ABSTRACT
Background: Several studies have evaluated COVID-19 convalescent plasma (CCP)'s safety and effectiveness in the prevention of severe COVID-19's worsening. Some of these studies have shown a trend for its efficacy in immunosuppressed patients and that CCP was safe. These studies were performed before the emergence of Omicron variant of SARS-CoV-2, which appeared in December 2021 in France. Aims: All CCP transfusions in France have been performed in a monitored use protocol allowed by the national agency of drug and blood components safety (ANSM). After giving their consent to be transfused, patients were followed to assess this compassionate therapy. All CCPs were qualified with a high titre of antibody, either by seroneutralization (SN) or an ELISA based surrogate for SN. We describe results of this follow-up with a focus on omicron infection. Methods: Consultative multidisciplinary meeting validated the indication for CCP and the order of a medical prescription of CCP. All CCP demands were sent to the EFS medical department to be pseudonymized. Initial and follow-up data of cases were recorded as requested for an assessment. Variables were analysed in relation with the last available follow-up. Results: From May 2020 to the end of February 2022, 1539 patients had received CCP, of whom 455 had an available follow-up more than 24 h after the last CCP transfusion. Most of them (99.8%) have got a comorbidity: 62.6% have a malignant hemopathy and 19.3% an auto-immune pathology. Among the At the time of CCP request, majority of patients (76.9%) were hospitalized without mechanical ventilation (MV), 18.2% were intubated and a few were not hospitalized for COVID-19 (1.3%) but for another reason. At the last available follow-up, 26.2% were dead but the majority (40.9%) have left the hospital, 23.7% were hospitalized without MV and 9.2% were intubated. Variables associated with a decreased percentage of death were: • The young age (p < 0.0001;N = 455) and the female gender (p = 0.0177;N = 455). • The better state at the time of CCP request (p < 0.0001;N = 439). • The longer delay between the beginning of symptoms and the transfusion (p = 0.0023;N = 445). • A trend was observed for immunosuppression, but it did not reach statistical significance (p = 0.0548;N = 346). There were no difference between Infection due to Omicron variant compared to other variants (p = 0.1560;N = 443). However, follow-up was available in only 33 patients infected with omicron (32.7% of transfused patients infected with omicron) while it was available in 410 patients infected with others SARS-CoV-2 variants (94.4%). Among all transfused patients, 75 adverse events (AE) were reported in 1539 patients (4.8%). Imputability was excluded for 11. Allergy was the most frequent (N = 26;34.6% of AE) always scored as not severe, TACO have occurred in 8 patients, with possible or likely imputability, and TRALI have occurred in 3 patients with possible imputability in 2 cases and non evaluable in one case. Summary/Conclusions: CCP transfusion was more effective when the patient were in better state at the time of CCP request and in immunocompromised than in immunocompetent patients, but this was not statistically significant. Due to the low number of patients infected with omicron with an available follow-up at this day, no conclusion can be drawn on survival of these patients versus patients infected with previous variants.