The Epidemic of Covid-19 in Africa: Demographic Effect, Under-Reporting of Cases, Dynamical Complexity and Mitigation Strategies Impact

Background: The epidemic of Covid-19 has shown a different development in Africa in comparison with the other continents. The reasons for this remain unclear. Methods: Basic statistics are first applied to estimate the contributions of the elder people and the health systems capacities on the total numbers of cases and deaths. Differential equations are then reconstructed from the observational time series in order to analyse the dynamics of Covid-19 at the countries scale. The contact number is estimated as a function of time for a selection of seventeen African countries to investigate the effectiveness of the mitigation strategies. Findings: Taking into account the health systems capacity and the proportion of elder people enables to reduce considerably the differences of Covid-19 number of cases and death observed between Africa and Europe. The global modelling technique reveals the dynamical complexity of the epidemics: the dynamics is geographically very diversified, and in many contexts – strictly speaking – chaotic including situations of bistability. The time evolution of the contact number reveals a relatively poor comparison with the strength of control measures in place. Interpretation: The lower proportion of elder people in Africa enables to explain the lower total numbers of cases and deaths by 20.0 times on average (from 7.4 to 31) and corresponds to a real effect. Covid-19 numbers are however largely underestimated in Africa by a factor of 8.5 on average (from 1.6 to 55) due to the weakness of the health systems at country level. Although the dynamics of COVID-19 can be reasonably approximated by few variables, its dynamics is proven to be highly unpredictable on the long term. The analysis of the obtained models evidence very diversified dynamics. The efficiency of the mitigation strategy is confirmed only in a few countries. Funding Information: This work was supported by the French programs Fonds d’Urgence Muse (Montpellier Universite d’Excellence), Les Enveloppes Fluides et l’Environnement (CNRS-INSU), Defi Infinity (CNRS) and Programme National de Teledetection Spatiale (CNRS-INSU). Declaration of Interests: None to declare.