Li 2020.

Study characteristics
Methods	Trial design: RCT Type of publication: journal publication  Setting: hospital Recruitment dates: 14 February 2020‐1 April 2020 Country: China Language: English Number of centres: 7 Trial registration number: ChiCTR2000029757 Date of registration: NR
Participants	Age: median 70 years, IQR 62‐78 years  Gender: 60 male (58.3%), 43 female (41.7%) Ethnicity: NR Number of participants (recruited/allocated/evaluated): 103 (52 CP, 51 standard treatment) Severity of disease: severe or life‐threatening  Co‐morbidities: hypertension, cardiovascular disease, cerebrovascular disease, diabetes, liver disease, cancer, kidney disease Inclusion criteria: signed informed consent aged at least 18 years  COVID‐19 diagnosis based on PCR testing positive PCR result within 72 h prior to randomisation pneumonia confirmed by chest imaging clinical symptoms meeting the definitions of severe or life‐threatening COVID‐19 acceptance of random group assignment hospital admission willingness to participate in all necessary research studies and be able to complete the study follow‐up no participation in other clinical trials, such as antiviral trials, during the study period Exclusion criteria:  pregnancy or lactation immunoglobulin allergy IgA deficiency pre‐existing comorbidity that could increase the risk of thrombosis life expectancy < 24 h disseminated intravascular coagulation severe septic shock PaO2/FIO2 of < 100 severe congestive heart failure  detection of high titre of S protein–RBD‐specific IgG antibody (≥ 1:640) other contraindications as determined by the patient’s physicians participation in any antiviral clinical trials for COVID‐19 within 30 days prior to enrolment Previous treatments (e.g. experimental drug therapies, oxygen therapy, ventilation): antivirals, antibiotics, steroids, human Ig, Chinese herbal medicines, interferon
Interventions	CP therapy or hyperimmune immunoglobulin therapy: CP therapy Details of CP: Type of plasma: plasmapheresis Volume: 4‐13 mL/kg of recipient body weight, median 200 mL, IQR 200‐300 mL Number of doses: 1 (96%) or more Antibody test and antibody‐titre: only the plasma units with an S‐RBD–specific IgG titre of at least 1:640 were used correlating to serum neutralisation titre of 1:80  Pathogen inactivated or not: NR RT‐PCR tested: NR Details of donors: Gender: both, 18‐55 years suitable for blood donation  HLA and HNA antibody‐negative: NR Severity of disease: NR Timing from recovery from disease: discharged from hospital > 2 weeks RT‐PCR tested: lab‐confirmed COVID‐19 diagnosis, 2 negative PCR results from nasopharyngeal swabs at least 24 h apart prior to hospital discharge Treatment details, including time of plasma therapy (e.g. early stage of disease): severe to life‐threatening For studies including a control group: comparator (type): standard therapy Concomitant therapy: antivirals, antibiotics, steroids, human Ig, Chinese herbal medicines, interferon Duration of follow‐up: 28 days  Treatment cross‐overs: none Compliance with assigned treatment: 1 participant in control arm received CP, 1 participant in CP arm discontinued study
Outcomes	Primary study outcome(s): clinical improvement within 28 days (patient discharged alive or reduction of 2 points on a 6‐point disease severity scale) Primary review outcomes All‐cause mortality at hospital discharge: reported Time to death: reported Secondary review outcomes Number of participants with grade 3 and grade 4 AEs, including potential relationship between intervention and adverse reaction (e.g. TRALI, transfusion‐transmitted infection, TACO, TAD, acute transfusion reactions): reported Number of participants with SAEs: reported Improvement of clinical symptoms, assessed through need for respiratory support at up to 7 days; 8‐15 days; 16‐30 days: reported 30‐day and 90‐day mortality: reported Admission on the ICU: NR Length of stay on the ICU: NR Time to discharge from hospital: reported QoL: NR Additional study outcomes: rate of viral PCR to negative at up to 72 h
Notes	Sponsor/funding: this work was supported by the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (CIFMS) grants 2020‐I2M‐CoV19‐006, 2016‐I2M‐3‐024 (Dr Z. Liu), and 2017‐I2M‐1‐009 (Dr L. Li) and the Nonprofit Central Research Institute Fund of Chinese Academy of Medical Sciences grant 2018PT32016 (Dr Z. Liu) COIs: Dr Liu reports holding a pending patent on COVID‐19 testing. Dr Wu reports consulting for Verax Medical and Grifols, receiving royalties from UptoDate and AABB, and being a volunteer visiting professor and receiving travel support for giving medical education from the Chinese Institute of Blood Transfusion. No other disclosures were reported. Other: nil