Spatio-temporal modelling of COVID-19 infection and associated risk factors in Dakar, Senegal

The spread of infectious diseases is a major threat to global health and economy and the recent COVID-19 pandemic is a perfect illustration of this. Appropriately modelling and accurate prediction of the outcome of disease spread over time and across space is a critical step towards informed development of effective strategies for public health interventions. In low and middle-income countries, however, the scarcity of spatially disaggregated time-series infectious diseases data often limits the analysis of the burden of infectious disease at a broad-scale, and the effects of the contextual risk factors is not often fully captured. In this study, we investigate the spatiotemporal patterns of COVID-19 infection in Dakar at the neighbourhood level, and evaluate the impact of potential risk factors. Geostatistical models based on COVID-19 infection were used to explain and predict the spatiotemporal distribution of COVID-19 infection between June 2020 and June 2021. We specified a Bayesian regression model that incorporates a spatio-temporally autocorrelated random effect in order to quantify the evolution of the spatial patterns of the COVID-19 infection overtime. Results show significant strong spatial heterogeneity but relatively small temporal variations of the COVID 19 distribution, and a positive association between adjusted population density (mean of the posterior probability: 0.29, credible interval: 0.24-0.34) and residential areas (mean of the posterior probability: 1.25, credible interval: 0.66-1.83) with COVID-19 infection. Western areas are at higher risk of COVID-19 infection compared to eastern and less densely populated peripheral neighbourhoods. Measuring the role of contextual risk factors and mapping the at-risk areas can provide valuable insights for policymakers in low- and middle-income countries, enabling more targeted public health interventions. These efforts also support the management of endemic diseases and preparedness for future outbreaks.