Many SARS-CoV-2 variants have appeared over the last months, and many more
will continue to appear. Understanding the competition between these different vari-
ants could help make future predictions on the evolution of epidemics. In this talk
we will present our study which use a mathematical compartmental model to investi-
gate the impact of three different SARS-CoV-2 variants on the spread of COVID-19
across France. between Januarv-Mav 2021 (before vaccination was extended to the
full population). To this end, we use the data from Geodes (produced by Public
Health France) and a particle swarm optimisation algorithm, to estimate the model
parameters and further calculate a value for the basic reproduction number RO.
Sensitivity and uncertainty analysis is then used to better understand the impact
of estimated parameter values on the number of infections leading to both symp-
tomatic and asymptomatic individuals. The results confirmed that, as expected.
the alpha, beta and gamma variants are more transmissible than the original viral
strain. In addition, the sensitivity results showed that the beta/gamma variants
could have lead to a larger number of infections in France (of both symptomatic
and asymptomatic people).