Estimating Population Viral Load Contextual Exposure Using GPS-Derived Activity Spaces in Rural South Africa

Zhaoxing Wu; Haoyang Wu; Thulile Mathenjwa; Elphas Okango; Khai Hoan Tram; Margot Otto; Maxime Inghels; Paul Mee; Diego Cuadros; Hae-Young Kim; Till Bärnighausen; Frank Tanser; Adrian Dobra

arXiv · 2604.27338

Estimating Population Viral Load Contextual Exposure Using GPS-Derived Activity Spaces in Rural South Africa

Zhaoxing Wu·Haoyang Wu·Thulile Mathenjwa·Elphas Okango·Khai Hoan Tram·Margot Otto·Maxime Inghels·Paul Mee·Diego Cuadros·Hae-Young Kim·Till Bärnighausen·Frank Tanser·Adrian Dobra

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Abstract

This article introduces novel methodologies for estimating contextual exposure to HIV population viral load using GPS data. We propose a comprehensive analytical framework comprising (i) local (grid-cell level) estimation of HIV population viral load, (ii) derivation of individual activity spaces from GPS trajectories, and (iii) quantification of contextual exposure to HIV within these activity spaces. We integrate HIV surveillance and sociodemographic survey data with GPS-based mobility data collected in rural KwaZulu-Natal, South Africa, to characterize mobility patterns among young adults aged 20-30 years. Using derived measures of mobility and contextual exposure, we assess whether participants' sex and age systematically influence the magnitude, configuration, and heterogeneity of their mobility patterns. Furthermore, we describe analytical approaches to examine how contextual exposure to HIV evolves as activity spaces extend beyond static residential locations, outlining procedures to identify GPS-tracked participants at elevated risk of HIV acquisition. KEYWORDS: Population viral load exposure; GPS-based mobility analysis; Activity space

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Zhaoxing Wu, Haoyang Wu, Thulile Mathenjwa, Elphas Okango, Khai Hoan Tram, Margot Otto, Maxime Inghels, Paul Mee, Diego Cuadros, Hae-Young Kim, Till Bärnighausen, Frank Tanser, Adrian Dobra. 2026-04-30. Estimating Population Viral Load Contextual Exposure Using GPS-Derived Activity Spaces in Rural South Africa. https://arxiv.org/abs/2604.27338

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