Convalescent refers to anyone recovering from a disease. Plasma is the yellow, liquid part of blood that contains antibodies. Antibodies are proteins made by the body in response to infections.
Convalescent plasma from patients who have already recovered from coronavirus disease 2019 (COVID-19) may contain antibodies against COVID-19. The FDA has issued an Emergency Use Authorization for the use of convalescent plasma in hospitalized patients. It is also being investigated for the treatment of COVID-19 because there is no approved treatment for this disease.
Before issuing the EUA, the FDA concluded that, based on scientific evidence available, this product may be effective in treating COVID-19 and that the known and potential benefits of the product outweigh the known and potential risks of the product for patients hospitalized with COVID-19.
Source: US FDA