio R0 using the next-generation-matrix method. Using the interpretation of R0 we show that we can reduce the number of states-at-infection n to only considering three states-at-infection. This means that the stability analysis of the disease-free steady state of an (n +1)(n +2)-dimensional system is reduced to determining the dominant eigenvalue of a 3 × 3 matrix. We then show that a further reduction to a 2 × 2 matrix is possible where all matrix entries are in explicit form. This implies that an explicit expression for R0 can be found for every value of n.

Marital concurrency and HIV risk in 16 African countries

Research has identified sexual concurrency as a potential underlying driver of high HIV infection levels in sub-Saharan Africa, though few studies have explicitly examined the contribution of marital concurrency. Utilizing a multi-level model of Demographic and Health Surveys with HIV-biomarkers for sixteen African countries, this study assessed the relationship between an individual's HIV serostatus and rates of formal and informal marital concurrency (% polygamous unions, % extramarital partner past year) among married men and women. Mutually exclusive regional-level variables were constructed and modeled to test the contextual risk posed by living in a region with higher levels of formal and informal marital concurrency controlling for individual sexual partnerships and other covariates. Compared with regions where monogamous unions were more prevalent, the odds of having HIV were higher among individuals living in regions with more informal marital concurrency, but lower in regions with more polygamy, even accounting for individual-level sexual behavior. These results can help inform prevention policy and practice in sub-Saharan Africa.

Polygynous contexts, family structure, and infant mortality in sub-saharan Africa

Contextual characteristics influence infant mortality above and beyond family-level factors. The widespread practice of polygyny is one feature of many sub-Saharan African contexts that may be relevant to understanding patterns of infant mortality. Building on evidence that the prevalence of polygyny reflects broader economic, social, and cultural features and that it has implications for how families engage in the practice, we investigate whether and how the prevalence of polygyny (1) spills over to elevate infant mortality for all families, and (2) conditions the survival disadvantage for children living in polygynous families (i.e., compared with monogamous families). We use data from Demographic and Health Surveys to estimate multilevel hazard models that identify associations between infant mortality and region-level prevalence of polygyny for 236,336 children in 260 subnational regions across 29 sub-Saharan African countries. We find little evidence that the prevalence of polygyny influences mortality for infants in nonpolygynous households net of region-level socioeconomic factors and gender inequality. However, the prevalence of polygyny significantly amplifies the survival disadvantage for infants in polygynous families. Our findings demonstrate that considering the broader marital context reveals important insights into the relationship between family structure and child well-being.

Comparing Estimates of Multiple and Concurrent Partnerships Across Population Based Surveys: Implications for Combination HIV Prevention

We compare estimates of multiple and concurrent sexual partnerships from Demographic and Health Surveys (DHS) with comparable Population Services International (PSI) surveys in four African countries (Kenya, Lesotho, Uganda, Zambia). DHS data produce significantly lower estimates of all indicators for both sexes in all countries. PSI estimates of multiple partnerships are 1.7 times higher [1.4 for men (M), 3.0 for women (W)], cumulative prevalence of concurrency is 2.4 times higher (2.2 M, 2.7 W), the point prevalence of concurrency is 3.5 times higher (3.5 M, 3.3 W), and the fraction of multi-partnered persons who report concurrency last year is 1.4 times higher (1.6 M, 0.9 W). These findings provide strong empirical evidence that DHS surveys systematically underestimate levels of multiple and concurrent partnerships. The underestimates will contaminate both empirical analyses of the link between sexual behavior and HIV infection, and theoretical models for combination prevention that use these data for inputs.

[HIV disclosure in polygamous settings in Senegal]

In Senegal, where HIV prevalence is less than 1% and stigma remains important, 40% of marriages are polygamic. The purpose of this article is to describe and analyze the motivations, benefits and constraints related to HIV disclosure, and to explore specific situations related to polygamy. Data were collected through qualitative research based on in-depth repeated interviews on the experience of antiretroviral therapy and its social effects, conducted over a period of 10 years with people on antiretroviral treatment and their caregivers. Health professionals encourage people to disclose their HIV status, especially in certain circumstances such as preventing mother-to-child transmission of HIV. Nevertheless they are aware of the social risks for some patients, particularly women. Some health workers insist on disclosure, while others do not interfere with women who do not disclose to their partner, while highlighting their ethical dilemma. Interviews trace the changing attitudes of caregivers regarding disclosure. The majority of married women begin by sharing their HIV status with their mother, waiting for her to confirm that the contamination is not due to immoral behavior and to participate in implementing a strategy to maintain secrecy. In polygamous households, women try to disclose to their partner, keeping the secret beyond the couple. Some women fear disclosure by their husbands to co-spouses, whose attitudes can be very diverse: some stories relate collective rejection from the household; sometimes disclosure is made in a progressive way following the hierarchy of positions of each person in the household; another person reported the solidarity shown by her co-spouses who kept her HIV status a secret outside the household. The article shows the diversity of situations and their dynamics regarding both disclosure practices and their social effects.

Partnership concurrency and coital frequency

National HIV prevalence estimates across sub-Saharan Africa range from less than 1 percent to over 25 percent. Recent research proposes several explanations for the observed variation, including prevalence of male circumcision, levels of condom use, presence of other sexually transmitted infections, and practice of multiple concurrent partnerships. However, the importance of partnership concurrency for HIV transmission may depend on how it affects coital frequency with each partner. The coital dilution hypothesis suggests that coital frequency within a partnership declines with the addition of concurrent partners. Using sexual behavior data from rural Malawi and urban Kenya, we investigate the relationship between partnership concurrency and coital frequency, and find partial support for the coital dilution hypothesis. We conclude the paper with a discussion of our findings in light of the current literature on concurrency.

The changing cultural and economic dynamics of polygyny and concurrent sexual partnerships in Iringa, Tanzania

Polygyny has been identified both as a 'benign' form of concurrency and as the cultural basis of concurrent partnerships that are considered important drivers of the HIV epidemic in sub-Saharan Africa. This paper investigates the changing cultural and economic dynamics of polygyny in concurrency in Iringa, Tanzania, a region with traditions of polygyny and high prevalence of HIV. Our analysis of focus group discussions, in-depth interviews and key informant interviews indicate that contemporary concurrent partnerships differ from regional traditions of polygyny. Whereas in the past, polygyny reflected men's and their kin group's wealth and garnered additional prestige, polygyny today is increasingly seen as a threat to health, and as leading to poverty. Nevertheless, participants evoked the social prestige of polygyny to explain men's present-day concurrency, even outside the bounds of marriage, and despite continued social prohibitions against extramarital affairs. Difficult economic conditions, combined with this prestige, made it easier for men to engage in concurrency without the considerable obligations to wives and children in polygyny. Local economic conditions also compelled women to seek concurrent partners to meet basic needs and to access consumer goods, but risked greater moral judgement than men, especially if deemed to have excessive 'desire' for money.

Short-term Mobility and Increased Partnership Concurrency among Men in Zimbabwe

BACKGROUND

Migration has long been understood as an underlying factor for HIV transmission, and sexual partner concurrency has been increasingly studied as an important component of HIV transmission dynamics. However, less work has examined the role of short-term mobility in sexual partner concurrency using a network approach. Short-term mobility may be a risk for HIV for the migrant's partner as well either through the partner's risk behaviors while the migrant is away, such as the partner having additional partners, or via exposure to the return migrant.

METHODS

Using data from the 2010-11 Zimbabwe Demographic and Health Survey, weighted generalized linear regression models were used to investigate the associations between short-term mobility and partnership concurrency at the individual and partnership levels.

RESULTS

At the individual level, we find strong evidence of an association between short-term mobility and concurrency. Men who traveled were more likely to have concurrent partnerships compared to men who did not travel and the relationship was non-linear: each trip was associated with a 2% higher probability of concurrency, with a diminishing risk at 60 trips (p<0.001). At the partnership level, short-term mobility by the male only or both partners was associated with male concurrency. Couples in which the female only traveled exhibited less male concurrency.

CONCLUSIONS

Short-term mobility has the ability to impact population-level transmission dynamics by facilitating partnership concurrency and thus onward HIV transmission. Short-term migrants may be an important population to target for HIV testing, treatment, or social and behavioral interventions to prevent the spread of HIV.

Coital frequency and condom use in monogamous and concurrent sexual relationships in Cape Town, South Africa

Introduction

A decreased frequency of unprotected sex during episodes of concurrent relationships may dramatically reduce the role of concurrency in accelerating the spread of HIV. Such a decrease could be the result of coital dilution – the reduction in per-partner coital frequency from additional partners – and/or increased condom use during concurrency. To study the effect of concurrency on the frequency of unprotected sex, we examined sexual behaviour data from three communities with high HIV prevalence around Cape Town, South Africa.

Methods

We conducted a cross-sectional survey from June 2011 to February 2012 using audio computer-assisted self-interviewing to reconstruct one-year sexual histories, with a focus on coital frequency and condom use. Participants were randomly sampled from a previous TB and HIV prevalence survey. Mixed effects logistic and Poisson regression models were fitted to data from 527 sexually active adults reporting on 1210 relationship episodes to evaluate the effect of concurrency status on consistent condom use and coital frequency.

Results

The median of the per-partner weekly average coital frequency was 2 (IQR: 1–3), and consistent condom use was reported for 36% of the relationship episodes. Neither per-partner coital frequency nor consistent condom use changed significantly during episodes of concurrency (aIRR=1.05; 95% confidence interval (CI): 0.99–1.24 and aOR=1.01; 95% CI: 0.38–2.68, respectively). Being male, coloured, having a tertiary education, and having a relationship between 2 weeks and 9 months were associated with higher coital frequencies. Being coloured, and having a relationship lasting for more than 9 months, was associated with inconsistent condom use.

Conclusions

We found no evidence for coital dilution or for increased condom use during concurrent relationship episodes in three communities around Cape Town with high HIV prevalence. Given the low levels of self-reported consistent condom use, our findings suggest that if the frequency of unprotected sex with each of the sexual partners is sustained during concurrent relationships, HIV-positive individuals with concurrent partners may disproportionately contribute to onward HIV transmission.

Community viral load as a measure for assessment of HIV treatment as prevention

Community viral load, defined as an aggregation of individual viral loads of people infected with HIV in a specific community, has been proposed as a useful measure to monitor HIV treatment uptake and quantify its effect on transmission. The first reports of community viral load were published in 2009, and the measure was subsequently incorporated into the US National HIV/AIDS Strategy. Although intuitively an appealing strategy, measurement of community viral load has several theoretical limitations and biases that need further assessment, which can be grouped into four categories: issues of selection and measurement, the importance of HIV prevalence in determining the potential for ongoing HIV transmission, interpretation of community viral load and its effect on ongoing HIV transmission in a community, and the ecological fallacy (ie, ecological bias). These issues need careful assessment as community viral load is being considered as a public health measurement to assess the effect of HIV care on prevention.

Understanding culture and HIV/AIDS in sub-Saharan Africa

Early in the study of HIV/AIDS, culture was invoked to explain differences in the disease patterns between sub-Saharan Africa and Western countries. Unfortunately, in an attempt to explain the statistics, many of the presumed risk factors were impugned in the absence of evidence. Many cultural practices were stripped of their meanings, societal context and historical positioning and transformed into cofactors of disease. Other supposedly beneficial cultural traits were used to explain the absence of disease in certain populations, implicitly blaming victims in other groups. Despite years of study, assumptions about culture as a cofactor in the spread of HIV/AIDS have persisted, despite a lack of empirical evidence. In recent years, more and more ideas about cultural causality have been called into question, and often disproved by studies. Thus, in light of new evidence, a review of purported cultural causes of disease, enhanced by an understanding of the differences between individual and population risks, is both warranted and long overdue. The preponderance of evidence suggests that culture as a singular determinant in the African epidemic of HIV/AIDS falls flat when disabused of its biased and ethnocentric assumptions.

Measuring and modelling concurrency

This article explores three critical topics discussed in the recent debate over concurrency (overlapping sexual partnerships): measurement of the prevalence of concurrency, mathematical modelling of concurrency and HIV epidemic dynamics, and measuring the correlation between HIV and concurrency. The focus of the article is the concurrency hypothesis - the proposition that presumed high prevalence of concurrency explains sub-Saharan Africa's exceptionally high HIV prevalence. Recent surveys using improved questionnaire design show reported concurrency ranging from 0.8% to 7.6% in the region. Even after adjusting for plausible levels of reporting errors, appropriately parameterized sexual network models of HIV epidemics do not generate sustainable epidemic trajectories (avoid epidemic extinction) at levels of concurrency found in recent surveys in sub-Saharan Africa. Efforts to support the concurrency hypothesis with a statistical correlation between HIV incidence and concurrency prevalence are not yet successful. Two decades of efforts to find evidence in support of the concurrency hypothesis have failed to build a convincing case.

Is concurrency driving HIV transmission in sub-Saharan African sexual networks? The significance of sexual partnership typology

Recently, there has been debate about the role of concurrent partnerships in driving the transmission of HIV, particularly in Southern Africa, where HIV prevalence is up to 25 % in many heterosexual populations and where evidence from sexual behavior surveys also suggests high levels of male concurrency. While mathematical modeling studies have shown that concurrency has the potential to enhance the speed at which HIV spreads in a population, empirical studies up to now have failed to provide conclusive evidence supportive of these effects. Here we discuss some reasons for the apparent discrepancy between theoretical and empirical studies. We propose that studying the impact of concurrency on HIV transmission should be differentiated by taking more insight from social and behavioral studies on sexual partnerships into account. We also suggest that a more rigorous definition is needed for when a factor is considered a driving force for HIV epidemic spread. We illustrate this with a modeling example.

Polygyny, partnership concurrency, and HIV transmission in Sub-Saharan Africa

We study the relationship between polygyny and HIV infection using nationally representative survey data with linked serostatus information from 20 African countries. Our results indicate that junior wives in polygynous unions are more likely to be HIV positive than spouses of monogamous men, but also that HIV prevalence is lower in populations with more polygyny. With these results in mind, we investigate four explanations for the contrasting individual- and ecological-level associations. These relate to (1) the adverse selection of HIV-positive women into polygynous unions, (2) the sexual network structure characteristic of polygyny, (3) the relatively low coital frequency in conjugal dyads of polygynous marriages (coital dilution), and (4) the restricted access to sexual partners for younger men in populations where polygynous men presumably monopolize the women in their community (monopolizing polygynists). We find evidence for some of these mechanisms, and together they support the proposition that polygynous marriage systems impede the spread of HIV. We relate these results to the debate about partnership concurrency as a primary behavioral driver for the fast propagation of HIV in some parts of sub-Saharan Africa.

Dynamic concurrent partnership networks incorporating demography

We introduce a population model that incorporates From a mathematical point of view we deal with continuous-time Markov chains at the individual level, with the interaction between individuals captured by a global variable describing opportunities for new partnerships. We show that for large time a stationary distribution is attained and we deduce various statistical features of that distribution, with particular attention for concurrency, i.e. the overlap in time of multiple partnerships of one and the same individual. Our ultimate motivation is to model the spread of sexually transmitted infections in the population, for which the present paper serves as a prelude.

Risk behaviours by type of concurrency among young people in three STI clinics in the United States

BACKGROUND

Concurrent sexual partnerships can increase sexually transmissible infections (STI) transmission on a population level. However, different concurrency types may be associated with differential risks for transmission. To investigate this, we describe the prevalence and correlates of four specific concurrency types.

METHODS

Between 2001 and 2004, 1098 young adults attending three STI clinics were interviewed and tested for STIs. Characteristics associated with concurrency types were identified using logistic regression.

RESULTS

Approximately one-third of respondents reported reactive (34%), transitional (36%), compensatory (32%) and experimental (26%) concurrency. Among men, reactive concurrency was associated with not identifying as heterosexual, drug use and having sex the same day as meeting a partner. Among women, reactive concurrency was associated with African-American race and having >3 lifetime partners. Transitional concurrency was associated with >3 lifetime partners for men and women. Among men, compensatory concurrency was associated with African-American race; among women, there were no associations with compensatory concurrency. Among men, experimental concurrency was associated with >3 lifetime partners and having sex the same day as meeting a partner. Among women, experimental concurrency was associated with not identifying as heterosexual, drug use and having sex the same day as meeting a partner.

CONCLUSIONS

All concurrency types were common in this population and each was associated with a set of demographic and risk factors. Reactive and experimental concurrency types were associated with other high-risk behaviours, such as drug use.

Molecular epidemiology of HIV-1 transmission in a cohort of HIV-1 concordant heterosexual couples from Dakar, Senegal

Background

A large number of HIV-1 infections in Africa occur in married couples. The predominant direction of intracouple transmission and the principal external origins of infection remain important issues of debate.

Methods

We investigated HIV-1 transmission in 46 HIV-1 concordant positive couples from Dakar, Senegal. Intracouple transmission was confirmed by maximum-likelihood phylogenetic analysis and pairwise distance comparisons of HIV-1 env gp41 sequences from both partners. Standardized interview data were used to deduce the direction as well as the external sources of the intracouple transmissions.

Results

Conservative molecular analyses showed linked viruses in 34 (74%) couples, unlinked viruses in 6 (13%) couples, and indeterminate results for 6 (13%) couples. The interview data corresponded completely with the molecular analyses: all linked couples reported internal transmission and all unlinked couples reported external sources of infection. The majority of linked couples (93%) reported the husband as internal source of infection. These husbands most frequently (82%) reported an occasional sexual relationship as external source of infection. Pairwise comparisons of the CD4 count, antiretroviral therapy status, and the proportion of gp41 ambiguous base pairs within transmission pairs correlated with the reported order of infection events.

Conclusions

In this suburban Senegalese population, a majority of HIV-1 concordant couples showed linked HIV-1 transmission with the husband as likely index partner. Our data emphasize the risk of married women for acquiring HIV-1 as a result of the occasional sexual relationships of their husbands.

Measuring concurrency: an empirical study of different methods in a large population-based survey and evaluation of the UNAIDS guidelines

BACKGROUND

Recent UNAIDS guidelines recommend measuring concurrency 6 months before the interview date, based on overlapping partnership dates. This has theoretical advantages, but little is known about how well it can be measured in practice.

METHODS

The assumptions underlying the UNAIDS measure were tested using data from a sexual behaviour survey conducted in rural northern Malawi. All resident adults aged 15-59 were eligible. Questions included self-reported concurrency and dates for all marital and nonmarital partnerships in the past 12 months.

RESULTS

A total of 6796 women and 5253 men were interviewed, 83 and 72% of those eligible, respectively. Since few women reported multiple partners, detailed analysis was restricted to men. Overall 19.2% [95% confidence interval (CI) 18.1-20.2] of men self-reported concurrent relationships in the past year (almost all of those with more than one partner). Using overlapping dates the estimate was 16.7% (15.7-17.7). Excluding partnerships which tied on dates (making overlap uncertain) or restricting the analysis to the three most recent partners gave similar results. The UNAIDS 6-month measure was 12.0% (11.1-12.9), and current concurrency was 11.5% (10.6-12.4). The difference between dates-based and self-reported 12-month measures was much larger for unmarried men: 11.1% (9.7-12.4) self-reported; 7.1% (6.9-8.2) on dates. Polygyny (15% of married men) and the longer duration of relationships stabilized the estimates for married men. Nonmarital partnerships were under-reported, particularly those starting longer ago.

CONCLUSIONS

The difficulties of recall of dates for relationships, and under-reporting of partners lead to underestimation of concurrency using date-based measures. Self-reported concurrency is much easier to measure and appears more complete.

Sexual partnership patterns in malawi: implications for HIV/STI transmission

BACKGROUND

Concurrent sexual partnerships are believed to play an important role in HIV transmission in sub-Saharan Africa, but the contributions of concurrency to HIV and sexually transmitted infection (STI) spread depend on the details of infectious periods and relationship patterns. To contribute to the understanding of sexual partnership patterns in this region, we estimated partnership lengths, temporal gaps between partners, and periods of overlap across partners at an STI clinic in Lilongwe, Malawi.

METHODS

Participants underwent physical examinations and HIV tests, and responded to questionnaires about demographics and risk behaviors, including detailed questions about a maximum of 3 sexual partners in the previous 2 months. We calculated partnership length as the time between the first and most recent sexual contact with a partner, and gap length as the time between the most recent contact with 1 partner and the first contact with the next. We defined concurrent and consecutive partnerships as gap length ≤0 days and gap length >0 days, respectively.

RESULTS

In the study population (n = 183), 86% reported 0 or 1 partner, 5% reported multiple consecutive partnerships, and 9% reported concurrency. The mean partnership length was 858 days (median = 176 days). Gaps between consecutive partnerships were short (mean = 21 days), and overlaps across concurrent partners tended to be long (mean = 246 days).

CONCLUSIONS

Multiple sexual partnerships were uncommon, and partnerships were long on average. Among those reporting multiple recent partners, both long-term concurrency and narrowly spaced consecutive partnerships could present substantial risk for efficient transmission of HIV and classical STIs.

Global discourses and experiential speculation: Secondary and tertiary graduate Malawians dissect the HIV/AIDS epidemic

BACKGROUND

Since the beginning of the HIV/AIDS epidemic, the perspectives of secondary and tertiary school graduates in sub-Saharan Africa regarding the effectiveness of government and international HIV/AIDS policies and programmes have not been thoroughly examined. When extensive monetary aid is directed toward "development" in a country like Malawi, it is the educated elites - secondary and tertiary graduates who are heavily involved and influential in the domestic re-distribution and implementation of millions of dollars worth of aid - on whom international expectations fall to decrease the transmission of HIV. Many Malawian jobs related to public health and HIV/AIDS are created as a direct result of this funding and are occupied by the few secondary and tertiary graduates. Thus, it is a practical venture to understand their perspectives on highly contentious and heavily funded HIV/AIDS issues that affect their nation.

METHODS

Qualitative data was collected in this study in efforts to discover in-depth perspectives on the HIV/AIDS epidemic. Thirty-eight secondary and tertiary graduate Malawians took part in semi-structured interviews. Data was analysed using an early grounded theory approach and subsequent themes of "global discourses" and "experiential knowledge of HIV/AIDS" emerged.

RESULTS

This group of Malawians frequently responded to questions regarding healthcare and access to medicine, sexual behaviours and methods of reducing the spread of HIV/AIDS by citing and explaining the widespread, international and "proper" responses. The secondary and tertiary graduate Malawians also discussed these same topics in terms of what they perceive or have experienced. Experiential responses, such as the counter-productivity of circumcision and condoms, the overestimation of HIV/AIDS prevalence, and calls for more authoritarian policing of commercial sex work, were remarkably divergent from the HIV/AIDS discourse.

CONCLUSIONS

The opinions of this group of secondary and tertiary graduate Malawians do not always coincide with the current literature and policies. They give deeper insight into what is perceived and what may be taking place, and hint at what the future holds for their people. The widespread and divergent perspectives must be seriously considered because these experiences describe the potential positive and negative consequences that occur on the ground throughout Malawi as a result of HIV/AIDS policies.

HIV and concurrent sexual partnerships: modelling the role of coital dilution

BACKGROUND

The concurrency hypothesis asserts that high prevalence of overlapping sexual partnerships explains extraordinarily high HIV levels in sub-Saharan Africa. Earlier simulation models show that the network effect of concurrency can increase HIV incidence, but those models do not account for the coital dilution effect (non-primary partnerships have lower coital frequency than primary partnerships).

METHODS

We modify the model of Eaton et al (AIDS and Behavior, September 2010) to incorporate coital dilution by assigning lower coital frequencies to non-primary partnerships. We parameterize coital dilution based on the empirical work of Morris et al (PLoS ONE, December 2010) and others. Following Eaton et al, we simulate the daily transmission of HIV over 250 years for 10 levels of concurrency.

RESULTS

At every level of concurrency, our focal coital-dilution simulation produces epidemic extinction. Our sensitivity analysis shows that this result is quite robust; even modestly lower coital frequencies in non-primary partnerships lead to epidemic extinction.

CONCLUSIONS

In order to contribute usefully to the investigation of HIV prevalence, simulation models of concurrent partnering and HIV epidemics must incorporate realistic degrees of coital dilution. Doing so dramatically reduces the role that concurrency can play in accelerating the spread of HIV and suggests that concurrency cannot be an important driver of HIV epidemics in sub-Saharan Africa. Alternative explanations for HIV epidemics in sub-Saharan Africa are needed.