Based on the dose of prednisone you are taking, it is unlikely to have a significant immunosuppressive effect. However, since you have been taking cortisone for a year and a half, you may be considered immunocompromised. It is important to continue following recommended measures such as social distancing and hand washing to reduce the risk of contracting COVID-19, especially since you work in an administrative office in a hospital. It is commendable that you have limited your contact with clients to lower the risks. Stay safe and take care of yourself.