Convalescent plasma
Passive immunity is the administration of antibodies against an infective organism for the purpose of prevention and treatment of the disease caused by that agent. Passive immunity has a long-standing history before the development of antimicrobial therapy in the 1940s. However, for certain infections that do not require respondents to antimicrobial therapy, passive immunity is still used for such diseases. An adequate quantity of antibodies must be administered to achieve effective results of the therapy. The protection given by this antibody to the patient depends upon the concentration of the antibodies given and may last for weeks or months. The effectiveness of the sera varies with the type of virus. COVID-19 is an example of such a disease. In the meantime, plasma therapy is used as the best treatment for SARS-COV-2. Experimental studies show that patients with consolidation, extensive lung lesions, Sjogren syndrome, and GGO (GROUND-GLASS OPACIPICATION) treated with plasma therapy discharged healthy from the hospital[55]. According to the study convalescent plasma can be used to prevent diseases among those who are exposed to COVID-19 patients and to treat a patient with early symptoms[24]. However, little information is available on this topic, and fewer patients are used for clinical trials, so more studies and trials are needed.