  Almost every country in the world is battling to limit the spread of
COVID-19. As the world strives to get an effective medication to control the
disease, appropriate intervention measures, for now, remains one of the
effective methods to reduce the spread of the disease. Optimal control
strategies have proven to be an effective method in curtailing the spread of
infectious diseases. In this paper, a model has been formulated to study
transmission dynamics of the disease. Basic properties of the model such as the
basic reproduction number, equilibrium points and stability of the equilibrium
points have been determined. Sensitivity analysis was carried on to determine
the impact of the model parameters on the basic reproduction number. We also
introduced a compartment for the deceased and examined the behaviour of
COVID-19 related deaths. The numerical simulation prediction is consistent with
real data from Ghana for the period March 2020 to March 2021. The simulation
revealed the disease had less impact on the population during the first seven
months of the outbreak. To help contain the spread of the disease, time
dependent optimal controls were incorporated into the model and Pontryagin
maximum principle was used to characterize vital conditions of the optimal
control model. Numerical simulations of the optimal control model showed that,
combination of optimal preventive strategies such as nose mask and vaccination
are effective to significantly decrease the number of COVID-19 cases in
different compartments of the model. Vaccination decreases the susceptibility
to the disease whereas mask usage preserved the susceptible population from
extinction.
