a. Passive immunization group (Group A). *20 high risk exposed persons (HCPs) who are nasopharyngeal swab SARSCoV-2 PCR ... Passive immunization using hyper immunoglobulin preparations against measles as well as early treatment was proven effective ... 4 units of COVID19 FFP for passive immunization or treatment of early disease. The advantages of this approach is that it is ... the use of COVID19 convalescent serum for the preparation of hyper immunoglobulins to be used for passive immunization as well ...