Spatiotemporal dynamics of epidemiology diseases: mobility based risk and short-term prediction modeling of COVID-19

Abstract

Nowadays, epidemiological modeling is applied to a wide range of diseases, communicable and non-communicable, namely AIDS, Ebola, influenza, Dengue, Malaria, Zika. More recently, in the context of the last pandemic declared by the World Health Organization (WHO), several studies applied these models to SARS-CoV-2. Despite the increasing number of researches using spatial analysis, some constraints persist that prevent more complex modeling such as capturing local epidemiological dynamics or capturing the real patterns and dynamics. For example, the unavailability of: (i) epidemiological information such as the frequency with which it is made available; (ii) sociodemographic and environmental factors (e.g., population density and population mobility) at a finer scale which influence the evolution patterns of infectious diseases; or (iii) the number of cases information that is also very dependent on the degree of testing performed, often with severe territorial disparities and influenced by context factors. Moreover, the delay in case reporting and the lack of quality control in epidemiological information is responsible for biases in the data that lead to many results obtained being subject to the ecological fallacy, making it difficult to identify causal relationships. Other important methodological limitations are the control of spatiotemporal dependence, management of non-linearity, ergodicy, among others, which can impute inconsistencies to the results. In addition to these issues, social contact, is still difficult to quantify in order to be incorporated into modeling processes. This study aims to explore a modeling framework that can overcome some of these modeling methodological limitations to allow more accurate modeling of epidemiological diseases. Based on Geographic Information Systems (GIS) and spatial analysis, our model is developed to identify group of municipalities where population density (vulnerability) has a stronger relationship with incidence (hazard) and commuting movements (exposure). Specifically, our framework shows how to operate a model over data with no clear trend or seasonal pattern which is suitable for a short-term predicting (i.e., forecasting) of cases based on few determinants. Our tested models provide a good alternative for when explanatory data is few and the time component is not available, once they have shown a good fit and good short-term forecast ability.

Keywords: ergodic; forecasting; mobility; non-linearity; risk; simple exponential smoothing.

Figure 1

Context of Mainland Portugal in Europe.

Figure 2

Percentage of inhabitants working outside the municipality (A) and average commuting time (B).

Figure 3

Home work/school commuting.

Figure 4

Methodological workflow scheme.

Figure 5

Density probability of the number of SARS-CoV-2 infected cases by commuting movements in the human health and social support sector (A), the construction sector (B), the public administration and defense sector (C) and the students sector (D).

Figure 6

Risk of SARS-CoV-2 infections considering existing cases, population density and commuting movements in the human health and social support sector (A), the construction sector (B), the public administration and defense sector (C) and the students sector (D).

Figure 7

Global model scheme.

Figure 8

Regional model forecast for two municipalities of MAP and two of MAL.