**2.8 Convalescent plasma**

There was a hypothesis that plasma collected from the persons who have recovered from Covid-19 may contain antibodies against SARS-CoV-2, which may be used as a treatment tool. A case series was done in China where 5 critically ill patients with confirmed Covid-19 and Acute respiratory distress syndrome (ARDS) were selected [57]. They received two consecutive transfusions of 200 mL to 250 mL of convalescent plasma (total dose: 400 mL) with a SARS-CoV-2-specific antibody (IgG) titer more than 1:1,000. After receiving the plasma, the SOFA score of the patients decreased and ventilator parameters of the patients (pO2/FiO2 ratio) of the patient improved, and viral load decreased by day 12. ARDS resolved in four patients by Day 12 and 3 were weaned off the ventilators by 2 weeks. Further trials are needed the study the effectiveness of convalescent plasma. FDA is encouraging people who have fully recovered from COVID-19 for at least two weeks to donate plasma. FDA had issued guidance providing recommendations to health care providers & investigators on administration and study of COVID-19 convalescent plasma during the public health emergency. FDA issued a EUA for convalescent plasma on August 23, 2020, although convalescent plasma did not show any stoppage of progression to severe COVID-19 or all-cause mortality in the PLACID trial [58, 59]. In a trial published in NEJM in November 2020, in 228 patients receiving convalescent plasma and 105 receiving placebo at 30 days, there was not any significant difference among the clinical outcome distribution (odds ratio [OR], 0.83 (95% CI, 0.52–1.35; P = 0.46). Mortality in the plasma group was 10.96% as compared to 11.43% in the placebo group [risk difference 0.46% points (95% CI, −7.8 to 6.8) [60].
