Demographics of first-time donors returning for donation during the pandemic: COVID-19 convalescent plasma versus standard blood product donors.

BACKGROUND: Previous studies have demonstrated low first-time donor return rates (DRR) following catastrophic events. Little is known, however, about the influence of demographic factors on the DRR of first-time donors during the COVID-19 pandemic, including the unique motivation of COVID-19 convalescent plasma (CCP) donors as compared to non-CCP donors. STUDY DESIGN AND METHODS: Thirteen blood collection organizations submitted deidentified data from first-time CCP and non-CCP donors returning for regular (non-CCP) donations during the pandemic. DRR was calculated as frequencies. Demographic factors associated with returning donors: race/ethnicity, gender, and generation (Gen Z: 19-24, Millennial: 25-40, Gen X: 41-56, and Boomer: ≥57 years old), within the CCP and non-CCP first-time cohorts were compared using chi-square test at p < .05 statistical significance. RESULTS: From March 2020 through December 2021, there were a total of 44,274 first-time CCP and 980,201 first-time non-CCP donors. DRR were 14.6% (range 11.9%-43.3%) and 46.6% (range 10.0%-76.9%) for CCP and non-CCP cohorts, respectively. Age over 40 years (Gen X and Boomers), female gender, and White race were each associated with higher return in both donor cohorts (p < .001). For the non-CCP return donor cohort, the Millennial and Boomers were comparable. CONCLUSION: The findings demonstrate differences in returning donor trends between the two donor cohorts. The motivation of a first-time CCP donor may be different than that of a non-CCP donor. Further study to improve first-time donor engagement would be worthwhile to expand the donor base with a focus on blood donor diversity emphasizing engagement of underrepresented minorities and younger donors.

High-titer post-vaccine COVID-19 convalescent plasma for immunocompromised patients during the first omicron surge.

BACKGROUND: Transplant and hematologic malignancy patients have high Coronavirus disease 2019 (COVID-19) mortality and impaired vaccination responses. Omicron variant evades several monoclonal antibodies previously used in immunocompromised patients. Polyclonal COVID-19 convalescent plasma (CCP) may provide broader neutralizing capacity against new variants at high titers. Vaccination increases severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) titer in convalescent donors. METHODS: We conducted a retrospective chart review of hospitalized immunocompromised patients with COVID-19 who received high-titer CCP during the first omicron surge, collected from vaccinated donors within 6 months of pre-omicron COVID-19. Data on safety and outcomes were extracted. RESULTS: A total of 44 immunocompromised patients were included, 59.1% with solid organ transplant, 22.7% with hematopoietic cell transplant, 11.4% with hematologic malignancy, and 6.8% with autoimmune disease. Overall, 95% of CCP units transfused were from recently recovered and vaccinated donors and had SARS-CoV-2 antibody results 8- to 37-fold higher than the Food and Drug Administration's cutoff for high-titer CCP. There were two mild transfusion reactions. A total of 30-day mortality was 4.5%. There were no differences in 100-day mortality by underlying diagnosis, levels of immunosuppression, and timing of CCP administration. Patients with higher immunosuppression had significantly higher mean World Health Organization clinical progression scores at 30-day post-CCP compared to those with lower immunosuppression. CONCLUSIONS: CCP is a safe, globally available treatment for immunocompromised patients with COVID-19. Mortality was lower in our cohort than that of COVID-19 patients with similar immunocompromising conditions. Post-vaccine CCP with very high titers should be prioritized for study in immunocompromised patients. Post-vaccine CCP has the potential to keep pace with new variants by overcoming mutations at sufficiently high titer.

Interferon-γ Release Assay for Accurate Detection of Severe Acute Respiratory Syndrome Coronavirus 2 T-Cell Response.

We investigated feasibility and accuracy of an interferon-γ release assay (IGRA) for detection of T-cell responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Whole blood IGRA accurately distinguished between convalescent and uninfected healthy blood donors with a predominantly CD4+ T-cell response. SARS-CoV-2 IGRA may serve as a useful diagnostic tool in managing the coronavirus disease 2019 pandemic.

Active surveillance of serious adverse events following transfusion of COVID-19 convalescent plasma.

BACKGROUND: The reported incidence of adverse reactions following Coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) transfusion has generally been lower than expected based on the incidence of transfusion reactions that have been observed in studies of conventional plasma transfusion. This raises the concern for under-reporting of adverse events in studies of CCP that rely on passive surveillance strategies. MATERIALS AND METHODS: Our institution implemented a protocol to actively identify possible adverse reactions to CCP transfusion. In addition, we retrospectively reviewed the charts of inpatients who received CCP at Stanford Hospital between May 13, 2020 and January 31, 2021. We determined the incidence of adverse events following CCP transfusion. RESULTS: A total of 49 patients received CCP. Seven patients (14%) had an increased supplemental oxygen requirement within 4 h of transfusion completion, including one patient who was intubated during the transfusion. An additional 11 patients (total of 18, 37%) had increased oxygen requirements within 24 h of transfusion, including 3 patients who were intubated. Six patients (12%) fulfilled criteria for transfusion-associated circulatory overload (TACO). CONCLUSION: Using an active surveillance strategy, we commonly observed adverse events following the transfusion of CCP to hospitalized patients. It was not possible to definitively determine whether or not these adverse events are related to CCP transfusion. TACO was likely over-diagnosed given overlap with the manifestations of COVID-19. Nevertheless, these results suggest that the potential adverse effects of CCP transfusion may be underestimated by reports from passive surveillance studies.

Use of Outpatient-Derived COVID-19 Convalescent Plasma in COVID-19 Patients Before Seroconversion.

Background: Transfusion of COVID-19 convalescent plasma (CCP) containing high titers of anti-SARS-CoV-2 antibodies serves as therapy for COVID-19 patients. Transfusions early during disease course was found to be beneficial. Lessons from the SARS-CoV-2 pandemic could inform early responses to future pandemics and may continue to be relevant in lower resource settings. We sought to identify factors correlating to high antibody titers in convalescent plasma donors and understand the magnitude and pharmacokinetic time course of both transfused antibody titers and the endogenous antibody titers in transfused recipients. Methods: Plasma samples were collected up to 174 days after convalescence from 93 CCP donors with mild disease, and from 16 COVID-19 patients before and after transfusion. Using ELISA, anti-SARS-CoV-2 Spike RBD, S1, and N-protein antibodies, as well as capacity of antibodies to block ACE2 from binding to RBD was measured in an in vitro assay. As an estimate for viral load, viral RNA and N-protein plasma levels were assessed in COVID-19 patients. Results: Anti-SARS-CoV-2 antibody levels and RBD-ACE2 blocking capacity were highest within the first 60 days after symptom resolution and markedly decreased after 120 days. Highest antibody titers were found in CCP donors that experienced fever. Effect of transfused CCP was detectable in COVID-19 patients who received high-titer CCP and had not seroconverted at the time of transfusion. Decrease in viral RNA was seen in two of these patients. Conclusion: Our results suggest that high titer CCP should be collected within 60 days after recovery from donors with past fever. The much lower titers conferred by transfused antibodies compared to endogenous production in the patient underscore the importance of providing CCP prior to endogenous seroconversion.

Efficient Identification of High-Titer Anti-Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antibody Plasma Samples by Pooling Method.

CONTEXT.­: The ongoing COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has elicited a surge in demand for serologic testing to identify previously infected individuals. In particular, antibody testing is crucial in identifying COVID-19 convalescent plasma, which has been approved by the Food and Drug Administration under the Emergency Use Authorization for use as passive immunotherapy for hospitalized patients infected with COVID-19. Currently, high-titer COVID-19 convalescent plasma can be qualified by Ortho's Vitros COVID-19 IgG antibody test. OBJECTIVE.­: To explore the use of an efficient testing method to identify high-titer COVID-19 convalescent plasma for use in treating COVID-19-infected patients and track COVID-19 positivity over time. DESIGN.­: We evaluated an enzyme-linked immunosorbent assay (ELISA)-based method that detects antibodies specific to the SARS-CoV-2 receptor binding domain (RBD) with individual and pooled plasma samples and compared its performance against the Vitros COVID-19 IgG antibody test. Using the pooled RBD-ELISA (P-RE) method, we also screened more than 10 000 longitudinal healthy blood donor samples to assess seroprevalence. RESULTS.­: P-RE demonstrates 100% sensitivity in detecting Food and Drug Administration-defined high-titer samples when compared with the Vitros COVID-19 IgG antibody test. Overall sensitivity of P-RE when compared with the Vitros COVID-19 IgG antibody test and our individual sample RBD-ELISA (I-RE) were 83% and 56%, respectively. When screening 10 218 healthy blood donor samples by P-RE, we found the seroprevalence correlated with the local infection rates with a correlation coefficient of 0.21 (P < .001). CONCLUSIONS.­: Pooling plasma samples can be used to efficiently screen large populations for individuals with high-titer anti-RBD antibodies, important for COVID-19 convalescent plasma identification.