Methods
We retrospectively analyzed the data from a nationwide, observational and multicentric study based on the French CCP Early Access Program. Between December 29th 2021 and March 16th 2022, 32 centers located in France requested the use of CCP during the SARS-CoV-2 Omicron variant wave. Due to underlying disease or treatment administered, patients with hematological malignancy (HM), solid organ transplanted recipients (SOTR) or those treated for autoimmune disease (AID) were considered immunosuppressed and eligible for CCP early access program. Infection with a B1 or BA.2 SARS-CoV-2 subvariants was documented on nasopharyngeal swab. We considered a threshold of positivity for anti-Spike antibodies of > 260 BAU/mL, as the ability of vaccines to prevent severe forms of COVID-198. Every patient was informed of the study protocol and none refused to participate. Data was anonymized according to the French Law and ethical clearance was obtained from the French Infectious Diseases Society (CER-MIT 2022-0702).
We administered two consecutive transfusions of two ABO compatible high titers convalescent plasma units (200-220 mL each) at days 0 and 1. Transfused CCP were initially provided by pre-Omicron convalescent vaccinated donors with very high anti-spike IgG ratio (> 9, ELISA Euroimmun) to ensure anti-Omicron seroneutralization ability9 and after mid-January 2022 by Omicron convalescent vaccinated donors with high-anti spike IgG ratio (> 6, ELISA Euroimmun). The primary outcome was the overall survival (OS) at day 28 after plasma infusion (d28).