Results of the CAPSID randomized trial for high-dose convalescent plasma in patients with severe COVID-19

J Clin Invest. 2021 Oct 15;131(20):e152264. doi: 10.1172/JCI152264.


BACKGROUNDCOVID-19 convalescent plasma (CCP) has been considered a treatment option for COVID-19. This trial assessed the efficacy of a neutralizing antibody containing high-dose CCP in hospitalized adults with COVID-19 requiring respiratory support or intensive care treatment.METHODSPatients (n = 105) were randomized 1:1 to either receive standard treatment and 3 units of CCP or standard treatment alone. Control group patients with progress on day 14 could cross over to the CCP group. The primary outcome was a dichotomous composite outcome of survival and no longer fulfilling criteria for severe COVID-19 on day 21.ResultsThe primary outcome occurred in 43.4% of patients in the CCP group and 32.7% in the control group (P = 0.32). The median time to clinical improvement was 26 days in the CCP group and 66 days in the control group (P = 0.27). The median time to discharge from the hospital was 31 days in the CCP group and 51 days in the control group (P = 0.24). In the subgroup that received a higher cumulative amount of neutralizing antibodies, the primary outcome occurred in 56.0% of the patients (vs. 32.1%), with significantly shorter intervals to clinical improvement (20 vs. 66 days, P < 0.05) and to hospital discharge (21 vs. 51 days, P = 0.03) and better survival (day-60 probability of survival 91.6% vs. 68.1%, P = 0.02) in comparison with the control group.ConclusionCCP added to standard treatment was not associated with a significant improvement in the primary and secondary outcomes. A predefined subgroup analysis showed a significant benefit of CCP among patients who received a larger amount of neutralizing antibodies.Trial NCT04433910.FundingBundesministerium für Gesundheit (German Federal Ministry of Health): ZMVI1-2520COR802.

Keywords: COVID-19; Clinical Trials; Immunoglobulins.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antibodies, Neutralizing / administration & dosage
  • Antibodies, Neutralizing / therapeutic use
  • Antibodies, Viral / administration & dosage
  • Antibodies, Viral / therapeutic use
  • COVID-19 / immunology
  • COVID-19 / physiopathology
  • COVID-19 / therapy*
  • Combined Modality Therapy
  • Cross-Over Studies
  • Female
  • Humans
  • Immunization, Passive / adverse effects
  • Immunization, Passive / methods
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Pandemics
  • Prospective Studies
  • SARS-CoV-2* / immunology
  • Severity of Illness Index
  • Treatment Outcome


  • Antibodies, Neutralizing
  • Antibodies, Viral

Supplementary concepts

  • COVID-19 serotherapy

Associated data