Background We evaluate the current prevalence of serological markers for HBV and HCV in blood donors and estimated HCV incidence and residual transfusion-transmitted risk at three large Brazilian blood centers. Material and Methods Data on whole blood and platelet donations were collected from January through December 2007 and analyzed by center, donor type (replacement vs. community), age, sex, donation status (first-time vs. repeat), and serological results for HBsAg, anti-HBc and anti-HCV. HBV (HBsAg+/anti-HBc+) and HCV (anti-HCV) prevalence rates were calculated for all first time donations. HCV incidence was derived including inter-donation intervals that preceded first repeat donations given during the study and HCV residual risk was estimated for transfusions derived from repeat donors. Results There were 307,354 donations from January through December 2007. Overall prevalence of concordant HBsAg and anti-HBc reactivity was 289 per 100,000 donations and of anti-HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% CI 0.77-7.03) per 100,000 person-years, and residual risk of HCV window-phase infections was estimated at 5.0 per million units transfused. Conclusion Improvement in blood donor selection, socioeconomic conditions and preventive measures, implemented over time, may have helped to decrease prevalence of hepatitis B and C viruses, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of hepatitis B and C viral markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening methods and counseling strategies.

Background The efficacy of convalescent plasma (CP), an alternative for the treatment of COVID‐19, depends on high titers of neutralizing antibodies (nAbs), but assays for quantifying nAbs are not widely available. Our goal was to develop a strategy to predict high titers of nAbs based on the results of anti‐SARS‐CoV‐2 immunoassays and the clinical characteristics of CP donors. Study Design and Methods A total of 214 CP donors were enrolled and tested for the presence of anti‐SARS‐CoV‐2 antibodies (IgG) using two commercial immunoassays: EUROIMMUN (ELISA) and Abbott (Chemiluminescence). Quantification of nAbs was performed using the Cytopathic Effect‐based Virus Neutralization test. Three criteria for identifying donors with nAbs ≥ 1:160 were tested: – C1: Curve ROC; − C2: Conditional decision tree considering only the IA results and – C3: Conditional decision tree including both the IA results and the clinical variables. Results The performance of the immunoassays was similar referring to both S/CO and predictive value for identifying nAbs titers ≥1:160. Regarding the studied criteria for identifying CP donors with high nAbs titers: (a) C1 showed 76.1% accuracy if S/CO = 4.65, (b) C2 presented 76.1% accuracy if S/CO ≥4.57 and (c) C3 had 71.6% accuracy if S/CO was ≥4.57 or if S/CO was between 2.68‐4.57 and the last COVID‐19‐related symptoms were recent (within 19 days). Conclusion SARS‐CoV‐2 IgG immunoassays (S/CO) can be used to predict high anti‐SARS‐CoV‐2 nAbs titers. This study has proposed different criteria for identifying donors with ≥1:160 nAbs titers, all with high efficacy.

Background This study evaluated demographic profiles and prevalence of serologic markers of donors who used CUE in order to assess the effectiveness of CUE and guide public policies regarding the use of CUE for enhancing safety versus jeopardizing the blood supply by dropping CUE. Material and Methods We conducted a cross-sectional analysis of whole blood donations at a large public blood center in São Paulo from July 2007 through June 2009, and compared demographic data and confirmed serologic results among donors who used and who have never used CUE (CUE never). Results There were 265,550 whole blood units collected from 181,418 donors from July 2007 through June 2009. A total of 9,659 (3.6%) units were discarded, 2,973 (1.1%) because CUE was used at the current donation (CUE now) and 6,685 (2.5%) because CUE was used in the past (CUE past). The CUE rate was highest among donors with less than 8 years of education (OR=2.78; CI = 2.51–3.08). CUE now donations were associated with higher positive infectious disease marker rates than CUE never donations (OR= 1.41; CI = 1.13–1.77), whereas CUE past donations were not (OR=1.04; CI = 0.75–1.45). Conclusion The CUE process results in a high rate of unit discard. CUE use on an individual donation appears predictive of a high risk marker positive donation and, thus appears to contribute modestly to blood safety. The policy of discarding units from donors, who have previously CUE positive donations, does not improve safety and should be discontinued.

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Background and objectives To date, it is unclear whether antigen matching is effective in reducing antibody development and whether transfusing blood from non‐Caucasian donors reduces alloimmunization in sickle cell disease patients (SCP). This study was designed to evaluate the effectiveness of an antigen‐matching strategy supplied by a mixed donor population, in reducing alloimmunization in SCPs. Methods Eighty SCPs transfused with C‐, E‐ and K‐matched units and 2000 donors were genotyped for the most relevant RBC antigens, and resulting genotypic frequencies were compared. Also, alloantibodies specificity and clinical complications were evaluated in SCPs. Results A high alloimmunization rate was observed despite the prophylaxis protocol (62·1%). The main cause underlying lack of effectiveness was transfusion of non‐matched units in external hospitals. Even though our donor population was ethnically mixed, it still exhibited antigenic differences in relation to SCPs (C and Fya). Frequency of clinical complications was similar between alloimmunized and non‐alloimmunized patients. Conclusions Prospective antigen matching is an unattractive alloimmunization prophylaxis for SCPs if not associated with strategies to minimize the hazards related to transfusions at non‐index hospitals. Even in a highly mixed donor population, antigenic discrepancies in SCPs are high, increasing the risk of antibody development.