The first safety study communications overview, Early Safety Indicators of COVID-19 Convalescent Plasma in 5,000 Patients, for the national expanded access program for convalescent plasma has been published https://www.medrxiv.org/content/10.1101/2020.05.12.20099879v1

The report tells us:

• Mayo Clinic and collaborators reported safety data on the first 5,000 hospitalized patients transfused with investigational convalescent plasma as part of the U.S. Food and Drug Administration’s national Expanded Access Program (EAP) for COVID-19.
• The early indicators suggest experimental convalescent plasma is safe in treating severely ill patients.
• At this time, convalescent plasma is the only antibody-based therapy available for COVID-19.
• Patients received plasma between April 3 and May 3. The seven-day incidence of mortality was 14.9%. Sixty-six percent of the patients were in the ICU, and nearly 20% carried the diagnosis of multi-organ dysfunction or failure. Importantly, the reports of serious adverse events related to transfusion of the plasma was small (<1%).
• The researchers note that while the study was not designed to evaluate the efficacy of convalescent plasma, a seven day incidence of mortality of 14.9% in this number of patients indicates “no signal of toxicity beyond what is expected from plasma use in severely ill patients.”
• It is important to note that this is a first safety report and does not provide any findings on the effectiveness of convalescent plasma in the treatment of COVID-19. Also, the EAP is ongoing and data are still being gathered. This is not a clinical trial; there is no control arm.