Modelling the role of quarantine escapees on COVID-19 dynamics

The recent outbreak of the novel coronavirus (COVID-19) pandemic which originated from the Wuhan City of China has devastated many parts of the globe. At present, non-pharmaceutical interventions are the widely available measures being used in combating and controlling this disease. There is great concern over the rampant unaccounted cases of individuals skipping the border during this critical period in time. We develop a deterministic compartmental model to investigate the impact of escapees on the transmission dynamics of COVID-19 in Zimbabwe. A suitable Lyapunov function has been used to show that the disease-free equilibrium is globally asymptotically stable provided [R]0 < 1. We performed global sensitivity analysis using the Latin-hyper cube sampling method and partial rank correlation coefficients to determine the most influential model parameters on the short and long term dynamics of the pandemic, so as to minimize uncertainties associated with our variables and parameters. Results confirm that there is a positive correlation between the number of escapees and the reported number of COVID-19 cases. It is shown that escapees are largely responsible for the rapid increase in local transmissions. Also, the results from sensitivity analysis show that an increase in the governmental role actions and a reduction in immigration rate will help to control and contain the disease spread.