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First Author:  Ralph Rogers et al.  

Journal/preprint name: medRxiv 

Tags: immunity, antibodies, convalescent plasma, clinical trial 


In this paper Rogers et al. investigate the efficacy of convalescent plasma (CP) therapy for COVID-19 patients. 64 patients who received CP were compared to 177 patients that previously received standard of care in the same centre. The control patients were chosen for similar age, sex, pre-existing conditions and COVID diagnosis. The study did not show any differences in the primary and secondary outcomes, there was no impact of CP on all cause in-hospital mortality or in the length of the hospitalization. 3 patients (2.8%) experienced adverse events. CP treatment showed improvement in time to hospital discharge in a subgroup of patients over 65. 

Research Highlights 

  1. CP does not improve all cause in-hospital mortality 

  1. CP does not improve length of the hospitalization 

  1. Patients experienced an unusually high number of adverse events 

Impact for COVID-19 research:  

  • This study shows that CP treatment (just approved in the USA for emergency use) does not improve COVID-19 outcomes for hospitalized patients 

  • Bigger studies are needed to see if the trend towards benefit seen especially in older patients can be repeated or if it is a result of the limited number of patients in the study 


  • Study Typeclinical trial 

  • Important cell lines/viral models used: N/A 

  • Key Techniques: Antibody titration 


The study addresses its own limitation in an extensive way. These limitations are: 

  • Limited number of patients. 

  • The control cohort was not collected at the same time as the treated cohort. Standard of care for COVID-19 treatment has shifted between the two cohorts. 

  • The antibody title of the CP given to the patients was not measured in advance. Some of the patients received suboptimal amounts of antibody, this could have impacted the efficacy of the treatment 

  • The patients experienced a greater than expected number of adverse effects. It is difficult in the case of severe COVID-19 patients to determine the cause of the adverse effect and some could have been attributed to the treatment in error. 

  • The study highlights how the treatment could be effective in older patients, but the number of patients in this subgroup is too small to draw definitive conclusions