Prevalence of anti-tick-borne encephalitis virus (TBEV) antibodies in Swiss blood donors in 2014-2015.

BACKGROUND: Disease morbidity of tick-borne encephalitis (TBE) has been increasing over the last decades. Since the 1990s, however, no extensive seroprevalence studies on TBE in humans have been performed in Switzerland. Here we assessed the prevalence of anti-TBE virus (TBEV) antibodies among different groups of the Swiss blood donor population. MATERIALS AND METHODS: The study was carried out from July 2014 to January 2015. Blood donors participating in the study (n=9,328) were asked to fill in a questionnaire relating to vaccination against or infection with different flaviviruses, and blood samples were collected. All samples were screened for the presence of anti-TBEV IgG antibodies using ELISA testing. Seropositivity rates in different groups of blood donors were compared using Chi square tests with Bonferroni correction. RESULTS: In 2014 and 2015, 24.6% of healthy Swiss blood donors indicated vaccination against TBE. Among vaccinated blood donors, antibody prevalence was significantly higher in younger (<40y: 85.3%) than older individuals (≥40 to <55y: 80.0%, ≥55y: 76.7%; p=0.005). In non-vaccinated individuals, antibody prevalence was significantly higher in younger (<40y: 10.0%) than older (≥40 to <55y: 4.0%, ≥55y: 3.9%; p<0.005), male (6.8%) than female (3.7%, p<0.0001), and blood donors from endemic (7.0%) than border (6.2%) or non-endemic regions (4.2%, p<0.001). Possible asymptomatic infection, as defined by positive IgG ELISA results in blood donors indicating no vaccination against TBEV, was found in 5.6%. DISCUSSION: Our data importantly complement the knowledge on TBEV vaccination rates and estimate the frequency of subclinical TBE in Switzerland.

Low-Frequency Blood Group Antigens in Switzerland.

BACKGROUND: High-frequency blood group antigens (HFA) are present in >90% of the human population, according to some reports even in >99% of individuals. Therefore, patients lacking HFA may become challenging for transfusion support because compatible blood is hardly found, and if the patient carries alloantibodies, the cross-match will be positive with virtual every red cell unit tested. METHODS: In this study, we applied high-throughput blood group SNP genotyping on >37,000 Swiss blood donors, intending to identify homozygous carriers of low-frequency blood group antigens (LFA). RESULTS: 326 such individuals were identified and made available to transfusion specialists for future support of patients in need of rare blood products. CONCLUSION: Thorough comparison of minor allele frequencies using population genetics revealed heterogeneity of allele distributions among Swiss blood donors which may be explained by the topographical and cultural peculiarities of Switzerland. Moreover, geographically localized donor subpopulations are described which contain above-average numbers of individuals carrying rare blood group genotypes.

Red blood cell use in Switzerland: trends and demographic challenges.

BACKGROUND: Several studies have raised concerns that future demand for blood products may not be met. The ageing of the general population and the fact that a large proportion of blood products is transfused to elderly patients has been identified as an important driver of blood shortages. The aim of this study was to collect, for the first time, nationally representative data regarding blood donors and transfusion recipients in order to predict the future evolution of blood donations and red blood cell (RBC) use in Switzerland between 2014 and 2035. MATERIALS AND METHODS: Blood donor and transfusion recipient data, subdivided by the subjects' age and gender were obtained from Regional Blood Services and nine large, acute-care hospitals in various regions of Switzerland. Generalised additive regression models and time-series models with exponential smoothing were employed to estimate trends of whole blood donations and RBC transfusions. RESULTS: The trend models employed suggested that RBC demand could equal supply by 2018 and could eventually cause an increasing shortfall of up to 77,000 RBC units by 2035. DISCUSSION: Our study highlights the need for continuous monitoring of trends of blood donations and blood transfusions in order to take proactive measures aimed at preventing blood shortages in Switzerland. Measures should be taken to improve donor retention in order to prevent a further erosion of the blood donor base.

Hemovigilance monitoring of platelet septic reactions with effective bacterial protection systems.

BACKGROUND: Delayed, large-volume bacterial culture and amotosalen/ultraviolet-A light pathogen reduction are effective at reducing the risk of bacterial proliferation in platelet concentrates (PCs). Hemovigilance programs continue to receive reports of suspected septic transfusion reactions, most with low imputability. Here, we compile national hemovigilance data to determine the relative efficacy of these interventions. STUDY DESIGN AND METHODS: Annual reports from the United Kingdom, France, Switzerland, and Belgium were reviewed between 2005 and 2016 to assess the risk of bacterial contamination and septic reactions. RESULTS: Approximately 1.65 million delayed, large-volume bacterial culture-screened PCs in the United Kingdom and 2.3 million amotosalen/ultraviolet-A-treated PCs worldwide were issued with no reported septic fatalities. One definite, one possible, and 12 undetermined/indeterminate septic reactions and eight contaminated "near misses" were reported with delayed, large-volume bacterial cultures between 2011 and 2016, for a lower false-negative culture rate than that in the previous 5 years (5.4 vs. 16.3 per million: odds ratio, 3.0; 95% confidence interval, 1.4-6.5). Together, the Belgian, Swiss, and French hemovigilance programs documented zero probable or definite/certain septic reactions with 609,290 amotosalen/ultraviolet-A-treated PCs (<1.6 per million). The rates were significantly lower than those reported with concurrently transfused, nonpathogen-reduced PCs in Belgium (<4.4 vs. 35.6 per million: odds ratio, 8.1; 95% confidence interval,1.1-353.3) and with historic septic reaction rates in Switzerland (<6.0 vs. 82.9 per million: odds ratio, 13.9; 95% confidence interval, 2.1-589.2), and the rates tended to be lower than those from concurrently transfused, nonpathogen-reduced PCs in France (<4.7 vs. 19.0 per million: odds ratio, 4.1; 95% confidence interval, 0.7-164.3). CONCLUSION: Pathogen reduction and bacterial culture both reduced the incidence of septic reactions, although under-reporting and strict imputability criteria resulted in an underestimation of risk.

Donor Safety in Haemapheresis: Development of an Internet-Based Registry for Comprehensive Assessment of Adverse Events from Healthy Donors.

BACKGROUND: Currently, there is an extensive but highly inconsistent body of literature regarding donor adverse events (AEs) in haemapheresis. As the reports diverge with respect to types and grading of AEs, apheresis procedures and machines, the range of haemapheresis-related AEs varies widely from about 0.03% to 6.6%. METHODS: The German Society for Transfusion Medicine and Immunohaematology (DGTI) formed a 'Haemapheresis Vigilance Working Party' (Arbeitsgemeinschaft Hämapheresevigilanz; AGHV) to create an on-line registry for comprehensive and comparable AE assessment with all available apheresis devices in all types of preparative haemapheresis: plasmapheresis (PLS), plateletpheresis (PLT), red blood cell apheresis, all kind of leukaphereses (autologous/allogeneic blood stem cell apheresis, granulocyte apheresis, lymphocyte/monocyte apheresis) and all possible types of multi-component apheresis. To ensure the comparability of the data, the AGHV adopted the 'Standard for Surveillance of Complications Related to Blood Donation' from the International Society for Blood Transfusion in cooperation with the International Haemovigilance Network (IHN) and the American Association of Blood Banks for AE acquisition and automated evaluation. The registry is embedded in a prospective observational multi-centre study with a study period of 7 years. RESULTS: A preliminary evaluation encompassed the time period from January, 2012 to December, 2015. During this time, the system proved to be safe and stable. Out of approximately 345,000 haemaphereses 16,477 AEs were reported (4.9%) from 20 participating centres. The majority of AEs occurred in PLSs (63%), followed by PLT (34.5%) and SC (2.2%). Blood access injuries (BAI) accounted for about 55% of the supplied AEs, whereas citrate toxicity symptoms, vasovagal reactions and technical events (e.g. disposable leakages, software failures) rather equally affected haemaphereses at 8-15%. Out of 12,348 finalized AEs, 8,759 (70.1%) were associated with a procedure-related break-off, with BAI being the prevailing cause (5,463/8,759; 62.4%). An automated centre- and procedure-specific AE evaluation according to the latest IHN standard and AGHV pre-settings is available within a few minutes. CONCLUSIONS: An on-line electronic platform for comprehensive assessment and centre-specific automated evaluation of AEs in haemaphereses has been developed and proved to be stable and safe over a period of 4 years.

Too Many Blood Donors - Response Bias in the Swiss Health Survey 2012.

BACKGROUND: Data on blood donor status obtained from general surveys and health interview surveys have been widely used. However, the integrity of data on self-reported blood donor status from surveys may be threatened by sampling and non-sampling error. Our study aimed to compare self-reported blood donors (including one-time as well as regular donors) from the Swiss Health Survey 2012 (SHS) with register-based blood donors recorded by blood establishments and evaluate the direction and magnitude of bias in the SHS. METHODS: We compared population-weighted SHS point estimates of the number of blood donors with their corresponding 95% confidence intervals to the respective figures from blood donor registries (birth cohorts 1978-1993) and estimates of donors based on period donor tables derived from blood donor registries (birth cohorts 1920-1993). RESULTS: In the birth cohorts 1978-1993, the SHS-predicted number of donors was 1.8 times higher than the respective number of donors based on registry data. Adjusting for foreign and naturalized Swiss nationals that immigrated after their 18th birthday, the SHS overall predicted number of donors was 1.6 times higher. Similarly, SHS estimates for the 1920-1993 birth cohorts were 2.4 and 2.1 times higher as compared to register-based estimates. Generally, the differences between SHS and register-based donors were more pronounced in men than in women. CONCLUSION: Self-reported blood donor status in the SHS is biased. Estimates of blood donors are substantially higher than respective estimates based on blood donor registries.

Reverse vertical transmission of hepatitis B virus (HBV) infection from a transfusion-infected newborn to her mother.

BACKGROUND & AIMS: Clinical cases of viral infections possibly involving the transfusion of blood components are systematically investigated. METHODS: Serological and molecular markers of hepatitis B virus were used including HBsAg, anti-HBc, anti-HBs, HBV DNA, and viral load. Full genome sequencing and phylogenetic analyses were performed. RESULTS: An acute HBV infection was diagnosed in the mother of a 16-month-old daughter who had been transfused at age three weeks with one quarter of a regular red cell concentrate (RCC). The repeat donor of the index donation was free of HBV markers in two previous donations but seroconverted to anti-HBc and anti-HBs 3 months post-donation of a unit containing only low level of HBV DNA. One other newborn recipient of the same RCC was asymptomatically HBV infected. A third newborn recipient whose mother had been HBV vaccinated and carried moderate level of anti-HBs was not infected. Full length nucleotide sequence identity between HBV strains from the mother and the two infected transfusion recipients provided evidence of the transfusion origin of all three infections in the absence of donor sequence. CONCLUSIONS: Reverse vertical HBV transmission was likely the result of casual mother contact with a baby carrying extremely high viral load. The blood products intended to immunodeficient newborn should be submitted to more thorough viral testing considering their increased susceptibility to infections.

Prospective, Paired Crossover Comparison of the in vitro Quality of Red Blood Cells Collected by the Automate for Blood Collection Device or by a Conventional Method.

BACKGROUND: The prevention of the citrate shock should improve the quality of red blood cells (RBCs). We compared a conventional whole blood donation method (CONV) with a 'Automate for Blood Collection' (ABC), enabling a metered addition of anticoagulant and hence a correct and constant RBC-to-anticoagulant ratio throughout donation. We evaluated the performance of the ABC device and the storage quality of RBC units. MATERIAL AND METHODS: The study was designed as prospective, paired crossover study with two groups of 20 donors donating first with the ABC or CONV and switching to the alternative method after 12 weeks. We measured the processing data of donations and the storage quality of RBCs on days 1, 28, and 42. RESULTS: ABC whole blood donations showed a slightly higher volume before and after filtration. ABC-derived RBC units revealed higher values for haematocrit, mean cellular volume, potassium and lower values for mean corpuscular haemoglobin concentration and sodium until day 42. They further showed faster glucose consumption and lactate production until day 28. CONCLUSION: The ABC device is suitable for whole blood collection. The quality of the obtained RBCs is comparable to that of CONV. Avoiding the citrate shock by the described method did not improve the investigated RBC storage quality parameters.