The development of the HIV epidemic in Karonga District, Malawi

Sexual Networks and Behavioral Characteristics of HIV-Positive Male Military Members, Female Sex Workers, and Male Civilians

Military members and female sex workers (FSWs) may be more likely to acquire or transmit HIV. Mapping HIV transmission across these high-risk populations and identifying behaviors associated with sexual network clustering are needed for effective HIV prevention approaches. A cross-sectional study recruited participants newly diagnosed with HIV among militaries, civilians, and FSWs in Zambia, Senegal, and Democratic Republic of the Congo (DRC). Participants were interviewed on behaviors and provided blood samples for HIV-1 partial pol sequencing. Genetic-distance based network analyses inferred putative relationships between HIV-1 partial pol sequences. Bivariate logistic regression models identified variables associated with clustering in a sexual network. 908 participants were included (n = 313 FSWs, n = 297 military, n = 298 civilians). 311 blood samples were sequenced and had survey data, of which 93 (29.9%) were genetically linked, forming 36 transmission clusters. All but one cluster were comprised of participants from the same country, including one large cluster (n = 12; 9 FSWs and 3 civilians) from DRC. A large mixed-country cluster (n = 9) including 7 men (4 civilians, 3 military) and 2 FSWs was observed. The odds of clustering in a sexual network were elevated for DRC participants, FSWs, and those cohabitating with a sexual partner. Findings underscore the importance of identifying linkages in high-risk populations to develop tailored HIV prevention strategies. Linkages across risk groups and countries illustrate the potential role of mobile populations in HIV transmission and acquisition. Larger studies including HIV recency testing may better elucidate biological and behavioral interactions between military, civilians, and FSWs.

Improving care engagement for mobile people living with HIV in rural western Kenya

BACKGROUND

Antiretroviral therapy (ART) assures major gains in health outcomes among people living with HIV, however, this benefit may not be realized by all due to care interruptions. Mobile populations comprise a subgroup that is likely to have sub-optimal care engagement, resulting in discontinuation of ART. We sought to evaluate the barriers to care engagement among highly mobile individuals living with HIV and explore options aimed at improving engagement in care for this group.

METHODS

Qualitative in-depth interviews were conducted in 2020 among a purposive sample of twelve persons living with HIV and eight health care providers in western Kenya, within a mixed methods study of mobility in communities participating in the SEARCH trial (NCT01864603). We explored the barriers to care engagement among mobile individuals living with HIV and explored different options aimed at enhancing care engagement. These included options such as a coded card containing treatment details, alternative drug packaging to conceal drug identity, longer refills to cover travel period, wrist bands with data storage capability to enable data transfer and "warm handoff" by providers to new clinics upon transfer. Data were inductively analyzed to understand the barriers and acceptability of potential interventions to address them.

RESULTS

Stigma and lack of disclosure, rigid work schedules, and unpredictability of travel were major barriers to care engagement for highly mobile individuals living with HIV. Additionally, lack of flexibility in clinic schedules and poor provider attitude were identified as health-system-associated barriers to care engagement. Options that enhance flexibility, convenience and access to care were viewed as the most effective means of addressing the barriers to care by both patients and providers. The most preferred option was a coded card with treatment details followed by alternative drug packaging to conceal drug identity due to stigma and longer refills to cover travel periods.

CONCLUSION

Highly mobile individuals living with HIV desire responsive, flexible, convenient and patient-centered care delivery models to enhance care engagement. They embraced simple health delivery improvements such as coded cards, alternative drug packaging and longer refills to address challenges of mobility.

Mobility is Associated with Higher-risk Sexual Partnerships Among Both Men and Women in Co-resident Couples in Rural Kenya and Uganda: A Longitudinal Cohort Study

Population mobility is associated with higher-risk sexual behaviors in sub-Saharan Africa and is a key driver of the HIV epidemic. We conducted a longitudinal cohort study to estimate associations between recent mobility (overnight travel away from home in past six months) or migration (changes of residence over defined geopolitical boundaries) and higher-risk sexual behavior among co-resident couples (240 couples aged ≥ 16) from 12 rural communities in Kenya and Uganda. Data on concurrent mobility and sexual risk behaviors were collected every 6-months between 2015 and 2020. We used sex-pooled and sex-stratified multilevel models to estimate associations between couple mobility configurations (neither partner mobile, male mobile/female not mobile, female mobile/male not mobile, both mobile) and the odds of higher-risk (casual, commercial sex worker/client, one night stand, inherited partner, stranger) and concurrent sexual partnerships based on who was mobile. On average across all time points and subjects, mobile women were more likely than non-mobile women to have a higher-risk partner; similarly, mobile men were more likely than non-mobile men to report a higher-risk partnership. Men with work-related mobility versus not had higher odds of higher-risk partnerships. Women with work-related mobility versus not had higher odds of higher-risk partnerships. Couples where both members were mobile versus neither had greater odds of higher-risk partnerships. In analyses using 6-month lagged versions of key predictors, migration events of men, but not women, preceded higher-risk partnerships. Findings demonstrate HIV risks for men and women associated with mobility and the need for prevention approaches attentive to the risk-enhancing contexts of mobility.

No increased HIV risk in general population near sex work sites: A nationally representative cross-sectional study in Zimbabwe

OBJECTIVES

Sex work sites have been hypothesised to be at the root of the observed heterogeneity in HIV prevalence in sub-Saharan Africa. We determined if proximity to sex work sites is associated with HIV prevalence among the general population in Zimbabwe, a country with one of the highest HIV prevalence in the world.

METHODS

In this cross-sectional study we use a unique combination of nationally representative geolocated individual-level data from 16,121 adults (age 15-49 years) from 400 sample locations and the locations of 55 sex work sites throughout Zimbabwe; covering an estimated 95% of all female sex workers (FSWs). We calculated the shortest distance by road from each survey sample location to the nearest sex work site, for all sites and by type of sex work site, and conducted univariate and multivariate multilevel logistic regressions to determine the association between distance to sex work sites and HIV seropositivity, controlling for age, sex, male circumcision status, number of lifetime sex partners, being a FSW client or being a stable partner of an FSW client.

RESULTS

We found no significant association between HIV seroprevalence and proximity to the nearest sex work site among the general population in Zimbabwe, regardless of which type of site is closest (city site adjusted odds ratio [aOR] 1.010 [95% confidence interval {CI} 0.992-1.028]; economic growth point site aOR 0.982 [95% CI 0.962-1.002]; international site aOR 0.995 [95% CI 0.979-1.012]; seasonal site aOR 0.987 [95% CI 0.968-1.006] and transport site aOR 1.007 [95% CI 0.987-1.028]). Individual-level indicators of sex work were significantly associated with HIV seropositivity: being an FSW client (aOR 1.445 [95% CI 1.188-1.745]); nine or more partners versus having one to three lifetime partners (aOR 2.072 [95% CI 1.654-2.596]).

CONCLUSIONS

Sex work sites do not seem to directly affect HIV prevalence among the general population in surrounding areas. Prevention and control interventions for HIV at these locations should primarily focus on sex workers and their clients, with special emphasis on including and retaining mobile sex workers and clients into services.

Mobility and its Effects on HIV Acquisition and Treatment Engagement: Recent Theoretical and Empirical Advances

PURPOSE OF REVIEW

We reviewed literature across multiple disciplines to describe issues with the measurement of population mobility in HIV research and to summarize evidence of causal pathways linking mobility to HIV acquisition risks and treatment engagement, with a focus on sub-Saharan Africa.

RECENT FINDINGS

While the literature on mobility and HIV remains hampered by problems and inconsistency in measures of mobility, the recent research reveals a turn towards a greater attentiveness to measurement and gender. Theoretical and heuristic models for the study of mobility and HIV acquisition and treatment outcomes have been published, but few studies have used longitudinal designs with clear ascertainment of exposures and outcomes for measurement of causal pathways. Notwithstanding these limitations, evidence continues to accumulate that mobility is linked to higher HIV incidence, and that it challenges optimal treatment engagement. Gender continues to be important: while men are more mobile than women, women's mobility particularly heightens their HIV acquisition risks. Recent large-scale efforts to find, test, and treat the individuals in communities who are most at risk of sustaining local HIV transmission have been severely challenged by mobility. Novel interventions, policies, and health systems improvements are urgently needed to fully engage mobile individuals in HIV care and prevention. Interventions targeting the HIV prevention and care needs of mobile populations remain few in number and urgently needed.

Accessing ART in Malawi while living in South Africa - a thematic analysis of qualitative data from undocumented Malawian migrants

The majority of international migrants from Malawi to South Africa are undocumented, and some of them are on ART. This study explored how these migrants manage to access ART. Qualitative data were collected using open-ended questions in semi-structured interviews. 23 returned undocumented Malawian migrants from South Africa participated in the study. Also, key informant discussions were held with three health workers. Data collection took place in April and May 2015 at a rural village of Namwera in Mangochi district in southern Malawi. Interviews were audio-recorded, transcribed and translated into English for thematic analysis. The guardians collected ART from health facilities in Malawi on behalf of the migrants. The guardians sent ART through truck and bus drivers to the migrants in South Africa. The migrants shared their ART. Others bought ART from the 'street pharmacies'. Others accessed ART from South African health facilities through the help of their South African friends. There are risks to dispensing ART to the migrants who do not themselves present at health facilities. There is value to more regular contacts between clients and health service system that is compromised by alternative strategies. It is better to deliver ART services in South Africa to the undocumented migrants.

Population mobility associated with higher risk sexual behaviour in eastern African communities participating in a Universal Testing and Treatment trial

INTRODUCTION

There are significant knowledge gaps concerning complex forms of mobility emergent in sub-Saharan Africa, their relationship to sexual behaviours, HIV transmission, and how sex modifies these associations. This study, within an ongoing test-and-treat trial (SEARCH, NCT01864603), sought to measure effects of diverse metrics of mobility on behaviours, with attention to gender.

METHODS

Cross-sectional data were collected in 2016 from 1919 adults in 12 communities in Kenya and Uganda, to examine mobility (labour/non-labour-related travel), migration (changes of residence over geopolitical boundaries) and their associations with sexual behaviours (concurrent/higher risk partnerships), by region and sex. Multilevel mixed-effects logistic regression models, stratified by sex and adjusted for clustering by community, were fitted to examine associations of mobility with higher-risk behaviours, in past 2 years/past 6 months, controlling for key covariates.

RESULTS

The population was 45.8% male and 52.4% female, with mean age 38.7 (median 37, IQR: 17); 11.2% had migrated in the past 2 years. Migration varied by region (14.4% in Kenya, 11.5% in southwestern and 1.7% in eastern and Uganda) and sex (13.6% of men and 9.2% of women). Ten per cent reported labour-related travel and 45.9% non-labour-related travel in past 6 months-and varied by region and sex: labour-related mobility was more common in men (18.5%) than women (2.9%); non-labour-related mobility was more common in women (57.1%) than men (32.6%). In 2015 to 2016, 24.6% of men and 6.6% of women had concurrent sexual partnerships; in past 6 months, 21.6% of men and 5.4% of women had concurrent partnerships. Concurrency in 2015 to 2016 was more strongly associated with migration in women [aRR = 2.0, 95% CI(1.1 to 3.7)] than men [aRR = 1.5, 95% CI(1.0 to 2.2)]. Concurrency in past 6 months was more strongly associated with labour-related mobility in women [aRR = 2.9, 95% CI(1.0 to 8.0)] than men [aRR = 1.8, 95% CI(1.2 to 2.5)], but with non-labour-related mobility in men [aRR = 2.2, 95% CI(1.5 to 3.4)].

CONCLUSIONS

In rural eastern Africa, both longer-distance/permanent, and localized/shorter-term forms of mobility are associated with higher-risk behaviours, and are highly gendered: the HIV risks associated with mobility are more pronounced for women. Gender-specific interventions among mobile populations are needed to combat HIV in the region.

Methods for sampling geographically mobile female traders in an East African market setting

Background

The role of migration in the spread of HIV in sub-Saharan Africa is well-documented. Yet migration and HIV research have often focused on HIV risks to male migrants and their partners, or migrants overall, often failing to measure the risks to women via their direct involvement in migration. Inconsistent measures of mobility, gender biases in those measures, and limited data sources for sex-specific population-based estimates of mobility have contributed to a paucity of research on the HIV prevention and care needs of migrant and highly mobile women. This study addresses an urgent need for novel methods for developing probability-based, systematic samples of highly mobile women, focusing on a population of female traders operating out of one of the largest open air markets in East Africa. Our method involves three stages: 1.) identification and mapping of all market stall locations using Global Positioning System (GPS) coordinates; 2.) using female market vendor stall GPS coordinates to build the sampling frame using replicates; and 3.) using maps and GPS data for recruitment of study participants.

Results

The location of 6,390 vendor stalls were mapped using GPS. Of these, 4,064 stalls occupied by women (63.6%) were used to draw four replicates of 128 stalls each, and a fifth replicate of 15 pre-selected random alternates for a total of 527 stalls assigned to one of five replicates. Staff visited 323 stalls from the first three replicates and from these successfully recruited 306 female vendors into the study for a participation rate of 94.7%. Mobilization strategies and involving traders association representatives in participant recruitment were critical to the study’s success.

Conclusion

The study’s high participation rate suggests that this geospatial sampling method holds promise for development of probability-based samples in other settings that serve as transport hubs for highly mobile populations.

High Mobility and HIV Prevalence Among Female Market Traders in East Africa in 2014

BACKGROUND

The contribution of women's mobility to the HIV/AIDS epidemic in Africa is poorly understood, despite women's high mobility and evidence that it is associated with higher-risk sexual behavior. We sought to measure levels of mobility, HIV prevalence, and related risk behaviors among female traders in Kisumu, Kenya.

METHODS

We used global positioning system mapping to develop a probability-based sample and recruited 305 female market traders for participation in a survey and voluntary HIV counseling and testing in 2014. We estimated HIV prevalence and fitted logistic regression models to measure associations between mobility, risk behaviors, and HIV infection.

RESULTS

HIV prevalence was 25.6% (95% confidence interval: 21.0 to 30.8); 11.5% had migrated (changed residence, over county, or national boundary) in the past year and 39.3% in the past 5 years. More than one-third (38.3%) spent nights away from main residence in the past month, with 11.4% spending more than a week away. Multiple partners were reported by 13.1% of women in the last year; 16% of married women reported a concurrent partnership. Mobility was not significantly associated with HIV prevalence, although recent short-term mobility was significantly correlated with higher numbers of sexual partners in the past year.

CONCLUSIONS

Female market traders were highly mobile, and HIV prevalence among traders was higher than in the general population of women of reproductive age in Kisumu (15.3% in 2013), and Nyanza Province, Kenya (16.1% in 2012). High HIV prevalence and risk behavior among women in this study warrant accelerated attention to HIV prevention and care needs of mobile women, including market traders.

Is it ethical to prevent secondary use of stored biological samples and data derived from consenting research participants? The case of Malawi

BACKGROUND

This paper discusses the contentious issue of reuse of stored biological samples and data obtained from research participants in past clinical research to answer future ethical and scientifically valid research questions. Many countries have regulations and guidelines that guide the use and exportation of stored biological samples and data. However, there are variations in regulations and guidelines governing the reuse of stored biological samples and data in Sub-Saharan Africa including Malawi.

DISCUSSION

The current research ethics regulations and guidelines in Malawi do not allow indefinite storage and reuse of biological samples and data for future unspecified research. This comes even though the country has managed to answer pertinent research questions using stored biological samples and data. We acknowledge the limited technical expertise and equipment unavailable in Malawi that necessitates exportation of biological samples and data and the genuine concern raised by the regulatory authorities about the possible exploitation of biological samples and data by researchers. We also acknowledge that Malawi does not have bio-banks for storing biological samples and data for future research purposes. This creates room for possible exploitation of biological samples and data collected from research participants in primary research projects in Malawi. However, research ethics committees require completion and approval of material transfer agreements and data transfer agreements for biological samples and data collected for research purposes respectively and this requirement may partly address the concern raised by the regulatory authorities. Our concern though is that there is no such requirement for biological samples and data collected from patients for clinical or diagnostic purposes. In conclusion, we propose developing a medical data and material transfer agreement for biological samples and data collected from patients for clinical or diagnostic purposes in both public and private health facilities that may end up in research centers outside Malawi. We also propose revision of the current research ethics regulations and guidelines in Malawi in order to allow secondary use of biological samples and data collected from primary research projects as a way of maximizing the use of collected samples and data. Finally, we call for consultation of all stakeholders within the Malawi research community when regulatory authorities are developing policies that govern research in Malawi.

Participation dynamics in population-based longitudinal HIV surveillance in rural South Africa

Population-based HIV surveillance is crucial to inform understanding of the HIV pandemic and evaluate HIV interventions, but little is known about longitudinal participation patterns in such settings. We investigated the dynamics of longitudinal participation patterns in a high HIV prevalence surveillance setting in rural South Africa between 2003 and 2012, taking into account demographic dynamics. At any given survey round, 22,708 to 30,495 persons were eligible. Although the yearly participation rates were relatively modest (26% to 46%), cumulative rates increased substantially with multiple recruitment opportunities: 68% of eligible persons participated at least once, 48% at least twice and 31% at least three times after five survey rounds. We identified two types of study fatigue: at the individual level, contact and consent rates decreased with multiple recruitment opportunities and, at the population level, these rates also decreased over calendar time, independently of multiple recruitment opportunities. Using sequence analysis and hierarchical clustering, we identified three broad individual participation profiles: consenters (20%), switchers (43%) and refusers (37%). Men were over represented among refusers, women among consenters, and temporary non-residents among switchers. The specific subgroup of persons who were systemically not contacted or refusers constitutes a challenge for population-based surveillance and interventions.

Disconnect between discourse and behavior regarding concurrent sexual partnerships and condom use: findings from a qualitative study among youth in Malawi

The practice of concurrent sexual partnerships (CP) is posited to be a contributor to the elevated risk of HIV transmission among youth in Malawi. The lens through which Malawian youth conceptualize the practices of CP and condom use has yet to be fully explored. The current study--a secondary data analysis of semi-structured in-depth interviews (n = 19) with Malawian youth aged 18 to 22 years--addresses this gap. Participants were interviewed about their sexual relationships and behavior, as well as their perceptions and knowledge regarding condom use and CP. In order to ensure that youth engaged in CP were oversampled, the recruitment process asked potential respondents to self-identify whether they currently participated in CP. Of the total sample (n = 19), 13 self-identified as currently engaging in CP. Data were analyzed using a grounded theory approach. This qualitative study highlights a disconnect between the high level of knowledge youth exhibit about HIV prevention methods and their actual reported condom use and CP behaviors. While some youth claimed to use condoms, their discourse demonstrated fluidity in that use changed over time, or interest in changing behavior was expressed, or was inconsistent between partnerships. The disconnect between knowledge of the consequences of risky sexual behavior and actual behavior was most evident among inconsistent condom users engaged in CP. This finding indicates knowledge alone has a limited role in the adoption of lower risk behaviors such as condom use and reduction of CP among youth. Moreover, findings from this study can inform HIV prevention programs operating in Malawi and the sub-Saharan Africa region by enabling them to provide tailored, more persuasive health promotion and prevention messaging.

Embracing different approaches to estimating HIV incidence, prevalence and mortality

Background:

Joint United Nations Programme on HIV/AIDS (UNAIDS) and Murray et al. have both produced sets of estimates for worldwide HIV incidence, prevalence and mortality. Understanding differences in these estimates can strengthen the interpretation of each.

Methods:

We describe differences in the two sets of estimates. Where possible, we have drawn on additional published data to which estimates can be compared.

Findings:

UNAIDS estimates that there were 6 million more people living with HIV (PLHIV) in 2013 (35 million) compared with the Murray et al. estimates (29 million). Murray et al. estimate that new infections and AIDS deaths have declined more gradually than does UNAIDS. Just under one third of the difference in PLHIV is in Africa, where Murray et al. have relied more on estimates of adult mortality trends than on data on survival times. Another third of the difference is in North America, Europe, Central Asia and Australasia. Here Murray et al. estimates of new infections are substantially lower than the number of new HIV/AIDS diagnoses reported by countries, whereas published UNAIDS estimate tend to be greater. The remaining differences are in Latin America and Asia where the data upon which the UNAIDS methods currently rely are more sparse, whereas the mortality data leveraged by Murray et al. may be stronger. In this region, however, anomalies appear to exist between the both sets of estimates and other data.

Interpretation:

Both estimates indicate that approximately 30 million PLHIV and that antiretroviral therapy has driven large reductions in mortality. Both estimates are useful but show instructive discrepancies with additional data sources. We find little evidence to suggest that either set of estimates can be considered systematically more accurate. Further work should seek to build estimates on as wide a base of data as possible.

Sexual and reproductive health and HIV in border districts affected by migration and poverty in Tanzania

OBJECTIVES

To assess HIV knowledge, attitudes, sexual practices and sexual and reproductive health (SRH) service delivery in border areas of Tanzania, with a view to support the prioritisation of SRH interventions in border areas.

METHODS

The target sample comprised randomly selected people living near the border, aged 15 to 49 years. To gather information, we utilised: (i) a standardised questionnaire (n = 86; 42 men and 44 women) previously used in national household surveys conducted by the Tanzanian government; (ii) focus group discussions (ten male groups, n = 47; ten female groups, n = 51); and (iii) semi-structured interviews with service providers (n = 37).

RESULTS

The mean number of sexual partners, frequency of multiple concurrent partnerships and engagement in transactional sex were significantly higher in the border community than in the national population. Knowledge about HIV was comparable with that in the general population. Access to SRH services was limited in the border areas.

CONCLUSION

Efforts to reduce HIV transmission and to improve SRH in the border areas should focus on gaps in service delivery rather than education and information activities alone. In addition, multi-sectorial efforts spanning the health, social, legal and private sectors addressing gender imbalances and poverty alleviation are imperative for reducing poverty-driven unsafe transactional sex.

Why are the benefits of increased resources not impacting the risk of HIV infection for high SES women in Cameroon?

Background

Despite evidence of a positive SES-HIV gradient in some SSA countries, researchers and policy-makers frequently assume that a range of protective interventions – increasing awareness of mechanisms of HIV transmission, techniques for prevention, greater access to health care facilities, and greater availability of condoms – will reduce the likelihood of contracting HIV, even among higher SES populations. We therefore explore the relationships between SES and these intervening behaviors to illuminate the complex factors that link SES and HIV among women in Cameroon.

Methods

We use bivariate and multivariate statistical analysis to examine patterns among the 5, 155 women aged 15–49 who participated in the 2004 CDHS.

Results

The results show a strong pattern where higher SES women have greater access to and use of health care facilities, higher levels of condom use, more HIV knowledge, and command higher power within their relationships, yet also have higher rates of HIV. These traditionally protective factors appear to be offset by riskier sexual behaviors on the part of women with increased resources, most notably longer years of premarital sexual experience, multiple partners in last 12 months, and sexual encounters outside of relationship. Multivariate analyses suggests net of the effect of other factors, women who command higher decision-making power, have greater access to health care, more negative attitudes toward wife beating, longer years of premarital sexual exposure, and partners with professional/white collar jobs (characteristics associated with rising SES) had higher odds of testing positive for HIV.

Conclusion

Results show that higher riskier sexual practices on part of high SES women offset benefits that may have accrued from their increased access to resources. The results suggest that traditional approaches to HIV prevention which rely on poverty reduction, improving access to health care, improving HIV knowledge, and boosting women’s social and economic power may be insufficient to address other drivers of HIV infection among women in SSA.

Underestimation of HIV prevalence in surveys when some people already know their status, and ways to reduce the bias

OBJECTIVE

To quantify refusal bias due to prior HIV testing, and its effect on HIV prevalence estimates, in general-population surveys.

DESIGN

Four annual, cross-sectional, house-to-house HIV serosurveys conducted during 2006-2010 within a demographic surveillance population of 33 000 in northern Malawi.

METHODS

The effect of prior knowledge of HIV status on test acceptance in subsequent surveys was analysed. HIV prevalence was then estimated using ten adjustment methods, including age-standardization; multiple imputation of missing data; a conditional probability equations approach incorporating refusal bias; using longitudinal data on previous and subsequent HIV results; including self-reported HIV status; and including linked antiretroviral therapy clinic data.

RESULTS

HIV test acceptance was 55-65% in each serosurvey. By 2009/2010 79% of men and 85% of women had tested at least once. Known HIV-positive individuals were more likely to be absent, and refuse interviewing and testing. Using longitudinal data, and adjusting for refusal bias, the best estimate of HIV prevalence was 7% in men and 9% in women in 2008/2009. Estimates using multiple imputations were 4.8 and 6.4%, respectively. Using the conditional probability approach gave good estimates using the refusal risk ratio of HIV-positive to HIV-negative individuals observed in this study, but not when using the only previously published estimate of this ratio, even though this was also from Malawi.

CONCLUSION

As the proportion of the population who know their HIV-status increases, survey-based prevalence estimates become increasingly biased. As an adjustment method for cross-sectional data remains elusive, sources of data with high coverage, such as antenatal clinics surveillance, remain important.

The relationship between orphanhood and child fostering in sub-Saharan Africa, 1990s-2000s

In countries most afflicted by HIV/AIDS in sub-Saharan Africa, orphanhood has increased dramatically, but the potential consequences of the increase have been mitigated by the ability of households to absorb orphans. This paper examines what the rising levels of orphanhood mean for the common practice of non-orphan child fostering in regions of high and low HIV prevalence in sub-Saharan Africa, which has a long history of child fostering. Using Demographic and Health Survey data from 135 regions within 14 sub-Saharan countries that undertake HIV testing and have had at least two surveys, we examine changes in fostering patterns. In most regions, we find a more accommodating relationship between orphan and non-orphan fostering: communities are able to absorb the demand for both orphans and non-orphans. Where HIV prevalence exceeds 10 per cent there is some evidence that the need to care for orphans is beginning to reduce opportunities for non-orphan fostering.

Very early anthropometric changes after antiretroviral therapy predict subsequent survival, in karonga, Malawi

BACKGROUND

Antiretroviral (ART) scale-up in Malawi has been achieved on a large scale based mainly on clinical criteria. Simple markers of prognosis are useful, and we investigated the value of very early anthropometric changes in predicting mortality.

METHODS

PRINCIPAL FINDINGS

Adult patients who initiated ART in Karonga District, northern Malawi, between September 2005 and August 2006 were included in a prospective cohort study, and followed for up to one year. We used Cox regression to examine the association between anthropometric changes at 2 and 6 weeks and deaths within the first year. 573 patients were included, of whom 59% were women; the median age at initiation was 37 and 64% were in WHO stage 4. Both body mass index (BMI) and mid-upper arm circumference (MUAC) increased linearly with increased time on ART, and were closely correlated with each other. There were 118 deaths. After 2 weeks on ART, a BMI increase of <0.5 kg/m(2) (HR 2.47, 95%CI 1.24-4.94, p=0.005) or a MUAC increase of <0.5cm (HR 2.79, 95%CI 1.19-6.55, p=0.008) were strong predictors of death, and these associations were stronger after adjusting for baseline charactertistics. Similar results were found after 6 weeks on ART.

CONCLUSIONS

Very early anthropometric changes, after 2 and 6 weeks on ART, are strong predictors of survival, independent of baseline characteristics. This should help identify patients requiring more detailed assessment where facilities are limited. MUAC is particularly valuable, requiring the simplest equipment and being appropriate for patients who have problems standing.

An inquiry into the uneven distribution of women's HIV infection in rural Malawi

Ecological comparisons in sub-Saharan Africa show that HIV prevalence is lower where men are generally circumcised than where they are not. Randomized controlled trials have found a 50-60% reduction in HIV acquisition for newly circumcised men. Yet in Malawi, HIV prevalence is highest in several districts in the Southern Region, where men are commonly circumcised. We draw upon a population-based sample of ever-married women to explore this unexpected finding. Our data show that in the southern district of Balaka, women with circumcised spouses have a lower probability of HIV infection compared to those with uncircumcised spouses. However, the strength of this effect is conditioned by specific marital histories: among women with circumcised spouses, those with multiple marriages and an absence of spousal co-residence have a higher probability of HIV infection than do those married once and those who have never lived apart from their spouses. The history of marital turnover and female-headed households among the ethnic groups of Balaka offer insight into the district's elevated HIV levels.

Tuberculosis in HIV voluntary counselling and testing centres in Dar es Salaam, Tanzania

The human immunodeficiency virus (HIV) has contributed to an increase in tuberculosis (TB) worldwide. HIV voluntary counselling and testing (VCT) centres are cost-effective for HIV screening. Therefore there is a potential of tapping into the success of VCT centres by incorporating TB screening. The aim of this study was to determine the extent of TB and TB/HIV co-infection among VCT centre attendees. We enrolled 1318 consecutive subjects from 2 VCT centres in Dar es Salaam. The diagnosis of TB was based on evidence of Mycobacterium tuberculosis in sputum or tissue aspirates following microscopy or culture. In the absence of M. tuberculosis, the presence of 2 of the following was considered: clinical features of TB, suggestive chest radiographs and response to anti-tuberculosis trial therapy. HIV was diagnosed in 347 (26%) subjects. TB was present in 101 (7.7%) subjects of whom 63 (62%) were diagnosed at VCT centres and 38 (38%) were known TB cases who came for HIV testing. Pulmonary TB (PTB) was detected in 52 (83%) subjects. The diagnosis of PTB was based on sputum culture in 35 (67%), sputum microscopy in 20 (38%), and clinical and radiological findings in 17 (33%) subjects. TB/HIV co-infection was detected in 70 (5.3%) subjects. PTB was common in stand-alone VCT centres. Therefore VCT centres could serve as an entry point for TB screening.

Gender, migration and HIV in rural KwaZulu-Natal, South Africa

Objectives

Research on migration and HIV has largely focused on male migration, often failing to measure HIV risks associated with migration for women. We aimed to establish whether associations between migration and HIV infection differ for women and men, and identify possible mechanisms by which women's migration contributes to their high infection risk.

Design

Data on socio-demographic characteristics, patterns of migration, sexual behavior and HIV infection status were obtained for a population of 11,677 women aged 15–49 and men aged 15–54, resident members of households within a demographic surveillance area participating in HIV surveillance in 2003–04.

Methods

Logistic regression was conducted to examine whether sex and migration were independently associated with HIV infection in three additive effects models, using measures of recent migration, household presence and migration frequency. Multiplicative effects models were fitted to explore whether the risk of HIV associated with migration differed for males and females. Further modeling and simulations explored whether composition or behavioral differences accounted for observed associations.

Results

Relative to non-migrant males, non-migrant females had higher odds of being HIV-positive (adjusted odds ratio [aOR] = 1.72; 95% confidence interval [1.49–1.99]), but odds were higher for female migrants (aOR = 2.55 [2.07–3.13]). Female migrants also had higher odds of infection relative to female non-migrants (aOR = 1.48 [1.23–1.77]). The association between number of sexual partners over the lifetime and HIV infection was modified by both sex and migrant status: For male non-migrants, each additional partner was associated with 3% higher odds of HIV infection (aOR = 1.03 [1.02–1.05]); for male migrants the association between number of partners and HIV infection was non-significant. Each additional partner increased odds of HIV infection by 22% for female non-migrants (aOR = 1.22 [1.12–1.32]) and 46% for female migrants (aOR = 1.46 [1.25–1.69]).

Conclusions

Higher risk sexual behavior in the context of migration increased women's likelihood of HIV infection.

Child mortality in rural Malawi: HIV closes the survival gap between the socio-economic strata

BACKGROUND

As HIV-related deaths increase in a population the usual association between low socioeconomic status and child mortality may change, particularly as death rates from other causes decline.

METHODS/PRINCIPAL FINDINGS

As part of a demographic surveillance system in northern Malawi in 2002-6, covering a population of 32,000, information was collected on socio-economic status of the households. Deaths were classified as HIV/AIDS-related or not by verbal autopsy. Poisson regression models were used to assess the association of socio-economic indicators with all-cause mortality, AIDS-mortality and non-AIDS mortality among children. There were 195 deaths in infants, 109 in children aged 1-4 years, and 38 in children aged 5-15. All-cause child mortality in infants and 1-4 year olds was similar in households with higher and lower socio-economic status. In infants 13% of deaths were attributed to AIDS, and there were no clear trends with socio-economic status for AIDS or non-AIDS causes. For 1-4 year olds 27% of deaths were attributed to AIDS. AIDS mortality was higher among those with better built houses, and lowest in those with income from farming and fishing, whereas non-AIDS mortality was higher in those with worse built houses, lowest in those with income from employment, and decreased with increasing household assets.

CONCLUSIONS/SIGNIFICANCE

In this population, since HIV infection among adults was initially more common among the less poor, childhood mortality patterns have changed. The usual gap in survival between the poor and the less poor has been lost, but because the less poor have been disproportionately affected by HIV, rather than because of relative improvement in the survival of the poorest.

Economic risk factors for HIV infection among women in rural Haiti: implications for HIV prevention policies and programs in resource-poor settings

AIMS

The goals of this study were to (1) estimate the prevalence of HIV infection among women accessing services at a women's health center in rural Haiti and (2) to identify economic risk factors for HIV infection in this population.

METHODS

Women who accessed healthcare services at this center between June 1999 and December 2002 were recruited to participate. The analysis was based on data from a case-control study of sexually transmitted diseases (STDs) in rural Haiti. HIV prevalence in the study population was 4%.

RESULTS

In multivariate analyses, partner occupation was associated with HIV infection in women, with mechanic (OR 9.0, 95% CI 1.8-45) and market vendor (OR 4.2, 95% CI 1.6-11) reflecting the strongest partner occupational risk factors. Partner's occupation as a farmer reduced the risk of infection in women by 60% (95% CI 0.14-1.1). Factors indicating low socioeconomic status (SES), such as food insecurity (OR 2.0, 95% CI 0.75-5.6) and using charcoal for cooking (OR 1.7, 95% CI 0.72-3.8) suggested an association with HIV infection.

CONCLUSIONS

Given pervasive gender inequality in Haiti, women's economic security often relies on their partners' income earning activities. Our findings show that although factors reflecting poverty are associated with HIV-positive status, stronger associations are observed for women whose partners indicated a more secure occupation (e.g., mechanic or market vendor). Policies and programs that expand access to education and economic opportunities for women and girls may have long-term implications for HIV prevention in Haiti and other resource-poor settings.

The Likoma Network Study: Context, data collection, and initial results

The extent and structure of sexual networks have important consequences for the spread of sexually transmitted diseases such as HIV. However, very few datasets currently exist that allow a detailed investigation of sexual networks in sub-Saharan African settings where HIV epidemics have become generalized. In this paper, we describe the context and methods of the Likoma Network Study (LNS), one of the few studies that have collected extensive information on sexual networks in sub-Saharan Africa. We start by reviewing theoretical arguments and empirical studies emphasizing the importance of network structures in the epidemiology of HIV and other sexually transmitted infections (STI). The island setting of this study is described, and we argue that the choice of an island as a research site limited potential biases that may make the collection of sexual network data difficult. We then document our empirical strategy for the collection of sexual network data and the subsequent identification of sexual network partners. A description of the protocol for the collection of biomarker data (HIV infection) is provided. Finally, we present initial results relating to the socioeconomic context of the island, the size and composition of sexual networks, the quality of the sexual network data, the determinants of successful contact tracing during the LNS, and the prevalence of HIV in the study population.

The condom divide: disenfranchisement of Malawi women by church and state

OBJECTIVE

To examine the impact of 2 mitigating social institutions, religious organizations, and the state, on Malawi women's vulnerability to HIV.

DESIGN

In-depth interviews with a purposive sample of 40 central leaders from 5 faith-based organizations in Malawi were recorded and transcribed as part of an on-going larger study. Qualitative description was used to identify themes and categories.

SETTING

Primarily urban and periurban areas of south-central Malawi.

PARTICIPANTS

A minimum of 6 leaders from each faith-based organization were interviewed; the mean age of the primarily male (68%) participants was 44 years (range 26-74).

RESULTS

Analysis of religious leaders' messages about HIV produced an overarching theme, the condom divide, which conceptualized the divergence between faith-based organizations and the state's prevention messages related to HIV prevention strategies.

CONCLUSION

Faith-based organizations have "demonized" state messages about condoms as promoting sin. The faith-based organizations' insistence on abstinence and faithfulness leaves women with few options to protect themselves. As socially conscious citizens of the world, nurses can increase the responsiveness to the disparate levels of suffering and death in countries like Malawi.

Socioeconomic status and HIV seroprevalence in Tanzania: a counterintuitive relationship

OBJECTIVE

To examine the relationship between multiple dimensions of socioeconomic status (SES) and HIV seroprevalence in Tanzania.

METHODS

Using a large nationally representative sample of 7515 sexually active adults drawn from the 2003-04 Tanzania HIV/AIDS Indicator Survey, we analysed the relationship between multiple SES measures and HIV seroprevalence using weighted logistic regression models.

RESULTS

In adjusted models, individuals in the highest quintile of standard of living had increased odds ratio (OR) of being HIV-positive (male: OR 2.38, 95% CI 1.17-4.82; female: OR 3.74, 95% CI 2.16-6.49). Occupational status was differentially associated with HIV in men and women; women in professional jobs had higher OR of being HIV-positive (OR 1.54, 95% CI 1.02-2.38), whereas unemployed men had higher risk of being HIV-positive (OR 3.49, 95% CI 1.43-8.58). No marked association was found between increasing education and HIV seroprevalence for men (P = 0.83) and women (P = 0.87).

CONCLUSION

Contrary to the prevailing perception that low SES individuals tend to be more vulnerable to HIV-infection, we found a positive association between standard of living and HIV-infection. Strategies aimed at reducing HIV-infection needs to be cognizant of the complex social heterogeneity in the patterns of HIV-infection.

Non-response bias in estimates of HIV prevalence due to the mobility of absentees in national population-based surveys: a study of nine national surveys

Objectives:

To measure the bias in national estimates of HIV prevalence in population-based surveys caused by mobility and refusal to test.

Methods:

Data from nine demographic and health surveys and AIDS indicator surveys were used. Non-responders were divided into three groups: (i) “refusals” who were interviewed but not tested; (ii) “refusals” who were present in the household but not interviewed or tested; and (iii) “absentees” who were absent from the household. Correction for HIV status was made for the non-responders using multiple imputation methods with logistic regression models based on a common set of household-level and individual-level sociodemographic and behavioural factors for those tested and stratified by mobility status.

Results:

The non-response groups were corrected to have higher risks of HIV than those who participated in the HIV tests, although these were only detected to be statistically significant in some of the countries. In Lesotho, the corrected prevalence for the absent household members was significantly higher than for those who were present in the household. However, the adjusted prevalences differed by less than a percentage point from the prevalences observed among those who were tested, so the overall effects of non-response on national estimates of HIV prevalence are minimal.

Conclusions:

The results indicate that the mobility of absentees does not substantially bias estimates of HIV prevalence from population-based surveys. None the less, if levels of non-response are high or if non-responders differ greatly from those who participate in HIV testing with respect to HIV status, non-response could still bias national estimates of HIV prevalence.

Uptake of HIV testing and outcomes within a Community-based Therapeutic Care (CTC) programme to treat severe acute malnutrition in Malawi: a descriptive study

BACKGROUND

In Malawi and other high HIV prevalence countries, studies suggest that more than 30% of all severely malnourished children admitted to inpatient nutrition rehabilitation units are HIV-infected. However, clinical algorithms designed to diagnose paediatric HIV are neither sensitive nor specific in severely malnourished children. The present study was conducted to assess : i) whether HIV testing can be integrated into Community-based Therapeutic Care (CTC); ii) to determine if CTC can improve the identification of HIV infected children; and iii) to assess the impact of CTC programmes on the rehabilitation of HIV-infected children with Severe Acute Malnutrition (SAM).

METHODS

This community-based cohort study was conducted in Dowa District, Central Malawi, a rural area 50 km from the capital, Lilongwe. Caregivers and children admitted in the Dowa CTC programme were prospectively (Prospective Cohort = PC) and retrospectively (Retrospective Cohort = RC) admitted into the study and offered HIV testing and counseling. Basic medical care and community nutrition rehabilitation was provided for children with SAM. The outcomes of interest were uptake of HIV testing, and recovery, relapse, and growth rates of HIV-positive and uninfected children in the CTC programme. Student's t-test and analysis of variance were used to compare means and Kruskall Wallis tests were used to compare medians. Dichotomous variables were compared using Chi2 analyses and Fisher's exact test. Stepwise logistic regression with backward elimination was used to identify predictors of HIV infection (alpha = 0.05).

RESULTS

1273 and 735 children were enrolled in the RC and PC. For the RC, the average age (SD) at CTC admission was 30.0 (17.2) months. For the PC, the average age at admission was 26.5 (13.7) months. Overall uptake of HIV testing was 60.7% for parents and 94% for children. HIV prevalence in severely malnourished children was 3%, much lower than anticipated. 59% of HIV-positive and 83% of HIV-negative children achieved discharge Weight-For-Height (WFH) > or = 80% of the NCHS reference median (p = 0.003). Clinical algorithms for diagnosing HIV in SAM children had poor sensitivity and specificity.

CONCLUSION

CTC is a potentially valuable entry point for providing HIV testing and care in the community to HIV infected children with SAM.

Use of antenatal clinic surveillance to assess the effect of sexual behavior on HIV prevalence in young women in Karonga district, Malawi

BACKGROUND

Antenatal clinic (ANC) surveillance is the primary source of HIV prevalence estimates in low-resource settings. In younger women, prevalence approximates incidence. Sexual behavior monitoring to explain HIV distribution and trends is seldom attempted in ANC surveys. We explore the use of marital history in ANC surveillance as a proxy for sexual behavior.

METHODS

Five ANC clinics in a rural African district participated in surveillance from 1999 to 2004. Unlinked anonymous HIV testing and marital history interviews (including age at first sex and socioeconomic variables) were conducted. Data on women aged <25 years were analyzed.

RESULTS

Inferred sexual exposure before marriage and after first marriage increased the adjusted odds of infection with HIV by more than 0.1 for each year of exposure. Increasing years within a first marriage did not increase HIV risk. After adjusting for age, women in more recent birth cohorts were less likely to be infected.

CONCLUSIONS

Marital status is useful behavioral information and can be collected in ANC surveys. Exposure in an ongoing first marriage did not increase the odds of infection with HIV in this age group. HIV prevalence decreased over time in young women. ANC surveillance programs should develop proxy sexual behavior questions, particularly in younger women.

Population-level effect of HIV on adult mortality and early evidence of reversal after introduction of antiretroviral therapy in Malawi

BACKGROUND

Malawi, which has about 80,000 deaths from AIDS every year, made free antiretroviral therapy available to more than 80 000 patients between 2004 and 2006. We aimed to investigate mortality in a population before and after the introduction of free antiretroviral therapy, and therefore to assess the effects of such programmes on survival at the population level.

METHODS

We used a demographic surveillance system to measure mortality in a population of 32,000 in northern Malawi, from August, 2002, when free antiretroviral therapy was not available in the study district, until February, 2006, 8 months after a clinic opened. Causes of death were established through verbal autopsies (retrospective interviews). Patients who registered for antiretroviral therapy at the clinic were identified and linked to the population under surveillance. Trends in mortality were analysed by age, sex, cause of death, and zone of residence.

FINDINGS

Before antiretroviral therapy became available in June, 2005, mortality in adults (aged 15-59 years) was 9.8 deaths for 1000 person-years of observation (95% CI 8.9-10.9). The probability of dying between the ages of 15 and 60 years was 43% (39-49) for men and 43% (38-47) for women; 229 of 352 deaths (65.1%) were attributed to AIDS. 8 months after the clinic that provided antiretroviral therapy opened, 107 adults from the study population had accessed treatment, out of an estimated 334 in need of treatment. Overall mortality in adults had decreased by 10% from 10.2 to 8.7 deaths for 1000 person-years of observation (adjusted rate ratio 0.90, 95% CI 0.70-1.14). Mortality was reduced by 35% (adjusted rate ratio 0.65, 0.46-0.92) in adults near the main road, where mortality before antiretroviral therapy was highest (from 13.2 to 8.5 deaths per 1000 person-years of observation before and after antiretroviral therapy). Mortality in adults aged 60 years or older did not change.

INTERPRETATION

Our findings of a reduction in mortality in adults aged between 15 and 59 years, with no change in those older than 60 years, suggests that deaths from AIDS were averted by the rapid scale-up of free antiretroviral therapy in rural Malawi, which led to a decline in adult mortality that was detectable at the population level.

Systematic review exploring time trends in the association between educational attainment and risk of HIV infection in sub-Saharan Africa

OBJECTIVE

To assess the evidence that the association between educational attainment and risk of HIV infection is changing over time in sub-Saharan Africa.

DESIGN AND METHODS

Systematic review of published peer-reviewed articles. Articles were identified that reported original data comparing individually measured educational attainment and HIV status among at least 300 individuals representative of the general population of countries or regions of sub-Saharan Africa. Statistical analyses were required to adjust for potential confounders but not over-adjust for variables on the causal pathway.

RESULTS

Approximately 4000 abstracts and 1200 full papers were reviewed. Thirty-six articles were included in the study, containing data on 72 discrete populations from 11 countries between 1987 and 2003, representing over 200,000 individuals. Studies on data collected prior to 1996 generally found either no association or the highest risk of HIV infection among the most educated. Studies conducted from 1996 onwards were more likely to find a lower risk of HIV infection among the most educated. Where data over time were available, HIV prevalence fell more consistently among highly educated groups than among less educated groups, in whom HIV prevalence sometimes rose while overall population prevalence was falling. In several populations, associations suggesting greater HIV risk in the more educated at earlier time points were replaced by weaker associations later.

DISCUSSION

HIV infections appear to be shifting towards higher prevalence among the least educated in sub-Saharan Africa, reversing previous patterns. Policy responses that ensure HIV-prevention measures reach all strata of society and increase education levels are urgently needed.

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.

Explaining continued high HIV prevalence in South Africa: socioeconomic factors, HIV incidence and sexual behaviour change among a rural cohort, 2001-2004

OBJECTIVES

To estimate HIV incidence and explore evidence for changing sexual behaviour over time among men and women belonging to different socioeconomic groups in rural South Africa.

DESIGN AND METHODS

A cohort study conducted between 2001 and 2004; 3881 individuals aged 14-35 years enumerated in eight villages were eligible. At least three household visits were made to contact each eligible respondent at both timepoints. Sexual behaviour data were collected in structured, respondent-focused interviews. HIV serostatus was assessed using an oral fluid enzyme-linked immunosorbent assay at each timepoint.

RESULTS

Data on sexual behaviour were available from 1967 individuals at both timepoints. A total of 1286 HIV-negative individuals at baseline contributed to the analysis of incidence. HIV incidence was 2.2/100 person-years among men and 4.9/100 person-years in women, among whom it was highest in the least educated group. Median age at first sex was lower among later birth cohorts. A higher number of previously sexually active individuals reported having multiple partners in the past year in 2004 than 2001. Condom use with non-spousal partners increased from 2001 to 2004. Migrant men more often reported multiple partners. Migrant and more educated individuals of both sexes and women from wealthier households reported higher levels of condom use.

DISCUSSION

HIV incidence is high in rural South Africa, particularly among women of low education. Some risky sexual behaviours (early sexual debut, having multiple sexual partners) are becoming more common over time. Condom use is increasing. Existing HIV prevention strategies have only been partly effective in generating population-level behavioural change.

HIV epidemic trend and antiretroviral treatment need in Karonga District, Malawi

We describe the development of the HIV epidemic in Karonga District, Malawi over 22 years using data from population surveys and community samples. These data are used to estimate the trend in HIV prevalence, incidence and need for antiretroviral treatment (ART) using a simple mathematical model. HIV prevalence rose quickly in the late 1980s and early 1990s, stabilizing at around 12% in the mid-1990s. Estimated annual HIV incidence rose quickly, peaking in the early 1990s at 2.2% among males and 3.1% among females, and then levelled off at 1.3% among males and 1.1% among females by the late 1990s. Assuming a 2-year eligibility period, both our model and the UNAIDS models predicted 2.1% of adults were in need of ART in 2005. This prediction was sensitive to the assumed eligibility period, ranging from 1.6% to 2.6% if the eligibility period was instead assumed to be 1.5 or 2.5 years, respectively.

Population and antenatal-based HIV prevalence estimates in a high contracepting female population in rural South Africa

Background

To present and compare population-based and antenatal-care (ANC) sentinel surveillance HIV prevalence estimates among women in a rural South African population where both provision of ANC services and family planning is prevalent and fertility is declining. With a need, in such settings, to understand how to appropriately adjust ANC sentinel surveillance estimates to represent HIV prevalence in general populations, and with evidence of possible biases inherent to both surveillance systems, we explore differences between the two systems. There is particular emphasis on unrepresentative selection of ANC clinics and unrepresentative testing in the population.

Methods

HIV sero-prevalence amongst blood samples collected from women consenting to test during the 2005 annual longitudinal population-based serological survey was compared to anonymous unlinked HIV sero-prevalence amongst women attending antenatal care (ANC) first visits in six clinics (January to May 2005). Both surveillance systems were conducted as part of the Africa Centre Demographic Information System.

Results

Population-based HIV prevalence estimates for all women (25.2%) and pregnant women (23.7%) were significantly lower than that for ANC attendees (37.7%). A large proportion of women attending urban or peri-urban clinics would be predicted to be resident within rural areas. Although overall estimates remained significantly different, presenting and standardising estimates by age and location (clinic for ANC-based estimates and individual-residence for population-based estimates) made some group-specific estimates from the two surveillance systems more predictive of one another.

Conclusion

It is likely that where ANC coverage and contraceptive use is widespread and fertility is low, population-based surveillance under-estimates HIV prevalence due to unrepresentative testing by age, residence and also probably by HIV status, and that ANC sentinel surveillance over-estimates prevalence due to selection bias in terms of age of sexual debut and contraceptive use. The results presented highlight the importance of accounting for unrepresentative testing, particularly by individual residence and age, through system design and statistical analyses.

Quantifying HIV-1 transmission due to contaminated injections

Assessments of the importance of different routes of HIV-1 (HIV) transmission are vital for prioritization of control efforts. Lack of consistent direct data and large uncertainty in the risk of HIV transmission from HIV-contaminated injections has made quantifying the proportion of transmission caused by contaminated injections in sub-Saharan Africa difficult and unavoidably subjective. Depending on the risk assumed, estimates have ranged from 2.5% to 30% or more. We present a method based on an age-structured transmission model that allows the relative contribution of HIV-contaminated injections, and other routes of HIV transmission, to be robustly estimated, both fully quantifying and substantially reducing the associated uncertainty. To do this, we adopt a Bayesian perspective, and show how prior beliefs regarding the safety of injections and the proportion of HIV incidence due to contaminated injections should, in many cases, be substantially modified in light of age-stratified incidence and injection data, resulting in improved (posterior) estimates. Applying the method to data from rural southwest Uganda, we show that the highest estimates of the proportion of incidence due to injections are reduced from 15.5% (95% credible interval) (0.7%, 44.9%) to 5.2% (0.5%, 17.0%) if random mixing is assumed, and from 14.6% (0.7%, 42.5%) to 11.8% (1.2%, 32.5%) under assortative mixing. Lower, and more widely accepted, estimates remain largely unchanged, between 1% and 3% (0.1-6.3%). Although important uncertainty remains, our analysis shows that in rural Uganda, contaminated injections are unlikely to account for a large proportion of HIV incidence. This result is likely to be generalizable to many other populations in sub-Saharan Africa.

A high prevalence of HIV-1 infection among pregnant women living in a rural district of north Uganda severely affected by civil strife

This study aims at estimating the recent trends in HIV-1 prevalence and the factors associated with infection among pregnant women in the Gulu District of north Uganda, a rural area severely affected by civil strife. In 2000-2003, a total of 4459 antenatal clinic attendees of Lacor Hospital were anonymously tested for HIV-1 infection. The overall and age-specific prevalence did not show any significant trend over time. The age-standardized prevalence slightly declined, from 12.1% in 2000 to 11.3% in 2003. Increased age [20-24 years: adjusted odds ratio (AOR) 1.63; 95% CI 1.18-2.25; >or=25 years: AOR 2.56; 95% CI 1.91-3.44], residence in urban areas (AOR 1.76; 95% CI 1.41-2.18), being unmarried (AOR 1.60; 95% CI 1.27-2.01), increased age of partner (25-34 years: AOR 1.87; 95% CI 1.29-2.73; >or=35 years: AOR 2.68; 95% CI 1.72-4.16), modern occupation of partner (AOR 1.98; 95% CI 1.53-2.58), and short time of residence at the current address (AOR 1.36; 95% CI 1.05-1.76) were associated with infection. The HIV-1 prevalence in this rural district is high and similar to that observed in urban antenatal clinics, probably reflecting the effect of the last 18 years of civil strife.

Emergence of a three codon deletion in gag p17 in HIV type 1 subtype C long-term survivors, and general population spread

In a population-based study in northern Malawi we investigated HIV-1 subtype C gag and env gene sequences associated with long-term survival. DNA samples were available from 31 individuals surviving between population surveys carried out in the 1980s and 1990s. Most survivors with paired sequences dating from the 1980s and the 1990s had a three codon deletion in the gag p17 region of the sequence retrieved from the sample collected in the 1990s that was not present in the sequence from the same individual dating from the 1980s. This deletion was also not present in any other 1980s sequences from Malawi, but was common in samples collected in Malawi in the 1990s. The deletion is equivalent to the loss of three amino acids in the D helix region of the gag protein, and may be associated with longer survival and onward transmission.

Changing association between schooling levels and HIV-1 infection over 11 years in a rural population cohort in south-west Uganda

BACKGROUND

Previous studies have found that in Africa, a greater risk of HIV infection is often found in groups with higher educational attainment. However, some serial cross-sectional studies have found greater reductions in HIV prevalence among more educated groups, especially in cohorts of young adults. More recent studies have found some instances where higher schooling levels are associated with lower HIV prevalence.

METHODS

We describe changes in the association between schooling levels, HIV prevalence and condom use in a rural population-based cohort between 1989/1990 and 1999/2000, in Masaka District, Uganda.

RESULTS

In 1989-1990, higher educational attainment was associated with higher risk of HIV-1 infection, especially among males, but once odds ratios are adjusted for age, no significant relation between schooling and HIV infection remains. In 1999-2000, there is, for females aged 18-29 years, a significant relationship between higher educational attainment and lower HIV prevalence, even after adjustment for age, gender, marital status and wealth (P for trend 0.01). Tests for interaction, significant for males and both genders combined, show that more schooling has been shifting towards an association with less HIV infection between 1989-1990 and 1999-2000, especially for young individuals. Condom use increased during the study period and this increase has been concentrated among more educated individuals.

CONCLUSIONS

These findings suggest that over a decade more educated young adults, especially females, have become more likely to respond to HIV/AIDS information and prevention campaigns by effectively reducing their sexual risk behaviour.

Patterns of movement and risk of HIV infection in rural Zimbabwe

BACKGROUND

High rates of population movement may have helped spread human immunodeficiency virus (HIV) in southern Africa, including Zimbabwe, but whether mobility continues to influence the epidemic is unclear.

METHODS

The relationship between movement, risk behaviors, and prevalence of HIV was assessed from a general population survey of >9800 adults in 12 rural communities in Manicaland province in eastern Zimbabwe.

RESULTS

HIV prevalence varied with socioeconomic development. In community centers, prevalence among women was 49.9% (95% confidence interval [CI], 46.1%-53.6%), compared with 24.7% (95% CI, 22.6%-26.7%) in the least-developed subsistence-farming areas. Mobility was not associated with risk of HIV infection, except for those who migrated between rural locations. Among migrant agricultural workers, prevalence was 38.8% (95% CI, 33.1%-44.6%) for women and 26.4% (95% CI, 23.8%-28.9%) for men, compared with 29.7% (95% CI, 28.3%-31.1%) and 20.9% (95% CI, 19.3%-22.4%) for other sexually active women and men, respectively. Risk was increased if an individual traveled to Harare in the last month, without their spouse, but this risk was not transferred to the partner.

CONCLUSION

Rural-urban migration does not appear to be responsible for maintaining the high HIV prevalence in rural Zimbabwe, but rates of HIV infection may be affected by rural-rural migration.

Donkey Work: Women, Religion, and HIV/AIDS in Malawi

Addressed in this article are the familial, cultural and religious influences on Malawi women that contribute to HIV/AIDS. Thirty-nine adult Malawi women representing voluntary assistance groups, religious groups, and university women participated in 3 focus groups in Malawi. Interview data were taped, transcribed, and analyzed using qualitative descriptive analysis. Findings revealed that multiple burdens in the lives of Malawi women resulting from poverty and responsibility for family members are made more onerous by religious institutions, sexual practices, and cultural beliefs. In conclusion, women's "donkey work" may result in at-risk sexual behavior as a means of survival, thus increasing the incidence of HIV/AIDS. Alleviating the burdens involves efforts from religious groups and restructuring of belief systems.

Timing and reconstruction of the most recent common ancestor of the subtype C clade of human immunodeficiency virus type 1

Human immunodeficiency virus type 1 (HIV-1) subtype C is responsible for more than 55% of HIV-1 infections worldwide. When this subtype first emerged is unknown. We have analyzed all available gag (p17 and p24) and env (C2-V3) subtype C sequences with known sampling dates, which ranged from 1983 to 2000. The majority of these sequences come from the Karonga District in Malawi and include some of the earliest known subtype C sequences. Linear regression analyses of sequence divergence estimates (with four different approaches) were plotted against sample year to estimate the year in which there was zero divergence from the reconstructed ancestral sequence. Here we suggest that the most recent common ancestor of subtype C appeared in the mid- to late 1960s. Sensitivity analyses, by which possible biases due to oversampling from one district were explored, gave very similar estimates.

Does increased general schooling protect against HIV infection? A study in four African cities

BACKGROUND

The association between educational attainment and risk of HIV infection varies between populations and over time. Earlier studies in sub-Saharan Africa have found that those with more education are at increased risk of HIV infection.

METHODS

We investigated the associations between general schooling and both HIV and herpes simplex-2 (HSV-2) infection using data from the multicentre study on factors determining the differential spread of HIV in four African cities. Cross-sectional general population studies were conducted in 1997-1998 in Cotonou (Benin), Yaoundé (Cameroon), Kisumu (Kenya), and Ndola (Zambia), including about 2000 adults in each city.

RESULTS

There was no association between schooling and HIV infection in men or women in Kisumu or Ndola. Women in Yaoundé and men in Cotonou, with more schooling, were less likely to be HIV positive. These associations persisted after adjusting for sociodemographic factors. Similar trends in men in Yaoundé and women in Cotonou were not statistically significant. Increased schooling was associated with significantly decreased risk of HSV-2 infection in women in Kisumu and Ndola and men in Cotonou. In all the cities those with more education tended to report less risky sexual behaviour.

CONCLUSIONS

There was no evidence of an increased risk of HIV infection associated with education as seen in earlier studies. In each city there was some evidence of lower HIV or HSV-2 infection rates and less risky sexual behaviour associated with increased education levels. The most educated may be responding more readily to health education programmes. The challenge is to extend this to the rest of the population.

Transmission of HIV-1 infection in sub-Saharan Africa and effect of elimination of unsafe injections

During the past year, a group has argued that unsafe injections are a major if not the main mode of HIV-1 transmission in sub-Saharan Africa. We review the main arguments used to question the epidemiological interpretations on the lead role of unsafe sex in HIV-1 transmission, and conclude there is no compelling evidence that unsafe injections are a predominant mode of HIV-1 transmission in sub-Saharan Africa. Conversely, though there is a clear need to eliminate all unsafe injections, epidemiological evidence indicates that sexual transmission continues to be by far the major mode of spread of HIV-1 in the region. Increased efforts are needed to reduce sexual transmission of HIV-1.

Spatial bridges for the importation of gonorrhea and chlamydial infection

A study of heterosexuals with gonorrhea and/or chlamydial infection in King County, Washington, found that 5.2% of study participants had both local and geographically distant sex partners in the 60 days before diagnosis. Individuals who served as spatial bridges were of higher socioeconomic status and older than other patients.

BACKGROUND

Sexual mixing between distant geographic areas (spatial bridging) is important in the spread of antimicrobial resistance and new sexually transmitted disease pathogens.

GOAL

The goal was to define the extent of sexual mixing between persons with gonorrhea or chlamydial infection in King County, Washington, and persons outside the Seattle area, and to identify characteristics of persons and partnerships associated with spatial bridging.

METHODS

Patients contacted for purposes of partner notification were interviewed regarding demographics, sexual behavior, and the characteristics of their sex partners.

RESULTS

Of 2912 participants, 150 (5.2%) were spatial bridgers. Bridgers were of higher socioeconomic status than nonbridgers and more often reported concurrent partnerships. Over a 39-month period, bridgers and potential bridgers linked King County with 35 states and 13 foreign countries.

CONCLUSION

Spatial bridging could represent an important channel of transmission between geographic areas. These results highlight the need for linkage of prevention efforts across geographic boundaries.