Towards predicting daily national COVID-19 confirmed cases in Africa using selected weather and environmental parameters

Abstract

The contribution of weather and environmental factors (WEF) to the increase in daily confirmed cases of coronavirus disease 2019 (COVID-19) is not fully understood. This study focused on the influence of average national daytime temperature (^oC), night-time temperature (^oC), daytime relative humidity (%), night-time relative humidity (%), Ultraviolet index at noon, Aerosol Optical Depth and volumetric soil moisture (%) on the COVID-19 cases. Daily national COVID-19 data was obtained from Datopian of the total number of confirmed COVID-19 cases reported in Kenya, Ethiopia, Ghana, Nigeria, South Africa and Egypt. Daily COVID-19 data for the period 1st March 2020 and 31st July 2020 were compared with each of the six countries’ WEF. National area average time-series of the atmospheric parameters, using data from National Aeronautics and Space Administration (NASA) Giovanni website, were generated by computing spatial averages over the given variable for each country. Incubation period of COVID-19 ranged from 1- 14 days. Therefore, the effects of each parameter within 1, 5, and 14 days were examined. The analyses were conducted based on Pearson correlation coefficient. Generally, a marked heterogeneity of relationships of factors assessed was evident among the countries. Highest positive correlation was observed for Ultraviolet index 14 days earlier (r=0.852, p=0.000), while negative correlations were observed for daytime temperature 5 days earlier (r = -0.840, p=0.000), and on the day (r= -0.869, p=0.000), respectively. Generally night-time temperatures favored COVID-19 transmission more that daytime temperatures. Nigeria depicted relatively the highest sensitivity to weather and environmental factors. These findings may prove foundational in evolving predictive potential of COVID-19 transmission using weather and environmental factors.