Competitive exclusion of two viral strains of COVID-19

The pandemic COVID-19 has caused severe losses in public health and economy.One of the most difficult problems in prevention of the disease spread is the emergence of new variants.In this paper,a mathematical model is formulated,which captures the main feature of COVID-19 spread with two viral strains.It is shown by analytical method that the model exhibits the competitive exclusion principle,where one viral strain with the larger basic reproduction number is dominant and the viral strain with the smaller reproduction number is excluded.The results are important for the deployment of prevention policy of COVID-19.