COVID-19 vaccine effectiveness against SARS-CoV-2 infection in the United States prior to the Delta and Omicron-associated surges: a retrospective cohort study of repeat blood donors

To inform public health policy, it is critical to monitor COVID-19 vaccine effectiveness (VE), including against acquiring infection. We estimated VE using self-reported vaccination in a retrospective cohort of repeat blood donors who donated during the first half of 2021, demonstrating a viable approach for monitoring of VE via serological surveillance. Using Poisson regression, we estimated an overall VE of 88.8% (95% CI: 86.2–91.1), adjusted for demographic covariates and variable baseline risk. Time since first reporting vaccination, age, race-ethnicity, region, and calendar time were statistically significant predictors of incident infection.

Population-Weighted Seroprevalence From Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection, Vaccination, and Hybrid Immunity Among US Blood Donations From January to December 2021

BACKGROUND

Previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) vaccination, independently and combined ("hybrid immunity"), result in partial protection from subsequent infection and strong protection from severe disease. Proportions of the US population who have been infected, vaccinated, or have hybrid immunity remain unclear, posing a challenge for assessing effective pandemic mitigation strategies.

METHODS

In this serial cross-sectional study, nationwide blood donor specimens collected during January-December 2021 were tested for anti-spike and anti-nucleocapsid antibodies, and donor COVID-19 vaccination history of ≥1 dose was collected. Monthly seroprevalence induced from SARS-CoV-2 infection, COVID-19 vaccination, or both, were estimated. Estimates were weighted to account for demographic differences from the general population and were compared temporally and by demographic factors.

RESULTS

Overall, 1 123 855 blood samples were assayed. From January to December 2021, the weighted percentage of donations with seropositivity changed as follows: seropositivity due to vaccination without previous infection, increase from 3.5% (95% confidence interval, 3.4%-3.7%) to 64.0%, (63.5%-64.5%); seropositivity due to previous infection without vaccination, decrease from 15.6% (15.2%-16.0%) to 11.7% (11.4%-12.0%); and seropositivity due to hybrid immunity, increase from 0.7% (0.6%-0.7%) to 18.9% (18.5%-19.3%). Combined seroprevalence from infection, vaccination, or both increased from 19.8% (19.3%-20.2%) to 94.5% (93.5%-94.0%). Infection- and vaccination-induced antibody responses varied significantly by age, race-ethnicity, and region, but not by sex.

CONCLUSIONS

Our results indicate substantial increases in population humoral immunity from SARS-CoV-2 infection, COVID-19 vaccination, and hybrid immunity during 2021. These findings are important to consider in future COVID-19 studies and long-term pandemic mitigation efforts.

Does Religiosity Predict Blood Donation in Brazil?

The aim of this study was to investigate the association of religiosity with blood donation in a representative/stratified sample of primary healthcare users of Ribeirão Preto, São Paulo, Brazil. A cross-sectional study was conducted using the Duke University Religious Index-DUREL (dimensions: organizational, non-organizational, and intrinsic religiosity). Odds ratios adjusted by sex and age were used as measures of association. A total of 1055 individuals participated (79.7% females; mean age = 40.6 years); 23.3% had previously donated blood. Most reported having a religion and grew up in a religious environment. High frequencies of religiosity were observed. Similar DUREL scores were observed among participants who donated blood and those who did not. Family members and close friends had significant influence on participants' blood donation practices. Religiosity was not directly associated with blood donation despite the high prevalence and scores of religiosity. However, possible associations between religion and blood donation should consider mediating variables in future studies.

Cost-effectiveness of pathogen reduction technology for plasma and platelets in Québec: A focus on potential emerging pathogens

BACKGROUND

The last economic evaluation of pathogen reduction technology (PRT) in Canada was conducted in 2007. We reassessed the cost-effectiveness of PRT in the province of Québec (which has its own blood supplier) and included an evaluation of the potential impact of emerging pathogens on cost-effectiveness.

STUDY DESIGN AND METHODS

Decision analytic Markov models were developed to simulate the costs and quality-adjusted life-years (QALY) associated with PRT as an addition to existing safety measures for plasma and platelet products (except for bacterial culture). Models accounted for several infectious and noninfectious transfusion reactions, recipients' productivity losses ensuing from these reactions, and the impact of PRT on platelet function. Scenario analyses were conducted to evaluate the impact of a new highly contagious human immunodeficiency virus (HIV)-like or West Nile virus (WNV)-like pathogen, assuming various epidemiological scenarios.

RESULTS

In the base case, the incremental cost-effectiveness ratio (ICER) of PRT was estimated at $8,088,974/QALY gained. Assuming the presence of an HIV-like pathogen, the ICER was $265,209/QALY gained in the "average transmission" scenario, $1,274,445/QALY gained in the "rapid testing scenario," and $123,063/QALY gained in the "highly contagious" scenario. Assuming the presence of a WNV-like pathogen, the ICER was $7,469,167/QALY gained in the "average transmission" scenario and $6,652,769/QALY gained in the "highly contagious" scenario.

CONCLUSION

The cost-effectiveness of PRT may substantially improve in the event of a new, blood-borne pathogen. Given their significant impact on cost-effectiveness, the emergence of new pathogens should be considered when deciding whether to adopt PRT.

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P): A research program striving to improve blood donor safety and optimize transfusion outcomes across the lifespan

BACKGROUND

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P) is a new iteration of prior National Heart, Lung, and Blood Institute (NHLBI) REDS programs that focus on improving transfusion recipient outcomes across the lifespan as well as the safety and availability of the blood supply.

STUDY DESIGN AND METHODS

The US program includes blood centers and hospitals (22 including 6 free-standing Children's hospitals) in four geographic regions. The Brazilian program has 5 participating hemocenters. A Center for Transfusion Laboratory Studies (CTLS) and a Data Coordinating Center (DCC) support synergistic studies and activities over the 7-year REDS-IV-P program.

RESULTS

The US is building a centralized, vein-to-vein (V2V) database, linking information collected from blood donors, their donations, the resulting manufactured components, and data extracts from hospital electronic medical records of transfused and non-transfused patients. Simultaneously, the Brazilian program is building a donor, donation, and component database. The databases will serve as the backbone for retrospective and prospective observational studies in transfusion epidemiology, transfusion recipient outcomes, blood component quality, and emerging blood safety issues. Special focus will be on preterm infants, patients with sickle cell disease, thalassemia or cancer, and the effect of donor biologic variability and component manufacturing on recipient outcomes. A rapid response capability to emerging safety threats has resulted in timely studies related to Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2).

CONCLUSIONS

The REDS-IV-P program endeavors to improve donor-recipient-linked research with a focus on children and special populations while also maintaining the flexibility to address emerging blood safety issues.

Prevalence and Risk Factors for Human T-Cell Lymphotropic Virus (HTLV) in Blood Donors in Brazil-A 10-Year Study (2007-2016)

It is unknown whether HTLV-1/2 prevalence has been stable or changing with time in Brazil. We present a 10-year (2007–2016) analysis of HTLV-1/2 infection in first-time blood donors from four blood banks in Brazil. The Brazilian blood centers participating in this multicenter Recipient Epidemiology and Donor Evaluation Study (REDS) are located in Recife in the Northeast and in São Paulo, Rio de Janeiro and Belo Horizonte located in the Southeast of the country. A previous REDS study using the same database from 2007 to 2009 showed that the prevalence per 100,000 donors was 222 in Recife, 83 in Belo Horizonte and 101 in São Paulo. From 2007 to 2016, HTLV-1/2 prevalence was calculated by year, blood center and birth cohort. Covariates included age, gender, schooling, self-reported skin color and type of donation. From 1,092,174 first-blood donations, in the general analysis, HTLV-1/2 infection predominated in females, donors over 50 years of age, black skin color and less educated. The average prevalence was 228 per 100,000 donors in Recife, 222 in Rio de Janeiro, 104 in Belo Horizonte and 103 in São Paulo. In the 10-year analysis, HTLV-1/2 prevalence was stable, but a trend was observed toward an increase in HTLV-1/2 infection among younger people (p < 0.001), males (p = 0.049), those with white skin color (p < 0.001), and higher education (p = 0.014). Therefore, this 10-year surveillance of the infection showed stable HTLV-1/2 prevalence overall but a trend toward increased prevalence among the younger and more educated donors despite Brazilian policies to control sexually transmitted infections being in place for more than 10 years.

Genetic determinants of telomere length from 109,122 ancestrally diverse whole-genome sequences in TOPMed

Genetic studies on telomere length are important for understanding age-related diseases. Prior GWAS for leukocyte TL have been limited to European and Asian populations. Here, we report the first sequencing-based association study for TL across ancestrally-diverse individuals (European, African, Asian and Hispanic/Latino) from the NHLBI Trans-Omics for Precision Medicine (TOPMed) program. We used whole genome sequencing (WGS) of whole blood for variant genotype calling and the bioinformatic estimation of telomere length in n=109,122 individuals. We identified 59 sentinel variants (p-value <5×10-9) in 36 loci associated with telomere length, including 20 newly associated loci (13 were replicated in external datasets). There was little evidence of effect size heterogeneity across populations. Fine-mapping at OBFC1 indicated the independent signals colocalized with cell-type specific eQTLs for OBFC1 (STN1). Using a multi-variant gene-based approach, we identified two genes newly implicated in telomere length, DCLRE1B (SNM1B) and PARN. In PheWAS, we demonstrated our TL polygenic trait scores (PTS) were associated with increased risk of cancer-related phenotypes.

Economic implications of FDA platelet bacterial guidance compliance options: Comparison of single-step strategies

BACKGROUND

Bloodborne pathogens pose a major safety risk in transfusion medicine. To mitigate the risk of bacterial contamination in platelet units, FDA issues updated guidance materials on various bacterial risk control strategies (BRCS). This analysis presents results of a budget impact model updated to include 5- and 7-day pathogen reduced (PR) and large volumed delayed sampling (LVDS) BRCS.

STUDY DESIGN AND METHODS

Model base-case parameter inputs were based on scientific literature, a survey distributed to 27 US hospitals, and transfusion experts' opinion. The outputs include hospital budget and shelf-life impacts for 5- and 7-day LVDS, and 5- and 7-day PR units under three different scenarios: (1) 100% LVDS, (2) 100% PR, and (3) mix of 50% LVDS - and 50% PR.

RESULTS

Total annual costs from the hospital perspective were highest for 100% LVDS platelets (US$2.325M) and lowest for 100% PR-7 units (US$2.170M). Net budget impact after offsetting annual costs by outpatient reimbursements was 5.5% lower for 5-day PR platelets as compared to 5-day LVDS (US$1.663 vs. US$1.760M). A mix of 7-day LVDS and 5-day PR platelets had net annual costs that were 1.3% lower than for 100% 7-day LVDS, but 1.3% higher than for 100% 5-day PR. 7-day PR platelets had the longest shelf life (4.63 days), while 5-day LVDS had the shortest (2.00 days).

DISCUSSION

The model identifies opportunities to minimize transfusion center costs for 5- and 7-day platelets. Budget impact models such as this are important for understanding the financial implications of evolving FDA guidance and new platelet technologies.

Clonal hematopoiesis in sickle cell disease

BACKGROUND

Curative gene therapies for sickle cell disease (SCD) are currently undergoing clinical evaluation. The occurrence of myeloid malignancies in these trials has prompted safety concerns. Individuals with SCD are predisposed to myeloid malignancies, but the underlying causes remain undefined. Clonal hematopoiesis (CH) is a pre-malignant condition that also confers significant predisposition to myeloid cancers. While it has been speculated that CH may play a role in SCD-associated cancer predisposition, limited data addressing this issue have been reported.

METHODS

Here, we leveraged 74,190 whole genome sequences to robustly study CH in SCD. Somatic mutation calling methods were used to assess CH in all samples and comparisons between individuals with and without SCD were performed.

RESULTS

While we had sufficient power to detect a greater than 2-fold increased rate of CH, we found no detectable variation in rate or clone properties between individuals affected by SCD and controls. The rate of CH in individuals with SCD was unaltered by hydroxyurea use.

CONCLUSIONS

We did not observe an increased risk for acquiring detectable CH in SCD, at least as measured by whole genome sequencing. These results should help guide ongoing efforts and further studies that seek to better define the risk factors underlying myeloid malignancy predisposition in SCD and help ensure that curative therapies can be more safely applied.

FUNDING

Funding was provided by the New York Stem Cell Foundation and National Institutes of Health. The funders had no role in study design or reporting.

Current challenges of severe acute respiratory syndrome coronavirus 2 seroprevalence studies among blood donors: A scoping review

BACKGROUND AND OBJECTIVES

Blood donors are increasingly being recognized as an informative resource for surveillance. We aimed to review severe acute respiratory syndrome coronavirus 2 seroprevalence studies conducted among blood donors to investigate methodological biases and provide guidance for future research.

MATERIALS AND METHODS

We conducted a scoping review of peer-reviewed and preprint publications between January 2020 and January 2021. Two reviewers used standardized forms to extract seroprevalence estimates and data on methodology pertaining to population sampling, periodicity, assay characteristics, and antibody kinetics. National data on cumulative incidence and social distancing policies were extracted from publicly available sources and summarized.

RESULTS

Thirty-three studies representing 1,323,307 blood donations from 20 countries worldwide were included (sample sizes ranged from 22 to 953,926 donations). The majority of the studies (79%) reported seroprevalence rates <10% (ranging from 0% to 76% [after adjusting for waning antibodies]). Overall, less than 1 in 5 studies reported standardized seroprevalence rates to reflect the demographics of the general population. Stratification by age and sex were most common (64% of studies), followed by region (48%). A total of 52% of studies reported seroprevalence at a single time point. Overall, 27 unique assay combinations were identified, 55% of studies used a single assay and only 39% adjusted seroprevalence rates for imperfect test characteristics. Among the nationally representative studies, case detection was most underrepresented in Kenya (1:1264).

CONCLUSION

By the end of 2020, seroprevalence rates were far from reaching herd immunity. In addition to differences in community transmission and diverse public health policies, study designs and methodology were likely contributing factors to seroprevalence heterogeneity.

Donor genetic and non-genetic factors affecting red blood cell transfusion effectiveness

BACKGROUND

Red blood cell (RBC) transfusion effectiveness varies due to donor, component, and recipient factors. Prior studies identified characteristics associated with variation in hemoglobin increments following transfusion. We extended these observations, examining donor genetic and non-genetic factors affecting transfusion effectiveness.

METHODS

This is a multicenter retrospective study of 46,705 patients, and 102,043 evaluable RBC transfusions from 2013-2016 across 12 hospitals. Transfusion effectiveness was defined as hemoglobin, bilirubin, or creatinine increments following single RBC unit transfusion. Models incorporated a subset of donors with data on single nucleotide polymorphisms associated with osmotic and oxidative hemolysis in vitro. Mixed modelling accounting for repeated transfusion episodes identified predictors of transfusion effectiveness.

RESULTS

Blood donor (sex, Rh status, fingerstick hemoglobin, smoking), component (storage duration, gamma irradiation, leukoreduction, apheresis collection, storage solution), and recipient (sex, body mass index, race, age) characteristics were associated with hemoglobin and bilirubin but not creatinine increments following RBC transfusions. Increased storage duration was associated with increased bilirubin and decreased hemoglobin increments, suggestive of in vivo hemolysis following transfusion. Donor G6PD-deficiency and polymorphisms in SEC14L4, HBA2, and MYO9B genes were associated with decreased hemoglobin increments. Donor G6PD-deficiency and polymorphisms in SEC14L4 were associated with increased transfusion requirements in the subsequent 48 hours.

CONCLUSIONS

Donor genetic and other factors, such as RBC storage duration, affect transfusion effectiveness as defined by decreased hemoglobin or increased bilirubin increments. Addressing these factors will provide a precision medicine approach to improve patient outcomes, particularly for chronically-transfused RBC recipients, who would most benefit from more effective transfusion products.

Individualized risk trajectories for iron-related adverse outcomes in repeat blood donors

BACKGROUND

Despite a fingerstick hemoglobin requirement and 56-day minimum donation interval, repeat blood donation continues to cause and exacerbate iron deficiency.

STUDY DESIGN AND METHODS

Using data from the REDS-II Donor Iron Status Evaluation study, we developed multiclass prediction models to estimate the competing risk of hemoglobin deferral and collecting blood from a donor with sufficient hemoglobin but low or absent underlying iron stores. We compared models developed with and without two biomarkers not routinely measured in most blood centers: ferritin and soluble transferrin receptor. We generated and analyzed "individual risk trajectories": estimates of how each donors' risk developed as a function of the time interval until their next donation attempt.

RESULTS

With standard biomarkers, the top model had a multiclass area under the receiver operator characteristic curve (AUC) of 77.6% (95% CI [77.3%-77.8%]). With extra biomarkers, multiclass AUC increased to 82.8% (95% CI [82.5%-83.1%]). In the extra biomarkers model, ferritin was the single most important variable, followed by the donation interval. We identified three risk archetypes: "fast recoverers" (<10% risk of any adverse outcome on post-donation day 56), "slow recoverers" (>60% adverse outcome risk on day 56 that declines to <35% by day 250), and "chronic high-risk" (>85% risk of the adverse outcome on day 250).

DISCUSSION

A longer donation interval reduced the estimated risk of iron-related adverse outcomesfor most donors, but risk remained high for some. Tailoring safeguards to individual risk estimates could reduce blood collections from donors with low or absent iron stores.

Cost-effectiveness and budget impact of whole blood pathogen reduction in Ghana

BACKGROUND

Despite the promise of pathogen reduction for reducing transfusion-associated adverse events in sub-Saharan Africa, no health-economic assessment is publicly available.

STUDY DESIGN AND METHODS

We developed a mathematical risk reduction model to estimate the impact of nationwide whole blood pathogen reduction in Ghana on the incidence of six infectious and one non-infectious transfusion-associated adverse events. We estimated the lifetime direct healthcare costs and disability-adjusted life years lost for each adverse event. For HIV, HCV, and HBV, we simulated disease progression using Markov models, accounting for the likelihood and timing of clinical detection and treatment. We performed probabilistic and univariate sensitivity analysis.

RESULTS

Adding whole blood pathogen reduction to Ghana's blood safety portfolio would avert an estimated 19,898 (11,948-27,353) adverse events and 38,491 (16,444-67,118) disability-adjusted life years annually, primarily by averting sepsis (49%) and malaria (31%) infections. One year of pathogen reduction would cost an estimated $8,037,191 ($6,381,946-$9,880,760) and eliminate $8,656,389 ($4,462,614-$13,469,448) in direct healthcare spending on transfusion-associated adverse events. We estimate a 58% probability that the addition of pathogen reduction would reduce overall direct healthcare spending. Findings were most sensitive to uncertainty in the probability that a bacterially contaminated blood donation causes sepsis.

CONCLUSION

Whole blood pathogen reduction would substantially reduce the burden of known transfusion-associated adverse events in Ghana and may reduce overall healthcare spending. Additional benefits not captured by this analysis may include averting secondary transmission of infectious diseases, reducing non-medical costs, and averting new or re-emerging transfusion-transmitted infections.

Estimated US Infection- and Vaccine-Induced SARS-CoV-2 Seroprevalence Based on Blood Donations, July 2020-May 2021

IMPORTANCE

People who have been infected with or vaccinated against SARS-CoV-2 have reduced risk of subsequent infection, but the proportion of people in the US with SARS-CoV-2 antibodies from infection or vaccination is uncertain.

OBJECTIVE

To estimate trends in SARS-CoV-2 seroprevalence related to infection and vaccination in the US population.

DESIGN, SETTING, AND PARTICIPANTS

In a repeated cross-sectional study conducted each month during July 2020 through May 2021, 17 blood collection organizations with blood donations from all 50 US states; Washington, DC; and Puerto Rico were organized into 66 study-specific regions, representing a catchment of 74% of the US population. For each study region, specimens from a median of approximately 2000 blood donors were selected and tested each month; a total of 1 594 363 specimens were initially selected and tested. The final date of blood donation collection was May 31, 2021.

EXPOSURE

Calendar time.

MAIN OUTCOMES AND MEASURES

Proportion of persons with detectable SARS-CoV-2 spike and nucleocapsid antibodies. Seroprevalence was weighted for demographic differences between the blood donor sample and general population. Infection-induced seroprevalence was defined as the prevalence of the population with both spike and nucleocapsid antibodies. Combined infection- and vaccination-induced seroprevalence was defined as the prevalence of the population with spike antibodies. The seroprevalence estimates were compared with cumulative COVID-19 case report incidence rates.

RESULTS

Among 1 443 519 specimens included, 733 052 (50.8%) were from women, 174 842 (12.1%) were from persons aged 16 to 29 years, 292 258 (20.2%) were from persons aged 65 years and older, 36 654 (2.5%) were from non-Hispanic Black persons, and 88 773 (6.1%) were from Hispanic persons. The overall infection-induced SARS-CoV-2 seroprevalence estimate increased from 3.5% (95% CI, 3.2%-3.8%) in July 2020 to 20.2% (95% CI, 19.9%-20.6%) in May 2021; the combined infection- and vaccination-induced seroprevalence estimate in May 2021 was 83.3% (95% CI, 82.9%-83.7%). By May 2021, 2.1 SARS-CoV-2 infections (95% CI, 2.0-2.1) per reported COVID-19 case were estimated to have occurred.

CONCLUSIONS AND RELEVANCE

Based on a sample of blood donations in the US from July 2020 through May 2021, vaccine- and infection-induced SARS-CoV-2 seroprevalence increased over time and varied by age, race and ethnicity, and geographic region. Despite weighting to adjust for demographic differences, these findings from a national sample of blood donors may not be representative of the entire US population.

HIV residual risk in Canada for apheresis source plasma donation without deferral for men who have sex with men

BACKGROUND AND OBJECTIVES

In Canada, men having sex with men (MSM) are deferred for 3 months from last sexual contact to reduce human immunodeficiency virus (HIV) risk to recipients. The aim of this paper was to model the Canadian residual risk of HIV-positive source plasma incorporating pathogen inactivation (PI) under no MSM deferral scenarios for apheresis plasma donations.

MATERIALS AND METHODS

A combined Bayesian network (BN) and Monte Carlo approach were implemented to estimate the HIV residual risk under 3-month deferral compared with no deferral without quarantine scenarios for MSM donors. Models involve the stochastic generation of donation and its infection status based on its corresponding simulated donor profile. Viral load reduction conferred by PI used by source plasma fractionators was simulated. Model parameters were derived from Héma-Québec and Canadian Blood Services data, viral loads in a large sample of HIV-positive US blood donors, CSL Behring documentation and from published data.

RESULTS

In the most likely scenario for the 3-month deferral model, there were 2.71 positive donations per 1,000,000 donations (95% confidence interval [CI] 2.63-2.78). For the no-deferral model, there were 3.01 positive donations per 1,000,000 donations (95% CI 2.94-3.09). For both scenarios, the risk of having an infectious pool was 0 in 300,000 pools (95% CI 0-0.0000123) after consideration of PI.

CONCLUSION

Based on simulation results, there would be a negligible HIV residual risk associated with the removal of a time-based MSM deferral without quarantine for source plasma incorporating PI.

An international comparison of anti-SARS-COV-2 assays used for seroprevalence surveys from blood component providers

BACKGROUND AND OBJECTIVES

Access to large pools of healthy adult donors advantageously positions blood component providers to undertake anti-SARS-CoV-2 seroprevalence studies. While numerous seroprevalence reports have been published by blood operators during the COVID-19 pandemic, details on the assay used has not been well documented. The objectives of this study were to evaluate the diversity of assays being used by blood operators and assess how this may affect seroprevalence estimates.

MATERIALS AND METHODS

We surveyed 49 blood component providers from 39 countries. Questionnaire included information on the number and identity of assays used, the detected immunoglobulin(s) and target antigen, and performance characteristics (sensitivity, specificity).

RESULTS

Thirty-eight of the 49 contacted blood suppliers provided at least partial responses. The results indicate that 19 commercial and five in-house serology assays have been used by surveyed blood operators. The Abbott SARS-CoV-2 IgG assay was the most commonly used kit and utilized by 15 blood suppliers. Two assays did not detect IgG, but detected either IgM/IgA or IgM. 68·2% of assays targeted the spike protein and 50% the nucleocapsid protein, while 18·2% targeted both viral proteins. The sensitivity and specificity of IgG-specific assays ranged from 71·9% to 100% and from 96·2% to 100%, respectively. As of 18 October 2020, the seroprevalence was below 5% in 10 of 14 countries reporting.

CONCLUSION

Our results highlight the diversity of assays being used. Analyses comparing blood donor seroprevalence across countries should consider assay characteristics with optimization of signal/cut-off ratios and consistent methodology to adjust for waning antibody.

HIV primary drug resistance and associated HIV risk factors among HIV positive blood donors in Brazil from 2007 to 2017

BACKGROUND

Acquisition of HIV primary drug resistant (PDR) infection can lead to poor virologic and clinical outcomes in individuals and hampers public health efforts in epidemic control. Monitoring PDR in HIV-positive blood donors can be used to inform nationwide trends in the spread of drug-resistant HIV strains.

METHODS

We conducted a cross-sectional study using genetic sequence analysis to assess HIV pol sequences, PDR, and risk factors for infection using audio computer-assisted structured interviews in four large blood centers in Brazil from 2007 to 2017.

RESULTS

Of 716 HIV-positive blood donors, 504 (70.4%) were successfully sequenced. HIV clade B (73.2%) was the most prevalent subtype, followed by a mix of non-B (21.2%) sub-types. A twofold increase (from 4% to 8%) in recombinants prevalence was observed during the study period. Sixty-four (12.7%) presented PDR. Overall, HIV PDR prevalence remained stable during the study period. Drug resistance mutations for non-nucleoside reverse transcriptase inhibitors were found in 39 (7.7%) donors, while for nucleoside reverse transcriptase inhibitors were found in 26 (5.1%), and for protease inhibitors in 24 (4.8%) of HIV-infected donors. We did not find statistically significant differences in demographics, behavioural risk factors, or HIV genotypes when comparing volunteers with and without PDR.

CONCLUSION

The HIV PDR rate among donors remained stable during the study period. HIV-positive blood donors can be an informative population to monitor primary HIV resistance and ultimately may help to increase the knowledge and awareness of HIV risk factors and PDR.

Optimal portfolios of blood safety interventions: test, defer or modify?

A safe supply of blood for transfusion is a critical component of the healthcare system in all countries. Most health systems manage the risk of transfusion-transmissible infections (TTIs) through a portfolio of blood safety interventions. These portfolios must be updated periodically to reflect shifting epidemiological conditions, emerging infectious diseases, and new technologies. However, the number of available blood safety portfolios grows exponentially with the number of available interventions, making it impossible for policymakers to evaluate all feasible portfolios without the assistance of a computer model. We develop a novel optimization model for evaluating blood safety portfolios that enables systematic comparison of all feasible portfolios of deferral, testing, and modification interventions to identify the portfolio that is preferred from a cost-utility perspective. We present structural properties that reduce the state space and required computation time in certain cases, and we develop a linear approximation of the model. We apply the model to retrospectively evaluate U.S. blood safety policies for Zika and West Nile virus for the years 2017, 2018, and 2019, defining donor groups based on season and geography. We leverage structural properties to efficiently find an optimal solution. We find that the optimal portfolio varies geographically, seasonally, and over time. Additionally, we show that for this problem the approximated model yields the same optimal solution as the exact model. Our method enables systematic identification of the optimal blood safety portfolio in any setting and any time period, thereby supporting decision makers in efforts to ensure the safety of the blood supply.

Factors driving availability of COVID-19 convalescent plasma: Insights from a demand, production, and supply model

Background

COVID‐19 Convalescent Plasma (CCP) is a promising treatment for COVID‐19. Blood collectors have rapidly scaled up collection and distribution programs.

Methods

We developed a detailed simulation model of CCP donor recruitment, collection, production, and distribution processes. We ran our model using varying epidemic trajectories from 11 U.S. states and with key input parameters drawn from wide ranges of plausible values to identify key drivers of ability to scale collections capacity and meet demand for CCP.

Results

Utilization of available CCP collections capacity followed increases in COVID‐19 hospital discharges with a lag. Utilization never exceeded 75% of available capacity in most simulations. Demand was met for most of the simulation period in most simulations, but a substantial portion of demand went unmet during early, sharp increases in hospitalizations. For epidemic trajectories that included multiple epidemic peaks, second wave demand could generally be met due to stockpiles established during the decline from an earlier peak. Apheresis machine capacity (number of machines) and probability that COVID‐19 recovered individuals are willing to donate were the most important supply‐side drivers of ability to meet demand. Recruitment capacity was important in states with early peaks.

Conclusions

Epidemic trajectory was the most important determinant of ability to meet demand for CCP, although our simulations revealed several contributing operational drivers of CCP program success.

Sequencing of 53,831 diverse genomes from the NHLBI TOPMed Program

The Trans-Omics for Precision Medicine (TOPMed) programme seeks to elucidate the genetic architecture and biology of heart, lung, blood and sleep disorders, with the ultimate goal of improving diagnosis, treatment and prevention of these diseases. The initial phases of the programme focused on whole-genome sequencing of individuals with rich phenotypic data and diverse backgrounds. Here we describe the TOPMed goals and design as well as the available resources and early insights obtained from the sequence data. The resources include a variant browser, a genotype imputation server, and genomic and phenotypic data that are available through dbGaP (Database of Genotypes and Phenotypes)1. In the first 53,831 TOPMed samples, we detected more than 400 million single-nucleotide and insertion or deletion variants after alignment with the reference genome. Additional previously undescribed variants were detected through assembly of unmapped reads and customized analysis in highly variable loci. Among the more than 400 million detected variants, 97% have frequencies of less than 1% and 46% are singletons that are present in only one individual (53% among unrelated individuals). These rare variants provide insights into mutational processes and recent human evolutionary history. The extensive catalogue of genetic variation in TOPMed studies provides unique opportunities for exploring the contributions of rare and noncoding sequence variants to phenotypic variation. Furthermore, combining TOPMed haplotypes with modern imputation methods improves the power and reach of genome-wide association studies to include variants down to a frequency of approximately 0.01%.

Diversity of variant alleles encoding Kidd, Duffy, and Kell antigens in individuals with sickle cell disease using whole genome sequencing data from the NHLBI TOPMed Program

BACKGROUND

Genetic variants in the SLC14A1, ACKR1, and KEL genes, which encode Kidd, Duffy, and Kell red blood cell antigens, respectively, may result in weakened expression of antigens or a null phenotype. These variants are of particular interest to individuals with sickle cell disease (SCD), who frequently undergo chronic transfusion therapy with antigen-matched units. The goal was to describe the diversity and the frequency of variants in SLC14A1, ACKR1, and KEL genes among individuals with SCD using whole genome sequencing (WGS) data.

STUDY DESIGN AND METHODS

Two large SCD cohorts were studied: the Recipient Epidemiology and Donor Evaluation Study III (REDS-III) (n = 2634) and the Outcome Modifying Gene in SCD (OMG) (n = 640). Most of the studied individuals were of mixed origin. WGS was performed as part of the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine (TOPMed) program.

RESULTS

In SLC14A1, variants included four encoding a weak Jka phenotype and five null alleles (JKnull ). JKA*01N.09 was the most common JKnull . One possible JKnull mutation was novel: c.812G>T. In ACKR1, identified variants included two that predicted Fyx (FY*X) and one corresponding to the c.-67T>C GATA mutation. The c.-67T>C mutation was associated with FY*A (FY*01N.01) in four participants. FY*X was identified in 49 individuals. In KEL, identified variants included three null alleles (KEL*02N.17, KEL*02N.26, and KEL*02N.04) and one allele predicting Kmod phenotype, all in heterozygosity.

CONCLUSIONS

We described the diversity and distribution of SLC14A1, ACKR1, and KEL variants in two large SCD cohorts, comprising mostly individuals of mixed ancestry. This information may be useful for planning the transfusion support of patients with SCD.