Retrovirus Epidemiology Donor Study Research Articles

Machine learning for predicting Chagas disease infection in rural areas of Brazil.

Chagas disease is a severe parasitic illness that is prevalent in Latin America and often goes unaddressed. Early detection and treatment are critical in preventing the progression of the illness and its associated life-threatening complications. In recent years, machine learning algorithms have emerged as powerful tools for disease prediction and diagnosis. In this study, we developed machine learning algorithms to predict the risk of Chagas disease based on five general factors: age, gender, history of living in a mud or wooden house, history of being bitten by a triatomine bug, and family history of Chagas disease. We analyzed data from the Retrovirus Epidemiology Donor Study (REDS) to train five popular machine learning algorithms. The sample comprised 2,006 patients, divided into 75% for training and 25% for testing algorithm performance. We evaluated the model performance using precision, recall, and AUC-ROC metrics. The Adaboost algorithm yielded an AUC-ROC of 0.772, a precision of 0.199, and a recall of 0.612. We simulated the decision boundary using various thresholds and observed that in this dataset a threshold of 0.45 resulted in a 100% recall. This finding suggests that employing such a threshold could potentially save 22.5% of the cost associated with mass testing of Chagas disease. Our findings highlight the potential of applying machine learning to improve the sensitivity and effectiveness of Chagas disease diagnosis and prevention. Furthermore, we emphasize the importance of integrating socio-demographic and environmental factors into neglected disease prediction models to enhance their performance.

Probable transmission of hepatitis E virus (HEV) via transfusion in the United States.

Hepatitis E virus (HEV) can inapparently infect blood donors. To assess transfusion transmission of HEV in the United States, which has not been documented, a donor-recipient repository was evaluated. To identify donations that contained HEV RNA and were linked to patient-recipients with antibody evidence of HEV exposure, we assayed samples from the Retrovirus Epidemiology Donor Study (REDS) Allogeneic Donor and Recipient repository that represents 13,201 linked donations and 3384 transfused patients. Posttransfusion samples, determined to contain IgG anti-HEV by enzyme-linked immunosorbent assay, were reassayed along with corresponding pretransfusion samples for seroconversion (incident exposure) or at least fourfold IgG anti-HEV increase (reexposure). HEV-exposed patients were linked to donations in which HEV RNA was then detected by reverse-transcription quantitative polymerase chain reaction, confirmed by transcription-mediated amplification, and phylogenetically analyzed as subgenomic cDNA sequences. Among all patients, 19 of 1036 (1.8%) who had IgG anti-HEV before transfusion were reexposed; 40 of 2348 (1.7%) without pretransfusion IgG anti-HEV seroconverted. These 59 patients were linked to 257 donations, 1 of which was positive by reverse-transcription quantitative polymerase chain reaction and transcription-mediated amplification. Plasma from this donation contained 5.5 log IU/mL of HEV RNA that grouped with HEV genotype 3, clade 3abchij. The patient-recipient of RBCs from this donation had a greater than eightfold IgG increase; however, clinical data are unavailable. This is the first report of probable HEV transmission via transfusion in the United States, although it has been frequently observed in Europe and Japan. Additional data on the magnitude of the risk in the United States are needed.

The power of collaboration

The power of collaboration

Complex Relationship of Blood Group H, ABO Glycans, and Von Willebrand Factor Levels

BackgroundABO(H) is a carbohydrate blood group system expressed in multiple tissues including red blood cells, blood vessels, and mucosal surfaces. ABO is the largest known genetic modifier of plasma VWF level (VWF:Ag). It has been hypothesized that the effect of ABO on VWF is mediated by H glycan density. FUT2, the gene underlying Secretor phenotype, encodes a glycosyltransferase synthesizing H antigen in mucosal tissues, and variation in the gene has also previously been associated with VWF:Ag, but past studies have been conflicting. To clarify these relationships, we studied the relationship between VWF:Ag, ABH glycans, and FUT2 genotype. MethodsThe primary study group was a representative cohort of US blood donors from the Retrovirus Epidemiology Donor Study (REDS, N=499). A validation cohort of unrelated individuals was created from the Genes and Blood Clotting Study (GABC), healthy siblings between ages 14 and 35 years from University of Michigan, Ann Arbor, by choosing a random individual from each family (N=488). VWFAg was determined by ELISA in platelet poor plasma. Forensic techniques were adapted to detect ABH glycans in whole blood (REDS) or RBC-rich, frozen buffy coat (GABC). A and B glycans were detected using anti-A or anti-B (Immucor). A biotinylated Ulex europaeus agglutinin (UEA lectin, Vector Labs) was used to detect H. Relative A, B, and H antigen density was quantified on dot blots with ImageQuant (GE). In REDS, functional FUT2 alleles (Secretor) were determined by Sanger sequencing of FUT2 exon 2. FUT2 copy-number was assayed with real-time quantitative PCR. In GABC, FUT2 genotypes were determined through SNP genotyping (Illumina).In REDS, genotype data was phased (BEAGLE) to identify functional haplotypes. In GABC, functional alleles were inferred from the genotypes of two SNPs (rs601338, rs1047781) that determined secretor status in nearly all samples in REDS (see below). Multivariate regression was applied to VWF:Ag as a function H antigen density and O vs. non-O blood group, both separately and within the same model. All models were adjusted for age, gender, and self-reported ethnicity. ResultsABO blood group frequencies in both cohorts were similar to that of the US population. VWF:Ag differed significantly between ABO blood groups with lower values in blood group O versus non-O (REDS: ratio = 0.75, 95% CI [0.71, 0.80], p<2.2e-16, log-linear regression). H glycan density also differed between ABO blood group (p<2.2e-16, Kruskal-Wallis; O vs. non-O, ratio = 2.03, 95% CI [1.88, 2.19], p<2.2e-16). A significant fraction of H glycan density variation was attributable to ABO (REDS r2 =0.45; GABC r2 =0.34), but a wide range of H glycan density was observed in all blood groups, including within blood group O. In multivariate regression, both H glycan density and O versus non-O blood group, considered separately or in the same model, were significantly associated with VWF:Ag (REDS combined model: p = 2.9e-5 and 2.7e-4 for H glycan and blood group, respectively). In GABC but not in REDS, regression was also significant for an interaction between H glycan density and blood group (p = 0.031). Both cohorts estimated a stronger association of VWF:Ag with H in non-O blood groups.FUT2 sequencing in the REDS cohort identified 22 distinct FUT2 haplotypes. 99.5% (497/499) of individuals could be accurately assigned FUT2 genotypes based on the common W154* (rs601338) polymorphism alone. In GABC, this decreased to 94% (476/488) due to higher frequency of a hypomorphic allele (rs1047781) more commonly found in Asian individuals. In REDS, quantitative PCR did not identify copy-number variation at FUT2. There was no significant association between FUT2 genotype-predicted function and VWF:Ag or H glycan density in either cohort. ConclusionH glycan density correlated with VWF:Ag in both cohorts. H glycan density could mediate the association between ABO blood group and VWF:Ag. If so, this suggests a non-linear, complex relationship between H and VWF and a separate ABO mechanism cannot be excluded. In both cohorts, there was no association of FUT2 (Secretor) genotype with VWF. Our data suggest prior focused approaches to FUT2 genotyping are at risk to undercall non-functional alleles, particularly in cohorts with non-European ancestries. Taken together, these indicate blood group H may be a significant modifier of VWF:Ag, and that this effect is not due to the influence of Secretor phenotype. DisclosuresJohnsen:Octapharma: Other: Speaker; Biogen: Research Funding; CSL Behring: Other: Speaker.

Risk factors and epidemiology of human T-lymphotropic virus types 1 and 2 in US blood donors

Blood donations in the US are routinely screened for markers of human T-lymphotropic virus (HTLV). Seroprevalence and risk factors associated with HTLV-1 and -2 infection from the US Retrovirus Epidemiology Donor Study (REDS-II) Transfusion-Transmitted Viral Infection (TTVI) Rate and Risk Factor Study are reported. Among 14,809,334 blood donations screened during 2011-2012, 516 HTLV confirmed seropositive cases were identified, with an overall prevalence of 3.5 infections per 1,0 donations (95% CI: 3.2-3.8). A case-control study of risk factors from 90 donors with serology-confirmed HTLV-1 infection, 102 with HTLV-2 (cases), and 1,587 donors with false-positive results (controls) was conducted. Frequencies and adjusted odds ratios (AORs) from separate multivariable logistic regression analyses for HTLV-1 and -2 cases compared to controls are reported. Mean age was 48.0 (SD: 12.4), 52.3 (SD: 11.0) and 41.7 (SD: 15.7) years for HTLV-1, HTLV-2 cases and controls, respectively. Being a first-time donor, older, non-white, non-Hispanic female were significant demographic factors associated with both infections. HTLV-1 cases were more likely than controls to be Black (AOR: 13.3, 95% CI: 6.1-29.2), born outside of the US (AOR: 8.6, 95% CI: 4.0-18.4), have migrated (family or self) from an endemic area (AOR: 1.8, 95% CI: 1.2-2.7), report sex with an IDU (AOR: 10.9, 95% CI: 3.6-33.4) or have multiple partners (AOR: 3.1, 95% CI: 1.5-6.1). HTLV-2 cases were more likely to be Black (AOR: 15.4, 95% CI: 6.9-34.3), Native Americans (AOR: 10.7, 95% CI: 1.5-77.0), report sex with an IDU (AOR: 27.2, 95% CI: 9.7-75.8) or have multiple partners (AOR: 2.9, 95% CI: 1.5-5.7). US blood donors with HTLV-1 or -2 infection present with the known risk factors. Migration from endemic areas is mainly associated with HTLV-1 infection, while HTLV-2 is associated with Native American donors. Sexual risk behavior and IDU continue to be risk factors for both viruses.

Concerning iron balance in blood donors.

Concerning iron balance in blood donors.

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The Retrovirus Epidemiology Donor Study (REDS) program was established in the United States in 1989 with the purpose of increasing blood transfusion safety in the context of the HIV/AIDS and human T-lymphotropic virus epidemics. REDS and its successor, REDS-II were at first conducted in the US, then expanded in 2006 to include international partnerships with Brazil and China. In 2011, a third wave of REDS renamed the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) was launched. This seven-year research program focuses on both blood banking and transfusion medicine research in the United States of America, Brazil, China, and South Africa. The main goal of the international programs is to reduce and prevent the transmission of HIV/AIDS and other known and emerging infectious agents through transfusion, and to address research questions aimed at understanding global issues related to the availability of safe blood. This article describes the contribution of REDS-II to transfusion safety in Brazil. Articles published from 2010 to 2013 are summarized, including database analyses to characterize blood donors, deferral rates, and prevalence, incidence and residual risk of the main blood-borne infections. Specific studies were developed to understand donor motivation, the impact of the deferral questions, risk factors and molecular surveillance among HIV-positive donors, and the natural history of Chagas disease. The purpose of this review is to disseminate the acquired knowledge and briefly summarize the findings of the REDS-II studies conducted in Brazil as well as to introduce the scope of the REDS-III program that is now in progress and will continue through 2018.© 2014 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. All rights reserved.

The National Heart, Lung, and Blood Institute retrovirus epidemiology donor studies (Retrovirus Epidemiology Donor Study and Retrovirus Epidemiology Donor Study-II): twenty years of research to advance blood product safety and availability.

The Retrovirus Epidemiology Donor Study (REDS), conducted from 1989 to 2001, and the REDS-II, conducted from 2004 to 2012, were National Heart, Lung, and Blood Institute-funded, multicenter programs focused on improving blood safety and availability in the United States. The REDS-II also included international study sites in Brazil and China. The 3 major research domains of REDS/REDS-II have been infectious disease risk evaluation, blood donation availability, and blood donor characterization. Both programs have made significant contributions to transfusion medicine research methodology by the use of mathematical modeling, large-scale donor surveys, innovative methods of repository sample storage, and establishing an infrastructure that responded to potential emerging blood safety threats such as xenotropic murine leukemia virus-related virus. Blood safety studies have included protocols evaluating epidemiologic and/or laboratory aspects of human immunodeficiency virus, human T-lymphotropic virus 1/2, hepatitis C virus, hepatitis B virus, West Nile virus, cytomegalovirus, human herpesvirus 8, parvovirus B19, malaria, Creutzfeldt-Jakob disease, influenza, and Trypanosoma cruzi infections. Other analyses have characterized blood donor demographics, motivations to donate, factors influencing donor return, behavioral risk factors, donors' perception of the blood donation screening process, and aspects of donor deferral. In REDS-II, 2 large-scale blood donor protocols examined iron deficiency in donors and the prevalence of leukocyte antibodies. This review describes the major study results from over 150 peer-reviewed articles published by these 2 REDS programs. In 2011, a new 7-year program, the Recipient Epidemiology and Donor Evaluation Study-III, was launched. The Recipient Epidemiology and Donor Evaluation Study-III expands beyond donor-based research to include studies of blood transfusion recipients in the hospital setting and adds a third country, South Africa, to the international program.

The human platelet antigen‐21bw is relatively common among Asians and is a potential trigger for neonatal alloimmune thrombocytopenia

We and others have identified more than 20 low-frequency human platelet (PLT) antigens (HPAs) that can induce antibodies capable of causing neonatal alloimmune thrombocytopenia (NAIT).1–4 Like HPA-1a and HPA-4b, the antigens that most often trigger NAIT in Caucasian and Asian populations, respectively, the incidence of low-frequency antigens is likely to vary significantly in different ethnic and racial populations. We recently described HPA-21bw, a low-frequency antigen, responsible for a single case of severe NAIT in a presumed Caucasian family.1 The HPA-21bw antigen results from a G>A1960 mutation (RS70940817), in ITGB3, encoding PLT glycoprotein (GP) β3 subunit (GPIIIa) and creates a Glu>Lys substitution at Residue 628 in mature β3. No examples of HPA-21bw were identified in 100 unrelated Caucasian individuals.1 We recently encountered a second case of NAIT apparently caused by HPA-21bw in an Asian family (unpublished). The mutation encoding HPA-21bw was also identified in two of 38 Asian individuals tested in a hypertension and insulin resistance study according to the human SNP database (http://www.ncbi.nlm.nih.gov/projects/SNP; ss95216694). These observations suggested that HPA-21bw, like HPA-4b, might be more prevalent in Asian than in Caucasian populations and therefore a more common trigger for NAIT. To examine this possibility, we determined the gene frequency of the mutation encoding HPA-21bw in anonymized DNA samples identified by age, sex, and self-declared race/ethnicity obtained from the Retrovirus Epidemiology Donor Study (REDS) General Serum Repository of the National Heart, Lung, and Blood Institute (NHLBI) made available by the NHLBI Biologic Specimen and Data Repository guardian (BioLINCC). These specimens were collected from blood donors at five locations in the United States (Baltimore, Detroit, Los Angeles, Oklahoma City, and San Francisco) between December 1994 and December 1995. Anonymized samples were also obtained from Caucasian blood donors at BloodCenter of Wisconsin. Genotyping for HPA-21bw was performed with an allelic discrimination assay using PerfeCTa qPCR SuperMix, UNG, Low ROX (Quanta Biosciences, Gaithersburg, MD).2 Results are summarized in Table 1. No examples of HPA-21bw were found in 1110 unrelated Caucasians, 611 African Americans, or 252 Hispanic blood donors. However, 6 of 531 Asians donors were HPA-21a/bw (prevalence, 1.1%; gene frequency, 0.0056). TABLE 1 Frequency analysis of HPA-21bw in various populations We used the exact binomial methods for statistical inference: Clopper-Pearson confidence intervals (CIs) and Fisher’s exact test. The prevalence of HPA-21bw among Asians, estimated as 1.1% (95% CI, 0.4%–2.4%) is significantly greater than in Caucasians (p = 0.001) and African Americans (p = 0.01). The comparison with Hispanics is not significant (p = 0.18); however, the sample size is too small for this comparison. Based on one-sided CIs we are 95% confident that the prevalence of HPA-21bw among Caucasians is less than 0.3%, among African Americans less than 0.5%, and among Hispanics less than 1.2%. To date the HPA-4b (Penb) polymorphism in GPIIIa is the most common trigger for antibodies that cause NAIT in the Asian population. Having an allelic frequency of 0.0045, HPA-4b is expressed in approximately 1% of the Asian population.5 In contrast HPA-6bw in GPIIIa, though found in 2.7% of the Asian population,5 is not a common trigger of NAIT. Taking into consideration that HPA-21bw is known to initiate severe NAIT,1 has already been implicated as the trigger for NAIT in one Asian family (unpublished), and has an allelic frequency of 0.2% to 2.2% (95% confidence limits) in the Asian population, routine typing for this antigen in cases of suspected NAIT involving Asian families appears indicated.

Risk behavior disclosure among blood donors in Sao Paulo, Brazil

Risk behavior disclosure among blood donors in Sao Paulo, Brazil

Demographics of successful, unsuccessful and deferral visits at six blood centers over a 4‐year period

Descriptions of donor demographics are of value in formulating recruitment and retention strategies. The demographics of successful (SV), unsuccessful (UV; meaning a nonuseable unit), and deferred (DV) donor visits over a 4-year period were investigated using Retrovirus Epidemiology Donor Study (REDS)-II databases. Fourteen deferral categories were created that included low hematocrit (Hct) or hemoglobin (Hb), feeling unwell, malaria travel, malaria other, couldn't wait, blood pressure or pulse, medical diagnosis, medication, test results, higher-risk behavior, variant Creutzfeldt-Jakob disease (CJD), CJD, needle exposure or tattoo, and other. Rates per 10,000 donor presentations were determined for each category globally and for six subcategorizations (first-time or repeat donor status, sex, race/ethnicity, age, education, and fixed or mobile donation location). Deferral rates were also calculated on simultaneous stratifications of donor status, sex, and race/ethnicity. Of 5,607,922 donor presentations there were 4,553,145 SVs (81.2%), 302,828 UVs (5.4%), and 751,381 DVs (13.4%). Overall rates of deferral ranged from 0.6 per 10,000 presentations for CJD, human growth hormone, or dura mater exposure to 777 per 10,000 presentations for low Hct or Hb. Deferral rates were remarkably different by first-time or repeat donor status, sex, race/ethnicity, and other demographics. The highest overall deferral rate was 3953 per 10,000 presentations, or nearly 40% in first-time, female, Asian donors, and the lowest rate was 5.6% in repeat, male, white donors. Successful donation visits according to demographic characteristics need to be placed within the context of all donor visits. Deferral rates indicate that the burden of donor deferral is high. Efforts to expand the diversity of the donor base through recruitment of minority donors may bring additional challenges because certain deferral reasons were proportionally much higher in these groups.

Progress in monitoring blood safety

Progress in monitoring blood safety

The Residual Risk of Transfusion-Transmitted HIV Infection in a Public Brazilian Blood Center.

Estimating risks of transfusion-transmitted infections is essential for monitoring blood safety and for helping physicians and patients decide about the risks/benefits of an allogeneic transfusion. In 2000, the residual risk of HIV in our institution was estimated in 1/325,000 units transfused and the prevalence of HIV among all blood donors was 0.06%. The goal of this study was to calculate the current residual risk of transfusion-transmitted HIV infection in the Regional Blood Center of Ribeirão Preto, University of São Paulo, Brazil. We evaluated 292,587 repeated donations of a total of 403,568 donations between january/2002 and december/2005. During this period, we identified 43 seroconversions among the repeated donors. The serological tests performed were 2 different enzyme immunoassays (EIA): HIV 1/2 and a conjugated p24 antigen/antibody as screening tests and Western Blot as a confirmatory test for all positive samples. In order to calculate the residual risk, we used the incidence rate/window period (IR/WP) model, developed in parallel by investigators from the National Heart, Lung and Blood Institute-sponsored Retrovirus Epidemiology Donor Study (REDS), the CDC and the American Red Cross. The IR takes into account the number of incident cases (numerator), the total number of repeated donations and the mean interdonation interval length (multiplication of the last two entities provides the number of person-years at risk or denominator). The mean interdonation interval length can be substituted for the mean seroconversion interval length for all incident cases if the first one can not be accurately measured, so we used this alternative. Once the IR is known, we calculated the residual risk dividing the IR by 365.25 days and then multiplying by the WP of the test used (p24=15 days). Our results are: IR= 43 cases/292,587 repeated donations × 3.2 years = 4.59×10−5. The current residual risk is (IR/365.25 days) × 15 days= 1.5/million units transfused or 1/667,000 units. The prevalence of HIV among all blood donors in 2005 was 0.035%. Although we know that the correlation between prevalence and residual risk is not straightforward, they have a certain degree of correlation and they both have declined since 2000. During these last 5 years, we have made some modifications in our donor selection towards a more rigorous donor screening and since january/2002 we have introduced the p24 antigen/antibody EIA as part of the screening serological tests. We concluded that the more stringent donor risk factor screening and the introduction of the p24 antigen test have substantially reduced the residual risk of transfusion-transmitted HIV infection in our institution.

The RADAR repository: a resource for studies of infectious agents and their transmissibility by transfusion

An ongoing issue in transfusion medicine is whether newly identified or emerging pathogens can be transmitted by transfusion. One method to study this question is through the use of a contemporary linked donor-recipient repository. The Retrovirus Epidemiology Donor Study Allogeneic Donor and Recipient (RADAR) repository was established between 2000 and 2003 by seven blood centers and eight collaborating hospitals. Specimens from consented donors were collected, components from their donations were routed to participating hospitals, and recipients of these units gave enrollment and follow-up specimens for long-term storage. The repository was designed to show that zero transmissions to enrolled recipients would indicate with 95 percent confidence that the transfusion transmission rate of an agent with prevalence of 0.05 to 1 percent was lower than 25 percent. The repository contains pre- and posttransfusion specimens from 3,575 cardiac, vascular, and orthopedic surgery patients, linked to 13,201 donation specimens. The mean number of RADAR donation exposures per recipient is 3.85. The distribution of components transfused is 77 percent red cells, 13 percent whole blood-derived platelet concentrates, and 10 percent fresh frozen plasma. A supplementary unlinked donation repository containing 99,906 specimens from 84,339 donors was also established and can be used to evaluate the prevalence of an agent and validate assay(s) performance before accessing the donor-recipient-linked repository. Recipient testing conducted during the establishment of RADAR revealed no transmissions of human immunodeficiency virus, hepatitis C virus, or human T-lymphotropic virus. RADAR is a contemporary donor-recipient repository that can be accessed to study the transfusion transmissibility of emerging agents.

Mammalian brain consumption by blood donors in the United States: brains today, deferred tomorrow?

Theoretical concerns of possible variant CJD (vCJD) transmission by transfusion have led to deferral of US donors potentially exposed to the bovine spongiform encephalopathy agent. Although the efficacy of these policies is unknown, impact on blood collections has been substantial. Under the precautionary principle, deferral of donors consuming bovine (or other mam-malian) brains, possibly contaminated with the vCJD agent, might be considered. Blood donors were surveyed to determine lifetime mammalian brain consumption. The Retrovirus Epidemiology Donor Study (REDS) conducted an anonymous mail survey of 92,581 donors from eight US blood centers. Responses were received from 52,650 donors (57%). Of these, 6.4 percent reported lifetime brain consumption; bovine (3.6%) and hog brains (1.7%) were the most common. Bovine brain consumption varied fourfold by center (1.7-7.0%) and was highest among male (4.5%), older (age 55+, 6.5%), foreign-born (9.2%), Asian (7.2%), and Hispanic (8.6%) donors. Among bovine brain consumers, 67 percent engaged in the practice 4 times or less, 79 percent were repeat donors, and 61 percent reported giving at least 11 donations in the past 10 years. Following the precautionary principle, further steps to reduce the theoretical vCJD risk could include deferring donors who eat bovine (or other mammalian) brains. The impact of such a policy would not be trivial, especially in areas with older, foreign-born, Asian, or Hispanic donors. Cautious implementation and periodic evaluation of deferral policies is warranted.

The mantra of blood safety: time for a new tune?

The mantra of blood safety: time for a new tune?

Prevalence and clinical features of HTLV neurologic disease in the HTLV Outcomes Study.

Almost 20 years after its discovery, the prevalence and clinical course of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM, also known as tropical spastic paraparesis [TSP]) remain poorly defined. Whereas the causative association of HTLV-I and HAM/TSP is generally recognized, controversy still surrounds the relationship between HTLV-II and HAM/TSP. The HTLV Outcomes Study (HOST-formerly Retrovirus Epidemiology Donor Study [REDS]) is a prospective cohort study including 160 patients with HTLV-I, 405 patients with HTLV-II, and 799 uninfected controls who have been followed every 2 years since 1990-1992. Clinical outcomes are measured by health interviews and examinations, and blood samples are obtained. Six cases of HTLV-I-associated myelopathy (3.7%, 95% CI 1.4 to 8.0) and four cases of HTLV-II myelopathy (1.0%, 95% CI 0.3 to 2.5) have been diagnosed since the formation of the cohort. There have been no cases of HAM/TSP diagnosed among HTLV-negative subjects (0.0%, 95% CI 0.0 to 0.5). Clinical features of the cases include lower extremity hyperreflexia, variably associated with weakness, spasticity, and bladder dysfunction. Systematic screening of HTLV-infected blood donors reveals a high prevalence of HAM/TSP. The clinical course of HAM/TSP appears highly variable. HTLV-II-associated myelopathy generally presents with milder and more slowly progressive signs and symptoms.

The cost‐effectiveness of NAT for HIV, HCV, and HBV in whole‐blood donations

The risk of viral infection associated with blood transfusion is lower than ever before because of aggressive screening and testing practices. NAT technology has lowered that risk even further but at an additional cost to the health-care system. Marginal cost-effectiveness of NAT for HIV, HCV, and HBV in whole-blood donations was calculated with a previously published Markov decision model. This model was updated with disease incidence data from all 2001 American Red Cross whole-blood donations as well as window-period data from the Retrovirus Epidemiology Donor Study (REDS). Whole-blood donation NAT for HIV and HCV is expected to cost between 155 US dollars million (minipool NAT) and 428 million US dollars(single-donation NAT) per year in the US and avert 4 to 7 HIV infections and 56 to 59 HCV infections. Adding HBV NAT would be expected to avert 9 to 37 HBV infections at an additional cost of between 39 million US dollars and 130 million US dollars per year. Overall, NAT would cost between 4.7 million US dollars and 11.2 million US dollars per quality-adjusted life-year saved. Discontinuing HIV p24 antigen and HBc testing would offset this somewhat. The cost-effectiveness of whole-blood NAT is poor. The testing cost would need to decrease significantly to bring the cost-effectiveness in line with most other accepted medical practices.

Effect of a national disaster on blood supply and safety: the September 11 experience.

An understanding of characteristics of blood donors donating in times of crisis may help predict blood supply safety and donor return patterns. To characterize the volume of donations and prevalence of infectious disease markers in blood donated by US donors responding to the September 11, 2001, terrorist attacks, and to evaluate return rates in those who donated for the first time. Cross-sectional survey data from the National Heart, Lung, and Blood Institute Retrovirus Epidemiology Donor Study for 4 weeks before and 4 weeks starting with September 11, 2001, and the corresponding 8-week period in 2000. A total of 327065 volunteer blood donors making 373628 allogeneic donations at 5 large regional US blood centers. Changes in number of donations overall and by first-time and repeat status, prevalence of infectious disease markers, estimated risks of transfusion-transmitted viral infections, and first-time donor return rates. About 20000 allogeneic donations were collected weekly in the 4 weeks preceding September 11, whereas approximately 49 000 (2.5-fold increase) and approximately 26000 to 28000 (1.3-fold to 1.4-fold increases) donations were made per week in the first and in the second through fourth weeks starting with September 11, respectively. All demographic groups donated more than usual after the attacks, and after adjusting for seasonal and annual variation there was a 5.2-fold (95% confidence interval, 5.0-5.4) increase in the number of first-time donations vs a 1.5-fold (1.4-1.5) increase in the number of repeat donations made in the first week starting on September 11 vs the 4 weeks before. The weekly proportion of repeat donors returning after not donating for 10 or more years increased from 2% before September 11 to 6% in the first week starting with September 11. Donations confirmed positive for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B surface antigen nearly tripled between 1 week before September 11 (0.1%) and 1 week after the attacks (0.3%), largely explained by the increase in first-time and lapsed repeat donors. Estimated viral residual risks increased slightly after the attacks (HIV, 1/1.5 million vs 1/1.8 million donations; HCV, 1/1.3 million vs 1/1.6 million; hepatitis B virus, 1/140000 vs 1/170000). First-time donor 12-month return rates for 2000 and 2001 were similar, approximately 28% (P =.37) for donors in the first week starting with September 11 (or September 12, 2000) and 30% (P =.69) for the second to fourth weeks. The September 11 events resulted in an influx of first-time donors without substantial increase in absolute risk of transfusion-transmissible viral infections. First-time donor return rates were equally relatively low before and after the attacks, suggesting that those donating in times of crisis have return behaviors similar to those of other first-time donors. Their relatively low return rates reinforce the need for education about the importance of donating regularly.

First-time blood donors: demographic trends.

With changing demographics of the United States population and the continuous need to recruit new donors, it is important to monitor the demographic profile of first-time donors and to evaluate changes in the donor pool to improve recruitment targeting. First-time whole blood (n = 901,862) donors at five United States blood centers between 1991 and 1996 were analyzed. The total number of first-time donors appears to be decreasing. Over the 6-year period, there was an overall increase in the proportion of Hispanic and other minority first-time donors and a concurrent decrease in the proportion of white donors at Retrovirus Epidemiology Donor Study centers. Other variables, including age, sex, and education, did not show a consistent trend. The demographic profile of first-time donors is changing. These data highlight the importance for blood centers to continuously monitor the donor population. A better understanding of the donor population may help blood centers adjust their donor outreach, recruitment, and retention programs. New recruitment efforts appear needed to counter general apathy toward donating blood, and minority groups appear to be receptive to becoming blood donors.