Background/Objectives: The United States is facing a national blood shortage, which is a function of the reduced number of donors since the COVID-19 pandemic and the increasing use of balanced hemostatic resuscitation for severely bleeding trauma patients. As a result, recent attempts to define futility based on clinical and laboratory criteria have been proposed. There is no literature on the frequency of institutional futility protocols, either at hospitals or blood collection centers. Methods: The Association for the Advancement of Blood & Biotherapies sent out a survey to 800 United States hospitals and blood collection centers to determine the frequency of trauma futility protocols and the need to limit blood for non-trauma patients due to high use in trauma patients. Results: 213 (26.6%) institutions responded. 10.8% of hospitals and blood collection centers reported having a trauma futility protocol, and those hospitals and blood collection centers with futility protocols were more likely to have needed to limit blood to non-trauma patients due to high consumption by trauma patients. Conclusions: Trauma futility protocols at hospitals and blood collection centers are uncommon. Because of the national shortage of blood products available for trauma and non-trauma cases, implementing institutional trauma futility protocols may help to curb the incidence of blood limitation to non-trauma patients. Increased awareness and communication between blood bankers and traumatologists during the declaration of futility may reduce blood wastage and enhance the nation's blood supply reservoirs.

BACKGROUND:Following FDA guidance, US blood collectors changed donor deferral for men who have sex with men (MSM) from indefinite to a 12 month deferral in 2016 (12 m), and for MSM and several other exposure risks to 3 month deferrals in 2020 (3 m). We evaluated first-time donor (FTD) HIV incidence and demographics during these periods. STUDY DESIGN AND METHODS:We estimated cross-sectional HIV incidence and incidence rate differences in FTD based on routine donation nucleic acid testing (NAT) and serology with additional limiting antigen (LAg)-Avidity immunoassay and viral load testing. We estimated incidence in the two policy periods (12 and 3 m), incidence trends in two-year intervals between 2015 and 2023, and used multivariable Poisson regression to assess demographic correlates of incident infection. RESULTS:HIV incidence in FTD during the 12 m deferral period was 2.82 infections/105 person-years (PY) [95% CI: 2.12, 3.67] and during the 3 m deferral period, it was 1.88/105 PY (95% CI: 1.18, 2.67), a statistically significant decline (p < .05). Over the period 2015-2023, incidence was stable. Male sex, younger age, Black or African American race, Hispanic ethnicity, and residence in the South were associated with incident infection in regression analysis, but the time-based deferral policy periods were not. DISCUSSION:HIV incidence in FTD did not increase between 2015 and 2023. An overall decline in HIV incidence in the 3 m deferral period compared with the 12 m deferral period was evident. These results provide no indication of an increased residual risk of transfusion-transmitted HIV from FTD in the United States with the reduced deferral periods.

BACKGROUND:Rho(D) immune globulin (RhIg) is used to reduce RhD alloimmunization in pregnancy. This study describes potential causes for RhD alloimmunization after the development and implementation of RhIg. STUDY DESIGN AND METHODS:This retrospective descriptive study investigated RhD-negative patients born in 1965-2005 with anti-D newly identified during 2018-2022. Transfusion, pregnancy, intravenous drug abuse, and transplantation were considered potential alloimmunization sources. RESULTS:There were 1200 study patients (852 females; 348 males) at 30 institutions in 5 countries (USA, Canada, UK, New Zealand, Brazil). Most patients had a single potential source of alloimmunization identified (857/1200, 71%), most commonly pregnancy among females (537/852, 63%) and transfusion among males (180/348, 52%). When multiple potential sources were included, males were more likely than females to have a history of transfusion (235/348 [68%] vs. 149/852 [17%], p < .0001) and confirmed or suspected intravenous drug abuse (100/348 [29%] vs. 138/852 [16%], p < .0001). Among females with a history of pregnancy, 119/718 (17%) had healthcare access issues, 120/718 (17%) had pregnancy in a country where they may not have received RhIg, and 21/718 (3%) refused RhIg. Among patients with a history of transfusion, males were more likely than females to have received RhD-positive red blood cells or whole blood (143/235 [61%] vs. 30/149 [20%], p < .0001) and/or platelets (84/235 [36%] vs. 19/149 [13%], p < .0001). DISCUSSION:Pregnancy was the most frequently identified potential source of RhD alloimmunization among females. Transfusion was most frequent in males. Intravenous drug abuse as a common potential source among patients with RhD alloimmunization merits further study.

INTRODUCTION:Patients with sickle cell disease (SCD) are transfused phenotypically-matched red blood cells (RBCs) for various indications. While screening for units that are sicklenegative is standard practice, the transfusion of RBCs containing other hemoglobin variants can be of concern to transfusion services and clinicians due to possible adverse events. Thus, this study aimed to review possible adverse events in patients with SCD with transiently acquired hemoglobin variants. METHODS:A case series of pediatric patients with SCD receiving chronic transfusions are presented, along with a systematic review of patients with SCD who were noted to have a transiently acquired hemoglobin variant. Data and patient outcomes were extracted and summarized. RESULTS:For the case series, 3 pediatric patients had transiently noted HbC peaks, with no adverse events documented. For the systematic review, 12 studies were included with a total of 75 patients with SCD. HbC was the most common hemoglobin variant in > 90 %. Other variants noted were: HbD, HbJ, HbD/G, HbG- Philadelphia, HbA2', and HbO-Arab. The maximum peak of reported variants was < 20 % (14 % for HbC). No clinically significant adverse events were reported secondary to these transiently acquired variants. CONCLUSION:Transiently acquired hemoglobin variants are commonly encountered in transfused patients with SCD, with no reported clinically significant adverse outcomes. Because phenotypic matching prioritizes donors with similar racial backgrounds, it increases the likelihood that the donor may carry hemoglobin variants. Blood centers and transfusion services should be aware of this phenomenon and avoid deferring donors with nonsickle hemoglobin variants.

BACKGROUND:The Mirasol® Pathogen Reduction Technology System was developed to reduce transfusion-transmitted diseases in platelet (PLT) products. STUDY DESIGN AND METHODS:MiPLATE trial was a prospective, multicenter, controlled, randomized, non-inferiority (NI) study of the clinical effectiveness of conventional versus Mirasol-treated Apheresis PLTs in participants with hypoproliferative thrombocytopenia. The novel primary endpoint was days of ≥Grade 2 bleeding with an NI margin of 1.6. RESULTS:After 330 participants were randomized, a planned interim analysis of 297 participants (145 MIRASOL, 152 CONTROL) receiving ≥1 study transfusion found a 2.79-relative rate (RR) in the MIRASOL compared to the CONTROL in number of days with ≥Grade 2 bleeding (95% confidence interval [CI] 1.67-4.67). The proportion of subjects with ≥Grade 2 bleeding was 40.0% (n = 58) in MIRASOL and 30.3% (n = 46) in CONTROL (RR = 1.32, 95% CI 0.97-1.81, p = .08). Corrected count increments were lower (p < .01) and the number of PLT transfusion episodes per participant was higher (RR = 1.22, 95% CI 1.05-1.41) in MIRASOL. There was no difference in the days of PLT support (hazard ratio = 0.86, 95% CI 0.68-1.08) or total number of red blood cell transfusions (RR = 1.12, 95% CI 0.91-1.37) between MIRASOL versus CONTROL. Transfusion emergent adverse events were reported in 119 MIRASOL participants (84.4%) compared to 133 (82.6%) participants in CONTROL (p = NS). DISCUSSION:This study did not support that MIRASOL was non-inferior compared to conventional platelets using the novel endpoint number of days with ≥Grade 2 bleeding in MIRASOL when compared to CONTROL.

Background: Transfusion-transmissible infection (TTI) prevalence among US blood donors has been widely documented. Here we estimate the prevalence of donors presenting with >= 2 TTIs (multiple infections past or present referred to as coinfections) and describe their demographics and associations. Methods: Data from the Transfusion-Transmissible Infections Monitoring System were compiled for October 2020-September 2023 (3 years). Prevalence per million donations (pmd) was calculated for each TTI coinfection combination with demographic characteristics summarized. The odds of each TTI coinfection combination were estimated using logistic regression. Reactivity by NAT and/or serology (HIV, HBV, and HCV) defined donors as consensus positive (CP) for each infection while serology-based algorithms defined syphilis CP and the subset with active syphilis infections (ASIs). Results: About 22 million donations were included, with 212 coinfections (9.7 pmd). Around 2% of donations positive for any TTI (n = 10,516) were coinfections. Coinfection prevalence per TTI combination ranged from 0.3 pmd for HIV CP and HCV CP, to 4.3 pmd for HIV CP and syphilis CP. There were high proportions of coinfections from donors who were male, aged 25-54 years, white or black, first time, and residing in the southern US Census Region. The odds of a second TTI occurring in an individual donor with a TTI ranged from 23 (95% CI: 13, 41) times more likely for HBV CP and ASI to 395 (95% CI: 298, 524) times more likely for HIV CP and ASI. Conclusions: Coinfections are relatively uncommon among blood donors in the United States; however, associations exist among HIV, HBV, HCV, and syphilis infections.

TransfusionVolume 63, Issue 9 p. 1778-1781 LETTERS TO THE EDITOR A regional red cell antibody registry improves patient safety but is underutilized Daniel S. Jones Jr, Daniel S. Jones Jr orcid.org/0000-0003-0492-2291 Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorGina Folk, Gina Folk Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorJack Wilson, Jack Wilson Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorZachary Hausner, Zachary Hausner Information Technology Applications, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorJulie Kirkegaard, Julie Kirkegaard orcid.org/0009-0001-6390-6454 Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorAlexandra Jimenez, Alexandra Jimenez Medical Services, New York Blood Center, New York, New York, USASearch for more papers by this authorJed B. Gorlin, Jed B. Gorlin Medical & Regulatory Affairs, Innovative Blood Resources, St. Paul, Minnesota, USASearch for more papers by this authorPatricia A. Shi, Corresponding Author Patricia A. Shi [email protected] orcid.org/0000-0002-7954-0055 Medical Services, New York Blood Center, New York, New York, USA Correspondence Patricia A. Shi, Medical Services, New York Blood Center, New York, New York, USA. Email: [email protected]Search for more papers by this author Daniel S. Jones Jr, Daniel S. Jones Jr orcid.org/0000-0003-0492-2291 Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorGina Folk, Gina Folk Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorJack Wilson, Jack Wilson Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorZachary Hausner, Zachary Hausner Information Technology Applications, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorJulie Kirkegaard, Julie Kirkegaard orcid.org/0009-0001-6390-6454 Immunohematology Reference Laboratory, Community Blood Center of Kansas City, Kansas City, Missouri, USASearch for more papers by this authorAlexandra Jimenez, Alexandra Jimenez Medical Services, New York Blood Center, New York, New York, USASearch for more papers by this authorJed B. Gorlin, Jed B. Gorlin Medical & Regulatory Affairs, Innovative Blood Resources, St. Paul, Minnesota, USASearch for more papers by this authorPatricia A. Shi, Corresponding Author Patricia A. Shi [email protected] orcid.org/0000-0002-7954-0055 Medical Services, New York Blood Center, New York, New York, USA Correspondence Patricia A. Shi, Medical Services, New York Blood Center, New York, New York, USA. Email: [email protected]Search for more papers by this author First published: 12 September 2023 https://doi.org/10.1111/trf.17504 Daniel S. Jones and Gina Folk are co-first authors. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat REFERENCES 1Schwickerath V, Kowalski M, Menitove JE. Regional registry of patient alloantibodies: first-year experience. Transfusion. 2010; 50: 1465–1470. 2van Gammeren AJ, van den Bos AG, Som N, Veldhoven C, Vossen R, Folman CC. A national transfusion register of irregular antibodies and cross (X)-match problems: TRIX, a 10-year analysis. Transfusion. 2019; 59: 2559–2566. 3Powell Z, Jiang N, Shrestha R, Jackson DE. Would a National Antibody Register contribute to improving patient outcomes? Blood Transfus. 2022; 20: 132–142. 4Ditomasso J, Liu Y, Heddle NM. The Canadian transfusion surveillance system: what is it and how can the data be used? Transfus Apher Sci. 2012; 46: 329–335. 5Sackett K, Kjell A, Schneider AM, Cohn CS. A field analysis trial comparing the turnaround times of routine and STAT red blood cell immunohematology testing. Immunohematology. 2017; 33: 1–5. Volume63, Issue9September 2023Pages 1778-1781 ReferencesRelatedInformation

BACKGROUND:Blood center organizations (BCOs) have traditionally offered two gender choices (male or female) on the donor history questionnaire (DHQ). Our BCO was one of the first in the United States to offer additional options on our DHQ to improve the experience for gender nonconforming donors.STUDY DESIGN AND METHODS:Three years of data were analyzed from all blood donation visits between March 2019 and March 2022. Donors were stratified by gender categories and generation as follows: Gen Z, Millennial, Gen X, Boomers, and Silent. First time donor status, donor deferrals and infectious disease rates were evaluated for each category.RESULTS:Donor gender makeup included 127,072 (99.78%) Male/Female (M/F) and 282 (0.22%) Trans/Other (T/O) donors. The return rate for first-time donors was 36.75% for M/F donors compared to 33.84% for T/O donors. The generational breakdown of our T/O donors is 71.28% Gen Z, 21.99% Millennial, 3.19% Gen X, 3.55% Boomers and none from the Silent Generation. Comparing high risk DHQ deferrals, there were 719 (0.57%) M/F deferrals and 18 (6.38%) T/O deferrals. Disease marker testing resulted in 2314 (0.56%) deferrals of M/F donors compared to 2 (0.41%) T/O deferrals.CONCLUSION:Increased gender options on the DHQ allowing gender diverse self-identification enhances inclusivity. Transgender and nonbinary individuals accounted for a minority of donors, most of whom are younger, and have a comparable return rate to M/F donors. Shifts in donor policies can ensure inclusivity of this diverse population and provide an opportunity to expand the base of eligible donors.

Vox SanguinisVolume 117, Issue 3 p. E21-E43 International Forum International Forum on Gender Identification and Blood Collection: Responses Suchitra Pandey, Suchitra PandeySearch for more papers by this authorJed B. Gorlin, Jed B. GorlinSearch for more papers by this authorMary Townsend, Mary TownsendSearch for more papers by this authorNancy Van Buren, Nancy Van BurenSearch for more papers by this authorJennifer N. S. Leung, Jennifer N. S. LeungSearch for more papers by this authorCheuk-kwong Lee, Cheuk-kwong Lee orcid.org/0000-0002-3939-564X Search for more papers by this authorKatja van den Hurk, Katja van den HurkSearch for more papers by this authorNatalia Casamitjana, Natalia CasamitjanaSearch for more papers by this authorRoser Valles, Roser VallesSearch for more papers by this authorEva Alonso, Eva AlonsoSearch for more papers by this authorYvette Marie Miller, Yvette Marie MillerSearch for more papers by this authorPascale Richard, Pascale RichardSearch for more papers by this authorGeneviève Woimant, Geneviève WoimantSearch for more papers by this authorPierre Tiberghien, Pierre Tiberghien orcid.org/0000-0002-9310-8322 Search for more papers by this authorEugene Zhiburt, Eugene ZhiburtSearch for more papers by this authorTerrie Butler-Foster, Terrie Butler-Foster orcid.org/0000-0003-2166-6031 Search for more papers by this authorMindy Goldman, Mindy Goldman orcid.org/0000-0001-9904-9952 Search for more papers by this authorLise Sofie H. Nissen-Meyer, Lise Sofie H. Nissen-MeyerSearch for more papers by this authorAurora Espinosa, Aurora EspinosaSearch for more papers by this authorHany Kamel, Hany KamelSearch for more papers by this authorMarj Bravo, Marj BravoSearch for more papers by this authorLuiz Amorim Filho, Luiz Amorim FilhoSearch for more papers by this authorMargarida Pecego, Margarida PecegoSearch for more papers by this authorMarc Germain, Marc GermainSearch for more papers by this authorIsabelle Rabusseau, Isabelle RabusseauSearch for more papers by this authorEilat Shinar, Eilat ShinarSearch for more papers by this authorHana Raz, Hana RazSearch for more papers by this authorNabajyoti Choudhury, Nabajyoti ChoudhurySearch for more papers by this authorNidhi Bhatnagar, Nidhi BhatnagarSearch for more papers by this authorKelsi Hurt, Kelsi HurtSearch for more papers by this authorMelissa Lopez, Melissa LopezSearch for more papers by this authorRita A. Reik, Rita A. ReikSearch for more papers by this authorYongmei Nie, Yongmei NieSearch for more papers by this authorYang Hung, Yang HungSearch for more papers by this authorLethola Pheello, Lethola PheelloSearch for more papers by this authorNancy Dunbar, Nancy Dunbar nancy.m.dunbar@hitchcock.org Search for more papers by this author Suchitra Pandey, Suchitra PandeySearch for more papers by this authorJed B. Gorlin, Jed B. GorlinSearch for more papers by this authorMary Townsend, Mary TownsendSearch for more papers by this authorNancy Van Buren, Nancy Van BurenSearch for more papers by this authorJennifer N. S. Leung, Jennifer N. S. LeungSearch for more papers by this authorCheuk-kwong Lee, Cheuk-kwong Lee orcid.org/0000-0002-3939-564X Search for more papers by this authorKatja van den Hurk, Katja van den HurkSearch for more papers by this authorNatalia Casamitjana, Natalia CasamitjanaSearch for more papers by this authorRoser Valles, Roser VallesSearch for more papers by this authorEva Alonso, Eva AlonsoSearch for more papers by this authorYvette Marie Miller, Yvette Marie MillerSearch for more papers by this authorPascale Richard, Pascale RichardSearch for more papers by this authorGeneviève Woimant, Geneviève WoimantSearch for more papers by this authorPierre Tiberghien, Pierre Tiberghien orcid.org/0000-0002-9310-8322 Search for more papers by this authorEugene Zhiburt, Eugene ZhiburtSearch for more papers by this authorTerrie Butler-Foster, Terrie Butler-Foster orcid.org/0000-0003-2166-6031 Search for more papers by this authorMindy Goldman, Mindy Goldman orcid.org/0000-0001-9904-9952 Search for more papers by this authorLise Sofie H. Nissen-Meyer, Lise Sofie H. Nissen-MeyerSearch for more papers by this authorAurora Espinosa, Aurora EspinosaSearch for more papers by this authorHany Kamel, Hany KamelSearch for more papers by this authorMarj Bravo, Marj BravoSearch for more papers by this authorLuiz Amorim Filho, Luiz Amorim FilhoSearch for more papers by this authorMargarida Pecego, Margarida PecegoSearch for more papers by this authorMarc Germain, Marc GermainSearch for more papers by this authorIsabelle Rabusseau, Isabelle RabusseauSearch for more papers by this authorEilat Shinar, Eilat ShinarSearch for more papers by this authorHana Raz, Hana RazSearch for more papers by this authorNabajyoti Choudhury, Nabajyoti ChoudhurySearch for more papers by this authorNidhi Bhatnagar, Nidhi BhatnagarSearch for more papers by this authorKelsi Hurt, Kelsi HurtSearch for more papers by this authorMelissa Lopez, Melissa LopezSearch for more papers by this authorRita A. Reik, Rita A. ReikSearch for more papers by this authorYongmei Nie, Yongmei NieSearch for more papers by this authorYang Hung, Yang HungSearch for more papers by this authorLethola Pheello, Lethola PheelloSearch for more papers by this authorNancy Dunbar, Nancy Dunbar nancy.m.dunbar@hitchcock.org Search for more papers by this author First published: 20 September 2021 https://doi.org/10.1111/vox.13193Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume117, Issue3March 2022Pages E21-E43 RelatedInformation

We assessed the feasibility of a highly sensitive immunoassay method based on single molecule array (Simoa) technology to detect IgG and IgA antibodies against SARS-CoV-2 spike protein receptor binding domain (RBD) in saliva from individuals with natural or vaccine-induced COVID-19 immunity. The performance of the method was compared to a laboratory-developed SARS-CoV-2 RBD total antibody enzyme-linked immunosorbent assay (ELISA). Paired serum and saliva specimens were collected from individuals (n = 40) prior to and 2 weeks after receiving an initial prime COVID-19 vaccine dose (Pfizer/BioNTech BNT162b2 or Moderna mRNA-1273). Saliva was collected using a commercially available collection device (OraSure Inc.) and SARS-CoV-2 RBD IgG antibodies were measured by an indirect ELISA using concentrated saliva samples and a Simoa immunoassay using unconcentrated saliva samples. The IgG results were compared with paired serum specimens that were analyzed for total RBD antibodies using the ELISA method. The analytical sensitivity of the saliva-based Simoa immunoassay was five orders of magnitude higher than the ELISA assay: 0.24 pg/mL compared to 15 ng/mL. The diagnostic sensitivity of the saliva ELISA method was 90% (95% CI 76.3–97.2%) compared to 91.7% (95% CI 77.5–98.2%) for the Simoa immunoassay without total IgG-normalization and 100% (95% CI 90.3–100%) for the Simoa immunoassay after total IgG-normalization when compared to the serum ELISA assay. When analyzed using the SARS-CoV-2 RBD IgG antibody ELISA, the average relative increase in antibody index (AI) between the saliva of the post- and pre-vaccinated individuals was 8.7 (AI post/pre ). An average relative increase of 431 pg/mL was observed when the unconcentrated saliva specimens were analyzed using the Simoa immunoassay (SARS-CoV-2 RBD IgG post/pre ). These findings support the suitability of concentrated saliva specimens for the measurement of SARS-CoV-2 RBD IgG antibodies via ELISA, and unconcentrated saliva specimens for the measurement of SARS-CoV-2 RBD IgG and IgA using an ultrasensitive Simoa immunoassay.

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.

The Association for the Advancement of Blood and Biotherapies developed clinical practice guidelines for the appropriate use of COVID-19 convalescent plasma. This article describes the evidence and rationale for recommendations for inpatient and outpatient treatment and prophylaxis.

The authors have no substantial conflicts of interest.

Updated US Infectionand Vaccine-Induced SARS-CoV-2 Seroprevalence Estimates Based on Blood Donations, July 2020-December 2021 By testing for both SARS-CoV-2 spike and nucleocapsid antibodies, seroprevalence studies can estimate the proportion of a population with antibodies from previous infection (nucleocapsid antibody or infection-induced seroprevalence) and from infection or vaccination (spike antibody or combined infectionand vaccineinduced seroprevalence). US seroprevalence from July 2020 to May 2021 based on blood donations was reported previously.1 This report includes monthly estimates through the conclusion of the study in December 2021.

Data sharing not applicable to this article as no datasets were generated or analysed during the current study