In this paper, a Covid-19 pandemic model with five compartments is presented. Model assumptions, flowchart and the system of model equations are included. It is found that the solutions for the model equations exist and they are unique, positive and bounded. Hence, the present model is termed as mathematically well-posed and biologically meaningful. Mathematical analysis, sensitivity analysis are conducted in order to draw meaningful conclusions. Sensitivity analysis on the model equations reveal that the immunity loss has a positive impact while vaccination and treatment have negative impact on the effective reproduction number. The research results assert that the pandemic can be kept under control by enhancing vaccination and treatment facilities and similarly by implementing suitable methods to reduce loss of immunity. Outcomes of both qualitative and quantitative analyses are included and described elaborately. Disease free equilibrium point is identified and it's local and global stability analyses are conducted using powerful techniques like Routh-Hurwitz criteria and Lyapunov function method. Detailed description of the model is presented in the text of the paper lucidly.