Coronavirus disease 19 (COVID-19) is provoking the greatest global health crisis of this generation. With no vaccine or specific antiviral treatment available to date, the use of convalescent plasma (CP) from recovered COVID-19 patients has been considered a potential curative strategy. To demonstrate its efficacy and safety, clinical studies are ongoing or planned in various EU Member States. Unfortunately, there lacks a coordinated approach involving a large number of blood establishments (BEs) and clinical centres to harmonise protocols and guidelines, to standardise assays for characterising the potency of the plasma and to validate clinical outcome which will be of great importance to ensure that significant conclusions can be drawn. SUPPORT-E brings together major European BEs with world leading research capabilities with the aim to support high quality clinical and scientific evaluation of COVID-19 CP (CCP) and thereby achieve a consensus on the appropriate use of CCP in the treatment of COVID-19 across EU Member States. Hence, SUPPORT-E will advance the current state-of-the-art by delivering the much needed harmonised evidence-based recommendations with respect to the use of CPP in clinical trials and monitored access programmes for COVID-19 patients in Europe. Further, standardised informative in vitro assays providing scientific insights that could support such recommendations will also be developed. SUPPORT-E offers an EU-wide collaboration between Member States, BEs and clinical centres in order to close the knowledge gap and to ensure applicability of the recommendations for all EU Members States. SUPPORT-E represents the first European Union coordinated research effort on passive immunotherapy, sharing data and protocols in real-time and pooling efforts to decrease the time as much as possible for validating CCP as a valid therapeutic treatment and also providing a basis for further optimisation by combined approaches with other anti-viral treatments.