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Background: In the Netherlands, blood donor screening for hepatitis B virus (HBV) consists of HBsAg screening since the 1970s, HBV DNA minipool testing (MP-NAT) since 2008, and anti-HBc screening since 2011. Anti-HBc reactivity causes deferral only if anti-HBs titers are <200 IU/mL, or when anti-HBc was acquired during follow-up., Study Design and Methods: Over 5.5 million donations from 582,459 Dutch donors were screened for HBV DNA, HBsAg, anti-HBc, and, if anti-HBc positive, also for anti-HBs. The added value, expressed as the yield of (potentially) infectious and/or recent HBV infections versus unnecessary donor loss, was evaluated for each of the three HBV screening tests., Results: HBV donor screening identified 89 HBV-infected donors with at least two reactive HBV markers (MP-NAT, HBsAg and/or anti-HBc). Single HBV-marker yield was: 5 MP-NAT-only, 0 HBsAg-only, and 20 anti-HBc-only donors. In addition, anti-HBc screening yielded 1,067 potentially infectious donors at risk for occult HBV infection (OBI). In total, 4,126 (0.71%) donors were anti-HBc-reactive at first-time screening, and 1,098 (0.19%) seroconverted during follow-up. Anti-HBc-related donor loss was limited to 2,627 (0.45%) donors using anti-HBs titers and two-strike programs. Donor loss due to MP-NAT and HBsAg screening was extremely low: 0 and 128 donors, respectively., Conclusion: HBV donor screening could be limited to MP-NAT and anti-HBc screening. MP-NAT and anti-HBc improved blood safety by intercepting infectious donations from donors with recent infection or OBI, while HBsAg did not. Unnecessary donor loss related to anti-HBc screening is substantial but does not endanger the continuity of the blood supply., (© 2021 AABB.)

Pigs are suspected to be a major source of zoonotic hepatitis E virus (HEV) infection in industrialized countries, but the transmission route(s) from pigs to humans are ill-defined. Sequence comparison of HEV isolates from pigs with those from blood donors and patients in 372 samples collected in the Netherlands in 1998 and 1999 and between 2008 and 2015 showed that all sequences were genotype 3 except for six patients (with travel history). Subgenotype 3c (gt3c) was the most common subtype. While the proportion of gt3c increased significantly between 1998 and 2008, it remained constant between 2008 and 2015. Among the few circulating HEV subtypes, there was no difference observed between the human and the pig isolates. Hepatitis E viruses in humans are very likely to originate from pigs, but it is unclear why HEV gt3c has become the predominant subtype in the Netherlands.

Awareness of infection with SARS-CoV-2 is crucial for the effectiveness of COVID-19 control measures. Here, we investigate awareness of infection and symptoms in relation to antibodies against SARS-CoV-2 in healthy plasma donors. We asked individuals donating plasma across the Netherlands between May 11 th and 18 th 2020 to report COVID-19-related symptoms, and we tested for antibodies indicative of a past infection with SARS-CoV-2. Among 3,676 with antibodies, and from questionnaire data, 239 (6.5%) are positive for SARS-CoV-2 antibodies. Of those, 48% suspect no COVID-19, despite the majority reporting symptoms; 11% of seropositive individuals report no symptoms and 27% very mild symptoms at any time during the first peak of the epidemic. Anosmia/ageusia and fever are most strongly associated with seropositivity. Almost half of seropositive individuals do not suspect SARS-CoV-2 infection. Improved recognition of COVID-19 symptoms, in particular, anosmia/ageusia and fever, is needed to reduce widespread SARS-CoV-2 transmission., Competing Interests: The authors declare no competing interests., (© 2021 The Author(s).)

The world is combating an ongoing COVID-19 pandemic with health-care systems, society and economies impacted in an unprecedented way. It is unclear how many people have contracted the causative coronavirus (SARS-CoV-2) unknowingly and are asymptomatic. Therefore, reported COVID-19 cases do not reflect the true scale of outbreak. Here we present the prevalence and distribution of antibodies to SARS-CoV-2 in a healthy adult population of the Netherlands, which is a highly affected country, using a high-performance immunoassay. Our results indicate that one month into the outbreak (i) the seroprevalence in the Netherlands was 2.7% with substantial regional variation, (ii) the hardest-hit areas showed a seroprevalence of up to 9.5%, (iii) the seroprevalence was sex-independent throughout age groups (18-72 years), and (iv) antibodies were significantly more often present in younger people (18-30 years). Our study provides vital information on the extent of exposure to SARS-CoV-2 in a country where social distancing is in place.

Background and Objectives: The perception of transfusion-transmitted infections (TTIs) is sensitive to various concerns besides the probability and impact of infection, and some of these concerns may be ethically relevant. This paper aims to advance thinking about blood safety policies by exploring and explaining stakeholders' reasons to consider TTI risks tolerable or intolerable., Materials and Methods: Inspired by critical empirical ethics and phenomenological hermeneutics, we held interviews and focus group discussions to explore the moral experience of policymakers, hematologists, blood donors and recipients. Respondents were invited to discuss general concerns about the blood supply, to address the tolerability of TTI risks compared with other hazards and to comment on the costs of blood safety. Arguments for tolerance or intolerance towards TTI risks were analysed qualitatively., Results: Stakeholders' views could be clustered into seven categories: (1) clinical impact; (2) probability of infection; (3) avoidability of infection; (4) cost and health benefits; (5) other consequences of safety measures; (6) non-consequentialist ethical arguments; and (7) stakeholders' interests. Various arguments were offered that resonate with current ethical thinking about blood safety. Assuming that resources spent on inefficient blood safety measures could be applied more beneficially elsewhere, for example, responders typically expressed tolerance towards TTI risks. Some other arguments seem novel, for instance arguments for risk intolerance based on the low probability of infection and arguments for risk tolerance if patients have a poor prognosis., Conclusion: Understanding the moral experience of stakeholders enriches ethical debate about blood safety and prepares developing more widely acceptable policies., (© 2019 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd on behalf of International Society of Blood Transfusion.)

Background: The screening of Dutch blood donations for West Nile virus (WNV) may be imminent, as WNV emerges in nearby countries and more donors travel to WNV-affected regions. Since 2016 the related, mosquito-borne Usutu virus (USUV) causes seasonal mortality in Dutch birds. To what extent will human USUV infections affect Dutch WNV donor screening?, Study Design and Methods: From April through September 2018, plasma samples from blood donations in blackbird-rich regions were stored. When increased bird mortality was reported in August, samples from July, August, and September were tested for USUV-RNA in pools of eight, using a home-brew combined WNV/USUV-PCR assay. Reactive pools were deconstructed. Original plasma units and samples of previous and follow-up donations of reactive donors were tested for USUV- and WNV-RNA, and for antibody responses., Results: The number of USUV RNA-positive, WNV RNA-negative donations was 0 of 2688 donations in July, 6 of 4416 in August (1:736), and 1 of 4936 in September. The seven infected donors tested negative for USUV-RNA in preceding and follow-up donations. For 6 donors, seroconversion for USUV-antibodies was demonstrated. All index donations tested positive in a commonly used PCR-assay for WNV donor screening. Three exposed recipients did not show signs of infection. Screening a random subset of 1092 donations from September for USUV-IgG antibodies showed that 22 donors tested reactive; for three donors retrospective testing identified an USUV PCR-positive pre-seroconversion donation., Conclusion: Seasonal USUV infection in Dutch blood donors is common. Cross-reactivity in molecular assays for WNV-screening occurs, but can be resolved using USUV- and WNV-specific PCR-primers and sequencing of viral RNA., (© 2019 AABB.)

Background: Deferral of men who have sex with men (MSM) from blood donation is highly debated. We therefore investigated their suitability to donate blood., Methods: We compared the antibody prevalence of 10 sexually and transfusion-transmissible infections (TTIs) among 583 MSM and 583 age-matched repeat male blood donors. MSM were classified as low risk (lr) or medium-to-high risk (hr) based on self-reported sexual behavior and as qualified or unqualified using Dutch donor deferral criteria. Infection pressure (IP) was defined as the number of antibody-reactive infections, with class A infections (human immunodeficiency virus-1/2, hepatitis B virus, hepatitis C virus, human T-cell lymphotropic virus-1/2, syphilis) given double weight compared to class B infections (cytomegalovirus, herpes simplex virus-1/2, human herpesvirus 8, hepatitis E virus, parvovirus B19)., Results: Donors had a lower median IP than qualified lr-MSM and qualified hr-MSM (2 [interquartile range {IQR}, 1-2] vs 3 [IQR, 2-4]; P < .001). Low IP was found in 76% of donors, 39% of qualified lr-MSM, and 27% of qualified hr-MSM. The prevalence of class A infections did not differ between donors and qualified lr-MSM but was significantly higher in qualified hr-MSM and unqualified MSM. Recently acquired class A infections were detected in hr-MSM only. Compared to blood donors, human herpesviruses were more prevalent in all MSM groups (P < .001)., Conclusions: IP correlates with self-reported risk behavior among MSM. Although lr-MSM might form a low threat for blood safety with regard to class A infections, the high seroprevalence of human herpesviruses in lr-MSM warrants further investigation., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

During 2006-2016, hepatitis B virus (HBV) was detected in nearly 400 blood donors in the Netherlands and Flanders. Donor demographics and self-reported risk factors as disclosed during the donor exit interview were compared to HBV phylogenies of donor and reference sequences. First-time donors with chronic HBV-infection were often immigrants (67%) infected with genetically highly diverse strains of genotypes A (32%), B (8%), C (6%), D (53%) and E to H (1%). Each subtype was strongly associated with donor ethnicity. In contrast, 57/62 (93%) of acute/recent HBV infections occurred among indigenous donors, of whom 67% was infected with one specific widely circulating epidemic HBV-A2 lineage. HBV typing identified three distinct epidemiological profiles: the import of chronic HBV infections through migration, longstanding transmission of non-epidemic HBV-A2 strains within western-Europe, and the active transmission of one epidemic HBV-A2 strain most likely fueled by sexual risk behavior., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Separate transmission networks for human immunodeficiency virus (HIV) coexist. Molecular typing of viral genomes can provide insight in HIV transmission routes in donors for whom risk behavior-based donor selection failed., Study Design and Methods: This study includes all HIV-infected Dutch and Flemish donors in the period 2005 to 2014 (n = 55). Part of the HIV polymerase (pol) gene was amplified, sequenced, and compared with more than 10,000 HIV strains obtained from HIV-infected Dutch and Flemish patients. The most likely transmission route was determined based on HIV phylogeny and the donor's self-reported risk behavior during the exit interview., Results: HIV-infected donors were predominantly male (69%), were repeat donors (73%), were born in the Netherlands or Belgium (95%), and harbored HIV Subtype B (68%). Seventy-five percent of HIV-infected male donors were part of robust phylogenetic clusters linked to male-to-male sex, while only 24% of HIV-infected male donors reported male-to-male sex during posttest counseling. Sex between men and women accounted for 13% of HIV infections in male donors and 93% of HIV infections in female donors based on phylogenetic analysis. Only 40% of HIV-infected female donors had HIV Subtype B; 65% of female donors reported a foreign partner and indeed HIV sequences interspersed with sequences from HIV-endemic areas abroad, in particular sub-Saharan Africa., Conclusion: HIV typing helps to understand HIV transmission routes in donor populations. We found substantial underreporting of male-to-male sex among HIV-infected male donors. Donor education on HIV risk factors and the danger of window-period donations and a donor environment that encourages frank disclosure of sexual behavior will contribute to a decrease of HIV-infected donors., (© 2017 AABB.)

Background: The incidence of hepatitis E virus (HEV) has increased substantially in Europe recently, thereby threatening blood safety. A cost-effectiveness analysis for HEV screening of blood donations in the Netherlands was performed., Study Design and Methods: A simulation model was developed to mimic the process of donation, infections in the donor population, donation testing, and transmission to transfusion recipients. The variability of viral loads among donors was modeled using observed loads. The number of (incurable) chronic HEV infections among organ and stem cell transplant patients and the costs avoided by implementing blood screening were estimated., Results: HEV screening of whole blood donations in pools of 24 would prevent 4.52 of the 4.94 transfusion-associated chronic HEV infections expected annually, at approximately €310,000 per prevented chronic case. Per case not curable by ribavirin prevention, costs are approximately 10 times higher. Selective screening, if logistically feasible, could reduce screening costs by 85%. Sensitivity analyses show that uncertainty in the HEV transmissibility and the frequency of HEV clearing greatly impact the estimated cost-effectiveness. Of all HEV infections nationwide one in 700 is estimated to be due to blood transfusion, while for chronic infections this is one in 3.5., Conclusion: Despite uncertainties in our estimates, preventing HEV transmission by screening of blood donations appears not excessively expensive compared to other blood-screening measures in the Netherlands. However, the impact on HEV disease burden may be relatively small as only a minority of all HEV cases is transmitted by blood transfusion., (© 2017 AABB.)

Background: Blood donors unaware of Trypanosoma cruzi infection may donate infectious blood. Risk factors and the presence of T. cruzi antibodies in at-risk Dutch blood donors were studied to assess whether specific blood safety measures are warranted in the Netherlands., Methodology: Birth in a country endemic for Chagas disease (CEC), having a mother born in a CEC, or having resided for at least six continuous months in a CEC were considered risk factors for T. cruzi infection. From March through September 2013, risk factor questions were asked to all donors who volunteered to donate blood or blood components. Serum samples were collected from donors reporting one or more risk factors, and screened for IgG antibodies to T. cruzi by EIA., Results: Risk factors for T. cruzi infection were reported by 1,426 of 227,278 donors (0.6%). Testing 1,333 at-risk donors, none (0.0%; 95%, CI 0.0-0.4%) was seroreactive for IgG antibodies to T. cruzi. A total of 472 donors were born in a CEC; 553 donors reported their mother being born in a CEC; and 1,121 donors reported a long-term stay in a CEC. The vast majority of reported risk factors were related to Suriname and Brazil. Overall, the participants resided for 7,694 years in CECs, which equals 2.8 million overnight stays. Of those, 1.9 million nights were spent in Suriname., Conclusions/significance: Asymptomatic T. cruzi infection appears to be extremely rare among Dutch blood donors. Blood safety interventions to mitigate the risk of T. cruzi transmission by transfusion would be highly cost-ineffective in the Netherlands, and are thus not required.

Background: The incidence of hepatitis E virus (HEV) infection in the Netherlands is high. Blood donors are not routinely screened for HEV infection, but since January 2013, donations used for the production of solvent/detergent (S/D)-treated plasma have been screened for HEV RNA., Study Design and Methods: Donations were screened for HEV RNA in pools of 96 and 192 donations. In addition, all donations made between 60 days before and after each HEV RNA-positive donation were tested individually for HEV RNA and anti-HEV immunoglobulin G., Results: The screening of 59,474 donations between January 2013 and December 2014 resulted in identification of 45 HEV RNA-positive donations (0.076%) from 41 donors. HEV RNA loads ranged from 80 to 2.3 × 10(6) IU/mL. The number of positive donations increased significantly over time (p = 0.03). Thirty-three of 90 donations made up to 60 days before or after HEV RNA-positive donations were positive when tested individually, while they had not been detected in the pool screening. The mean duration of HEV viremia in the healthy blood donor is estimated to be 68 days., Conclusion: The incidence of HEV infection in the Netherlands is high and increased during the study period. In 2013 and 2014, HEV RNA was detected in 1 per 762 donations intended for production of S/D plasma., (© 2015 AABB.)

Background: Risk behavior-based donor selection procedures are widely used to mitigate the risk of transfusion-transmissible infections (TTIs), but their effectiveness is disputed in countries with low residual risks of TTIs., Study Design and Methods: In 1995 to 2014, Dutch blood donors infected with hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV), or syphilis were interviewed by trained medical counselors to identify risk factors associated with TTIs. Trends in the prevalence and incidence of TTIs were analyzed using binomial regression models., Results: A total of 972 new donors and 381 repeat donors had TTIs. New donors had higher rates of TTIs compared to repeat donors. Although the HBV and HCV prevalence gradually decreased over time, the incidence of all five TTIs remained stable during the past two decades. In new donors the TTIs had the following risk profiles: "blood-blood contact" for HCV, "unprotected sex" for HIV and syphilis, and "country of birth" for HBV and HTLV. In infected repeat donors, sexual risk factors predominated for all TTIs. At posttest counseling, 28% of infected repeat donors admitted to risk factors leading to permanent donor exclusion if revealed during the donor selection procedure (predominantly male-to-male sex and recent diagnosis of syphilis)., Conclusion: The prevalence and incidence of TTIs among Dutch blood donors are six- to 60-fold lower than in the general Dutch population, illustrating the effectiveness of donor selection procedures. However, at least a quarter of infected donors appeared noncompliant to the donor health questionnaire (DHQ), suggesting that DHQs, or the way donor questioning is implemented, can be improved., (© 2015 AABB.)

Background: The increasing incidence of reported hepatitis E cases in Europe has focused attention on hepatitis E virus (HEV) and the risk of transfusion-transmitted hepatitis E. The aim of this study was to investigate the prevalence of antibodies to HEV (anti-HEV) among Danish blood donors in 2013 and to compare it to previous studies in Denmark. In addition we wanted to compare the relative reactivity of two different assays., Study Design and Methods: Samples from 504 blood donors were collected and analyzed for anti-HEV with an in-house assay developed at the National Institutes of Health (NIH). In addition the samples were analyzed with the Wantai anti-HEV assay. Demographic information and possible HEV exposure was collected by self-administered questionnaire., Results: Using the NIH assay the prevalence of anti-HEV among Danish blood donors was 10.7% and with the Wantai assay the prevalence of anti-HEV was 19.8% (p < 0.001). In both cases the presence of anti-HEV was significantly correlated with increasing age. In addition, anti-HEV as measured by the Wantai test was significantly associated with contact with children (p = 0.01), but in multivariate analysis only age was associated with anti-HEV in both assays. By the NIH assay, the prevalence had declined from 20.6% in 2003 to 10.7% in 2013., Conclusions: Anti-HEV prevalence had decreased by half among Danish blood donors over 10 years, but was still highly prevalent. The difference in reactivity of the two assays demonstrates the importance of using the same assay when comparing the anti-HEV prevalence in populations over time., (© 2015 AABB.)

Background: Infectious window period donations slip through routine donor screening procedures. To explore the potential value of predonation screening of candidate donors, we compared the proportion of incident transfusion-transmissible infections in candidate donors, in first-time donors, and in repeat donors., Study Design and Methods: A retrospective analysis was performed of all incident hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) infections in candidate, first-time, and repeat donors in the Netherlands during the period 2009 to 2013., Results: In total, 176,716 candidate donors, 144,226 first-time donations, and 4,143,455 repeat donations were screened for HBV, HCV, and HIV infection. Acute HBV infection was identified in the predonation sample of six candidate donors. One first-time donor, testing HIV-negative at predonation screening, tested positive for anti-HIV and HIV RNA in the first donation 29 days later. Among repeat donations we identified 15, one, and six incident HBV, HCV and HIV infections, respectively. The proportion of incident infections among candidate donors/first-time donations/repeat donations was for HBV, 3.40/0/0.36; for HCV, 0/0/0.02; and for HIV 0/0.69/0.14 per 100,000, respectively., Conclusion: Predonation screening of candidate donors very likely causes a loss of donations, but it might prevent undetected window period donations. Further studies are necessary to determine the value of predonation screening as an additional safety measure., (© 2014 AABB.)

Background: The Netherlands experienced major Q fever outbreaks from 2007 through 2009. An increasing number of human chronic Q fever cases has been reported in the affected area. Blood donors unaware of chronic Coxiella burnetii infection might be infectious for transfusion recipients. Local blood donations were screened for serologic signs of chronic Coxiella infection., Study Design and Methods: From August 2012 through January 2013, a total of 2490 serum samples were collected from all consenting blood donors in the most affected Q fever outbreak area and screened for Phase II anti-Coxiella immunoglobulin G antibodies using an enzyme-linked immunosorbent assay (ELISA). (Phase II antibodies are considered indicative for resolved or ongoing Coxiella infection.) Reactive samples were confirmed by quantitative immunofluorescent Phase I and II antibody testing. A Phase I antibody titer of at least 1024 was considered indicative for chronic Coxiella infection. For 179 donors archived samples from 2009 and 2010 were available to study the long-term course of Coxiella antibodies., Results: A total of 110 of 2490 donors were confirmed positive for Phase II Coxiella antibodies (4.4%; 95% confidence interval, 3.7%-5.3%), of which 79 were reactive for Phase I antibodies, with a maximum titer of 256. In 15 of 24 donors (62.5%), testing positive for Phase II antibodies in 2009 and 2010, ELISA reactivity had declined to negativity in 2012 and 2013., Conclusion: After large Q fever outbreaks in the Netherlands, no sign of potentially infectious chronic Coxiella infection was found among blood donors in the most affected area. Using an ELISA for detection, Coxiella antibodies in previously exposed donors waned quickly., (© 2014 AABB.)

Background: Since 2007, large outbreaks of Q fever occurred in the Netherlands. The unprecedented number of Q fever infections resulted in the need for the Dutch blood transfusion service to evaluate the risk of transmission of Coxiella burnetii via blood., Study Design and Methods: A lookback procedure (recipient tracing) was performed for transfused blood products of whole blood donors with confirmed C. burnetii infection within 3 weeks before to 3 weeks after blood donation. Repository samples of index donations were tested with real-time polymerase chain reaction (PCR) for C. burnetii DNA. Hospitals were asked to review the medical records of recipients and-if considered necessary-to test the recipients for infection with C. burnetii., Results: From 2007 through 2011, a total of 33 blood donors notified the blood bank of infection with C. burnetii. Thirteen donations fulfilled the criteria for a lookback procedure (18 blood products). C. burnetii PCR was positive in 1 of 13 repository samples of index donations. Blood products were transfused to 18 recipients. Information was retrieved from 12 of them; seven were tested for C. burnetii. Two recipients showed positive serology. However, transmission of C. burnetii via transfusion was unlikely, especially since most recipients lived in the same Q fever-affected area as the donors., Conclusion: Blood donors who have clinical Q fever around the time of blood donation are unlikely to test positive for C. burnetii by PCR in repository samples. Transmission of C. burnetii via transfusion of blood products could not be demonstrated in a lookback exercise., (© 2012 American Association of Blood Banks.)

Background: In 2007, 2008, and 2009 outbreaks of Q-fever occurred in The Netherlands with increasing magnitude. The 2009 outbreak with 2354 reported cases is the largest human Q-fever outbreak ever recorded. To assess the extent of infection and the safety of donated blood, we tested local blood donations for presence of Coxiella burnetii antibodies and DNA., Study Design and Methods: Starting May 2009, more than 40,000 serum samples were collected from all consenting blood donors in the areas with high Q-fever incidence. The 1004 samples from the areas with the highest number of reported cases were tested for C. burnetii DNA by polymerase chain reaction; seroprevalence and incidence were determined using enzyme-linked immunosorbent assay and immunofluorescence assays (IFAs) in the subset of 543 donors of whom a follow-up sample was available., Results: A total of 6 of 1004 donor samples tested reactive for C. burnetii DNA. Confirmatory testing (IFA) on the index and follow-up samples demonstrated seroconversion in two donors, high-level preexisting antibodies in one donor, and no seroconversion in three donors. Immunoglobulin (Ig)G testing of the 543 serum pairs showed that 66 were reactive in the latest sample, of which 10 represented seroconversions., Conclusion: In the area with highest incidence during a large Q-fever outbreak, 3 of 1004 blood donations contained C. burnetii DNA (0.3%; 95% confidence interval, 0.1%-1.0%). A total of 66 of 543 (12.2%) donors tested positive for anti-Coxiella IgG. Ten seroconversions were detected, resulting in an incidence of 5.7% per year, which is more than 10-fold higher than the local number of reported clinical cases (0.47% per year)., (© 2011 American Association of Blood Banks.)

Background: To improve transfusion policy and to increase understanding of the spread of hepatitis C virus (HCV) in the general population, HCV infections among voluntary Dutch blood donors were examined with molecular epidemiologic techniques., Study Design and Methods: During 6 years, 1997 through 2002, confirmed anti-HCV-positive donors were interviewed on HCV-associated risk behavior with a standardized questionnaire. Additionally, HCV isolates were genotyped, partially sequenced, and compared to sequences obtained from Dutch injecting drug users (IDUs)., Results: HCV prevalence and incidence rates among Dutch donors were extremely low; the residual risk of transmitting HCV was calculated to be 1 in 30 million donations. Former IDUs (21%), transfusion recipients (30%), and immigrants (>12%) were identified as major HCV risk groups. Cryptogenic transmission caused 18 percent of infections among new donors and all infections among repeat donors. Compared to IDUs, genotype distribution among donors was highly diverse; major subtypes were 3a (27%), 1a (24%), 1b (24%), 2a/b (10%), and 4 (9%). Half of the donors were infected with IDU-related subtypes 1a and 3a, whereas subtype 1b mainly spread via blood transfusion and various other nosocomial modes of transmission in the past. HCV infections acquired in endemic countries could be clearly identified based on genotype., Conclusion: Different modes of transmission are linked to infections with certain HCV subtypes, suggesting separate HCV epidemics, but spillover between different risk groups underlines the value of molecular epidemiologic techniques to gain insight into the origin and dynamics of HCV infections on a population level.

Background: As of 2004, the European Pharmacopoeia demands that plasma pools for production of anti-D immunoglobulin should not contain more than 104 IU per mL of parvovirus B19 (B19V) DNA. Hence, before pooling, highly viremic donations have to be identified, and after pooling the level of B19V DNA must be determined. The performance of a new real-time B19V DNA PCR test (Roche, Mannheim, Germany) was studied, using a DNA extractor (NucliSens, bioMerieux, Boxtel, the Netherlands) for isolation of nucleic acid, and using a DNA quantification test (LightCycler apparatus, Roche, Mannheim, Germany) for amplification and detection., Study Design and Methods: Dilutions of the international B19V DNA standard and reference preparations were tested to determine the precision, linear range, and accuracy of the assay and to calculate the factor for conversion of B19V DNA copies to IUs. The internal control signals, invalid test results, and the effect of cryo-poor plasma were studied as a measure for robustness. Routine performance was assessed by testing 164 manufacturing pools (not screened for B19V) and 1048 test pools of 480 donations each., Results: The copies-to-IU conversion factor was calculated to be 3.34 (95% CI, 3.07-3.63). The assay appears linear between 10(3) and 10(7) IU per mL. Between 10(3) and 10(5) IU per mL, the test can discriminate samples differing a factor two in B19V DNA content. Overall, 0.78 percent of the test results were invalid. Of 127 B19V DNA negative control plasma samples, 7 were contaminated with low levels of B19V DNA. Of 164 nonscreened manufacturing plasma pools, 92 contained B19V DNA (56%); 13 contained more than 10(4) IU per mL. Of 503,040 donations, 29 contained more than 5 x 10(6) IU per mL B19V DNA (1:17,346)., Conclusion: The B19V DNA quantification test (LightCycler, Roche ) is suitable for quantitative, routine, in-process measurement of B19V DNA levels in plasma pools, using the DNA extractor (NucliSens, bioMerieux) for nucleic acid isolation.

Background: In the Netherlands, blood donor screening for hepatitis B virus (HBV) consists of HBsAg screening since the 1970s, HBV DNA minipool testing (MP‐NAT) since 2008, and anti‐HBc screening since 2011. Anti‐HBc reactivity causes deferral only if anti‐HBs titers are <200 IU/mL, or when anti‐HBc was acquired during follow‐up. Study design and methods: Over 5.5 million donations from 582,459 Dutch donors were screened for HBV DNA, HBsAg, anti‐HBc, and, if anti‐HBc positive, also for anti‐HBs. The added value, expressed as the yield of (potentially) infectious and/or recent HBV infections versus unnecessary donor loss, was evaluated for each of the three HBV screening tests. Results: HBV donor screening identified 89 HBV‐infected donors with at least two reactive HBV markers (MP‐NAT, HBsAg and/or anti‐HBc). Single HBV‐marker yield was: 5 MP‐NAT‐only, 0 HBsAg‐only, and 20 anti‐HBc‐only donors. In addition, anti‐HBc screening yielded 1,067 potentially infectious donors at risk for occult HBV infection (OBI). In total, 4,126 (0.71%) donors were anti‐HBc‐reactive at first‐time screening, and 1,098 (0.19%) seroconverted during follow‐up. Anti‐HBc‐related donor loss was limited to 2,627 (0.45%) donors using anti‐HBs titers and two‐strike programs. Donor loss due to MP‐NAT and HBsAg screening was extremely low: 0 and 128 donors, respectively. Conclusion: HBV donor screening could be limited to MP‐NAT and anti‐HBc screening. MP‐NAT and anti‐HBc improved blood safety by intercepting infectious donations from donors with recent infection or OBI, while HBsAg did not. Unnecessary donor loss related to anti‐HBc screening is substantial but does not endanger the continuity of the blood supply. [ABSTRACT FROM AUTHOR]

The polyomavirus family currently includes thirteen human polyomavirus (HPyV) species. In immunocompromised and elderly persons HPyVs are known to cause disease, such as progressive multifocal leukoencephalopathy (JCPyV), haemorrhagic cystitis and nephropathy (BKPyV), Merkel cell carcinoma (MCPyV), and trichodysplasia spinulosa (TSPyV). Some recently discovered polyomaviruses are of still unknown prevalence and pathogenic potential. Because HPyVs infections persist and might be transferred by blood components to immunocompromised patients, we studied the seroprevalence of fourteen polyomaviruses in adult Dutch blood donors. For most polyomaviruses the observed seroprevalence was high (60–100%), sometimes slightly increasing or decreasing with age. Seroreactivity increased with age for JCPyV, HPyV6 and HPyV7 and decreased for BKPyV and TSPyV. The most recently identified polyomaviruses HPyV12, NJPyV and LIPyV showed low overall seroprevalence (~5%) and low seroreactivity, questioning their human tropism. Altogether, HPyV infections are common in Dutch blood donors, with an average of nine polyomaviruses per subject. [ABSTRACT FROM AUTHOR]

Background: The incidence of autochthonous hepatitis E virus genotype 3 (HEV gt3) infections in Western Europe is high. Although pigs are a major reservoir of the virus, the exact sources and transmission route(s) of HEV gt3 to humans remain unclear. Methods: To determine the role of meat consumption at a population level, the seroprevalence of anti-HEV IgG antibodies was compared between Dutch blood donors with a vegetarian lifestyle and donors who consume meat on a daily basis. Results: The age-weighted anti-HEV IgG seroprevalence among donors not eating meat was significantly lower than among meat-eating donors (12.4% vs 20.5%, p = 0.002). For both groups the prevalence strongly increased with age and the difference in prevalence was apparent for all age groups. Conclusions: Compared with meat-eating donors, the incidence of HEV infection is significantly lower among donors not eating meat, indicating that meat consumption is a major risk factor for HEV infection. [ABSTRACT FROM AUTHOR]

Tolerance for blood transfusion risks is very low, as evidenced by the implementation of expensive blood tests and the rejection of gay men as blood donors. Is this low risk tolerance supported by the precautionary principle, as defenders of such policies claim? We discuss three constraints on applying (any version of) the precautionary principle and show that respecting these implies tolerating certain risks.Consistencymeans that the precautionary principle cannot prescribe precautions that it must simultaneously forbid taking, considering the harms they might cause.Avoiding counterproductivityrequires rejecting precautions that cause more harm than they prevent.Proportionalityforbids taking precautions that are more harmful than adequate alternatives. When applying these constraints, we argue, attention should not be restricted to harms that are human caused or that affect human health or the environment. Tolerating transfusion risks can be justified if available precautions have serious side effects, such as high social or economic costs. [ABSTRACT FROM AUTHOR]

Background: The incidence of hepatitis E virus (HEV) has increased substantially in Europe recently, thereby threatening blood safety. A cost-effectiveness analysis for HEV screening of blood donations in the Netherlands was performed.Study Design and Methods: A simulation model was developed to mimic the process of donation, infections in the donor population, donation testing, and transmission to transfusion recipients. The variability of viral loads among donors was modeled using observed loads. The number of (incurable) chronic HEV infections among organ and stem cell transplant patients and the costs avoided by implementing blood screening were estimated.Results: HEV screening of whole blood donations in pools of 24 would prevent 4.52 of the 4.94 transfusion-associated chronic HEV infections expected annually, at approximately €310,000 per prevented chronic case. Per case not curable by ribavirin prevention, costs are approximately 10 times higher. Selective screening, if logistically feasible, could reduce screening costs by 85%. Sensitivity analyses show that uncertainty in the HEV transmissibility and the frequency of HEV clearing greatly impact the estimated cost-effectiveness. Of all HEV infections nationwide one in 700 is estimated to be due to blood transfusion, while for chronic infections this is one in 3.5.Conclusion: Despite uncertainties in our estimates, preventing HEV transmission by screening of blood donations appears not excessively expensive compared to other blood-screening measures in the Netherlands. However, the impact on HEV disease burden may be relatively small as only a minority of all HEV cases is transmitted by blood transfusion. [ABSTRACT FROM AUTHOR]

Background: To reduce the rate of transfusion-transmitted hepatitis B virus (HBV), HBV DNA testing was introduced for all Dutch blood donations in 2008, in addition to the existing screening for HBV surface antigen (HBsAg). This study describes the lookback results for repeat donors with an "HBV DNA-only" test result (HBV DNA-positive and HBsAg-negative).Study Design and Methods: From November 2008 until June 2011, a total of 2.3 million blood donations were tested for HBV DNA and 22 donors showed the HBV DNA-only profile. Four donors had early preseroconversion HBV infection, two showed suppressed infection after vaccination, and 16 donors had occult chronic HBV infection (OBI). Potentially infectious donations were traced back as far as 1992. If possible the recipients were tested for current and past HBV infection.Results: A total of 416 implicated donations could be traced in blood bank records, involving 448 issued blood products. For 170 (38%) of the recipients no information was obtained from the hospitals; 196 (44%) recipients had died, and 82 (18%) were tested for HBV. Six recipients tested positive for current (n = 4) or past (n = 2) HBV infection. For two recipients transfusion was ruled out as the source of infection. Three patients showed HBV DNA sequences matching with the HBV in one common OBI donor. Overall, in four of 82 tested recipients (5%) HBV transmission was likely.Conclusion: In our lookback study HBV testing was possible in only a minority (18%) of potentially exposed recipients. A low transmission rate (5%) was observed in recipients of blood components from donors with OBI. [ABSTRACT FROM AUTHOR]

Background: The availability of costly safety measures against transfusion-transmissible infections forces Western countries to confront difficult ethical questions. How to decide about implementing such measures? When are such decisions justified? As a preliminary to addressing these questions, we assessed which concerns shape actual donor blood safety policymaking in five Western countries.Study Design and Methods: Our qualitative study involved determining which issues had been discussed in advisory committee meetings and capturing these issues in general categories. Appropriate documents were identified in collaboration with local decision-making experts in Canada, Germany, the Netherlands, the United States, and the United Kingdom. The introduction of hepatitis B virus nucleic acid testing and selected measures against variant Creutzfeldt-Jakob disease, West Nile virus, and Q-fever were chosen as cases representing decision-making on safety measures with high costs and low or uncertain added safety.Results: A broad inventory of concerns was established, including: 1) nine categories of advantages and disadvantages of candidate safety policies; 2) six kinds of difficulties in assessing risks and forecasting the effects of safety policies; 3) 13 decision-making principles; and 4) six kinds of practical barriers hampering the translation of candidate policies into decisions.Conclusion: Blood safety policymaking involves a wide variety of competing concerns, and approaches to reconcile these considerations are themselves contested. Developing a systematic decision-making approach requires ethical reflection on, among others, reasonable costs of safety and the value of transparency in public policy. [ABSTRACT FROM AUTHOR]

Background In the Netherlands, universal antibody to hepatitis B core antigen (anti- HBc) donor screening was introduced in July 2011 to intercept potentially infectious donations slipping through hepatitis B surface antigen ( HBsAg) and hepatitis B virus ( HBV) DNA minipool screening ( HBV DNA MP6). Study Design and Methods The yield and donor loss were evaluated after the first 2 years of universal anti- HBc donor screening. A total of 382,173 donors were tested for anti- HBc and, if positive, for antibody to HBsAg (anti- HBs). Anti- HBc-reactive donors with anti- HBs of less than 200 IU/ L were deferred, but repeat donors were allowed retesting after 6 months if anti- HBs was less than 10 IU/ mL. Anti- HBc false positivity was estimated using the crude anti- HBc signal, family name-based ethnicity scoring, and donor follow-up. Results Anti- HBc screening identified 13 confirmed or potential HBsAg- and HBV DNA MP6-negative recent HBV infections. In addition, 820 anti- HBc-reactive donors with low anti- HBs titers (<200 IU/ mL), potentially harboring occult HBV infection ( OBI), were identified and deferred. Overall, 1583 (0.41%) donors were deferred: 1178 (0.31%) during first-time anti- HBc screening, 361 (0.09%) anti- HBc seroconverters, and 44 (0.01%) donors with waning anti- HBs titers. Only 188 of 1583 (12%) deferred donors could be reentered upon retesting. Estimated anti- HBc false positivity was 16%, but varied greatly among anti- HBc-reactive donors with and without anti- HBs (8% vs. 62%). Conclusion Anti- HBc testing has improved the safety of the Dutch blood supply but its exact yield remains difficult to determine, due to the complexity of confirming anti- HBc reactivity and OBI. In a low-endemic country, donor loss associated with anti- HBc screening is sustainable, but adds to the already considerable list of donor exclusions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Screening of blood units for hepatitis B virus (HBV) DNA identifies donations collected during the window period (WP) of the acute infection and may improve viral safety of the blood supply. It also leads to the detection of occult hepatitis B infection (OBI). STUDY DESIGN AND METHODS: From January 2005 to December 2006, a total of 383,267 blood units were screened for hepatitis B surface antigen (HBsAg) and HBV DNA in two transfusion centers in Madrid, using either individual-donation nucleic acid testing (ID-NAT) or minipool (MP-NAT) of eight donations (MP8). Samples positive for HBV DNA and negative for HBsAg were confirmed by a second molecular test, the viral DNA was quantified, and a genome fragment including the region encoding the major hydrophilic region (MHR) of HBsAg was sequenced. RESULTS: The overall yield of HBV DNA–positive, HBsAg-negative units was 1 in 21,282 (18 cases), higher when using ID-NAT than MP8-NAT (1:9862 vs. 1:51,011; p < 0.01). Four donations (1/95,817) were collected during the infectious pre-HBsAg WP, one during an early recovery stage, and the remaining 13 (1/29,482) were OBIs, six of whom had no detectable antibody to HBsAg. Low-level Genotype D HBV DNA was detected in all OBI cases; the frequencies of this genotype and MHR amino acid substitutions were significantly higher than reported from unselected Spanish HBsAg carriers. Donors with OBI had normal aminotransferase levels and were significantly older than donors carrying HBsAg. CONCLUSIONS: Blood donors in the WP and with OBI are not uncommon in Madrid and are detected at a higher frequency with ID-NAT than MP-NAT. [ABSTRACT FROM AUTHOR]