Brief Report

Palk, Laurence; Blower, Sally

doi:10.1097/qai.0000000000000526

Cited by 27 publications

(19 citation statements)

References 21 publications

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“…Temporary migration in Lesotho is related to employment; there is circular migration within the country to work in agriculture or the textile industry, and cross-border migration to work in the mines in South Africa. Previous studies of Lesotho have shown that (on average) residents who travel have higher numbers of sex partners than those who do not, and men who travel frequently have an increased risk of HIV infection (17). Permanent migration may also have facilitated the spatial diffusion of HIV.…”

Section: Discussionmentioning

confidence: 99%

Using geospatial mapping to design HIV elimination strategies for sub-Saharan Africa

Coburn

Blower

2017

Sci. Transl. Med.

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UNAIDS, and the WHO, plan to use “treatment as prevention” (TasP) to eliminate HIV. The rationale is that treating HIV-infected individuals reduces their infectivity. We present a novel geostatistical framework for implementing the rollout of TasP in sub-Saharan Africa. We focus on Lesotho, because UNAIDS has identified their epidemic as a priority for elimination. Our framework is based on a density of infection (DoI) map that we generate by gridding high-resolution demographic data, and spatially smoothing georeferenced HIV-testing data. The map reveals the geographic dispersion pattern of HIV-infected individuals, both diagnosed and undiagnosed. We use the map to design a treatment allocation strategy that optimizes, under resource constraints, the efficiency of resource utilization. Using this strategy (rather than the current treatment allocation strategy) would make it easier to find, diagnose and treat individuals. We also use our framework to evaluate the feasibility of UNAIDS’ elimination plan. We show the feasibility of reaching specific treatment coverage levels depends upon the geographic dispersion pattern of HIV-infected individuals, and that this pattern reflects the spatial demographics of Lesotho. Only 20% of HIV-infected individuals live in urban areas; most live in rural settlements where the DoI is less than six infected individuals/km2. Given these conditions, it will be almost impossible to reach a very high coverage of treatment. Therefore, the UNAIDS elimination plan is unlikely to succeed in Lesotho. Taken together, our results show that the spatial demographics of populations will significantly hinder, and may even prevent, the elimination of HIV in sub-Saharan Africa.

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Section: Discussionmentioning

confidence: 99%

Using geospatial mapping to design HIV elimination strategies for sub-Saharan Africa

Coburn

Blower

2017

Sci. Transl. Med.

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“…There may be a high risk of cross border importation of HIV infections from South Africa into the specific areas on the border that we have identified. Our previous research found travel was associated with an increased risk of HIV infection for men who traveled frequently 14 . Therefore these regions may be particularly suitable for interventions that target migrant workers and discordant couples; notably, there is a high level of discordancy (14%) in Lesotho 24 .…”

Section: Discussionmentioning

confidence: 92%

“…Individuals who change residency, either on a permanent or temporary basis, often maintain links with their home communities; this linkage can connect localized HIV epidemics 3 . Previous research has focused on individuals who travel, finding an association between mobility and increased sexual behavior, and between mobility and risk of HIV infection 4 5 6 7 8 9 10 11 12 13 14 . The effect of couple separation on the partner who stays at home and does not travel has received little attention; specifically, it is not known whether a partners’ absence increases the likelihood of having extramarital partners and subsequently the risk of HIV infection.…”

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confidence: 99%

Mapping divided households and residency changes: the effect of couple separation on sexual behavior and risk of HIV infection

Palk¹,

Blower

2015

Sci Rep

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Using census data we identify geographic patterns in residency changes in Lesotho over a decade. Using kriging to spatially interpolate data from 8,510 households we identify regions where households have members temporarily living away from home (divided households). Further, using a multivariate analysis and data from 2,026 couples we determine whether a partners’ absence increases the likelihood of having extramarital partners and/or risk of HIV infection. Approximately 40% of individuals moved between 2001 and 2011; mainly to, and within, urbanized regions. Many households are divided: ~40% have members elsewhere in Lesotho, ~30% in South Africa (SA). Geographic patterns are apparent; they differ based on where the household member is living. Many couples were temporarily separated: ~50% of wives, ~20% of husbands. Separation was not a risk factor for HIV. Only men were more likely to have extramarital partners if their spouse was away: ~1.5 times if in Lesotho, ~3 times if in SA. The high degree of geographic mixing necessitates synchronizing interventions within Lesotho, and with SA, to successfully reduce transmission. It will be challenging to reduce concurrency in men with wives away from home. Our results are generalizable to other sub-Saharan countries where residency changes are common.

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“…Whilst these may appear obvious factors to include, statistical work continues to focus predominantly on the correlation between sexual behaviours and HIV prevalence and abstract categories of mobility (McGrath, et al, 2015;Palk and Blower 2015).…”

Section: Discussionmentioning

confidence: 99%

“…Whilst population mobility has played an important role in the historical spatial spread of the disease (Iliffe, 2006), linking geographically separate epidemics (Caldwell, Anarfi, & Caldwell, 1997;Tanser, Lesueur, Solarsh, & Wilkinson, 2000), current thinking within the health literature sees migrants as populations that are vulnerable to infection, engaging in higher levels of risky sexual behaviours than those who remain at home ( McGrath, Eaton, Newell and Hosegood 2015;Palk and Blower 2015;Schulyer et al, 2015). The standard narrative is that mobile individuals have sex while they are away from home for a range of reasons that include being separated temporarily from their spouses, and the enhanced opportunities for extra-marital sex that being away from home brings, and on return home transmit the virus to spouses or partners that have stayed behind (Deane, Johnston & Parkhurst 2013;Weine & Kashuba, 2012).…”

Section: Introductionmentioning

confidence: 99%

Exploring the relationship between population mobility and HIV risk: Evidence from Tanzania

Deane

Ngalya

Boniface

et al. 2016

Global Public Health

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Migration and population mobility has long been regarded as an important structural driver of HIV. Following initial concerns regarding the spatial spread of the disease, mobile populations are viewed to engage in higher levels of risky sexual behaviours than non-mobile groups. However, beyond the case studies of mineworkers and truck drivers, the statistical evidence is inconclusive, suggesting that the relationship between mobility and risk is not well understood. This study investigated how engaging in specific livelihoods that involve mobility influences sexual behaviour and HIV risk. A qualitative research project, including focus groups and in-depth interviews with key mobile groups, was conducted in Northern Tanzania. The findings show that the patterns and conditions of moving related to the requirements of each different economic activity influence the nature of relationships that mobile groups have whilst away, how and where local sexual networks are accessed, and the practicalities of having sex. This has further implications for condom use. Risk behaviours are also shaped by local sexual norms related to transactional sex, emphasising that the roles of mobility and gender are interrelated, overlapping, and difficult to disentangle.

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Brief Report

Cited by 27 publications

References 21 publications

Using geospatial mapping to design HIV elimination strategies for sub-Saharan Africa

Using geospatial mapping to design HIV elimination strategies for sub-Saharan Africa

Mapping divided households and residency changes: the effect of couple separation on sexual behavior and risk of HIV infection

Exploring the relationship between population mobility and HIV risk: Evidence from Tanzania

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