Tobian, Aaron A.R.

Abstract The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants severely limits available effective monoclonal antibody therapies. Effective drugs are also supply limited. COVID-19 convalescent plasma (CCP) qualified for high antibody levels effectively reduces immunocompetent outpatient hospitalization. The Food and Drug Administration currently allows outpatient CCP for the immunosuppressed. Viral-specific antibody levels in CCP can range 10- to 100-fold between donors, unlike the uniform viral-specific monoclonal antibody dosing. Limited data are available on the efficacy of polyclonal CCP to neutralize variants. We examined 108 pre-δ/pre-ο donor units obtained before March 2021, 20 post-δ COVID-19/postvaccination units, and 1 pre-δ/pre-ο hyperimmunoglobulin preparation for variant-specific virus (vaccine-related isolate [WA-1], δ, and ο) neutralization correlated to Euroimmun S1 immunoglobulin G antibody levels. We observed a two- to fourfold and 20- to 40-fold drop in virus neutralization from SARS-CoV-2 WA-1 to δ or ο, respectively. CCP antibody levels in the upper 10% of the 108 donations as well as 100% of the post-δ COVID-19/postvaccination units and the hyperimmunoglobulin effectively neutralized all 3 variants. High-titer CCP neutralizes SARS-CoV-2 variants despite no previous donor exposure to the variants.

AbstractConvalescent plasma, collected from donors who have recovered from a pathogen of interest, has been used to treat infectious diseases, particularly in times of outbreak, when alternative therapies were unavailable. The COVID‐19 pandemic revived interest in the use of convalescent plasma. Large observational studies and clinical trials that were executed during the pandemic provided insight into how to use convalescent plasma, whereby high levels of antibodies against the pathogen of interest and administration early within the time course of the disease are critical for optimal therapeutic effect. Several studies have shown outpatient administration of COVID‐19 convalescent plasma (CCP) to be both safe and effective, preventing clinical progression in patients when administered within the first week of COVID‐19. The United States Food and Drug Administration expanded its emergency use authorization (EUA) to allow for the administration of CCP in an outpatient setting in December 2021, at least for immunocompromised patients or those on immunosuppressive therapy. Outpatient transfusion of CCP and infusion of monoclonal antibody therapies for a highly transmissible infectious disease introduces nuanced challenges related to infection prevention. Drawing on our experiences with the clinical and research use of CCP, we describe the logistical considerations and workflow spanning procurement of qualified products, infrastructure, staffing, transfusion, and associated management of adverse events. The purpose of this description is to facilitate the efforts of others intent on establishing outpatient transfusion programs for CCP and other antibody‐based therapies.

Background and ObjectivesABO blood group may affect risk of SARS‐CoV‐2 infection and/or severity of COVID‐19. We sought to determine whether IgG, IgA and neutralizing antibody (nAb) to SARS‐CoV‐2 vary by ABO blood group.Materials and MethodsAmong eligible convalescent plasma donors, ABO blood group was determined via agglutination of reagent A1 and B cells, IgA and IgG were quantified using the Euroimmun anti‐SARS‐CoV‐2 ELISA, and nAb titres were quantified using a microneutralization assay. Differences in titre distribution were examined by ABO blood group using non‐parametric Kruskal–Wallis tests. Adjusted prevalence ratios (aPR) of high nAb titre (≥1:160) were estimated by blood group using multivariable modified Poisson regression models that adjusted for age, sex, hospitalization status and time since SARS‐CoV‐2 diagnosis.ResultsOf the 202 potential donors, 65 (32%) were blood group A, 39 (19%) were group B, 13 (6%) were group AB, and 85 (42%) were group O. Distribution of nAb titres significantly differed by ABO blood group, whereas there were no significant differences in anti‐spike IgA or anti‐spike IgG titres by ABO blood group. There were significantly more individuals with high nAb titre (≥1:160) among those with blood group B, compared with group O (aPR = 1·9 [95%CI = 1·1–3·3], P = 0·029). Fewer individuals had a high nAb titre among those with blood group A, compared with group B (aPR = 0·6 [95%CI = 0·4‐1·0], P = 0·053).ConclusionEligible CCP donors with blood group B may have relatively higher neutralizing antibody titres. Additional studies evaluating ABO blood groups and antibody titres that incorporate COVID‐19 severity are needed.

BACKGROUNDLeukoreduced (LR) or cytomegalovirus (CMV)‐seronegative cellular blood components are commonly used to reduce the risk of transfusion‐transmitted CMV infection in high‐risk patients.STUDY DESIGN AND METHODSWe performed a systematic review and meta‐analysis to evaluate the evidence for the use of LR cellular blood components with or without concurrent CMV testing of donor units in patients undergoing chemotherapy or solid organ and hematopoietic stem cell transplantation, in pregnant women, in very‐low‐birthweight infants, and in patients with primary immunodeficiency. We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus from 1980 through February 2015. Studies were included if they had a comparison group. Two independent reviewers selected and appraised studies. Meta‐analysis was performed when appropriate.RESULTSOf 457 studies screened, 11 were eligible. One study was excluded from the meta‐analysis because the comparison performed differed significantly from the others. Meta‐analysis of five studies that compared leukoreduction to transfusing CMV‐untested blood components showed no significant difference in clinical CMV infection (relative risk [RR], 0.26; 95% confidence interval [CI], 0.04‐1.57) or laboratory CMV infection (RR, 0.33; 95% CI, 0.08‐1.37). Meta‐analysis of three studies that compared leukoreduction to transfusing CMV‐seronegative cellular components showed no significant difference in laboratory CMV infection (RR, 2.18; 95% CI, 0.96‐4.98). Meta‐analysis of two studies that compared adding CMV testing to leukoreduction (vs. leukoreduction alone) showed no significant difference in clinical or laboratory CMV infection. The certainty in estimates was low for all comparisons.CONCLUSIONAt present, the scientific evidence does not favor a single strategy for reducing the risk of transfusion‐related CMV infection in high‐risk patients.