Sexual mixing patterns and sex-differentials in teenage exposure to HIV infection in rural Zimbabwe

Measuring trends in age at first sex and age at marriage in Manicaland, Zimbabwe

OBJECTIVE

To identify reporting biases and to determine the influence of inconsistent reporting on observed trends in the timing of age at first sex and age at marriage.

METHODS

Longitudinal data from three rounds of a population-based cohort in eastern Zimbabwe were analysed. Reports of age at first sex and age at marriage from 6837 individuals attending multiple rounds were classified according to consistency. Survival analysis was used to identify trends in the timing of first sex and marriage.

RESULTS

In this population, women initiate sex and enter marriage at younger ages than men but spend much less time between first sex and marriage. Among those surveyed between 1998 and 2005, median ages at first sex and first marriage were 18.5 years and 21.4 years for men and 18.2 years and 18.5 years, respectively, for women aged 15-54 years. High levels of reports of both age at first sex and age at marriage among those attending multiple surveys were found to be unreliable. Excluding reports identified as unreliable from these analyses did not alter the observed trends in either age at first sex or age at marriage. Tracing birth cohorts as they aged revealed reporting biases, particularly among the youngest cohorts. Comparisons by birth cohorts, which span a period of >40 years, indicate that median age at first sex has remained constant over time for women but has declined gradually for men.

CONCLUSIONS

Although many reports of age at first sex and age at marriage were found to be unreliable, inclusion of such reports did not result in artificial generation or suppression of trends.

Role of widows in the heterosexual transmission of HIV in Manicaland, Zimbabwe, 1998-2003

BACKGROUND

AIDS is the main driver of young widowhood in southern Africa.

METHODS

The demographic characteristics of widows, their reported risk behaviours and the prevalence of HIV were examined by analysing a longitudinal population-based cohort of men and women aged 15-54 years in Manicaland, eastern Zimbabwe. The results from statistical analyses were used to construct a mathematical simulation model with the aim of estimating the contribution of widow behaviour to heterosexual HIV transmission.

RESULTS

413 (11.4%) sexually experienced women and 31 (1.2%) sexually experienced men were reported to be widowed at the time of follow-up. The prevalence of HIV was exceptionally high among both widows (61%) and widowers (male widows) (54%). Widows were more likely to have high rates of partner change and engage in a pattern of transactional sex than married women. Widowers took partners who were a median of 10 years younger than themselves. Mathematical model simulations of different scenarios of sexual behaviour of widows suggested that the sexual activity of widow(er)s may underlie 8-17% of new HIV infections over a 20-year period.

CONCLUSIONS

This combined statistical analysis and model simulation suggest that widowhood plays an important role in the transmission of HIV in this rural Zimbabwean population. High-risk partnerships may be formed when widowed men and women reconnect to the sexual network.

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.

Marital Aspirations, Sexual Behaviors, and HIV/AIDS in Rural Malawi

We explore how marital aspirations are related to the sexual behaviors of adolescents and young adults in Malawi, where HIV/AIDS prevalence among adults exceeds 10%. We also consider whether the specter of AIDS is shaping ideals about marriage. By combining survey data (N = 1,087) and in-depth interviews (N = 133) with young Malawians from the Malawi Diffusion and Ideational Change Project, we show that looking for and finding a suitable spouse are linked to sexual behaviors and, thus, HIV risks. Moreover, concerns about contracting HIV are closely tied to the ideal characteristics of a future spouse. Our findings draw long-overdue attention to the importance of marital aspirations in understanding adolescent sexual behaviors and risks in the era of AIDS.

Trends in age at first sex in Uganda: evidence from Demographic and Health Survey data and longitudinal cohorts in Masaka and Rakai

OBJECTIVES

To derive the best possible estimates of trends in age at first sex (AFS) among successive cohorts of Ugandan men and women based on all the data available from the Demographic and Health Surveys (DHS) and cohort studies in Masaka and Rakai districts.

METHODS

The datasets from the DHS, Masaka cohort and Rakai cohort were analysed separately. Survival analysis methods were used to estimate median AFS for men and women born in the 1950s-1980s and to compute hazard ratios for first sex, comparing later cohorts with earlier cohorts.

RESULTS

The DHS and Masaka data showed an increase in AFS in women in the more recent birth cohorts compared with those born before 1970, but this was less apparent in the Rakai data. Successive male cohorts in Masaka appeared first to have an increased AFS which subsequently decreased, a trend that was also apparent (but not significant) in the DHS data. Younger men in Rakai had an earlier AFS than those born before 1980.

CONCLUSIONS

Women in Uganda who were born after 1970 have, on average, had sex at a later age than those born earlier. For men, AFS has not changed consistently over the period in question. Differences between Masaka and Rakai may reflect socioeconomic differences. Most of the change in AFS occurred too late to have contributed to the initial decline in the incidence of HIV.

Influence of timing of sexual debut and first marriage on sexual behaviour in later life: findings from four survey rounds in the Kisesa cohort in northern Tanzania

OBJECTIVES

To evaluate quality of sexual debut and first marriage data, measure trends and study the association of risky sexual behaviour in youth with adult risk behaviour.

METHODS

Reports on age at first sex (AFS) and age at first marriage (AFM) from the Kisesa cohort study, 1994-2004, were evaluated for consistency and used to describe trends in median age-at-event and time spent single but sexually active in different birth cohorts. The association of these variables with marital stability and numbers of partners at later ages was explored using statistical regression techniques.

RESULTS

AFS and AFM were inconsistently reported by 32% and 33% of respondents, respectively, but there was no general tendency to report lower or higher ages at a later report date. In 10-year birth cohorts born between 1950-9 and 1980-9, male median AFS declined from 18.1 to 17.0 years and female median AFM rose from 16.2 to 16.6 years. Young people of both sexes currently spend longer sexually active but unmarried than previously. Early marriage is statistically associated with remarriage and polygamy; longer time between sexual debut and marriage is associated with higher numbers of partners at later stages of life.

CONCLUSION

Inconsistent reporting of age-at-event introduces noise but does not bias estimates of population level indicators. Lengthening time spent single and sexually active suggests that men and women entering first marriage will have been exposed to increased numbers of non-marital partners. Successful youth interventions may also influence adult behaviour.

Assessing evidence for behaviour change affecting the course of HIV epidemics: a new mathematical modelling approach and application to data from Zimbabwe

BACKGROUND

Determining whether interventions to reduce HIV transmission have worked is essential, but complicated by the potential for generalised epidemics to evolve over time without individuals changing risk behaviour. We aimed to develop a method to evaluate evidence for changes in risk behaviour altering the course of an HIV epidemic.

METHODS

We developed a mathematical model of HIV transmission, incorporating the potential for natural changes in the epidemic as it matures and the introduction of antiretroviral treatment, and applied a Bayesian Melding framework, in which the model and observed trends in prevalence can be compared. We applied the model to Zimbabwe, using HIV prevalence estimates from antenatal clinic surveillance and house-hold based surveys, and basing model parameters on data from sexual behaviour surveys.

RESULTS

There was strong evidence for reductions in risk behaviour stemming HIV transmission. We estimate these changes occurred between 1999 and 2004 and averted 660,000 (95% credible interval: 460,000-860,000) infections by 2008.

DISCUSSION

The model and associated analysis framework provide a robust way to evaluate the evidence for changes in risk behaviour affecting the course of HIV epidemics, avoiding confounding by the natural evolution of HIV epidemics.

The role of testing and counselling for HIV prevention and care in the era of scaling-up antiretroviral therapy

OBJECTIVE

HIV Testing and Counselling (TC) programmes are being scaled-up as part of efforts to provide universal access to antiretroviral treatment (ART).

METHODS AND FINDINGS

Mathematical modelling of TC in Zimbabwe shows that if universal access is to be sustained, TC must include prevention counselling that enables behaviour change among infected and uninfected individuals. The predicted impact TC is modest, but improved programmes could generate substantial reductions in incidence, reducing need for ART in the long-term.

CONCLUSIONS

TC programmes that focus only on identifying those in need of treatment will not be sufficient to bring the epidemic under control.

Disco funerals: a risk situation for HIV infection among youth in Kisumu, Kenya

OBJECTIVE

We investigated the so-called 'disco funeral' phenomenon in Kisumu, Kenya, whereby community members including adolescents congregate at the home of the deceased for several days, accompanied by music and dancing. We explored whether disco funerals are a risk situation for HIV/sexually transmitted infection infection among youth.

DESIGN

: Cross-sectional qualitative study.

METHODS

We conducted 44 in-depth interviews with male and female adolescents aged 15-20 years in Kisumu municipality in Nyanza Province, Kenya. We also made observations during six disco funerals.

RESULTS

Disco funerals were an important place for young people to hang out; they increased the opportunities to meet and engage in (risky) sexual activities. Many adolescents reported having casual sex on these occasions, sometimes with multiple partners, and mostly without condoms. Some girls were forced into sex, and there were several accounts of gang rape. Sex in exchange for money was reported frequently. Drugs and alcohol seemed to facilitate unprotected, multiple-partner, coerced, and transactional sex.

CONCLUSION

In Kisumu, a town with a generalized HIV/AIDS epidemic, the high AIDS mortality leads to frequent disco funerals. Because many adolescents are having unprotected, transactional, or coerced sex at these occasions, disco funerals might contribute to the high HIV prevalence among youth, especially among adolescent girls. HIV interventions urgently need to include outreach actions to youth who hang out at disco funerals and link up with parents and funeral organizers to reduce risk situations.

Marriage behavior response to prime-age adult mortality: evidence from Malawi

This article examines the effect of AIDS-related mortality of the prime-age adult population on marriage behavior among women in Malawi. A rise in prime-age adult mortality increases risks associated with the search for a marriage partner in the marriage market. A possible behavioral change in the marriage market in response to an increase in prime-age adult mortality is to marry earlier to avoid exposure to HIV/AIDS risks. We test this hypothesis by using micro data from Malawi, where prime-age adult mortality has drastically increased. In the analysis, we estimate the probability of prime-age adult mortality that sample women have observed during their adolescent period by utilizing retrospective information on deaths of their siblings. Empirical analysis shows that excess prime-age adult mortality in the local marriage market lowers the marriage age for females and shortens the interval between the first sex and first marriage.

Community influences on young people's sexual behavior in 3 African countries

OBJECTIVES

I examined the role of community-level factors in the reporting of risky sexual behaviors among young people aged 15 to 24 years in 3 African countries with varying HIV prevalence rates.

METHODS

I analyzed demographic and health survey data from Burkina Faso, Ghana, and Zambia during the period 2001 through 2003 to identify individual, household, and community factors associated with reports of risky sexual behaviors.

RESULTS

The mechanisms through which the community environment shaped sexual behaviors varied among young men and young women. Community demographic profiles were not associated with reports of risky sexual behavior among young women but were influential in shaping the behavior of young men. Prevailing economic conditions and the behaviors and attitudes of adults in the community were strong influences on young people's sexual behaviors.

CONCLUSIONS

These results provide strong support for a focus on community-level influences as an intervention point for behavioral change. Such interventions, however, should recognize specific cultural settings and the different pathways through which the community can shape the sexual behaviors of young men and women.

Young people's sexual partnerships in KwaZulu-Natal, South Africa: patterns, contextual influences, and HIV risk

Certain sexual partnering practices, such as multiple, concurrent, or age-discrepant partnerships, are known to increase HIV risk. Yet the underlying dynamics of young people's relationships are less clearly understood. Using household survey and qualitative data, this study examines partnership dynamics and characteristics in the context of HIV risk, including number of partners, age differences, partnership duration and concurrency, and frequency of contact among young people aged 15-24 in rural KwaZulu-Natal, South Africa. One-third of the men surveyed reported multiple and/or concurrent partnering, and one-fourth of the women had partners who were five years older than they were. Nonparticipation in civic organizations or school was correlated with higher-risk partnerships for women but not for men. On average, relationships lasted more than a year for the women and men surveyed, and were frequently characterized as "serious." Qualitative findings pointed to the sequential and overlapping nature of relationships, however, with distance and mobility being important influences. These fluid partnership patterns are an important feature of young people's sexual risk in the context of South Africa's severe HIV epidemic.

Age-disparate and intergenerational sex in southern Africa: the dynamics of hypervulnerability

This paper reviews the current state of knowledge on age-disparate sexual relationships in the context of the southern African HIV/AIDS hyperepidemic. Disproportionately high HIV infection rates among young women aged 15-24 years have been attributed to their greater involvement in relationships with older-aged partners. Whereas early studies emphasized economic concerns in the context of poverty as driving girls to accept or seek the attentions of older employed men, close-grained studies reveal a complex interplay of meanings and motives that prompt both men and women across socioeconomic strata to engage in intergenerational sex. Studies have revealed that age-disparate relationships are meaningful and perceived as beneficial at a number of levels, including social, physical, psychological, as well as economic and symbolic. In the context of growing economic inequalities and cultural expectations for men to give and women to receive a compensation for sex, relationships with older men are a common and readily available way through which young women gain materially, affirm self-worth, achieve social goals, increase longer-term life chances, or otherwise add value and enjoyment to life. Awareness of HIV risks in these relationships remains low. HIV prevention policies and programmes need to start from an understanding of how those engaged in risky behaviour perceive their sexual relationships and conceptualize the choices they make and the strategies they use. A more comprehensive policy on women and girls with better integration of communities in assessing and addressing issues, and an expansion of campaigns and programmes on the role of men as protectors and supporters of women are recommended.

Keep them in school: the importance of education as a protective factor against HIV infection among young South African women

OBJECTIVE

To identify risk factors for HIV infection among young women aged 15-24 years reporting one lifetime partner in South Africa. Design In 2003, we conducted a nationally representative household survey of sexual behaviour and HIV testing among 11 904 young people aged 15-24 years in South Africa. This analysis focuses on the subset of sexually experienced young women with only one reported lifetime sex partner (n = 1708).

METHODS

Using the proximate determinants framework and the published literature we identified factors associated with HIV in young women. The associations between these factors and HIV infection were explored in multivariable logistic regression models.

RESULTS

Of the young women, 15% reporting one lifetime partner were HIV positive. In multivariable analyses, young women who had not completed high school were more likely to be infected with HIV compared with those that had completed high school (AOR 3.75; 95% CI 1.34-10.46).

CONCLUSIONS

Young South African women in this population were at high risk of HIV infection despite reporting only having one lifetime partner. Few individual level factors were associated with HIV infection, emphasizing the importance of developing HIV prevention interventions that address structural and partner level risk factors.

Age differences at sexual debut and subsequent reproductive health: Is there a link?

BACKGROUND

Experiences at sexual debut may be linked to reproductive health later in life. Additionally, young women with older sexual partners may be at greater risk for HIV and sexually transmitted infections. This study examines sexual debut with an older partner and subsequent reproductive health outcomes among 599 sexually experienced women aged 15-24 who utilized voluntary counseling and testing or reproductive health services in Port-au-Prince, Haiti.

METHODS

Logistic regression models, controlling for socioeconomic and demographic factors, examined whether age differences at first sex were significantly associated with STI diagnosis in the previous 12 months and family planning method use at last intercourse.

RESULTS

Sixty-five percent of women reported sexual initiation with a partner younger or less than 5 years older, 28% with a partner 5 to 10 years older, and 7% with a partner 10 or more years older. There was a trend towards decreased likelihood of recent use of family planning methods in women who had first sexual intercourse with a partner 5 to 9 years older compared to women with partners who were younger or less than 5 years older. Age differences were not linked to recent STI diagnosis.

CONCLUSION

Programs focusing on delaying sexual debut should consider age and gender-based power differentials between younger women and older men. Future research should examine whether wide age differences at sexual debut are predictive of continued involvement in cross-generational relationships and risky sexual behaviors and explore the mechanisms by which cross-generational first sex and subsequent reproductive health may be connected.

An estimate of the global prevalence and incidence of herpes simplex virus type 2 infection

OBJECTIVE

To estimate the global prevalence and incidence of herpes simplex virus type 2 (HSV-2) infection in 2003.

METHODS

A systematic review was undertaken of published seroprevalence surveys describing the prevalence or incidence of HSV-2 by age and gender. For each of 12 regions, pooled prevalence values by age and gender were generated in a random-effect model. HSV-2 incidence was then estimated from these pooled values using a constant-incidence model. Values of the HSV-2 seroprevalence from the model fits were applied to the total population to estimate the numbers of people infected.

FINDINGS

The total number of people aged 15-49 years who were living with HSV-2 infection worldwide in 2003 is estimated to be 536 million, while the total number of people who were newly infected with HSV-2 in 2003 is estimated to be 23.6 million. While the estimates are limited by poor availability of data, general trends are evident. For example, more women than men were infected, and the number infected increased with age. Although prevalence varied substantially by region, predicted prevalence was mostly higher in developing regions than developed regions.

CONCLUSION

The prevalence of HSV-2 is relatively easy to measure since infection is lifelong and has a specific serological test. The burden of disease is less easy to quantify. Despite the often sparse data on which these estimates are based, it is clear that HSV-2 infection is widespread. The dramatic differences in prevalence between regions are worthy of further exploration.

Rethinking the heterosexual infectivity of HIV-1: a systematic review and meta-analysis

Studies of cumulative HIV incidence suggest that cofactors such as genital ulcer disease, HIV disease stage, and male circumcision influence HIV transmission; however, the heterosexual infectivity of HIV-1 is commonly cited as a fixed value (approximately 0.001, or one transmission per 1000 contacts). We sought to estimate transmission cofactor effects on the heterosexual infectivity of HIV-1 and to quantify the extent to which study methods have affected infectivity estimates. We undertook a systematic search (up to April 27, 2008) of PubMed, Web of Science, and relevant bibliographies to identify articles estimating the heterosexual infectivity of HIV-1. We used meta-regression and stratified random-effects meta-analysis to assess differences in infectivity associated with cofactors and study methods. Infectivity estimates were very heterogeneous, ranging from zero transmissions after more than 100 penile-vaginal contacts in some serodiscordant couples to one transmission for every 3.1 episodes of heterosexual anal intercourse. Estimates were only weakly associated with study methods. Infectivity differences, expressed as number of transmissions per 1000 contacts, were 8.1 (95 % CI 0.4-15.8) when comparing uncircumcised to circumcised susceptible men, 6.0 (3.3-8.8) comparing susceptible individuals with and without genital ulcer disease, 1.9 (0.9-2.8) comparing late-stage to mid-stage index cases, and 2.5 (0.2-4.9) comparing early-stage to mid-stage index cases. A single value for the heterosexual infectivity of HIV-1 fails to reflect the variation associated with important cofactors. The commonly cited value of 0.001 was estimated among stable couples with low prevalences of high-risk cofactors, and represents a lower bound. Cofactor effects are important to include in epidemic models, policy considerations, and prevention messages.

[Signs and symptoms associated with sexually transmitted infections in Brazil, 2005]

OBJECTIVE

Sexually transmitted infections (STIs) are a major determinant of population disease burden worldwide. The objective of the study was to assess self-reported morbidity associated to STIs according to gender.

METHODS

The study data were obtained from a 2005 study consisting of a multistage probabilistic sample of 5,040 respondents, aged 16-65 years, living in urban areas in Brazil. These data were compared with those from a previous 1998 study. Bivariate analyses were carried out using Pearson's chi-square test and simple linear regression followed by logistic regression.

RESULTS

In both men and women, the variables: previous HIV testing, personal belief in unfaithful love, and number of sexual partners in a lifetime were significantly associated to STIs. In women only, the covariates: low family income, living in the Center-West, Southeast and South regions, and reporting of physical violence were independently associated to STIs. In men, the variables associated were: age group (35 years or more), living in the South region and in the state of São Paulo, and self-perceived HIV infection risk.

CONCLUSIONS

Signs and symptoms associated to STIs have strong gender differences in the general population and education interventions should be specifically targeted to either men or women.

Using respondent-driven sampling methodology for HIV biological and behavioral surveillance in international settings: a systematic review

To determine operational and analytical characteristics of respondent-driven sampling (RDS) in international settings and to explore factors that may affect recruitment of most-at-risk populations using RDS, we reviewed HIV biological and behavioral surveillance studies that used this method outside of the United States. We identified 123 eligible studies, 59 from Europe, 40 from Asia and the Pacific, 14 from Latin America, seven from Africa and three from Oceania. Studies collectively recruited 32,298 participants between 2003 and 2007; 53% of studies were conducted among injecting drug users, which generally had faster recruitment compared with studies among sex workers. All but 13 studies reached > or = 90% of their intended sample size, and six studies failed to reach equilibrium for key variables. This review has shown that RDS is an effective technique, when designed and implemented appropriately, to sample most-at-risk populations for HIV biological and behavioral surveys.

Uptake of HIV voluntary counselling and testing services in rural Tanzania: implications for effective HIV prevention and equitable access to treatment

OBJECTIVE

To describe the associations between socio-demographic, behavioural and clinical characteristics and the use of HIV voluntary counselling and testing (VCT) services among residents in a rural ward in Tanzania.

METHODS

Eight thousand nine hundred and seventy participants from a community-based cohort were interviewed, provided blood for research HIV testing, and were offered VCT. Univariate and multivariate logistic regression was used to identify socio-demographic, clinical and behavioural factors associated with VCT use.

RESULTS

Although 31% (1246/3980) of men and 24% (1195/4990) of women expressed an interest in the service, only 12% of men and 7% of women subsequently completed VCT. Socio-demographic factors, such as marital status, area of residence, religion and ethnicity influenced VCT completion among males and females in different ways, while self-perceived risk of HIV, prior knowledge of VCT, and sex with a high-risk partner emerged as important predictors of VCT completion among both sexes. Among males only, those infected with HIV for 5 years or less tended to self-select for VCT compared to HIV-negatives (adjusted odds ratio = 1.43; 95% CI: 0.99-2.14). This contributed to a higher proportion of HIV-positive males knowing their status compared to HIV-positive females.

CONCLUSIONS

In this setting, a disproportionate number of HIV-positive women are failing to learn their status, which has implications for equitable access to onward referral for care and treatment services. Evidence that some high-risk behaviours may prompt VCT use is encouraging, although further interventions are required to improve knowledge about HIV risk and the benefits of VCT. Targeted interventions are also needed to promote VCT uptake among married women and rural residents.

Understanding the impact of male circumcision interventions on the spread of HIV in southern Africa

Background

Three randomised controlled trials have clearly shown that circumcision of adult men reduces the chance that they acquire HIV infection. However, the potential impact of circumcision programmes – either alone or in combination with other established approaches – is not known and no further field trials are planned. We have used a mathematical model, parameterised using existing trial findings, to understand and predict the impact of circumcision programmes at the population level.

Findings

Our results indicate that circumcision will lead to reductions in incidence for women and uncircumcised men, as well as those circumcised, but that even the most effective intervention is unlikely to completely stem the spread of the virus. Without additional interventions, HIV incidence could eventually be reduced by 25–35%, depending on the level of coverage achieved and whether onward transmission from circumcised men is also reduced. However, circumcision interventions can act synergistically with other types of prevention programmes, and if efforts to change behaviour are increased in parallel with the scale-up of circumcision services, then dramatic reductions in HIV incidence could be achieved. In the long-term, this could lead to reduced AIDS deaths and less need for anti-retroviral therapy. Any increases in risk behaviours following circumcision , i.e. ‘risk compensation’, could offset some of the potential benefit of the intervention, especially for women, but only very large increases would lead to more infections overall.

Conclusions

Circumcision will not be the silver bullet to prevent HIV transmission, but interventions could help to substantially protect men and women from infection, especially in combination with other approaches.

Social contacts and mixing patterns relevant to the spread of infectious diseases

BACKGROUND

Mathematical modelling of infectious diseases transmitted by the respiratory or close-contact route (e.g., pandemic influenza) is increasingly being used to determine the impact of possible interventions. Although mixing patterns are known to be crucial determinants for model outcome, researchers often rely on a priori contact assumptions with little or no empirical basis. We conducted a population-based prospective survey of mixing patterns in eight European countries using a common paper-diary methodology.

METHODS AND FINDINGS

7,290 participants recorded characteristics of 97,904 contacts with different individuals during one day, including age, sex, location, duration, frequency, and occurrence of physical contact. We found that mixing patterns and contact characteristics were remarkably similar across different European countries. Contact patterns were highly assortative with age: schoolchildren and young adults in particular tended to mix with people of the same age. Contacts lasting at least one hour or occurring on a daily basis mostly involved physical contact, while short duration and infrequent contacts tended to be nonphysical. Contacts at home, school, or leisure were more likely to be physical than contacts at the workplace or while travelling. Preliminary modelling indicates that 5- to 19-year-olds are expected to suffer the highest incidence during the initial epidemic phase of an emerging infection transmitted through social contacts measured here when the population is completely susceptible.

CONCLUSIONS

To our knowledge, our study provides the first large-scale quantitative approach to contact patterns relevant for infections transmitted by the respiratory or close-contact route, and the results should lead to improved parameterisation of mathematical models used to design control strategies.

Antenatal clinic HIV data found to underestimate actual prevalence declines: evidence from Zambia

OBJECTIVE

To determine to what extent antenatal clinic (ANC)-based estimates reflect HIV prevalence trends among men and women in a high prevalence urban population.

METHODS

Examination of data from serial population-based HIV surveys in 1995 (n = 2115), 1999 (n = 1962) and 2003 (n = 2692), and ANC-based surveillance in 1994 (n = 450), 1998 (n = 810) and 2002 (n = 786) in the same site in Lusaka, Zambia. The population-based surveys recorded refusal rates between 6% and 10% during the three rounds.

RESULTS

Among ANC attendees, prevalence declined by 20% (25.0% to 19.9%; P = 0.101) in the age group 15-24 years and was stable overall. In the general population, the prevalence declined by 49% (P < 0.001) and by 32% (P < 0.001) in age group 15-24 and 15-49, respectively. Among women only, HIV prevalence declined by 44% (22.5% to 12.5%; P < 0.001) and by 27% (29.6% to 21.7%; P < 0.001) in age group 15-24 and 15-49 years, respectively. In addition, prevalence substantially declined in higher educated women aged 15-24 years (20.7% to 8.5%, P < 0.001).

CONCLUSION

ANC-based estimates substantially underestimated declines in HIV prevalence in the general population. This seemed to be partially explained by a combination of marked differentials in prevalence change by educational attainment and changes in fertility-related behaviours among young women. These results have important implications for the interpretation of ANC-based HIV estimates and underscore the importance of population-based surveys.

Mathematical models for HIV transmission dynamics: tools for social and behavioral science research

HIV researchers have long appreciated the need to understand the social and behavioral determinants of HIV-related risk behavior, but the cumulative impact of individual behaviors on population-level HIV outcomes can be subtle and counterintuitive, and the methods for studying this are rarely part of a traditional social science or epidemiology training program. Mathematical models provide a way to examine the potential effects of the proximate biologic and behavioral determinants of HIV transmission dynamics, alone and in combination. The purpose of this article is to show how mathematical modeling studies have contributed to our understanding of the dynamics and disparities in the global spread of HIV. Our aims are to demonstrate the value that these analytic tools have for social and behavioral sciences in HIV prevention research, to identify gaps in the current literature, and to suggest directions for future research.

The dynamics of intergenerational sexual relationships: the experience of schoolgirls in Botswana

BACKGROUND

Studies conducted in several sub-Saharan African countries have revealed that women and girls engage in intergenerational sexual relationships without the protection of condoms, giving cause for concern about HIV transmission. These relationships often occur against the girls' will and for many reasons, including reasons associated with subsistence. However, some young women do act as active social agents who rationally engage in intergenerational sexual exchanges oriented towards consumption. The present study examines the dynamics of intergenerational sexual relationships among schoolgirls in Botswana.

METHODS

In-depth interviews were conducted with 15 schoolgirls who were currently in an intergenerational sexual relationship. The social, cultural and economic factors that cause young girls to engage in these relationships and how intergenerational sex contributes to unsafe sexual practices were examined.

RESULTS

The findings revealed that not all girls were passive and controlled by their older sexual partners. Some derived pleasure, enjoyment, love and equal partnership in these sexual relationships. They displayed a capacity to take charge of their own sexual lives by insisting on and engaging in safe-sex behaviours. Another set of girls had little or no decision-making power. Their relationships with older boyfriends were characterised by coercion and manipulation. Negotiation for condom use was difficult for this group.

CONCLUSIONS

Effective policy and practice can be informed by the findings, leading to a reduction in HIV transmission as a result of intergenerational sex. In particular, the study has drawn attention to girls who are able to assert themselves within intergenerational sexual relationships and successfully negotiate safe sex. These strategies can be incorporated in programs to assist girls who face challenges and difficulties in negotiating safe sex with older men.

LINKING POVERTY AND INCOME SHOCKS TO RISKY SEXUAL BEHAVIOUR: EVIDENCE FROM A PANEL STUDY OF YOUNG ADULTS IN CAPE TOWN

Is there a link between household income and income stress, and risky sexual behaviour of young people? Anecdotal and qualitative evidence suggests this may be the case, but there is little quantitative research measuring this relationship. We use two waves of new data from the Cape Area Panel Study to investigate this link for 2,993 African and coloured youths aged 14 to 22 in 2002. In the process, we discuss one type of research design that could allow for a causal interpretation of the effect of income poverty on HIV risk. This design plausibly separates out the effect of income stress from the effect of living in a poor household by comparing behaviours across households with and without negative economic shocks, conditional on baseline income. Our results indicate that females in poorer households are more likely to be sexually active in 2002 and more likely to sexually debut by 2005. In addition, girls in households experiencing negative economic shocks are more likely to reduce condom use between 2002 and 2005. However, they are less likely to have multiple partners in 2002 or have transitioned to multiple partners by 2005. Males who experienced a negative shock are more likely to have multiple partners. Despite the tight research design for assessing shocks, the findings on the impacts of shocks do not generate clear recommendations for policy. There appears to be no systematic difference in condom use at last sex by household income levels or income shocks.

Degree distributions in sexual networks: a framework for evaluating evidence

OBJECTIVE

We present a likelihood based statistical framework to test the fit of power-law and alternative social process models for the degree distribution, and derive the sexually transmitted infection epidemic predictions from each model.

STUDY DESIGN

Five surveys from the United States are analyzed. Model fit is formally compared via Akaike Information Criterion and Bayesian Information Criterion, and substantively assessed via the prediction of a generalized epidemic.

RESULTS

Formal goodness-of-fit tests do not consistently identify any model as the best all around fit to the US data. Power-law models predict a generalized sexually transmitted infection epidemic in the United States, while most alternative models do not.

CONCLUSIONS

Power-law models do not fit the data better than alternative models, and they consistently make inaccurate epidemic predictions. Better models are needed to represent the behavioral basis of sexual networks and the structures that result, if these data are to be used for disease transmission modeling.

Economic Status, Informal Exchange, and Sexual Risk in Kisumu, Kenya

Many observers believe that wealthy men play a disproportionate role in the continuing spread of HIV/AIDS infection in sub-Saharan Africa through their involvement in informal exchange relationships, where money and gifts (referred to as "transfers") are given to a range of nonmarital sexual partners. In this case, wealthier men are riskier sexual partners because they can afford to give larger transfers, which have been found to be negatively associated with condom use. Alternatively, wealthier men might have greater incentives to practice safe sex at later stages of the epidemic or wealthier men might match with female partners who have particularly strong preferences for condom use. Accordingly, economic status would be positively associated with condom use. We use survey data from urban Kisumu, Kenya, to investigate the various mechanisms through which economic status is associated with sexual risk behavior. Our results show that wealth is positively associated with transfers; wealth is uncorrelated with condom use, however. The characteristics of wealthier men's female partners also do not differ from the characteristics of poorer men's partners. We conclude that wealthier men have stronger preferences for condom use, which offsets the negative effect of larger transfers that they give to their sexual partners.

Estimation of multiple transmission rates for epidemics in heterogeneous populations

One of the principal challenges in epidemiological modeling is to parameterize models with realistic estimates for transmission rates in order to analyze strategies for control and to predict disease outcomes. Using a combination of replicated experiments, Bayesian statistical inference, and stochastic modeling, we introduce and illustrate a strategy to estimate transmission parameters for the spread of infection through a two-phase mosaic, comprising favorable and unfavorable hosts. We focus on epidemics with local dispersal and formulate a spatially explicit, stochastic set of transition probabilities using a percolation paradigm for a susceptible-infected (S-I) epidemiological model. The S-I percolation model is further generalized to allow for multiple sources of infection including external inoculum and host-to-host infection. We fit the model using Bayesian inference and Markov chain Monte Carlo simulation to successive snapshots of damping-off disease spreading through replicated plant populations that differ in relative proportions of favorable and unfavorable hosts and with time-varying rates of transmission. Epidemiologically plausible parametric forms for these transmission rates are compared by using the deviance information criterion. Our results show that there are four transmission rates for a two-phase system, corresponding to each combination of infected donor and susceptible recipient. Knowing the number and magnitudes of the transmission rates allows the dominant pathways for transmission in a heterogeneous population to be identified. Finally, we show how failure to allow for multiple transmission rates can overestimate or underestimate the rate of spread of epidemics in heterogeneous environments, which could lead to marked failure or inefficiency of control strategies.

Sex, money, and premarital partnerships in southern Malawi

In this paper, I argue two main points. First, in premarital, sexual partnerships in rural Malawi, the purpose of money exchange extends beyond the alleviation of female partners' economic constraints, and, second, by clarifying this broader purpose, it becomes possible to recognize where women exert control over their own sexual selves. These findings come from field observations and a rich set of in-depth interviews (N=54), bolstered on occasion by survey data, conducted with young women and men, aged 15-24 years, in the Balaka district in the southern region of the country. This research demonstrates that, contrary to typical expectations, money and gift transfers in sexual partnerships are part and parcel of the courting practices of young Malawian women and men. Transfers are as much about the expression of love and commitment as they are about meeting the financial needs of women or the acquisition of sex for men. Using narrative information to shed light on the semiotics of the sex-money link, these findings from Malawi offer a new perspective that broadens usual interpretations of transactional sex, the understanding of which is critical in fighting AIDS.

Sexual network structure and the spread of HIV in Africa: evidence from Likoma Island, Malawi

BACKGROUND

Whereas sexual relationships among low-risk individuals account for the majority of HIV infections in sub-Saharan Africa, limited knowledge exists about the structure and characteristics of sexual networks among the general population in sub-Saharan Africa.

OBJECTIVES

To investigate the population-level structure of sexual networks connecting the young adult population of several villages on Likoma Island (Malawi), and analyse the structural position of HIV-positive individuals within the sexual network.

DESIGN AND METHODS

A cross-sectional sociocentric survey of sexual partnerships and biomarkers of prevalent HIV infections.

RESULTS

The study documents the existence of a large and robust sexual network linking a substantial fraction of the island's young adult population: half of all sexually active respondents were connected in a giant network component, and more than a quarter were linked through multiple independent chains of sexual relationships. This high network connectivity emerges within short time frames. The prevalence of HIV also varied significantly across the network, with sparser regions having a higher HIV prevalence than densely connected components. Several risk factors related to sexual mixing patterns help explain differentials in HIV prevalence across network locations.

CONCLUSION

Contrary to claims that sexual networks in rural sub-Saharan Africa are too sparse to sustain generalized HIV epidemics, the structure of the networks observed in Likoma appears compatible with a broad diffusion of HIV among lower-risk groups. The non-homogeneous distribution of HIV infection within the network suggests that network characteristics are an important determinant of the dynamics of HIV spread within a population.

Same race and older partner selection may explain higher HIV prevalence among black men who have sex with men

In a community-based survey in San Francisco, black men who have sex with men (MSM) had higher rates of same-race/ethnicity sexual partnerships and partners 10 or more years older compared with other MSM. Differences in sexual networks may explain why black MSM have higher HIV prevalence than other MSM despite lower levels of risk behavior.

Household and community income, economic shocks and risky sexual behavior of young adults: evidence from the Cape Area Panel Study 2002 and 2005

OBJECTIVE

To describe recent trends in adolescent sexual behavior in Cape Town, South Africa, and to determine whether household and community poverty and negative economic shocks predict risky sexual behavior.

DATA

Matched survey data on 2993 African and coloured youth from the Cape Area Panel Study 2002 and 2005.

MAIN OUTCOME MEASURES

Sexual debut, multiple sexual partners in past year, condom use at last sex, measured in 2002 and 2005.

METHODS

We tested for changes over time in reported sexual behavior and estimate multivariate probit models to measure the association between 2002 individual, household and community characteristics and 2005 sexual behavior.

RESULTS

There was a statistically significant increase in condom use and a decrease in the incidence of multiple sexual partners between 2002 and 2005 for young women aged 17-22 years. Young women in households with 10% higher income were 0.53% less likely to debut sexually by 2005; young men in communities with a 10% higher poverty rate were 5% less likely to report condom use at last sex. Negative economic shocks are associated with a 0.04% increase in the probability of multiple partnerships for young women. Education is positively correlated with sexual debut for young women and with multiple partnerships for both sexes.

CONCLUSION

Trends in sexual behavior between 2002 and 2005 indicate significant shifts towards safer practices. There is little evidence of a relationship between negative economic shocks, household and community poverty, and risky behavior. We hypothesize that the unexpected positive relationship between education and sexual debut may be driven by peer effects in schools with substantial age mixing.

Relating diarrheal disease to social networks and the geographic configuration of communities in rural Ecuador

Social networks and geographic structures of communities are important predictors of infectious disease transmission. To examine their joint effects on diarrheal disease and how these effects might develop, the authors analyzed social network and geographic data from northern coastal Ecuador and examined associations with diarrhea prevalence. Between July 2003 and May 2005, 113 cases of diarrhea were identified in nine communities. Concurrently, sociometric surveys were conducted, and households were mapped with geographic information systems. Spatial distribution metrics of households within communities and of communities with respect to roads were developed that predict social network degree in casual contact ("contact") and food-sharing ("food") networks. The mean degree is 25-40% lower in communities with versus without road access and 66-94% lower in communities with lowest versus highest housing density. Associations with diarrheal disease were found for housing density (comparing dense with dispersed communities: risk ratio = 3.3, 95% confidence interval (CI): 1.1, 10.0) and social connectedness (comparing lowest with highest degree communities: risk ratio = 3.4, 95% CI: 1.1, 10.1 in the contact network and risk ratio = 4.9, 95% CI: 1.1, 21.9 in the food network). Some of these differences may be related to more new residents, lower housing density, and less social connectedness in road communities.

Measuring Sex Partner Concurrency: It’s What’s Missing That Counts

BACKGROUND

Sex partner concurrency is an important determinant of STI transmission dynamics, yet its measurement is not standardized.

GOAL

: We assessed the agreement, compared correlates, and investigated data quality and completeness between 2 common concurrency measures.

STUDY DESIGN

Young adults (ages 18-26) attending public STD clinics between 2001 and 2004 in Seattle, St. Louis, and New Orleans, provided data on 2 or more sex partners in a computer-administered survey interview (N = 680). Concurrency with last partner was measured in 2 ways: (a) a direct question about other sexual contacts during the most recent sexual relationship and (b) overlapping start and end dates of the 2 most recent relationships.

RESULTS

Although 56% reported concurrency by direct questioning and 54% by overlapping dates, the kappa statistic for agreement between measures was only fair (0.395). Indeed, 29% of those reporting concurrent partners by the direct question did not do so by overlapping dates and 26% of participants concurrent by overlapping dates were not concurrent by the direct question. Each of the measures had dissimilar correlates, and concurrency data were missing or uninterpretable more often for the overlapping dates measure (21.3%) than the direct question (1.8%).

CONCLUSIONS

Concurrency was common by both measures but the measures were not interchangeable. Although the overlapping dates measure provided information about partnership duration, it is subject to missing or uninterpretable data. The direct question substantially minimized the amount of missing data and may be more appropriate for use with computer-administered survey interview.

The social epidemiology of HIV transmission among African American women who use drugs and their social network members

Despite 15 years of prevention efforts, recent increases in HIV infection have been documented for Black women in the US. Little is known about the role played by HIV status disclosure in high HIV prevalence communities. 180 Black women who used drugs in the past 30 days were recruited between May 2002 and May 2004 in New York City. Women were administered a structured network questionnaire and HIV serotested. Risk practices, HIV status disclosure within networks and mixing patterns by known HIV status are examined. Most (85%) women had used crack in the past 30 days; 48 (27%) had injected drugs, 65 (36%) reported anal sex, and 99 (55%) reported sex work at some time. Forty (22%) women were HIV-seropositive; 29 (16%) knew their seropositive status. Of high risk individual behaviours, only a history of sex work was associated with an HIV-seropositive status [(aOR=3.0; 95%CI: 1.3-7.3), p=.01]. Few (7%) of 600 network members disclosed an HIV positive status, although 73% were sex or drug use partners. Women who knew themselves to be HIV-infected were more likely than other women to report HIV-infected network members [(OR=1.5; 95%CI: 1.1-6.4), p=.03]. However, only 51% of network members disclosed an HIV status and women disclosed to 50% of their network members. In a context of high background HIV prevalence and low levels of HIV status disclosure, serodiscordant mixing patterns likely facilitate transmission.

The factors influencing transactional sex among young men and women in 12 sub-Saharan African countries

Transactional sex may put young women and young men in sub-Saharan Africa at increased risk of contracting sexually transmitted infections (STIs), including HIV/AIDS. This behavior may also put young women at higher risk of pregnancy and childbearing. Policymakers and program managers need to know what factors put youth at increased risk. We investigated this issue using logistic regression analyses of data from male and female modules of Demographic and Health Surveys from 12 sub-Saharan African countries. We found that young men and young women are at greater risk of engaging in transactional sex than are older people. Unmarried young women and young men were significantly more likely to engage in transactional sex than married youth. Based on these results, our conclusions were that programs geared toward reducing the incidence of transactional sex or protecting men and women already in transactional sexual relationships should be aimed at both young women and young men. Due to our finding that unmarried young women and young men are more vulnerable to experiencing transactional sex, programs to prevent transactional sex should be specifically directed to this subgroup of young people.

The influence of social and sexual networks in the spread of HIV and syphilis among men who have sex with men in Shanghai, China

OBJECTIVES

To analyze characteristics of social and sexual networks and their role as risk factors for HIV and syphilis among men who have sex with men (MSM) in Shanghai, China.

DESIGN

: A cross-sectional study.

METHODS

We recruited 477 participants using a snowball sampling method. We administered a face-to-face questionnaire and provided testing and counseling for HIV and syphilis.

RESULTS

The prevalences of HIV and markers for syphilis were 1.47% (95% confidence interval [CI]: 0.59 to 3.01) and 13.47% (95% CI: 10.53 to 16.88), respectively. The independent factors associated with lower risk for syphilis infection were having a contact network, overlap of social and sexual networks, meeting other MSM at the gym or through the Internet, having 3 to 5 lifetime male anal sex partners, and having a female steady sex partner. A larger male sexual network size, having been married, being more knowledgeable about HIV, having 6 or more lifetime male anal sex partners, and having steady male or female sex partners were independently associated with having unprotected anal or vaginal intercourse.

CONCLUSIONS

Significant associations were found between network characteristics and syphilis infection and unprotected sex. Network-based interventions should be developed to reduce this HIV risk among MSM in China.

Female Genital Cutting and HIV/AIDS Among Kenyan Women

Female genital cutting (FGC) and HIV/AIDS are both highly prevalent in sub-Saharan Africa, and researchers have speculated that the association may be more than coincidental. Data from 3167 women aged 15-49 who participated in the 2003 Kenya Demographic and Health Survey (KDHS) are used to test the direct and indirect associations of FGC with HIV. Our adjusted models suggest that FGC is not associated directly with HIV, but is associated indirectly through several pathways. Cut women are 1.72 times more likely than uncut women to have older partners, and women with older partners are 2.65 times more likely than women with younger partners to test positive for HIV Cut women have 1.94 times higher odds than uncut women of initiating sexual intercourse before they are 20, and women who experience their sexual debut before age 20 have 1.73 times higher odds than those whose sexual debut comes later of testing positive for HIV. Cut women have 27 percent lower odds of having at least one extra-union partner, and women with an extra-union partner have 2.63 times higher odds of testing positive for HIV. Therefore, in Kenya, FGC may be an early life-course event that indirectly alters women's odds of becoming infected with HIV through protective and harmful practices in adulthood.

Risks and Benefits of Multiple Sexual Partnerships: Beliefs of Rural Nigerian Adolescent Males

Drawing on interview data from rural Nigeria, the article explores male youth perceptions of the risks and benefits of multiple sexual partnerships. Participants associated having multiple sexual partners with several harmful health and nonhealth outcomes, including sexually transmitted infections, and frequently confirmed that the practice also bolsters their sense of maleness and boosts their acceptance and ranking among peers. Young males' involvement in multiple sexual partnerships should not be seen as always consequent on their ignorance of and/or indifference to the risks inherent in the behavior. It could also result from the integrality of the behavior to the social processes through which male youths validate their masculinity, mark their transition from boyhood to malehood, and configure their identities to gain acceptance into a local male peer community. Sexuality education curricula that ignore adolescents' understandings of the benefits of their sexual practices may not deliver expected objectives.

Associations between sexual behaviour change in young people and decline in HIV prevalence in Zambia

Background

Evidence suggests that HIV prevalence amongst young Zambians has declined recently, especially in higher-education groups. We studied trends in key sexual behaviour indicators among 15–24 year-olds from 1995 to 2003, including the associations between sexual behaviour change and education.

Methods

The data stem from a series of three population-based surveys conducted in 1995 (n = 1720), 1999 (n = 1946) and 2003 (n = 2637). Logistic regression and Extended Mantel Haenszel Chi Square for linear trends were used to compare the three surveys.

Results

Men and lower-education groups reported more than one sexual partner in the year immediately prior to the survey more frequently than did women and higher-education groups (p < 0.01), but these proportions declined regardless of sex and residence. Substantial delays in child-bearing were observed, particularly among higher-education and urban respondents. Condom use at least for casual sexual intercourse increased from 1995 to 2003; the level was highest among urban and higher-education groups. The number of women reporting frequent dry sex using traditional agents fell during the period. Participants from the rural area and those with less education reported more sexual experience than urban and higher-education participants in 2003. The reported number of sexual partners during the year immediately prior to the survey was a factor that reduced the association between HIV and survey times among sexually active young urban men and women.

Conclusion

High risk behaviours clearly decreased, especially in higher-educated and urban groups, and there is a probable association here with the decline in HIV prevalence in the study population. Fewer sexual partners and condom use were among the core factors involved for both sexes; and for women a further factor was delayed child-bearing.

Age at first sex and HIV infection in rural Zimbabwe

Beginning sexual activity introduces an individual to the risk of acquiring sexually transmitted infections. In this study, cross-sectional behavioral data linked to HIV-status from 4,138 men and 4,948 women interviewed in rural Zimbabwe are analyzed to investigate the distribution and consequences of early first sex. We find that age at first sex (at a median age of 19 years for males and 18 years for females) has declined among males over the past 30 years but increased recently among females. Those in unskilled employment, those not associated with a church, and women without a primary education begin to have sex earlier than others. Early sexual debut before marriage precedes a lifetime of greater sexual activity but with more consistent condom use. Women who begin to have sex earlier than others of their age are more likely to be infected with HIV. This finding can be explained by their having a greater lifetime number of sexual partners than those whose first sexual experience occurs later.

Impact and process evaluation of integrated community and clinic-based HIV-1 control: a cluster-randomised trial in eastern Zimbabwe

BACKGROUND

HIV-1 control in sub-Saharan Africa requires cost-effective and sustainable programmes that promote behaviour change and reduce cofactor sexually transmitted infections (STIs) at the population and individual levels.

METHODS AND FINDINGS

We measured the feasibility of community-based peer education, free condom distribution, income-generating projects, and clinic-based STI treatment and counselling services and evaluated their impact on the incidence of HIV-1 measured over a 3-y period in a cluster-randomised controlled trial in eastern Zimbabwe. Analysis of primary outcomes was on an intention-to-treat basis. The income-generating projects proved impossible to implement in the prevailing economic climate. Despite greater programme activity and knowledge in the intervention communities, the incidence rate ratio of HIV-1 was 1.27 (95% confidence interval [CI] 0.92-1.75) compared to the control communities. No evidence was found for reduced incidence of self-reported STI symptoms or high-risk sexual behaviour in the intervention communities. Males who attended programme meetings had lower HIV-1 incidence (incidence rate ratio 0.48, 95% CI 0.24-0.98), and fewer men who attended programme meetings reported unprotected sex with casual partners (odds ratio 0.45, 95% CI 0.28-0.75). More male STI patients in the intervention communities reported cessation of symptoms (odds ratio 2.49, 95% CI 1.21-5.12).

CONCLUSIONS

Integrated peer education, condom distribution, and syndromic STI management did not reduce population-level HIV-1 incidence in a declining epidemic, despite reducing HIV-1 incidence in the immediate male target group. Our results highlight the need to assess the community-level impact of interventions that are effective amongst targeted population sub-groups.