Comparison of allocation strategies of convalescent plasma to reduce excess infections and mortality from SARS-CoV-2 in a US-like population.

BACKGROUND: While the use of convalescent plasma (CP) in the ongoing COVID-19 pandemic has been inconsistent, CP has the potential to reduce excess morbidity and mortality in future pandemics. Given constraints on CP supply, decisions surrounding the allocation of CP must be made. STUDY DESIGN AND METHODS: Using a discrete-time stochastic compartmental model, we simulated implementation of four potential allocation strategies: administering CP to individuals in early hospitalization with COVID-19; administering CP to individuals in outpatient settings; administering CP to hospitalized individuals and administering any remaining CP to outpatient individuals and administering CP in both settings while prioritizing outpatient individuals. We examined the final size of SARS-CoV-2 infections, peak and cumulative hospitalizations, and cumulative deaths under each of the allocation scenarios over a 180-day period. We compared the cost per weighted health benefit under each strategy. RESULTS: Prioritizing administration to patients in early hospitalization, with remaining plasma administered in outpatient settings, resulted in the highest reduction in mortality, averting on average 15% more COVID-19 deaths than administering to hospitalized individuals alone (95% CI [11%-18%]). Prioritizing administration to outpatients, with remaining plasma administered to hospitalized individuals, had the highest percentage of hospitalizations averted (22% [21%-23%] higher than administering to hospitalized individuals alone). DISCUSSION: Convalescent plasma allocation strategy should be determined by the relative priority of averting deaths, infections, or hospitalizations. Under conditions considered, mixed allocation strategies (allocating CP to both outpatient and hospitalized individuals) resulted in a larger percentage of infections and deaths averted than administering CP in a single setting.

Clinical Practice Guidelines From the Association for the Advancement of Blood and Biotherapies (AABB): COVID-19 Convalescent Plasma.

DESCRIPTION: Coronavirus disease 2019 convalescent plasma (CCP) has emerged as a potential treatment of COVID-19. However, meta-analysis data and recommendations are limited. The Association for the Advancement of Blood and Biotherapies (AABB) developed clinical practice guidelines for the appropriate use of CCP. METHODS: These guidelines are based on 2 living systematic reviews of randomized controlled trials (RCTs) evaluating CCP from 1 January 2019 to 26 January 2022. There were 33 RCTs assessing 21 916 participants. The results were summarized using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) method. An expert panel reviewed the data using the GRADE framework to formulate recommendations. RECOMMENDATION 1 (OUTPATIENT): The AABB suggests CCP transfusion in addition to the usual standard of care for outpatients with COVID-19 who are at high risk for disease progression (weak recommendation, moderate-certainty evidence). RECOMMENDATION 2 (INPATIENT): The AABB recommends against CCP transfusion for unselected hospitalized persons with moderate or severe disease (strong recommendation, high-certainty evidence). This recommendation does not apply to immunosuppressed patients or those who lack antibodies against SARS-CoV-2. RECOMMENDATION 3 (INPATIENT): The AABB suggests CCP transfusion in addition to the usual standard of care for hospitalized patients with COVID-19 who do not have SARS-CoV-2 antibodies detected at admission (weak recommendation, low-certainty evidence). RECOMMENDATION 4 (INPATIENT): The AABB suggests CCP transfusion in addition to the usual standard of care for hospitalized patients with COVID-19 and preexisting immunosuppression (weak recommendation, low-certainty evidence). RECOMMENDATION 5 (PROPHYLAXIS): The AABB suggests against prophylactic CCP transfusion for uninfected persons with close contact exposure to a person with COVID-19 (weak recommendation, low-certainty evidence). GOOD CLINICAL PRACTICE STATEMENT: CCP is most effective when transfused with high neutralizing titers to infected patients early after symptom onset.

Acquired platelet storage container leaks and contamination with environmental bacteria: A preventable cause of bacterial sepsis.

BACKGROUND: Apheresis platelets (AP) may be contaminated by environmental bacteria via container defects acquired during processing, transport, storage, or transfusion, as highlighted by a recent series of septic reactions related to Acinetobacter spp. and other bacterial strains. STUDY DESIGN AND METHODS: The frequency and nature of acquired container defect reports to one manufacturer were evaluated from January 2019 to July 2020. The published incidence of contamination and sepsis due to environmental bacteria with culture screened AP in the United States was reviewed for the period of 2010-2019. RESULTS: Review of a manufacturers' records showed 23 US reports of leaks involving 24 containers attributed to postmanufacturing damage, at a rate of 44 per million distributed storage containers. Analysis of returned containers showed evidence of scratches, impressions, and/or piercings. Literature review of US hemovigilance data revealed that environmental bacteria comprised 7% of confirmed positive primary bacterial culture screens, were responsible for 14%-16% of reported septic, and 8 of 28 (29%) fatal reactions with bacterial-culture screened AP. Sepsis cases have been reported with culture screened, point-of-issue (POI) tested, or pathogen-reduced AP. DISCUSSION: Environmental contamination of AP is rare but can cause sepsis. Container damage provides a pathway for contamination after culture screening, POI bacteria testing, or pathogen reduction. Blood collectors and transfusion services should have procedures to ensure proper inspection, handling, storage, and transport of AP to avoid damage and should enhance efforts to detect defects prior to release and to eliminate bacteria from all contacting surfaces to minimize the risk of contamination.

Access to and safety of COVID-19 convalescent plasma in the United States Expanded Access Program: A national registry study.

BACKGROUND: The United States (US) Expanded Access Program (EAP) to coronavirus disease 2019 (COVID-19) convalescent plasma was initiated in response to the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. While randomized clinical trials were in various stages of development and enrollment, there was an urgent need for widespread access to potential therapeutic agents. The objective of this study is to report on the demographic, geographical, and chronological characteristics of patients in the EAP, and key safety metrics following transfusion of COVID-19 convalescent plasma. METHODS AND FINDINGS: Mayo Clinic served as the central institutional review board for all participating facilities, and any US physician could participate as a local physician-principal investigator. Eligible patients were hospitalized, were aged 18 years or older, and had-or were at risk of progression to-severe or life-threatening COVID-19; eligible patients were enrolled through the EAP central website. Blood collection facilities rapidly implemented programs to collect convalescent plasma for hospitalized patients with COVID-19. Demographic and clinical characteristics of all enrolled patients in the EAP were summarized. Temporal patterns in access to COVID-19 convalescent plasma were investigated by comparing daily and weekly changes in EAP enrollment in response to changes in infection rate at the state level. Geographical analyses on access to convalescent plasma included assessing EAP enrollment in all national hospital referral regions, as well as assessing enrollment in metropolitan areas and less populated areas that did not have access to COVID-19 clinical trials. From April 3 to August 23, 2020, 105,717 hospitalized patients with severe or life-threatening COVID-19 were enrolled in the EAP. The majority of patients were 60 years of age or older (57.8%), were male (58.4%), and had overweight or obesity (83.8%). There was substantial inclusion of minorities and underserved populations: 46.4% of patients were of a race other than white, and 37.2% of patients were of Hispanic ethnicity. Chronologically and geographically, increases in the number of both enrollments and transfusions in the EAP closely followed confirmed infections across all 50 states. Nearly all national hospital referral regions enrolled and transfused patients in the EAP, including both in metropolitan and in less populated areas. The incidence of serious adverse events was objectively low (<1%), and the overall crude 30-day mortality rate was 25.2% (95% CI, 25.0% to 25.5%). This registry study was limited by the observational and pragmatic study design that did not include a control or comparator group; thus, the data should not be used to infer definitive treatment effects. CONCLUSIONS: These results suggest that the EAP provided widespread access to COVID-19 convalescent plasma in all 50 states, including for underserved racial and ethnic minority populations. The study design of the EAP may serve as a model for future efforts when broad access to a treatment is needed in response to an emerging infectious disease. TRIAL REGISTRATION: ClinicalTrials.gov NCT#: NCT04338360.

Pandemic blood donor demographics - Do changes impact blood safety?

BACKGROUND: COVID-19 safety measures and possibly SARS-CoV-2 antibody testing may alter blood donor demography, which has the potential to alter blood safety. We characterized pre-pandemic and pandemic rates of donor infectious disease marker (IDM) reactivity which reflect the residual risk of transfusion-transmitted infections (TTIs) undetectable by current testing. METHODS: This cross-sectional analysis of allogeneic blood donor presentations and successful donations in a large national US blood collector identifies changes in self-reported behavioral risk factors and IDM reactivity. Data on allogeneic blood donor presentations and successful donations from March 1 through August 31, 2020 and the same period in 2019 were retrieved from the blood center's computer system. Donor demographics and deferrals for reported behavioral risk factors and confirmed-positive IDMs were compared in pre-pandemic and pandemic periods. RESULTS: With increasing mobile blood drive cancellations, pandemic donors were more likely than 2019 donors to be female, over age 30, non-Hispanic Whites, and have a post-secondary degree. First-time donations (at highest risk for confirmed-positive IDMs) did not substantially increase. Pandemic donors reported fewer behavioral risks and IDMs declined among these donors. Mid-pandemic introduction of screening for SARS-CoV-2 antibodies did not affect IDM rates. CONCLUSIONS: Unlike disasters, which tend to bring out more first-time donors with increased IDM reactivity and TTI residual risk, COVID-19 donors had lower IDM rates which were not affected by SARS-CoV-2 antibody testing. Already-low TTI residual risk is likely to have declined as a result.

An international comparison of HIV prevalence and incidence in blood donors and general population: a BEST Collaborative study.

BACKGROUND AND OBJECTIVES: Efficiency in mitigating HIV transmission risk by transfusion may vary internationally. We compared HIV prevalence and incidence in blood donors across different jurisdictions in relation to those rates in the general population and differences in deferral practices. MATERIALS AND METHODS: Data from 2007 to 2016 were collected in Australia, Brazil (São Paulo), Canada, England, France, Italy, Ireland, Japan, the Netherlands, New Zealand, Norway, Spain (Basque Country), USA (Vitalant) and Wales. For each country/region, the number of HIV antibody-positive donations and nucleic acid testing (NAT)-only-positive donations was broken down according to first-time or repeat donor status, along with the relevant denominators. RESULTS: There is a modest correlation between HIV prevalence among first-time donors and HIV prevalence in the general population. However, rates of HIV-positive donations in repeat donors, a proxy for incidence, do not correlate with incidence rates in the general population. Rates in donors from Italy and Basque Country, where deferral criteria for men having sex with men are less stringent, are higher compared with most other jurisdictions. Rates of NAT-only-positive donations are extremely low and do not differ significantly after adjustment for multiple comparisons. CONCLUSION: Donor HIV rates are only weakly associated with those observed in the general population. Countries with less stringent deferral criteria have higher HIV rates in their donor population, but the rates remain very low.

Donor iron depletion: beneficial or burdensome?

Most purported benefits of blood donation have not been proven. While studies suggest individuals with type II diabetes have transiently improved postdonation glycemic control, the mechanism is unknown. Blood donors with nonanemic or mildly anemic iron deficiency can develop pica and undergo unnecessary diagnostic procedures. Lower infant birth weight has been documented in female blood donors. In other healthy populations, reversible fatigue and exercise capacity impairment occur with mild iron deficiency. The effects of donor iron depletion on cognition and neurocognitive outcomes after pregnancy continue to be studied. Blood collectors are beginning to implement enhanced educational and interventional measures to prevent iron depletion in at-risk donors.

Safety of blood donation by individuals over age 70 and their contribution to the blood supply in five developed countries: a BEST Collaborative group study.

BACKGROUND: Some countries impose an upper age limit on whole blood and double RBC donation while others do not. We evaluated the safety of blood donation in older individuals (≥71 years), and their contribution to the blood supply of five countries. STUDY DESIGN AND METHODS: Twelve blood center members of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative from four countries with no upper age limit for whole blood and double RBC donation (Canada, New Zealand, England, and the United States) or an upper age limit of 80 (Australia) provided 2016 data on donors and donations, deferral rates, and vasovagal reactions by donor age and sex. Donors under age 24 were included in the number of total donors and donations, but not in deferral and reaction rate comparisons. RESULTS: Older donors accounted for 1.0% (New Zealand) to 4.3% (United States) of donors, and 1.5% (New Zealand) to 5.6% (United States) of donations; most were between ages 71 and 76. The deferral rate was higher in older compared to 24- to 70-year-old males, but very similar between older and younger females. In contrast, vasovagal reaction rates were either lower (male donors) or similar (female donor for reactions with loss of consciousness) in older compared to 24- to 70-year-old donors. CONCLUSIONS: Exclusion solely based on older age appears to be unwarranted based on safety concerns such as donor reactions. Healthy older individuals can continue to safely donate and make a significant contribution to the blood supply past arbitrary age limits.

How do we manage iron deficiency after blood donation?

Blood donors and the RBCs and other components they willingly provide are essential in the delivery of healthcare in all parts of the world. Nearly 70% of donated blood comes from repeat or committed donors. The amount of iron removed in the 10 min or so it takes to withdraw a unit of blood (500 ml, plus 25 ml for testing) requires over 24 weeks to replace on a "standard" diet, i.e., without added iron in the form of supplements The cumulative effect of repeat blood donations without adequate iron replacement or a longer wait between donations results in iron deficiency (ID) in many donors, low haemoglobin deferral (~8% of donation attempts), and frank anaemia in some. Moreover, ID can be associated with side effects that can impact a blood donor's health, such as fatigue, cognitive changes and other neuromuscular symptoms. In an effort to better identify and prevent ID, blood collection agencies are recommending various strategies, including changes in the donation interval, donation frequency, testing of iron status and iron supplementation. In this review, we present the evidence basis for these strategies and suggest our own approaches to improving iron balance in blood donors.

Ferritin testing to characterize and address iron deficiency in young donors.

BACKGROUND: Iron deficiency is observed in blood donors who meet hemoglobin requirements for donation. Frequent donation results in negative iron balance, and teenage donors may thus be at risk for adverse health consequences. STUDY DESIGN AND METHODS: Blood Systems implemented ferritin testing on all successful 16- to 18-year-old (teen) donations. Low ferritin (LF) was defined as less than 20 ng/mL in females and less than 30 ng/mL in males. Donors with LF were deferred from red blood cell (RBC) donations (12 months for females, and 6 for males) and counseled to take low-dose iron for 60 days. A ferritin value less than 26 ng/mL indicated iron-deficient erythropoiesis and less than 12 ng/mL absent iron stores. RESULTS: Over 16 months, 110,417 teen donations were tested and represented 10.5% of all successful donations. The rate of absent iron stores was 9.0% (1.9% male; 15.9% female) and of iron-deficient erythropoiesis, 31.9% (12.4% male; 50.6% female). The rate of LF deferrals was 26.9% (16.7% male; 36.6% female). The proportion of LF donors decreased with increasing predonation hemoglobin and rose with increasing RBC donations in the prior 24 months. Seasonality in LF deferrals and the RBC contribution from teen donors was observed. CONCLUSIONS: Ferritin testing of teen donors identified individuals with LF who might benefit from risk mitigation. LF is more common in teenage female than male donors and those with RBC donations in the prior 24 months. An appreciable number of new/lapsed donors presented with LF, however. These data may be useful in guiding future risk mitigation efforts.

Impact of changes to donor hemoglobin criteria on the rate of donor deferral.

BACKGROUND: The Food and Drug Administration's requirements for "Blood and Blood Components Intended for Transfusion or Further Manufacturing Use" (Final Rule) effective May 2016 changed eligibility criteria for blood donors. A multivariate analysis was performed to measure its impact on donor deferral rates. STUDY DESIGN AND METHODS: Four blood centers submitted data for similar 6-month periods before and after implementation of the Final Rule. Data included presenting donors, units collected, deferrals, intended products from deferred donors, deferral reasons, presenting donor demographics, donor hemoglobin (Hgb), hematocrit (HCT), pulse, blood pressure (BP), temperature, and other reasons for deferral. Data were aggregated and periods compared. RESULTS: After Final Rule implementation, successful donations decreased by 1.3% (83.1%-81.9%), despite a 0.2% increase in presenting donors. The rate of Hgb/HCT, pulse, and deferrals increased, while deferrals for other reasons decreased. Male Hgb/HCT deferral rates increased 1.2% (4213 total). Black male donors' Hgb/HCT deferral rate increased (2.7%-5.2%) but was counterbalanced by an overall 3.7% decrease in black female Hgb/HCT deferrals. While Hgb/HCT deferrals of black donors remained stable overall (17.0% vs. 16.2%), this trend was not observed by all centers. Deferrals for pulse increased (0.2%), as did BP deferrals (0.2%). CONCLUSION: Although there was a small increase in presenting donors after implementation of the Final Rule, there was a decrease in successful donations. While it appeared that deferral in black donors was unchanged, this trend was not observed across all centers. Pulse and BP deferrals rose dissimilarly among centers, according to individual procedures.

Improved yield of minimal proportional sample volume platelet bacterial culture.

BACKGROUND: Reports of septic transfusion reactions (STRs) after transfusion of culture-negative platelets (PLTs) justify more effective prevention strategies. Pathogen reduction technologies or performance of additional point-of-issue testing are proposed strategies to enhance safety through Day 5 of storage. STUDY DESIGN AND METHODS: Trima leukoreduced apheresis PLTs (APs) were collected during two study periods (45 and 31 months) using standard procedures, with target settings adjusted during the second period to maintain split rate after increased culture volume. Primary testing for bacterial contamination was performed using BacT/ALERT 3D with sampling from the mother bag 24 to 36 hours after collection. Two culture approaches were compared: in Period A, an 8-mL sample in one aerobic culture bottle (CB), and in Period B a minimal proportional sample volume (PSV) of at least 3.8% of mother bag volume into one to three aerobic CBs (7-10 mL per bottle). RESULTS: In Periods A and B, 188,389 and 159,098 AP collections were tested, respectively. The true-positive (TP) rate in Period A was 0.90 per 10,000 collections and in Period B was 1.83 per 10,000 (p < 0.05). In Period B, 12 of 29 (41%) TP results had discrepant CB results (DCBRs; at least one of multiple bottles without growth). The false-positive rate in Period B, 15.05 per 10,000 collections, was significantly higher than that of Period A, 3.66 per 10,000. One contaminated collection resulting in STR(s) was reported in each study period. Implementation of PSV was operationally successful and did not impact the AP split rate. CONCLUSION: Proportional sample volume improved the sensitivity of primary testing and identified collections that could have escaped detection had only a single bottle with 8- to 10-mL volume been used. PSV may represent another approach to enhanced PLT safety for 5-day storage without a requirement for secondary testing.

Improved donor safety in high-volume apheresis collections.

BACKGROUND: Separators use 1960s sex-based nomograms to estimate apheresis donor blood volume and to calculate the 15% maximum extracorporeal and collection volumes. As US body habitus changes, proportional overestimation of the maximum safe collection volume may become clinically significant with large-volume collections. We correlated 2 years of vasovagal reaction (VVR) data with 148,416 Trima apheresis procedure parameters to identify trends. STUDY DESIGN AND METHODS: Only platelet/plasma with or without red blood cell (RBC) procedures yielded collection volumes of at least 900 mL with no saline replacement. Vasovagal events of any severity were correlated by sex with actual collection volume and donor estimated blood volume (EBV). We performed multivariable analysis incorporating the factors that influence VVR rates to assess the significance of EBV and collection volume. RESULTS: VVR rates nearly doubled in male donors who had collection volumes greater than 1050 mL. No reaction threshold could be identified in female donors. This was confirmed in multivariable analysis that included donor sex, age, donation experience, draw time, and reporting location. CONCLUSION: Limiting apheresis collections to the lesser of 1050 mL or 15% EBV may reduce VVR rates. Further confirmation of this finding by other collection centers is desirable.

An association between ABO group and HLA antibody detection.

BACKGROUND: US blood centers can screen female plateletpheresis donors with a history of one or more pregnancies for both Class I and Class II anti-HLA antibodies using one of two platforms. One is a flow-based assay that yields a quantitative result and the other an enzyme-linked immunosorbent assay (ELISA) that yields either a positive or a negative result (above or below cutoff). STUDY DESIGN AND METHODS: The results of HLA antibody screening tests were analyzed by donor ABO group. Results from large and small American blood collection centers using both platforms were analyzed. Positivity rates were compared by chi-square test and the results stratified by parity using the Mann-Whitney test. RESULTS: No differences in parity were noted among donors of different ABO groups, but a significantly higher rate of HLA antibody positivity was observed among group O donors for the ELISA (31% of group O donors vs. 21% of non-group O donors, p < 0.0001). The higher rate of positivity was primarily due to Class I reactivity. This difference in antibody frequency was not observed at centers using the flow-based assay. CONCLUSION: Centers using the ELISA may have a higher rate of permanent deferral from plateletpheresis donation among group O female donors. Although the reasons for the higher rate of reactivity on Class I ELISA testing are unknown, this could result from test system characteristics or differences in group O donor antibody strength or specificity.

Comparison of donor and general population demographics over time: a BEST Collaborative group study.

BACKGROUND: We compared donor and general population demographics over time to provide insight into current donation patterns and the future adequacy of the blood supply. STUDY DESIGN AND METHODS: Seventeen blood center members of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative from 12 countries provided the number of donors and people in the general population by demographic category for 2001 and 2011, changes in age criteria, and percentage of first-time donors. We calculated the median age of donors and the general population and determined the percentage of each group in age and sex cohorts. RESULTS: Age criteria vary, with upper limits recently liberalized in several countries. In 2011, the percentage of first-time donors ranged from 10% to 41%. The median age of the donor and general population increased from 2001 to 2011 in most countries, as did the percentage of the general population over 60. The youngest donor cohort is overrepresented to a variable degree; this tendency increased over time. Although still underrepresented, older donors contributed more in 2011. A large middle-aged cohort is aging at a rate exceeding the progression of time, while 25- to 45-year-olds are relatively underrepresented. CONCLUSIONS: All participating countries are experiencing aging of their general population. Donor demographics differ substantially between countries; this can be only partly explained by population demographics and age criteria. Many countries have an aging middle-aged donor and population cohort and are increasingly relying on their youngest donors to contribute disproportionately to the blood supply.

First cases of Zika virus-infected US blood donors outside states with areas of active transmission.

BACKGROUND: Zika virus (ZIKV) is transmitted by Aedes mosquitos and can result in severe congenital and adult neurologic abnormalities. ZIKV has rapidly spread northward through Central America and the Caribbean and autochthonous cases have been identified in the continental United States. High rates of ZIKA RNA positivity were detected in blood donors during previous epidemics. ZIKV transmission by transfused blood from healthy donor components has been a growing concern. STUDY DESIGN AND METHODS: Individual-donation aliquots of plasma from volunteer blood donors were tested individually with an investigational Procleix ZIKV assay. Initially reactive samples were tested for ZIKV RNA in plasma and red blood cells (RBCs) and for ZIKV-specific antibodies in serum. A confirmed positive classification required confirmation of RNA and/or detection of ZIKV antibodies in index and/or follow-up samples. RESULTS: Between September 19 and November 30, 2016, a total of 466,834 donations were screened for ZIKV RNA. Five donors (one in approx. 93,000) were reactive for ZIKV RNA by both the Procleix ZIKV assay and supplemental testing. The donations were collected outside areas considered as having active transmission, and all five donors had travel exposures. A lookback case demonstrated no infection despite transfusion of a Zika IgG-positive platelet (PLT) component with probable low levels of ZIKV RNA. CONCLUSIONS: This report describes the first ZIKV-positive donors detected outside areas with active transmission. These donors most likely represent travel-acquired "tail-end infections" with prolonged RBC-associated ZIKV RNA. The lack of transmission to the recipient of an apheresis PLT may suggest that these units are not infectious.