HIV seroincidence and correlates of seroconversion in a cohort of male factory workers in Harare, Zimbabwe

Cost-effectiveness of a combination strategy to enhance the HIV care continuum in Swaziland: Link4Health

INTRODUCTION

Link4Health, a cluster-RCT, demonstrated the effectiveness of a combination strategy targeting barriers at various HIV continuum steps on linkage to and retention in care; showing effectiveness in achieving linkage to HIV care within 1 month plus retention in care at 12 months after HIV testing for people living with HIV (RR 1.48, 95% CI 1.19-1.96, p = 0.002). In addition to standard of care, Link4Health included: 1) Point-of-care CD4+ count testing; 2) Accelerated ART initiation; 3) Mobile phone appointment reminders; 4) Care and prevention package including commodities and informational materials; and 5) Non-cash financial incentive. Our objective was to evaluate the cost-effectiveness of a scale-up of the Link4Health strategy in Swaziland.

METHODS AND FINDINGS

We incorporated the effects and costs of the Link4Health strategy into a computer simulation of the HIV epidemic in Swaziland, comparing a scenario where the strategy was scaled up to a scenario with no implementation. The simulation combined a deterministic compartmental model of HIV transmission with a stochastic microsimulation of HIV progression calibrated to Swaziland epidemiological data. It incorporated downstream health costs potentially saved and infections potentially prevented by improved linkage and treatment adherence. We assessed the incremental cost-effectiveness ratio of Link4Health compared to standard care from a health sector perspective reported in US$2015, a time horizon of 20 years, and a discount rate of 3% in accordance with WHO guidelines.[1] Our results suggest that scale-up of the Link4Health strategy would reduce new HIV infections over 20 years by 11,059 infections, a 7% reduction from the projected 169,019 cases and prevent 5,313 deaths, an 11% reduction from the projected 49,582 deaths. Link4Health resulted in an incremental cost per infection prevented of $13,310 and an incremental cost per QALY gained of $3,560/QALY from the health sector perspective.

CONCLUSIONS

Using a threshold of <3 x per capita GDP, the Link4Health strategy is likely to be a cost-effective strategy for responding to the HIV epidemic in Swaziland.

Culture, myths and panic: Three decades and beyond with an HIV/AIDS epidemic in Zimbabwe

Zimbabwe is going through a generalised acquired immunodeficiency syndrome (AIDS) epidemic. The first five years of the epidemic (1985-1990) were characterised by lack of medicines against human immunodeficiency virus (HIV), and an exponential increase in prevalence (65-fold) and incidence (13-fold), which were fuelled by high-risk sexual behaviour. The high HIV prevalence, mortality and stigma yielded great fear and panic in the population, which are thought to have led to confusion and hopelessness, and, in turn, increased risky sexual behaviour. The country's government and civil society embarked on HIV awareness campaigns that are claimed to have played a central role in slowing down the epidemic since the mid-2000s. HIV-related mortality then fell by 70% between 2003 and 2013, which is attributed to high uptake of antiretroviral therapy (ART) and prevention of mother-to-child transmission (95%) prophylaxis. However, the epidemic has been characterised by a low paediatric ART coverage (35% in 2011 to 46.12% in 2013). Year 2014 saw an increase in adolescent and young adult HIV prevalence, which may be signalling a rebound of the epidemic. A more holistic approach which deals with the epidemic in its socio-political context is required to effectively lower the country's HIV burden.

Does marital status matter in an HIV hyperendemic country? Findings from the 2012 South African National HIV Prevalence, Incidence and Behaviour Survey

South Africa has experienced declining marriage rates and the increasing practice of cohabitation without marriage. This study aims to improve the understanding of the relationship between marital status and HIV in South Africa, an HIV hyperendemic country, through an analysis of findings from the 2012 South African National HIV Prevalence, Incidence and Behaviour Survey. The nationally representative population-based cross-sectional survey collected data on HIV and socio-demographic and behavioural determinants in South Africa. This analysis considered respondents aged 16 years and older who consented to participate in the survey and provided dried blood spot specimens for HIV testing (N = 17,356). After controlling for age, race, having multiple sexual partners, condom use at last sex, urban/rural dwelling and level of household income, those who were married living with their spouse had significantly reduced odds of being HIV-positive compared to all other marital spouses groups. HIV incidence was 0.27% among respondents who were married living with their spouses; the highest HIV incidence was found in the cohabiting group (2.91%). Later marriage (after age 24) was associated with increased odds of HIV prevalence. Our analysis suggests an association between marital status and HIV prevalence and incidence in contemporary South Africa, where odds of being HIV-positive were found to be lower among married individuals who lived with their spouses compared to all other marital status groups. HIV prevention messages therefore need to be targeted to unmarried populations, especially cohabitating populations. As low socio-economic status, low social cohesion and the resulting destabilization of sexual relationships may explain the increased risk of HIV among unmarried populations, it is necessary to address structural issues including poverty that create an environment unfavourable to stable sexual relationships.

Migration intensity has no effect on peak HIV prevalence: an ecological study

Background

Correctly identifying the determinants of generalized HIV epidemics is crucial to bringing down ongoing high HIV incidence in these countries. High rates of migration are believed to be an important determinant of HIV prevalence. This study has two aims. Firstly, it evaluates the ecological association between levels of internal and international migration and national peak HIV prevalence using thirteen variables from a variety of sources to capture various aspects of internal and international migration intensity. Secondly, it examines the relationship between circular migration and HIV at an individual and population-level in South Africa.

Methods

Linear regression was used to analyze the association between the various measures of migration intensity and peak national HIV prevalence for 141 countries and HIV prevalence by province and ethnic group in South Africa.

Results

No evidence of a positive ecological association between national migration intensity and HIV prevalence was found. This remained the case when the analyses were limited to the countries of sub-Saharan Africa. On the whole, countries with generalized HIV epidemics had lower rates of internal and external migration. Likewise, no association was found between migration and HIV positivity at an individual or group-level in South Africa.

Conclusion

These results do not support the thesis that migration measured at the country level plays a significant role in determining peak HIV prevalence.

Impact of interventions targeting unhealthy alcohol use in Kenya on HIV transmission and AIDS-related deaths

BACKGROUND

HIV remains a major cause of preventable morbidity and mortality in Kenya. The effects of behaviors that accompany unhealthy alcohol consumption are a pervasive risk factor for HIV transmission and progression. Our objective was to estimate the portion of HIV infections attributable to unhealthy alcohol use and to evaluate the impact of hypothetical interventions directed at unhealthy alcohol use on HIV infections and deaths.

METHODS

We estimated outcomes over a time horizon of 20 years using a computer simulation of the Kenyan population. This computer simulation integrates a compartmental model of HIV transmission with a mechanistic model of HIV progression that was previously validated in sub-Saharan Africa. Integration of the transmission and progression models allows simultaneous consideration of alcohol's effects on HIV transmission and progression (e.g., lowering antiretroviral adherence may increase transmission risk by elevating viral load, and may simultaneously increase progression by increasing the likelihood of AIDS). The simulation considers important aspects of heterogeneous sexual mixing patterns, including assortativeness of partners by age and activity level, age-discordant relationships, and high activity subgroups. Outcomes included number of new HIV infections, number of AIDS deaths, and infectivity (number of new infections per infected person per year).

RESULTS

Our model estimated that the effects of behaviors accompanying unhealthy alcohol consumption are responsible for 13.0% of new HIV infections in Kenya. An alcohol intervention with effectiveness similar to that observed in a published randomized controlled trial of a cognitive-behavioral therapy-based intervention in Kenya (45% reduction in unhealthy alcohol consumption) could prevent nearly half of these infections, reducing their number by 69,858 and reducing AIDS deaths by 17,824 over 20 years. Estimates were sensitive to assumptions with respect to the magnitude of alcohol's underlying effects on condom use, antiretroviral therapy adherence, and sexually transmitted infection prevalence.

CONCLUSIONS

A substantial number of new HIV infections in Kenya are attributable to unhealthy alcohol use. An alcohol intervention with the effectiveness observed in a published randomized controlled trial has the potential to reduce infections over 20 years by nearly 5% and avert nearly 18,000 deaths related to HIV.

How do different eligibility guidelines for antiretroviral therapy affect the cost-effectiveness of routine viral load testing in sub-Saharan Africa?

BACKGROUND

Increased eligibility guidelines of antiretroviral therapy (ART) may lead to greater routine viral load monitoring. However, in resource-constrained settings, the additional resources required by greater routine viral load monitoring may impair ability to comply with expanded eligibility guidelines for ART.

OBJECTIVE

We use a published validated computer simulation of the HIV epidemic in East African countries (expanded to include transmission as well as disease progression) to evaluate the cost-effectiveness of routine viral load monitoring.

METHODS

We explored alternative scenarios regarding cost, frequency, and switching threshold of routine viral load monitoring (including every 6 or every 12 months; and switching thresholds of 1000, or 10 000 copies/ml), as well as alternative scenarios regarding ART initiation (200, 350, 500  cells/μl, and no CD4 cell threshold). For each ART initiation strategy, we sought to identify the viral load monitoring strategy at which the incremental cost-effectiveness ratio (ICER) of more frequent routine viral load testing became more favorable than the ICER of more expansive ART eligibility. Cost inputs were based on data provided by the Academic Model Providing Access to Healthcare (AMPATH), and disease progression inputs were based on prior published work. We used a discount rate of 3%, a time horizon of 20 years, and a payer perspective.

RESULTS

Across a wide range of scenarios, and even when considering the beneficial effect of virological monitoring at reducing HIV transmission, earlier ART initiation conferred far greater health benefits for resources spent than routine virological testing, with ICERs of approximately $1000 to $2000 for earlier ART initiation, versus ICERs of approximately $5000 to $25 000 for routine virological monitoring. ICERs of viral load testing were insensitive to the cost of the viral load test, because most of the costs originated from the downstream higher costs of later regimens. ICERs of viral load testing were very sensitive to the relative cost of second-line compared with first-line regimens, assuming favorable value when the costs of these regimens were equal.

CONCLUSION

If all HIV patients are not yet treated with ART starting at 500  cells/μl and costs of second regimens remain substantially more expensive than first-line regimens, resources would buy more population health if they are spent on earlier ART rather than being spent on routine virological testing.

HIV decline in Zimbabwe due to reductions in risky sex? Evidence from a comprehensive epidemiological review

BACKGROUND

Recent data from antenatal clinic (ANC) surveillance and general population surveys suggest substantial declines in human immunodeficiency virus (HIV) prevalence in Zimbabwe. We assessed the contributions of rising mortality, falling HIV incidence and sexual behaviour change to the decline in HIV prevalence.

METHODS

Comprehensive review and secondary analysis of national and local sources on trends in HIV prevalence, HIV incidence, mortality and sexual behaviour covering the period 1985-2007.

RESULTS

HIV prevalence fell in Zimbabwe over the past decade (national estimates: from 29.3% in 1997 to 15.6% in 2007). National census and survey estimates, vital registration data from Harare and Bulawayo, and prospective local population survey data from eastern Zimbabwe showed substantial rises in mortality during the 1990s levelling off after 2000. Direct estimates of HIV incidence in male factory workers and women attending pre- and post-natal clinics, trends in HIV prevalence in 15-24-year-olds, and back-calculation estimates based on the vital registration data from Harare indicated that HIV incidence may have peaked in the early 1990s and fallen during the 1990s. Household survey data showed reductions in numbers reporting casual partners from the late 1990s and high condom use in non-regular partnerships between 1998 and 2007.

CONCLUSIONS

These findings provide the first convincing evidence of an HIV decline accelerated by changes in sexual behaviour in a southern African country. However, in 2007, one in every seven adults in Zimbabwe was still infected with a life-threatening virus and mortality rates remained at crisis level.

Prevalence and correlates of concurrent sexual partnerships in Zambia

Concurrent partnerships may cause more rapid spread of HIV in a population. We examined how the prevalence of parallel relationships changed among men and women aged 15-49 in Zambia from 1998 to 2003 using data collected during the Sexual Behavior Surveys 1998, 2000, and 2003. Predictors of concurrent partnerships among men were studied by univariate and multivariate regression analyses. Thirteen percent of rural and 8% of urban men reported more than one ongoing relationship in 1998, and these proportions declined to 8% and 6%, respectively in 2003. The proportion of women reporting concurrent relationships was 0-2%. The most important predictors of concurrency were early sexual debut, being married, early marriage and absence from home. The reduction in concurrent sexual partnerships is consistent with reductions in other sexual risk behaviors found in other studies and may have contributed to the recently observed decline in HIV prevalence in Zambia.

Lack of evidence for frequent heterosexual transmission of human herpesvirus 8 in Zimbabwe

BACKGROUND

There is conflicting evidence about the contribution of heterosexual transmission to the spread of human herpesvirus 8 (HHV-8) in southern Africa. This study evaluated the hypothesis that HHV-8 infection is associated with risk factors for human immunodeficiency virus type 1 (HIV-1) and other sexually transmitted infections among Zimbabwean men.

METHODS

HHV-8 seroprevalence was determined for 2750 participants in the Zimbabwe AIDS Prevention Project cohort of male factory workers in Harare, Zimbabwe. Potential associations of HHV-8 antibody detection with risk factors for HIV-1 infection were examined by univariate analysis. Variables with P < .1 in the univariate analysis were included in a multivariate logistic regression model. HHV-8 seroprevalence was also determined among 297 heterosexual couples.

RESULTS

Prevalence of HHV-8, HIV-1, and HHV-8 and HIV-1 coinfection was 28.5% (95% confidence interval [CI], 26.8%-30.2%), 19.5% (95% CI, 18.0%-20.9%), and 6.5% (95% CI, 5.6%-7.5%), respectively. Detection of HHV-8 antibodies was independently associated with older age and HIV-1 infection but not with number of recent sex partners, marital status, education, condom use, prior sexually transmitted infections, payment for sex, chronic hepatitis B infection, or incident HIV-1 infection. HHV-8 seroprevalence was 31.7% (95% CI, 26.3-37.0) among wives in the couples tested, but HHV-8 infection of wives was not associated with HHV-8 infection of husbands (odds ratio, 1.08; 95% CI, 0.62-1.88; P = .8).

CONCLUSIONS

HHV-8 and HIV-1 infection did not have common sexual risk factors among urban Zimbabwean men. Sexual transmission does not explain the high prevalence of HHV-8 in this population.

Reported number of sexual partners: comparison of data from four African longitudinal studies

OBJECTIVE

To compare reported numbers of sexual partners in Eastern and Southern Africa.

METHODS

Sexual partnership data from four longitudinal population-based surveys (1998-2007) in Zimbabwe, Uganda and South Africa were aggregated and overall proportions reporting more than one lifetime sexual partner calculated. A lexis-style table was used to illustrate the average lifetime sexual partners by site, sex, age group and birth cohort. The male-to-female ratio of mean number of partnerships in the last 12 months was calculated by site and survey. For each single year of age, the proportion sexually active in the past year, the mean number of partners in the past year and the proportion with more than one partner in the past year were calculated.

RESULTS

Over 90% of men and women between 25 and 45 years of age reported being sexually active during the past 12 months, with most reporting at least one sexual partner. Overall, men reported higher numbers of lifetime sexual partners and partners in the last year than women. The male-to-female ratio of mean partnerships in the last year ranged from 1.41 to 1.86. In southern African cohorts, individuals in later birth cohorts reported fewer sexual partners and a lower proportion reported multiple partnerships compared with earlier birth cohorts, whereas these behavioural changes were not observed in the Ugandan cohorts. Across the four sites, reports of sexual partnerships followed a similar pattern for each sex.

CONCLUSIONS

The longitudinal results show that reductions in the number of partnerships were more evident in southern Africa than in Uganda.

Vulnerability of women in southern Africa to infection with HIV: biological determinants and priority health sector interventions

OBJECTIVE

To review biomedical determinants of women's vulnerability to infection with HIV and interventions to counter this, within the southern African context.

RESULTS

Apart from number of exposures, if any, several factors influence the efficiency of HIV transmission during sex. Acute HIV infection, with extraordinarily high semen viral load, in conjunction with concurrent partnerships maximizes this efficiency. Delaying sexual debut and avoiding HIV exposure among biologically and socially vulnerable youth is critical. Reducing unintended pregnancies keeps girls in school and prevents vertical (also possibly horizontal) transmission. Female condoms, especially newer versions, are an under-exploited prevention technology. Control of sexually transmitted infections (STI), which facilitate HIV acquisition and transmission, remains important, especially among the most at-risk populations. Pathogens, such as herpes simplex virus type 2, which contribute most to HIV transmission in southern Africa must be targeted, although the importance of bacterial vaginosis and Trichomonas vaginalis is under-recognized. Also, heavy episodic alcohol use affects sexual decision-making and condom skills. Moreover, prevailing social contexts, partly a consequence of poor leadership, constrain the behavioural 'choices' available for girls and women.

CONCLUSIONS

Priority health sector interventions for preventing HIV are: male and female condom programming; prevention and control of STI; outreach to most vulnerable populations; HIV testing in all patient-provider encounters; male circumcision; and the integration of HIV prevention within sexual and reproductive health services. Future interventions during acute HIV infection and microbicides will reduce women's biological vulnerability. Far-reaching measures, such as sexual equity and alcohol control, create conditions necessary for achieving sustained prevention results. These are, however, contingent on stronger, more informed cultural and political leadership.

Continued very high prevalence of HIV infection in rural KwaZulu-Natal, South Africa: a population-based longitudinal study

OBJECTIVE

To estimate the prevalence of HIV and associated sociodemographic factors including mobility and migration in a rural population in KwaZulu-Natal, South Africa.

METHODS

A household-based HIV serosurvey of a population that has been under longitudinal demographic surveillance since 2000. All residents (women aged 15-49 years; men aged 15-54 years) and a sample of non-residents ('migrants') who return periodically to their households in the area were identified and approached for finger-prick HIV testing.

RESULTS

A total of 8325/11 505 male and 11 542/14 396 female residents were traced. Of these, 4692 men and 6859 women consented to HIV testing. Overall, 27% of female and 13.5% of male residents were HIV infected. HIV prevalence peaked at 51% among resident women aged 25-29 years and 44% among resident men aged 30-34 years, with the highest infection rates of 57.5% among 26-year-old women. The female: male infection ratio for residents aged 15-19 years was 13.0. Many factors, including increased mobility, associated with an increased risk of HIV infection among residents, were also associated with non-participation. Among non-residents, 34% of men aged 15-54 years and 41% of women aged 15-49 years were HIV infected.

CONCLUSION

The extremely high prevalence of HIV suggests an urgent need to allocate adequate resources for HIV prevention and treatment in rural areas. Effective monitoring of the epidemic in Africa needs to include efforts to strengthen sentinel surveillance in rural areas and strategies for the surveillance of migrants and mobile individuals.

HIV incidence during a cluster-randomized trial of two strategies providing voluntary counselling and testing at the workplace, Zimbabwe

OBJECTIVE

To investigate HIV incidence during a trial of two voluntary counselling and testing (VCT) strategies. Counselling may promote beneficial behavioural change, although knowledge of negative status does not appear to contribute further benefit.

DESIGN

The parent cluster-randomized trial demonstrated much greater uptake of VCT when counselling and rapid testing were available on-site (intensive VCT) than through pre-paid vouchers to an external provider (standard VCT). Anonymous HIV tests had been requested from all employees at enrolment and after 2 years intervention.

METHODS

The study setting was 22 businesses in Harare, Zimbabwe. Participants were 3146 HIV-negative individuals remaining in employment at the end of intervention, of whom 2966 (94.3%) consented to repeat testing. VCT linked to basic HIV care was provided and the main outcome measures were HIV incidence under each study arm, as a retrospective secondary analysis.

RESULTS

Mean VCT uptake in this cohort was 70.7 and 5.2%, respectively, in the intensive and standard arms. Crude HIV incidence was 1.21 per 100 person-years, with non-significantly higher rates in the intensive VCT arm [mean site incidence 1.37 and 0.95 per 100 person-years, respectively; adjusted rate ratio 1.49 (95% confidence interval 0.79-2.80).

CONCLUSIONS

Highly acceptable VCT did not reduce HIV incidence in this predominantly male cohort. HIV incidence was highest in the high uptake VCT arm, lending support to a US trial in which rapid testing appeared to have adverse behavioural consequences in some HIV-negative clients. Careful comparison of outcomes under different counselling and testing strategies is needed to maximize HIV prevention from global scale-up of VCT.

HIV Incidence Among Women of Reproductive Age in Malawi and Zimbabwe

OBJECTIVE

The objective of this study was to determine the incidence of HIV-1.

GOAL

The goal of this study was to inform HIV prevention and vaccine trials by conducting a multisite study in Malawi and Zimbabwe.

STUDY DESIGN

Women of reproductive age were enrolled in a prospective study. They received 5 intensive HIV counseling and condom promotion sessions over 2 months. Subsequently, HIV-negative women completed quarterly follow-up visits. HIV incidence rates and predictors of HIV acquisition were assessed.

RESULTS

A total of 2016 HIV-negative women were enrolled in the condom promotion and counseling phase of the study. Of these, 1679 were tested for HIV during follow up and 113 women seroconverted, resulting in an overall HIV incidence rate of 4.7 per 100 women-years (95% confidence interval = 3.8-5.6). Incidence rates were similar across sites. The major predictors of HIV acquisition were young age, presence of sexually transmitted infections, being unmarried, and higher educational level.

CONCLUSION

The incidence of HIV continues to be high among women in both Malawi and Zimbabwe despite counseling and condom promotion.

HIV among pregnant women in Moshi Tanzania: the role of sexual behavior, male partner characteristics and sexually transmitted infections

BACKGROUND

Women continue to be disproportionately affected by HIV in Tanzania, and factors contributing to this situation need to be identified. The objective of this study was to determine social, behavioral and biological risk factors of HIV infection among pregnant women in Moshi urban, Tanzania. In 2002-2004, consenting women (N = 2654), attending primary health clinics for routine antenatal care were interviewed, examined and biological samples collected for diagnosis of HIV and other sexually transmitted/reproductive tract infections.

RESULTS

The prevalence of HIV was 6.9%. The risk for HIV was greater among women whose male partner; had other sexual partners (adjusted odds ratio [AOR], 15.11; 95% confidence interval [CI], 8.39-27.20), traveled frequently (AOR, 1.79; 95% CI, 1.22-2.65) or consumed alcohol daily (AOR, 1.68; 95% CI, 1.06-2.67). Other independent predictors of HIV were age, number of sex partners, recent migration, and presence of bacterial vaginosis, genital ulcer, active syphilis and herpes simplex virus type 2.

CONCLUSION

Development of programs that actively involve men in HIV prevention is important in reducing transmission of HIV in this population. Further, interventions that focus on STI control, the mobile population, sexual risk behavior and responsible alcohol use are required.

HIV incidence among post-partum women in Zimbabwe: risk factors and the effect of vitamin A supplementation

OBJECTIVE

To test whether post-partum vitamin A supplementation can reduce incident HIV among post-partum women and identify risk factors for HIV incidence.

DESIGN

Randomized, placebo-controlled trial

METHODS

Between November 1997 and January 2001, 14,110 women were randomly administered 400,000 IU vitamin A or placebo within 96 h post-partum. HIV incidence was monitored among 9562 HIV-negative women.

RESULTS

Cumulative incidence was 3.4% [95% confidence interval (CI), 3.0-3.8] and 6.5% (95% CI, 5.7-7.4) over 12 and 24 months post-partum, respectively. Vitamin A supplementation had no impact on incidence [hazard ratio (HR), 1.08; 95% CI, 0.85-1.38]. However, among 398 women for whom baseline serum retinol was measured, those with levels indicative of deficiency (< 0.7 micromol/l, 9.2% of those measured) were 10.4 (95% CI, 3.0-36.3) times more likely to seroconvert than women with higher concentrations. Furthermore, among women with low serum retinol, vitamin A supplementation tended to be protective against incidence (HR, 0.29; 95% CI, 0.03-2.60; P = 0.26), although not significantly so, perhaps due to limited statistical power. Severe anaemia (haemoglobin < 70 g/l) was associated with a 2.7-fold (95%CI, 1.2-6.1) greater incidence. Younger women were at higher risk of HIV infection: incidence declined by 5.7% (2.8-8.6) with each additional year of age.

CONCLUSION

Among post-partum women, a single large-dose vitamin A supplementation had no effect on incidence, although low serum retinol was a risk factor for seroconversion. Further investigation is required to determine whether vitamin A supplementation of vitamin-A-deficient women or treatment of anaemic women can reduce HIV incidence.

Mobility and HIV in Tanzanian couples: both mobile persons and their partners show increased risk

OBJECTIVE

To investigate how mobility is related to sexual risk behavior and HIV infection, with special reference to the partners who stay behind in mobile couples.

METHODS

HIV status, sexual behavior and demographic data of 2800 couples were collected in a longitudinal study in Kisesa, rural Tanzania. People were considered short-term mobile if they had slept outside the household at least once on the night before one of the five demographic interviews, and long-term mobile if they were living elsewhere at least once at the time of a demographic round.

RESULTS

Overall, whereas long-term mobile men did not report more risk behavior than resident men, short-term mobile men reported having multiple sex partners in the last year significantly more often. In contrast, long-term mobile women reported having multiple sex partners more often than resident women (6.8 versus 2.4%; P = 0.001), and also had a higher HIV prevalence (7.7 versus 2.7%; P = 0.02). In couples, men and women who were resident and had a long-term mobile partner both reported more sexual risk behavior and also showed higher HIV prevalence than people with resident/short-term mobile partners. Remarkably, risk behavior of men increased more when their wives moved than when they were mobile themselves.

CONCLUSIONS

More sexual risk behavior and an increased risk of HIV infection were seen not only in mobile persons, but also in partners staying behind. Interventions aiming at reducing risk behavior due to mobility should therefore include partners staying behind.

HIV-related sexual behaviour among migrants and non-migrants in a rural area of China: role of rural-to-urban migration

OBJECTIVE

To compare human immunodeficiency virus (HIV)-related sexual risks between temporary rural-to-urban migrants and non-migrants, and to explore the role of migration in HIV transmission in a rural area of China.

STUDY DESIGN

A cross-sectional study was conducted among 605 (302.5 couples, one male missing) marriage licence applicants.

METHODS

A two-part anonymous questionnaire was used. The first part included non-sensitive questions including demographics and HIV knowledge. Sensitive questions related to sexual behaviours were administered in the second part of the questionnaire using a tape recorder, earphones and an answer sheet.

RESULTS

Sixty-six percent (399/605) of the study subjects had migrated to a city for a temporary job. The proportions of migrants who had premarital sex (62%, 247/399) and multiple sexual partners (12%, 47/399) were significantly higher than those of non-migrants (52 and 6%, respectively). Among those who had multiple sexual partners, only 9% (4/47) of migrants and 8% (1/12) of non-migrants reported often or always using condoms with sexual partners other than their spouse. A low level of knowledge regarding HIV and acquired immunodeficiency syndrome was observed in both groups. Very few migrants (15%, 61/399) and non-migrants (10%, 20/206) perceived themselves to be at risk of HIV infection.

CONCLUSIONS

As both migrants and non-migrants are at risk of HIV infection, intervention programmes targeting reduction of HIV sexual risk behaviour should cover both groups in rural areas of China.

Is Sexual Contact With Sex Workers Important in Driving the HIV Epidemic Among Men in Rural Zimbabwe?

OBJECTIVE

To establish the importance of commercial sex in driving the HIV epidemic in the general population by determining risk factors for HIV infection among male mine and farm workers and estimating the fraction of prevalent HIV infections attributable to sexual contact with sex workers (SWs).

SETTING

Five commercial farms and 2 mines in Mashonaland West, Zimbabwe.

METHODS

A cross-sectional interviewer-administered questionnaire and urine survey of 1405 male workers. Urine samples were tested for HIV antibodies by a particle agglutination test and enzyme-linked immunosorbent assay and for Chlamydia trachomatis and Neisseria gonorrhoeae using a polymerase chain reaction assay.

RESULTS

The overall prevalence of HIV antibodies was 27.3% (95% confidence interval [CI]: 24.8 to 29.5), that of C. trachomatis was 1.5% (95% CI: 1.0 to 2.1), and that of N. gonorrhoeae was 0.5% (95% CI: 0.1 to 0.9). A total of 48.4% (95% CI: 45.8 to 51.0) of men reported ever having had sexual contact with an SW, and 29.3% (95% CI: 26.9 to 31.7) reported contact in the past year. HIV was more common among men who reported SW contact on univariate (1.9% [95% CI: 1.5 to 2.4]) and multivariate (1.4% [95% CI: 1.0 to 1.8]) analysis after adjusting for confounding. HIV was also strongly associated with self-reported genital ulceration in the previous 6 months (adjusted odds ratio [OR] = 3.1, 95% CI: 2.2 to 4.3). Genital ulceration and SW contact were highly correlated. A total of 19.6% of HIV infections in men could be attributed to ever having had sexual contact with an SW (95% CI: 10.8 to 27.6).

CONCLUSIONS

An appreciable proportion of HIV infection in men is attributable to sexual contact with SWs. Consideration should be given to developing interventions that target male clients of SWs.

Metaanalysis and metaregression in interpreting study variability in the impact of sexually transmitted diseases on susceptibility to HIV infection

BACKGROUND

Observational studies examining the effects of other sexually transmitted diseases (STDs) on HIV susceptibility differ in the populations observed and in which "other STDs" are examined. The extent to which an STD alters the risk of transmission of HIV may vary according to disease and population characteristics.

GOALS

The goals of this study were to review studies examining the effect of other STDs on HIV-1 susceptibility and to correlate their effect estimates with type of "other STD", study design, and population characteristics.

STUDY

Relevant studies with longitudinal design were identified through a systematic search of the PubMed database, and their evidence was critically evaluated. Metaregression techniques were then used to correlate study characteristics with corresponding effect estimates.

RESULTS

Of 31 studies included, 4 contained direct data on exposure to HIV-1. Three of these were inconclusive, the fourth indicating a strong relationship between STDs and transmission of HIV. Pooled effect estimates using all studies are statistically significant and indicate a 2- to 3-fold increase in risk of HIV-1 acquisition. Effect estimates corresponding some of the "other STD" categories exhibit heterogeneity, but no significant associations with study characteristics were found.

CONCLUSIONS

Most of the studies lack direct exposure data, lending them susceptible to exposure bias. Another problem may be measurement error about risk factors and STD status at time of HIV-1 infection. Because direct exposure data are difficult to come by (4 of 31 studies contained such data, all but 1 inconclusive), future observational studies on the influence of STDs on HIV-1 transmission should include quantitative analyses of the sensitivity of results to potential confounding and measurement error if they are to further understanding.

The West's moral obligation to assist developing nations in the fight against HIV/AIDS

The HIV/AIDS epidemic is increasingly a disease of the disadvantaged, a destroyer of nations, and a threat to global security and well-being. But this need not be so: the world has the scientific knowledge, technological innovations, and financial resources to significantly reduce the spread and suffering caused by the disease. This paper argues that the wealthy nations of the world, led by the United States, have a moral obligation to offer much greater assistance to developing countries where the epidemic is most severe. Using Zimbabwe as a case study, this essay examines the immediate and underlying factors behind the epidemic in order to make realistic and affordable policy recommendations that include new investments in global health care, debt relief, and long-term economic development. By demonstrating our ability to dramatically affect the future course and consequences of this unprecedented epidemic, the paper concludes that greater action is not only in the interest of public health, but is also a moral imperative. By investing the necessary resources to improve public health and to reduce global poverty, we promote and extend the fundamental rights and values that we profess to hold dear.

A critique of international indicators of sexual risk behaviour

OBJECTIVES

To investigate whether the indicators of sexual risk behaviour, defined by UNAIDS for use among members of general populations, have been found as risk factors, to examine how information on sexual behaviour is collected and summarised in order to calculate the indicators, and to look for possible sources of error in the data and in interpretation of those indicators.

METHODS

The literature on risk factors for HIV infection was reviewed. Indicators were calculated for countries where data were available for two or more points in time.

RESULTS

Indicators of sexual behaviour describe behaviours that are relevant to HIV risk and that are amenable to change. These behaviours do not correspond closely to the individual risk factors for HIV infection that have been identified in observational studies.

CONCLUSIONS

Although potential errors of both measurement and interpretation exist, most of the indicators currently defined can fulfil their purpose, providing they are used with caution. Many of the indicators should not be interpreted in isolation but need supporting information to make sense of trends or differences between groups. Much of this information is provided by other indicators. The source of the data used to calculate the indicator is potentially important and should always be provided with indicator estimates. Some estimate of the accuracy of the estimate, either by means of confidence intervals or the number of respondents, should be given.

Vulnerability to HIV/STIs among rural women from migrant communities in Nepal: a health and human rights framework

Human rights norms and standards can be applied to health issues as an analytical tool and as a framework to identify and shape interventions to reduce the impact of ill-health and improve the lives of individuals and populations. This article discusses how migration, health status, gender-based discrimination and access to education have an impact on HIV/STI vulnerability among rural women from migrant communities in Nepal. It is based on data from a clinic-based HIV/STI prevalence study with 900 women aged 15-49 from two rural communities in Kailali district, Western Nepal, and existing legal and policy data. Existing efforts to address HIV/STI vulnerability and risk in this population focus primarily on risk-taking behaviour and risk-generating situations, and largely fail to address contextual issues that create and facilitate risky behaviour and situations. Respecting, protecting and fulfilling the rights of individuals can reduce vulnerability to HIV/STI infection. Greater emphasis must be given to addressing the gender discrimination embedded in Nepalese culture, the acute lack of access to health care and education in rural areas, and the precarious economic, legal and social circumstances facing many migrants and their families.

The impact of migration on HIV-1 transmission in South Africa: a study of migrant and nonmigrant men and their partners

BACKGROUND

To investigate the association between migration and HIV infection among migrant and nonmigrant men and their rural partners.

GOAL

The goal was to determine risk factors for HIV-1 infection in South Africa.

STUDY DESIGN

This was a cross-sectional study of 196 migrant men and 130 of their rural partners, as well as 64 nonmigrant men and 98 rural women whose partners are nonmigrant. Male migrants were recruited at work in two urban centers, 100 km and 700 km from their rural homes. Rural partners were traced and invited to participate. Nonmigrant couples were recruited for comparison. The study involved administration of a detailed questionnaire and blood collection for HIV testing.

RESULTS

Testing showed that 25.9% of migrant men and 12.7% of nonmigrant men were infected with HIV ( P= 0.029; odds ratio = 2.4; 95% CI = 1.1-5.3). In multivariate analysis, main risk factors for male HIV infection were being a migrant, ever having used a condom, and having lived in four or more places during a lifetime. Being the partner of a migrant was not a significant risk factor for HIV infection among women; significant risk factors were reporting more than one current regular partner, being younger than 35 years, and having STD symptoms during the previous 4 months.

CONCLUSION

Migration is an independent risk factor for HIV infection among men. Workplace interventions are urgently needed to prevent further infections. High rates of HIV were found among rural women, and the migration status of the regular partner was not a major risk factor for HIV. Rural women lack access to appropriate prevention interventions, regardless of their partners' migration status.

High incidence of HIV-1 in South Africa using a standardized algorithm for recent HIV seroconversion

Southern Africa has among the highest rates of HIV-1 infection in the world as judged by cross-sectional HIV-1 prevalence surveys carried out among women attending antenatal clinics. Incidence rates, which provide information on the number of new cases of infection, are more informative of the current state of the epidemic than estimates of prevalence, which provide information on the rates averaged over some previous time. Cohort studies to measure incidence rates are expensive and difficult to carry out, however, and few have been done in Africa. A recently developed standardized algorithm for recent HIV-1 seroconversion (STARHS) based on a sensitive/less-sensitive enzyme-linked immunosorbent assay was used to determine the incidence of HIV-1 subtype C infection among women attending public sector antenatal clinics in Hlabisa, a rural district in KwaZulu-Natal, South Africa. The STAHRS results were confirmed by using a mathematic model to obtain an independent estimate of the age-specific incidence rates from the age-specific prevalence data. The data reveal extraordinarily high HIV-1 incidence rates in South Africa. In 1999, the annual incidence of HIV-1 among susceptible women aged 15 to 49 years standardized to the age distribution of adult women in Hlabisa was 17%. Incidence peaked among 22-year-old women at 24% per year. The HIV-1 incidence rates provide valuable additional information indicating that new infections are continuing unabated and that the HIV-1 epidemic is still growing in rural South Africa.

Clinical signs and symptoms in the assessment of immunodeficiency in men with subtype C HIV infection in Harare, Zimbabwe

PURPOSE

Providing low-cost interventions such as co-trimoxazole as prophylaxis against opportunistic infections among HIV-infected individuals depends on the identification of those at risk. This article describes the prevalence of self-reported signs and symptoms and CD4 cell counts in a cohort of 447 HIV seropositive men. A scoring system using self-reported signs and symptoms was developed and tested in the prediction of low CD4 cell counts. This approach may allow health care providers in low-resource settings to predict severe immunodeficiency and to provide care.

METHOD

Data on clinical manifestations of HIV infection and blood samples for HIV serology were collected prospectively from an ambulatory cohort of men seen at their workplace at enrollment and every 6 months thereafter. CD4+ cell counts were obtained on samples testing positive on ELISA. Using data reduction techniques and logistic modeling, we developed a prognostic score system.

RESULTS

20% of the men had CD4+ cell counts below 200. All reported signs and symptoms were more frequent in men with less than 200 CD4+ cell counts compared to men with CD4+ cell counts greater than 200. History of malaria, fever, lymphadenopathy, persistent diarrhea, persistent cough, and skin infections robustly predicted low CD4+ count. A scoring system equation was developed based on the coefficients of the multivariate logistic regression: 1x(tuberculosis) + 3.2x(herpes zoster) + 4.5x(malaria) + 5.7x(fever) + 5.8x(cough) + 8.2x(lymphadenopathy) + 8.5x(skin infection). Setting the score cutoff value greater than or equal 5, the model had moderately high sensitivity of 61% and specificity of 72%. The scoring system had an overall classification error rate of 30%.

CONCLUSION

By using this simple scoring system, physicians can correctly identify 72% of patients who do not require immediate intervention, thereby channeling scarce resources to those who have both low CD4+ cell counts and symptoms and are most likely to benefit from prophylactic and antiretroviral interventions.

Estimating the magnitude of STD cofactor effects on HIV transmission: how well can it be done?

BACKGROUND

If sexually transmitted disease (STD) cofactor effects are strong and STDs are highly prevalent, STD control can be a strategy for HIV prevention.

OBJECTIVE

To review possibilities for estimating cofactor effects of STDs on HIV transmission based on observational studies.

STUDY DESIGN

This study consisted of an analysis of factors influencing associations between HIV and STDs, which can bias STD cofactor studies, from a sexual network perspective. Study designs that reduce distortions and methods to improve estimates in the presence of confounding are discussed.

RESULTS

Standard statistical adjustments of cofactor estimates are insufficient because they ignore clustering between HIV and STDs in partners of study subjects, resulting from population heterogeneity in risk factors and assortative mixing. Reverse causation due to HIV-related immunosuppression may further inflate cofactor estimates. Misclassification of STDs and clustering between STDs can bias estimates in either direction. This study demonstrates quantitatively that ignorance of sexual network effects may result in considerable overestimation of cofactor magnitudes.

CONCLUSION

The limitations of observational studies complicate quantitative inferences on the role of STDs in HIV transmission.

A systematic review of the epidemiologic interactions between classic sexually transmitted diseases and HIV: how much really is known?

BACKGROUND

Many studies have explored the role of "classic" sexually transmitted diseases (STDs) in determining the pattern of HIV epidemics. However, the many different STDs may contribute in different ways, at different magnitudes.

GOAL

To review available studies on the bidirectional interactions of HIV and STDs to explore the extent of current knowledge on the different influences of the varied STDs in heterosexual HIV epidemics.

METHODS

Longitudinal studies on susceptibility and controlled studies on infectiousness and duration of disease identified on electronic databases through reference lists and citation indices up to the end of 1999 were systematically reviewed, including meta-analyses assessing the influence of STDs on susceptibility to HIV.

RESULTS

Studies have a clear publication bias with a significant result that hinders robust interpretation. However, genital ulcerative disease appears to have a greater impact than nonulcerative disease, and men are more affected than women by the effects of STDs on susceptibility to HIV. There is evidence that STDs increase the infectiousness of HIV from men to women, whereas the evidence is more equivocal for the infectiousness of women. Few studies identify the impact of different STDs, and there is a marked lack of studies investigating the impact of HIV infection on the transmission of other STDs.

CONCLUSIONS

A large body of work has measured the association between STDs and HIV. However, publication bias and gaps in the focus of studies mean that a detailed, quantitative understanding of the interaction requires much more attention.

HIV-1 incidence among male workers at a sugar estate in rural Malawi

OBJECTIVES

To determine incidence of HIV and associated risk factors in two cohorts of men working at a sugar estate in rural Malawi.

DESIGN

Prospective studies.

METHODS

After counseling and obtaining informed consent, male workers were tested for HIV-1 and syphilis. Baseline HIV-seronegative men were enrolled in two follow-up studies in 1994 and 1998, and were retested for HIV and syphilis at 6-month follow-up visits. Demographic, behavioral, and medical history was collected at baseline. Cumulative HIV incidence based on Kaplan-Meier methods was estimated. HIV incidence was also estimated per 100 person-years (p-y). Crude and adjusted rate ratios for the association of risk factors with incident HIV infection were obtained using Cox proportional hazards models.

RESULTS

HIV prevalence was 24.3% among 1692 men screened in 1994 and 21.0% among 1349 men screened in 1998 (p <.03). HIV incidence was extremely high during 1994 to 1995 (17.1% for that 1-year period). Incidence dramatically declined in 1996, averaging about 3.5% per year from 1996 through 1999. Among men enrolled in the 1998 cohort, HIV incidence during 1998 to 1999 was 3.8%. After controlling for potential confounders reactive syphilis was associated with a twofold risk of HIV acquisition in each cohort.

CONCLUSIONS

Urgent preventive measures are needed to control the spread of HIV in this economically important occupational cohort. In addition to conventional educational messages to reduce risky sexual behavior, treatment of other sexually transmitted diseases should be considered.

A multi-sectorial committee in directing HIV/AIDS-specific interventions in the occupational setting: an example from South Africa

We present a descriptive analysis of a mechanism to coordinate and implement human immunodeficiency virus (HIV) prevention and care in the occupational setting. The mechanism we describe is a multidisciplinary committee composed of stakeholders in the occupational health environment including unions, management, medical researchers, and medical personnel. The site chosen for the analysis was a South African sugar mill in rural KwaZulu-Natal. The factory is situated in an area of high HIV seroprevalence and has a workforce of 400 employees. The committee was initiated to coordinate a combined prevention-care initiative. The issues that were important in the formation of the committee included confidentiality, trust, and the traditional roles of the stakeholder relationships. When these points were addressed through the focus on a common goal, the committee was able to function in its role as a coordinating body. Central to this success was the inclusion of all stakeholders in the process, including those with traditionally opposing interests and legitimacy conferred by the stakeholders. This committee was functionally effective and demonstrated the benefit of a freestanding committee dedicated to addressing HIV/acquired immune deficiency syndrome (AIDS) issues. We describe the implementation and feasibility of a multisectoral committee in directing HIV/AIDS initiatives in the occupational setting in rural South Africa.

HIV infection and silicosis: the impact of two potent risk factors on the incidence of mycobacterial disease in South African miners

OBJECTIVE

To investigate the combined effects of HIV infection and silicosis on mycobacterial disease.

DESIGN AND SETTING

A retrospective cohort of 1374 HIV-positive and 2648 HIV-negative miners who attended a South African gold mining hospital and primary health clinics.

PARTICIPANTS

Miners who had been tested for HIV, with consent, at primary health clinics during 1991-1996, predominantly because of a symptomatic sexually transmitted disease.

RESULTS

Tuberculosis (TB) incidence was 4.9 and 1.1 per 100 person-years in HIV-positive and HIV-negative miners respectively. The incidence of Mycobacterium kansasii disease was also high (0.32 and 0.10 per 100 person-years, respectively). Silicosis was highly prevalent, implying inadequate dust control, and was a significant TB risk factor among both HIV-positive and HIV-negative men (adjusted incidence rate ratios 1.4-2.5 according to radiological severity). The data were consistent with the risks of silicosis and HIV combining multiplicatively, but did not fit an additive model. The incidence of HIV-associated TB increased significantly during the study, with no corresponding change in HIV-negative rates, to reach 16.1 per 100 person-years among HIV-positive silicotics.

CONCLUSIONS

The risks of silicosis and HIV infection combine multiplicatively, so that TB remains as much a silica-related occupational disease in HIV-positive as in HIV-negative miners, and HIV-positive silicotics have considerably higher TB incidence rates than those reported from other HIV-positive Africans. The increasing impact of HIV over time may indicate epidemic TB transmission with rapid disease development in HIV-infected miners. Similar but currently unrecognized interactions may be contributing to TB control problems in other industrializing countries affected by the HIV epidemic.

Improvement of clinical algorithms for the diagnosis of Neisseria gonorrhoeae and Chlamydia trachomatis by the use of Gram-stained smears among female sex workers in Accra, Ghana

BACKGROUND

Screening for cervical infection is difficult in developing countries. Screening strategies must be improved for high-risk women, such as female sex workers.

GOAL

To evaluate the sensitivity and specificity of screening algorithms for cervical infection pathogens among female sex workers in Accra, Ghana.

STUDY DESIGN

A cross-sectional study among female sex workers was conducted. Each woman underwent an interview and a clinical examination. Biologic samples were obtained for the diagnosis of HIV, syphilis, bacterial vaginosis, yeast infection, Trichomonas vaginalis, Neisseria gonorrhoeae, and Chlamydia trachomatis infection. Signs and symptoms associated with cervicitis agents were identified. Algorithms for the diagnosis of cervical infection were tested by computer simulations.

RESULTS

The following prevalences were observed: HIV, 76.6%; N. gonorrhoeae, 33.7%; C. trachomatis, 10.1%; candidiasis, 24.4%; T. vaginalis, 31.4%; bacterial vaginosis, 2.3%; serologic syphilis, 4.6%; and genital ulcers on clinical examination, 10.6%. The best performance of algorithms were reached when using a combination of clinical signs and a search for gram-negative diplococci on cervical smears (sensitivity, 64.4%; specificity, 80.0%).

CONCLUSIONS

In the algorithms, examination of Gram-stained genital smears in female sex workers without clinical signs of cervicitis improved sensitivity without altering specificity for the diagnosis of cervical infection.

Report of sexually transmitted diseases by HIV infected men during follow up: time to target the HIV infected?

OBJECTIVES

To compare the rate of self reported sexually transmitted diseases (STDs) among HIV infected men with men who remained HIV negative during follow up of a Harare male factory cohort.

METHODS

Male factory workers were offered enrolment and behavioural data were collected at entry then every 6 months, along with HIV testing. Self report of STDs was used to calculate incidence per 100 person years. Cox proportional hazards models examined independent risk factors for STDs, with hazard ratios (HRs).

RESULTS

At entry 20% of men were HIV infected and 11% reported STDs in the previous year. A total of 2777 (82%) of 3383 men enrolled were followed at least once. Compared with men who remained HIV negative, seroconverters had the highest incidence of STDs (16.8 per 100 person years; IRR = 3.3, 95% CI = 2.5-4.3); men enrolled HIV positive also reported higher STD incidence (14.5 per 100 person years, IRR = 2.8; 95% CI 2.3-5.5). Among HIV positive men, the only independent risk factor for report of urethral discharge was history of multiple partners (HR = 10, 95% CI 1.4-73.2).

CONCLUSION

HIV positive men reported threefold higher incidence of STDs than HIV negative men, many related to high risk sexual behaviour.

Sexually transmitted diseases and the increased risk for HIV transmission: implications for cost-effectiveness analyses of sexually transmitted disease prevention interventions

We estimated the annual number and cost of new HIV infections in the United States attributable to other sexually transmitted diseases (STDs). We used a mathematical model of HIV transmission to estimate the probability that a given STD infection would facilitate HIV transmission from an HIV-infected person to his or her partner and to calculate the number of HIV infections due to these facilitative effects. In 1996, an estimated 5,052 new HIV cases were attributable to the four STDs considered here: chlamydia (3,249 cases), syphilis (1,002 cases), gonorrhea (430 cases), and genital herpes (371 cases). These new HIV cases account for approximately $985 million U.S. in direct HIV treatment costs. The model suggested that syphilis is far more likely than the other STDs (on a per-case basis) to facilitate HIV transmission. This analysis provides a framework for incorporating STD-attributable HIV treatment costs into cost-effectiveness analyses of STD prevention programs.

Case-control study of risk factors for incident HIV infection in rural Uganda

OBJECTIVE

To identify risk factors associated with HIV incidence in a rural Ugandan population.

DESIGN

Case-control study.

METHODS

Men and women who seroconverted between 1990 and 1997 (cases) and seronegative subjects (controls) were drawn from a general population cohort of approximately 5000 adults in rural, southwestern Uganda. Information on risk factors was ascertained through a detailed interview and physical examination by clinicians who were blind to the study subjects' HIV status. All patients were interviewed within 2 years of their estimated date of seroconversion.

RESULTS

Data were available on 130 men (37 cases, 93 controls) and 133 women (46 cases, 87 controls). There was a significantly higher risk of infection in men (odds ratio [OR], 6.51; 95% confidence interval [CI], 1.06-39.84) and women (OR, 4.75; 95% CI, 1.26-17.9) who were unmarried and in a steady relationship, and in men who were divorced, separated, or widowed (OR, 4.33; 95% CI, 1.32-14.25) compared with those who were married. There was a significantly higher risk of HIV infection in men (OR, 3.78; 95% CI, 1.20-11.93) and women (OR, 20.78; 95% CI, 2.94-141.2) who reported > or =5 lifetime sexual partners compared with those who reported at most 1 partner. For men, there was an increased risk of infection associated with receiving increasing numbers of injections in the 6 months prior to interview (p < .001 for trend). Women reporting sex against their will in the year prior to interview were at higher risk of infection (OR, 7.84; 95% CI, 1.29-47.86; p = .020).

CONCLUSIONS

The strongest risk factor for HIV incidence in this rural Ugandan population is lifetime sexual partners. The increased risks found for women reporting coercive sex and men reporting injections require further investigation.

HIV incidence and HIV-associated mortality in a cohort of factory workers and their spouses in Tanzania, 1991 through 1996

OBJECTIVE

To describe HIV incidence and HIV-associated mortality in a cohort of factory workers and their spouses with access to adequate sexually transmitted diseases (STD) treatment services and moderate exposure to sexual health interventions.

METHODS

Follow-up visits at 4-month intervals and home follow-up of those who failed to keep appointments were used to estimate HIV incidence and mortality in a cohort of factory workers and their spouses in Mwanza, Tanzania, during 1991 to 1996.

RESULTS

HIV prevalence at intake was 10.5% and 15.3% among 1,594 men and 880 women, respectively. HIV incidence was just over 1/100 person-years (PY) in 1,427 men and 1.9/100 PY in 745 women. The main risk factors were related to sexual behavior and clinical evidence of an STD, although only one seventh of those with HIV seroconversions had had an STD during the period following the second-from-last follow-up visit. HIV incidence among discordant couples was 5.0 and 8.3/100 PY for 41 men and 37 women, respectively. Mortality rates were 9.0 and 7.8/1,000 PY for men and women, respectively, and 65% of male and 60% of female deaths were attributable to HIV infection.

CONCLUSIONS

In this factory population with good access to and use of STD treatment and with a moderate level of exposure to HIV prevention education, HIV incidence among men and women is still over 1/100 PY, which suggests a relatively high level of program effort is needed to lower incidence. More than half of all adult deaths were attributable to HIV, but greater increases in HIV-associated mortality are likely.

Spread of HIV infection in a rural area of Tanzania

OBJECTIVE

To assess the spread of HIV into rural areas.

METHODS

Since 1994 a demographic surveillance system (with 5-monthly rounds) and open adult cohort study have been established in a rural ward in Tanzania. Two sero-surveys of all resident adults aged 15-44 and 15-46 years were conducted in 1994 1995 and 1996-1997 respectively. Qualitative data were collected on mobility, bars and commercial sex.

RESULTS

Attendance of the two rounds of survey was 5820 (78%) and 6413 (80%) in 1994/1995 and 1996/1997 respectively. HIV prevalence increased from 5.8% to 6.6%. HIV incidence was 0.73 and 0.84 per 100 person years among men and women respectively. HIV incidence under the age of 20 years was low among both sexes. Striking differences in HIV prevalence and incidence were observed within the small geographic area studied: HIV prevalence in the trading center was twice that in the area surrounding the trading center (within 2 km) and three to four times that in the rural villages (within 8 km of the trading center). Aggregate level data showed significant differences between the trading center and nearby rural villages in terms of sexual behavior, commercial sex workers, mobility of the population, and alcohol use.

CONCLUSION

This study documents the existence of very substantial HIV prevalence and incidence differences within a small geographic rural area. The rapid decrease in HIV prevalence within a small rural area emphasizes the importance of concentrating HIV prevention efforts on high transmission areas, such as trading centers, especially in resource-poor settings. Furthermore, this has considerable implications for monitoring the spread of HIV through sentinel sites, as such sites are typically located in high transmission areas.

Primary subtype C HIV-1 infection in Harare, Zimbabwe

Heterosexual transmission of HIV-1 is widespread in Southern Africa. Heteroduplex mobility assays (HMA) and phylogenetic analyses of V3-V5 envelope (env) gene sequences demonstrate that subtype C predominates in Zimbabwe. To elucidate factors contributing to the epidemic in Zimbabwe, clinical and virologic characteristics of recently acquired subtype C HIV-1 infection among 21 men and 1 woman were determined. In 12 of 19 men providing clinical histories, a sexually transmitted infection preceded serologic evidence of HIV-1, and 14 of 19 men complained of rash or fever before seroconversion. Quantitative p24 antigen levels, reverse transcriptase activity, and HIV RNA levels of 22 viral isolates correlated with in vitro infectivity in peripheral blood mononuclear cells (p < .05). Biologic phenotype assessed in MT-2 cells demonstrated that 3 of 22 isolates (14%) were syncytia inducing (SI) and the remaining 19 nonsyncytium inducing (NSI). Early growth of virus in culture was associated with increased plasma HIV RNA levels, decreased CD4 cell levels, and SI virus. Recent subtype C HIV-1 infection through heterosexual transmission in Zimbabwe demonstrated clinical and virologic features consistent with reports of seroconversion to subtype B viruses.

From epidemiological synergy to public health policy and practice: the contribution of other sexually transmitted diseases to sexual transmission of HIV infection

OBJECTIVES

To review the scientific data on the role of sexually transmitted diseases (STDs) in sexual transmission of HIV infection and discuss the implications of these findings for HIV and STD prevention policy and practice.

METHODS

Articles were selected from a review of Medline, accessed with the OVID search engine. The search covered articles from January 1987 to September 1998 and yielded 2101 articles. Methods used to uncover articles which might have been missed included searching for related articles by author, and combing literature reviews. In addition, all abstracts under the category "sexually transmitted diseases" from the XI and XII International Conferences on AIDS (Vancouver 1996 and Geneva 1998) and other relevant scientific meetings were reviewed. Efforts were made to locate journal articles which resulted from the research reported in the identified abstracts. All original journal articles and abstracts which met one of the following criteria were included: (1) studies of the biological plausibility or mechanism of facilitation of HIV infectiousness or susceptibility by STDs, (2) prospective cohort studies (longitudinal or nested case-control) which estimate the risk of HIV infection associated with specific STDs or STD syndromes, or (3) intervention studies which quantitate the effect which STD treatment can have on HIV incidence.

RESULTS

Strong evidence indicates that both ulcerative and non-ulcerative STDs promote HIV transmission by augmenting HIV infectiousness and HIV susceptibility via a variety of biological mechanisms. These effects are reflected in the risk estimates found in numerous prospective studies from four continents which range from 2.0 to 23.5, with most clustering between 2 and 5. The relative importance of ulcerative and non-ulcerative STDs appears to be complex. Owing to the greater frequency of non-ulcerative STDs in many populations, these infections may be responsible for more HIV transmission than genital ulcers. However, the limited reciprocal impact of HIV infection on non-ulcerative STDs and the evidence that non-ulcerative STDs may increase risk primarily for the receptive partner (rather than bidirectionally) may modulate the impact of these diseases. The results of two community level randomised, controlled intervention trials conducted in Africa suggest that timely provision of STD services can substantially reduce HIV incidence, but raise additional questions about the optimal way to target and implement these services to achieve the greatest effect on HIV transmission.

CONCLUSIONS

Available data leave little doubt that other STDs facilitate HIV transmission through direct, biological mechanisms and that early STD treatment should be part of a high quality, comprehensive HIV prevention strategy. Policy makers, HIV prevention programme managers, and providers should focus initial implementation efforts on three key areas: (i) improving access to and quality of STD clinical services; (ii) promoting early and effective STD related healthcare behaviours; and (iii) establishing surveillance systems to monitor STD and HIV trends and their interrelations.

Current estimates of and future projections for adult deaths attributed to HIV infection in Zimbabwe

OBJECTIVE

Estimates of HIV prevalence in 1995 among all adults in Zimbabwe range between about 18% and 24%. The objective of this study was to estimate, for Zimbabwe, the impact of HIV infection on adult mortality, by age and gender, between 1995 and the year 2000.

METHODS

For this analysis, we used 1992 census data to estimate the number of non-HIV-related deaths, and a short-term projection model to estimate the number of deaths attributed to HIV infection in 1995 and the year 2000.

RESULTS

It was estimated that between 52% and 60% of all adult deaths in 1995 were attributed to HIV infection, and between 69% and 76% in both males and females in the group between 20 and 39 years of age. The estimated adult mortality rate per 1000 increased from 9.8 in 1987 (based on census data) to between 20.6 and 24.3 in 1995. For the year 2000, it was projected that between 66% and 73% of all adult deaths would be attributed to HIV infection, and between 81% and 86% in those aged 20 to 39 years. The estimated adult mortality rate in the year 2000 increased to between 29.1/1000 and 36.6/1000. Even if all transmission was assumed to cease after 1995, it was projected that >60% of adult deaths would be attributed to HIV in the year 2000. Adult population growth is projected to decrease to between 0.3% and 1.0% in the year 2000.

CONCLUSION

Results suggest that the impact of HIV infection on mortality in Zimbabwe is already severe and will continue to increase. Efforts to reduce numbers of new HIV infections today will serve to reduce the future burden of mortality, particularly in the longer term.

Sexual behaviour and risk assessment of HIV seroconvertors among urban male factory workers in Zimbabwe

Despite extensive HIV prevention programmes and knowledge of people dying of AIDS, people in Zimbabwe continue to be infected with HIV and other sexually transmitted infections (STIs). This paper presents selected case histories from interviews with 57 men who became HIV positive during follow up of 1678 seronegative male factory workers in Harare, and describes the circumstances in which they were exposed to infection. Youth was a major risk factor, with 47% of those who seroconverted aged between 18 and 24 yr. STIs were reported by 23% of the group in the seroconversion period, a marker of unprotected sex. Individuals did not recognise themselves or their partners as candidates for infection because of categorisation of high risk groups as "promiscuous" or clients of sex workers. Many were optimistic that they had changed sufficiently by using condoms more often or by avoiding sex workers. They made inaccurate assessments of who was safe for unprotected sex, based on judgements about their character, background and age. Over 40% of the seroconvertors had previously been counselled on staying HIV negative. Community approaches which nurture development of supportive group norms, respect for human rights and responsibilities, and safe environments for disclosure of HIV status, are vital for overcoming denial of risk at individual and societal levels. Special efforts targeted at youth are crucial since they have the highest risk of new infections and include use of media, drama, role models, advisory centres, peer education programmes. Health professionals need training and skills to enable people at risk of HIV infection to devise strategies based on more realistic personal risk assessment.