Hepatitis E Virus Infection in Voluntary Blood Donors in the Russian Federation

Transfusion-transmitted hepatitis E virus (HEV) infection is an increasing concern in many countries. We investigated the detection rate of HEV viremia in blood donors in Russia. A total of 20,405 regular repetitive voluntary non-renumerated blood donors from two regions (Moscow and Belgorod) were screened for HEV RNA using the cobas® HEV test in mini-pools of six plasma samples. Samples from each reactive pool were tested individually. The average HEV RNA prevalence was 0.024% (95% CI: 0.01-0.05%), or 1 case per 4081 donations. No statistically significant differences in HEV RNA prevalence were observed between the two study regions. The PCR threshold cycle (Ct) values ranged from 25.0 to 40.5 in reactive pools, and from 20.9 to 41.4 in reactive plasma samples when tested individually. The HEV viremic donors had different antibody patterns. Two donor samples were reactive for both anti-HEV IgM and IgG antibodies, one sample was reactive for anti-HEV IgM and negative for anti-HEV IgG, and two samples were seronegative. At follow-up testing 6 months later, on average, four donors available for follow-up had become negative for HEV RNA and positive for anti-HEV IgG. The HEV ORF2 sequence belonging to HEV-3 sub-genotype 3a was obtained from one donor sample. The sequencing failed in the other four samples from viremic donors, presumably due to the low viral load. In conclusion, the HEV RNA detection rate in blood donors in Russia corresponds with data from other European countries, including those that implemented universal donor HEV screening. These data support the implementation of HEV RNA donor screening to reduce the risk of transfusion-transmitted HEV infection in Russia.

Implementation of amotosalen plus ultraviolet A-mediated pathogen reduction for all platelet concentrates in France: Impact on the risk of transfusion-transmitted infections

BACKGROUND AND OBJECTIVES

Pathogen reduction (PR) technology may reduce the risk of transfusion-transmitted infections (TTIs), notably transfusion-transmitted bacterial infection (TTBI) associated with platelet concentrates (PCs). PR (amotosalen/UVA treatment) was implemented for all PCs transfused in France in November 2017. No bacterial detection was in place beforehand. The study aimed to assess the impact of PR PC on TTI and TTBI near-miss occurrences.

MATERIALS AND METHODS

TTI and TTBI near-miss occurrences were compared before and after 100% PR implementation. The study period ran from 2013 to 2022. Over 300,000 PCs were transfused yearly.

RESULTS

No PC-related transmission of human immunodeficiency virus, hepatitis C virus, hepatitis B virus and human T-cell lymphotropic virus was reported throughout the study period. PC-mediated hepatitis E virus and hepatitis A virus infections occurred irrespective of PR implementation. Mean PC-mediated TTBI occurrence before PR-PC implementation was 3/year (SD: 1; n = 15; 1/92,687 PC between 2013 and 2016) with a fatal outcome in two patients. Since PR implementation, one TTBI has been reported (day 4 PC, Bacillus cereus) (1/1,645,295 PC between 2018 and 2022; p < 0.001). Two PR PC quarantined because of a negative swirling test harboured bacteria: a day 6 PC in 2021 (B. cereus and Staphylococcus epidermidis) and a day 7 PC in 2022 (Staphylococcus aureus). Five similar occurrences with untreated PC were reported between 2013 and 2020.

CONCLUSION

Transfusion of 100% PR PC resulted in a steep reduction in TTBI occurrence. TTBI may, however, still occur. Pathogen-reduced PC-related TTI involving non-enveloped viruses occurs as well.

Haemovigilance survey and screening strategy for arthropod-borne viruses in blood donors from Argentina

Arthropod-borne viruses (arboviruses) count among emerging infections, which represent a major challenge for transfusion safety worldwide. To assess the risk of arboviruses-transmission by transfusion (ATT), we performed a survey to evaluate the potential threat for transfusion safety. Samples were retrospectively and randomly collected from donors who donated during the peak of dengue incidence in Cordoba (years: 2016 and 2019-2022). A cost-efficient strategy for molecular screening was implemented with a nucleic acid test (NAT) configured with Flavivirus and Alphavirus-universal degenerated primers targeting conserved gene regions. Besides, we evaluated the neutralizing antibody (NAb) prevalence by plaque reduction neutralization test (PRNT). A total of 1438 samples were collected. Among the NAT-screened samples, one resulted positive for Flavivirus detection. Subsequent sequencing of the PCR product revealed Saint Louis Encephalitis Virus (SLEV) infection (GeneBank accession number OR236721). NAb prevalence was 2.95% for anti-Dengue, 9.94% anti-SLEV, 1.09% anti-West Nile Virus, and 0% anti-Chikungunya. One of the NAb-positive samples also resulted positive for IgM against SLEV but negative by ARN detection. This is the first haemovigilance study developed in Argentina that evaluates the potential risk of ATT and the first research to determine the prevalence of NAb against Flavivirus through PNRT to avoid possible cross-reactions between Ab against Flavivirus. Herein, the finding of one SLEV-viremic donor and the detection of anti-SLEV IgM in a different donor demonstrated a potential threat for transfusion safety and emphasized the need for increased vigilance and proactive measures to ensure the safety of blood supplies.

Infectious etiologies among post-donation deferrals in a military blood donation center

BACKGROUND

The burden of transfusion-transmitted infections among blood recipients remains low due to extensive pre- and post-donation screening. However, the military has the unique challenge of providing blood in austere environments with limited testing capabilities. This study evaluates the infectious etiologies of deferred blood donors at a large military blood donation center.

METHODS

All blood donors at the Armed Service Blood Bank Center, San Antonio, between 2017 and 2022 with positive post-donation screening for hepatitis C (HCV), hepatitis B (HBV), human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV-I/II), Zika (2018-2021), West Nile virus, Trypanosoma cruzi, Treponema pallidum, or Babesia microti (2020-2022) were evaluated. Donors were deferred based on Food and Drug Administration (FDA) guidance.

RESULTS

Two-hundred and thirteen (213) donors met FDA criteria for deferral. T. pallidum (n = 45, 50.3 per 100,000), HCV (n = 34, 38.0 per 100,000), and HBV (n = 19, 21.2 per 100,000) were the most common pathogens among those with both positive screening and confirmatory testing. The majority of HIV (95%), Chagas (78%), HTLV-I/II (50%) deferrals were due to indeterminate confirmatory tests following initial positive screens. The majority of deferrals for HBV were for a second occurrence of a positive screen despite negative confirmatory testing.

CONCLUSION

The rates of post-donation deferral for transfusion-transmissible infections were low in this military cohort. Our findings suggest that donor testing in deployed service members should focus on HBV, HCV, and T. pallidum and highlight the need for better diagnostics for HIV, Chagas, and HTLV-I/II.

Hepatitis E Virus in Finland: Epidemiology and Risk in Blood Donors and in the General Population

Autochthonous hepatitis E (HEV) cases have been increasingly recognized and reported in Europe, caused predominantly by the zoonotic HEV genotype 3. The clinical picture is highly variable, from asymptomatic to acute severe or prolonged hepatitis in immunocompromised patients. The main route of transmission to humans in Europe is the ingestion of undercooked pork meat. Transfusion-transmitted HEV infections have also been reported. The aim of the study was to determine the HEV epidemiology and risk in the Finnish blood donor population. A total of 23,137 samples from Finnish blood donors were screened for HEV RNA from individual samples and 1012 samples for HEV antibodies. Additionally, laboratory-confirmed hepatitis E cases in 2016-2022 were extracted from national surveillance data. The HEV RNA prevalence data was used to estimate the risk of transfusion transmission of HEV in the Finnish blood transfusion setting. Four HEV RNA-positive were found, resulting in 1:5784 (0.02%) RNA prevalence. All HEV RNA-positive samples were IgM-negative, and genotyped samples represented genotype HEV 3c. HEV IgG seroprevalence was 7.4%. From the HEV RNA rate found in this study and data on blood component usage in Finland in 2020, the risk estimate for a severe transfusion-transmitted HEV infection is 1:1,377,000 components or one in every 6-7 years. In conclusion, the results indicate that the risk of transfusion-transmitted HEV (HEV TTI) in Finland is low. However, continuous follow-up of the HEV epidemiology in relation to the transfusion risk landscape in Finland is necessary, as well as promoting awareness in the medical community of the small risk for HEV TTI, especially for immunocompromised patients.

Seven years (2015-2021) of blood donor screening for HEV-RNA in France: lessons and perspectives

BACKGROUND

The French health authorities are considering expanding the current selective hepatitis E virus (HEV)-RNA testing procedure to include all donations in order to further reduce transfusion-transmitted HEV infection. Data obtained from blood donors (BDs) tested for HEV-RNA between 2015 and 2021 were used to assess the most efficient nucleic acid testing (NAT) strategy.

MATERIALS AND METHODS

Viral loads (VLs) and the plasma volume of blood components, as well as an HEV-RNA dose of 3.85 log IU as the infectious threshold and an assay with a 95% limit of detection (LOD) at 17 IU/mL, were used to assess the proportion of: (i) HEV-RNA-positive BDs that would remain undetected; and (ii) blood components associated with these undetected BDs with an HEV-RNA dose >3.85 log IU, considering 4 NAT options (Individual testing [ID], MP-6, MP-12, and MP-24).

RESULTS

Of the 510,118 BDs collected during the study period, 510 (0.10%) were HEV-RNA-positive. Based on measurable VLs available in 388 cases, 1%, 15.2%, 21.8%, and 32.6% of BDs would theoretically pass undetected due to a VL below the LOD of ID, MP-6, MP-12, and MP-24 testing, respectively. All BDs associated with a potentially infectious blood component would be detected with ID-NAT while 13% of them would be undetected with MP-6, 19.6% with MP-12, and 30.4% with MP-24 depending on the plasma volume. No red blood cell (RBC) components with an HEV-RNA dose >3.85 log IU would enter the blood supply, regardless of the NAT strategy used.

DISCUSSION

A highly sensitive ID-NAT would ensure maximum safety. However, an MP-based strategy can be considered given that: (i) the risk of transmission is closely related to the plasma volume of blood components; (ii) RBC are the most commonly transfused components and have a low plasma content; and (iii) HEV-RNA doses transmitting infection exceed 4 log IU. To minimise the potential risk associated with apheresis platelet components and fresh frozen plasma, less than 12 donations should be pooled using an NAT assay with a LOD of approximately 20 IU/mL.

Challenges for the maintaining the microbiological safety of the UK blood supply

The supply of blood, blood products and components in the UK, as elsewhere, is safe, although there is no cause for complacency. Use of blood, blood products and components is not without risk of morbidity and mortality. Transfusion-transmitted infections (TTIs) continue to occur and may severely affect the health and welfare of recipients. As indicated by recent and current inquiries, public interest in these TTIs is huge. The risk of TTI can be mitigated but not abolished. Measures to reduce risk include screening of donors, testing of donations and, where appropriate, treatment of donations. The introduction of newer screening tests might identify some infectious donations but come at a cost, which could exceed a justifiable limit. Thus, the recognition, detection, reporting and investigation of cases of possible TTIs need to be improved. Recipients of blood should understand that, although transfusion in the UK is safe, it is not free of risk and so should be provided with full information so that properly informed consent can be given.

Transfusion-Transmitted Cache Valley Virus Infection in a Kidney Transplant Recipient With Meningoencephalitis

BACKGROUND

Cache Valley virus (CVV) is a mosquito-borne virus that is a rare cause of disease in humans. In the fall of 2020, a patient developed encephalitis 6 weeks following kidney transplantation and receipt of multiple blood transfusions.

METHODS

After ruling out more common etiologies, metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) was performed. We reviewed the medical histories of the index kidney recipient, organ donor, and recipients of other organs from the same donor and conducted a blood traceback investigation to evaluate blood transfusion as a possible source of infection in the kidney recipient. We tested patient specimens using reverse-transcription polymerase chain reaction (RT-PCR), the plaque reduction neutralization test, cell culture, and whole-genome sequencing.

RESULTS

CVV was detected in CSF from the index patient by mNGS, and this result was confirmed by RT-PCR, viral culture, and additional whole-genome sequencing. The organ donor and other organ recipients had no evidence of infection with CVV by molecular or serologic testing. Neutralizing antibodies against CVV were detected in serum from a donor of red blood cells received by the index patient immediately prior to transplant. CVV neutralizing antibodies were also detected in serum from a patient who received the co-component plasma from the same blood donation.

CONCLUSIONS

Our investigation demonstrates probable CVV transmission through blood transfusion. Clinicians should consider arboviral infections in unexplained meningoencephalitis after blood transfusion or organ transplantation. The use of mNGS might facilitate detection of rare, unexpected infections, particularly in immunocompromised patients.

Prevalence of transfusion-transmitted infections in Saudi Arabia blood donors: A nationwide, cross-sectional study

OBJECTIVES

To establish a nationwide epidemiological profile of transfusion-transmittable infection (TTI) markers among seemingly healthy blood donors to update policies required to ensure blood safety.

METHODS

A nationwide, cross-sectional study was designed to examine donor demographics and TTI prevalence during 2020 using data provided by the Ministry of Health, Saudi Arabia.

RESULTS

Collectively, a total of 375,218 whole blood units were donated, of which 32,758 (8.7%) were excluded due to TTI-related risk. The exclusion was based on a positive nucleic acid amplification test (NAT) or seroreactivity to hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), human T-cell lymphotropic virus (HTLV-I/II), syphilis, or malaria. Notably, the central (37.6%) and southern (33%) regions were the epicenters of TTI-reactive blood donors. Hepatitis B virus markers accounted for 85.7% and were the overall most prevalent of TTI-positive donations, followed by HCV at 5.9% and syphilis at 5.6%. In particular, anti-HBc and HBsAg were most prevalent in the south, while HBV NAT was highest in the center.

CONCLUSION

Hepatitis B virus, HCV, and syphilis carry the greatest risk of TTI in Saudi Arabia. Including HBsAg screening is a necessary precautious measure to maintain blood safety.

Monkeypox and Transfusion Safety

In May of 2022, a multinational outbreak of monkeypox was recognized. It expanded rapidly and over the following three-plus months, more than 50,000 cases were reported from 100 countries, largely among gay or bisexual men. The causative agent is a poxvirus, related to smallpox and vaccinia viruses. Available information implies that the virus might be transfusion-transmissible, although no cases had been reported by late August, 2022. Current data are reviewed, and the potential impacts of transfusion transmission are discussed, along with potential interventions.

Human Immunodeficiency Virus and Syphilis Among Blood Donors at Western Oromia, Ethiopia

Background

Blood transfusion saves lives and improves health, but many patients requiring transfusion do not have timely access to safe blood. Human immunodeficiency virus and syphilis are the commonest transfused transmitted infections and threats to blood recipients. Proper donor selection and screening of the donated blood for major transfusion-transmitted infections evidently reduced challenge in blood safety. Therefore, the objective of this study was to determine the sero-prevalence HIV and syphilis infections among blood donors at East Wollega, West Ethiopia.

Patients and Methods

A five-year (from January 2015 to December 2019) retrospective study was conducted by reviewing blood donor laboratory test results from Nekemte blood bank which is serving hospitals in Western Oromia. Blood donor data were analyzed by Statistical Package for Social Sciences version 20 software.

Results

The total of 17,810 individual’s blood was screened during the study period. The overall prevalence of HIV, syphilis, and their co-infection was 222 (1.25%), 142 (0.80%), and 5 (0.03%), respectively. The prevalence of HIV was associated with unmarried (AOR: 2.4; 95% CI: 1.5, 5.2), male (AOR: 2.1; 95% CI: 1.5, 2.9), and blood donors resident in a rural area (AOR: 1.5; 95% CI: 1.5, 5.9). Besides, the prevalence of syphilis was associated with education, age, marital status and residence of study participant.

Conclusion

In the current study, the sero-prevalence of HIV and syphilis among blood donors was low, when it was compared to other sub-Saharan Africa country. However, to ensure the health of all recipients screening blood using standard methods is highly recommended.

Prolonged incubation period of hepatitis B in a recipient of a nucleic acid amplification test-negative hepatitis B virus window donation

BACKGROUND

The occurrence of transfusion-transmitted hepatitis B virus (HBV) infection has fallen dramatically due to continuous improvements in pre-transfusion laboratory testing. However, the characteristics of transfusion-transmitted HBV infection caused by individual donor nucleic acid amplification test (ID-NAT)-negative blood products are unclear.

CASE PRESENTATION

A 76-year-old woman with acute myeloid leukemia was diagnosed with transfusion-transmitted HBV infection after receiving apheresis platelets derived from an ID-NAT-negative blood donation. This case was diagnosed definitively as transfusion-mediated because complete nucleotide homology of a 1556 bp region of the HBV Pol/preS1-preS2-S genes and a 23 bp region of the HBV core promoter/precore between the donor and recipient strains was confirmed by PCR-directed sequencing. The case is uncommon with respect to the unexpectedly prolonged HBV-DNA incubation period of nearly 5 months after transfusion (previously, the longest period observed since the recent implementation of ID-NAT pre-transfusion laboratory testing in Japan was 84 days). Slow-replicating HBV genotype A2 may contribute to the prolonged incubation period; also, the quantity of apheresis platelets delivered in a large volume of plasma, and/or the immune response of the recipient suffering from a hematological neoplasm, may have contributed to establishment of HBV infection in the recipient. This was supported by analysis of three previously documented cases of transfusion-transmitted HBV infection by blood products derived from ID-NAT-negative donations in Japan.

CONCLUSION

Continuous monitoring of HBV infection for longer periods (>3 months) may be required after transfusion of blood components from an ID-NAT-negative HBV window donation.

Postdonation information during dengue outbreaks at a single blood center in Brazil: An ally against transfusion-transmitted infections

BACKGROUND:

Brazilian blood banks encourage donors to report postdonation information (PDI) regarding conditions that would lead to deferral in an attempt to retrieve distributed nonconforming blood.

OBJECTIVES:

This study evaluated the profile of donors reporting PDI, the impact on transfusion safety, and the possible impact on the discard of blood products.

SUBJECTS AND METHODS:

We analyzed 115 consecutive PDIs between May 2014 and July 2015, a period comprising two dengue-like syndrome (DLS) outbreaks.

RESULTS:

These PDIs accounted for 87,780 blood donations. The average time for PDIs since donation was 4 (0–23) days and 190 blood components were discarded. DLS accounted for 21.7% of the PDIs analyzed; 11 of the 23 samples tested were nucleic acid test (NAT) positive for dengue and 2 positive for Zika virus (ZIKV). Six of these PDIs were reported after blood components have been transfused: After NAT testing, one of these recipients was diagnosed with dengue and another one with ZIKV infection, both possible transfusions transmitted but without clinical consequences.

CONCLUSION:

The high number of recovered blood components due to PDI suggests that PDI remains a great ally in the fight against transfusion-transmitted infections and may be particularly useful during outbreaks of emerging potentially blood-borne pathogens.

Educational Case: A Case of Transfusion-Transmitted Babesiosis: Diagnostic Perspectives Across the Clinical Laboratory

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

Prevalence of hepatitis E viraemia among blood donors: a systematic review

BACKGROUND

Hepatitis E virus (HEV) is usually transmitted by faecal-oral route. Recent reports have documented HEV viraemia in donated blood units and HEV transmission through blood transfusion. This systematic review summarizes the available data on prevalence of HEV viraemia in blood donors.

METHODS

Electronic databases were searched on 17 December 2018 to identify full-text English papers reporting original data on prevalence of HEV RNA in donated blood units. Two authors independently extracted the relevant data, which were pooled using simple aggregation as well as a random-effects meta-analysis; heterogeneity was assessed using the I2 method.

RESULTS

In all, 59 data sets from 28 countries were identified. The available data showed marked heterogeneity. Of a total of 2 127 832 units studied, 561 (263·6 [95% confidence intervals = 242·7-286·4] per million units) tested positive for HEV RNA. On random-effects meta-analysis, the pooled prevalence was 60·9 [6·7-155·4] per million units. In the viraemic units, HEV RNA titre varied by nearly one million-fold, and most had genotype 3 HEV. The prevalence was higher in blood units with anti-HEV antibodies or elevated alanine aminotransferase. Only nearly one-fourth of viraemic units had anti-HEV antibodies.

CONCLUSIONS

The prevalence of HEV viraemia among healthy blood donors is low, though the available data had limited geographical representation and marked heterogeneity. There is a need for further data on HEV viraemia in blood donors from areas with non-3 HEV genotype preponderance.

Pseudomonas poae-Associated Fatal Septic Transfusion Reaction, Peoria, Illinois, USA, 2017

In the United States, fatal transfusion-transmitted infections from red blood cell units are rare. Although this pattern mostly reflects how inhospitable refrigerated red blood cell units are to contaminant growth, fatalities caused by microorganisms that can grow at storage temperature (4°C), but not in standard clinical blood cultures at 37°C, are probably underestimated. We analyzed a fatal red blood cell transfusion in Peoria, Illinois, USA, that occurred in 2017. Samples from the patient's whole blood and the red blood cell unit remained culture-negative during the investigation, despite direct visualization of gram-negative bacilli within the unit immediately after transfusion. We identified the bacteria as Pseudomonas poae, a nonpathogenic pseudomonad carrying multiple cold-shock domain protein genes, and confirmed its cold tolerance and inability to grow at 37°C. Our work indicates transfusion reaction workups need to include testing for psychrophilic organisms, which could explain the cause of other apparently culture-negative transfusion reactions.

When are infection risks of blood transfusion tolerable? Towards understanding the ethical views of stakeholders in the blood supply

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.

Hepatitis E virus - key points for the clinical haematologist

In recent years there has been a paradigm shift in our understanding of the epidemiology and clinical features of hepatitis E virus (HEV) infection. Once classically described as an acute hepatitis associated with waterborne outbreaks in areas of poor sanitation, HEV is now recognised to be endemic in Europe and is probably zoonotic in origin. Evidence for transfusion-transmitted HEV has prompted the introduction of blood donor screening in a number of countries, but the risk to the haematology patient from food sources remains. The aim of this review therefore, is to equip the clinical haematologist with the knowledge required to diagnose HEV infection and to aid decision-making in patient management. The article also provides information on addressing patient concerns about their risk of acquiring hepatitis E and how this risk can be mitigated.

Parvovirus B19: What Is the Relevance in Transfusion Medicine?

Parvovirus B19 (B19V) has been discovered in 1975. The association with a disease was unclear in the first time after the discovery of B19V, but meanwhile, the usually droplet transmitted B19V is known as the infectious agent of the “fifth disease,” a rather harmless children’s illness. But B19V infects erythrocyte progenitor cells and thus, acute B19V infection in patients with a high erythrocyte turnover may lead to a life-threatening aplastic crisis, and acutely infected pregnant women can transmit B19V to their unborn child, resulting in a hydrops fetalis and fetal death. However, in many adults, B19V infection goes unnoticed and thus many blood donors donate blood despite the infection. The B19V infection does not impair the blood cell counts in healthy blood donors, but after the acute infection with extremely high DNA concentrations exceeding 10¹⁰ IU B19V DNA/ml plasma is resolved, B19V DNA persists in the plasma of blood donors at low levels for several years. That way, many consecutive donations that contain B19V DNA can be taken from a single donor, but the majority of blood products from donors with detectable B19V DNA seem not to be infectious for the recipients from several reasons: first, many recipients had undergone a B19V infection in the past and have formed protective antibodies. Second, B19V DNA concentration in the blood product is often too low to infect the recipient. Third, after the acute infection, the presence of B19V DNA in the donor is accompanied by presumably neutralizing antibodies which are protective also for the recipient of his blood products. Thus, transfusion-transmitted (TT-) B19V infections are very rarely reported. Moreover, in most blood donors, B19V DNA concentration is below 1,000 IU/ml plasma, and no TT-B19V infections have been found by such low-viremic donations. Cutoff for an assay for B19V DNA blood donor screening should, therefore, be approximately 1,000 IU/ml plasma, if a general screening of blood donors for single donation blood components is considered at all: for the overwhelming majority of transfusion recipients, B19V infection is not relevant as well as for the blood donors. B19V DNA screening of vulnerable patients after transfusion seems to be a more reasonable approach than general blood donor screening.

Prevention of Transfusion-Transmitted Infections: Dilemmas

To make blood components and blood products safe, many safety measures are applied to avoid transfusion-transmitted infections. Defining a balanced safety policy is not easy, we face several dilemmas: How safe should blood be? Should we opt for maximal or optimal safety? Are perceived threats real and relevant? Should blood be clean while food, air, or mosquitoes are not? Is vCJD still a threat? It seems wise to discuss these issues more in the open.

Emerging infectious disease outbreaks: estimating disease risk in Australian blood donors travelling overseas

BACKGROUND AND OBJECTIVES

International travel assists spread of infectious pathogens. Australians regularly travel to South-eastern Asia and the isles of the South Pacific, where they may become infected with infectious agents, such as dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) viruses that pose a potential risk to transfusion safety. In Australia, donors are temporarily restricted from donating for fresh component manufacture following travel to many countries, including those in this study. We aimed to estimate the unmitigated transfusion-transmission (TT) risk from donors travelling internationally to areas affected by emerging infectious diseases.

MATERIALS AND METHODS

We used the European Up-Front Risk Assessment Tool, with travel and notification data, to estimate the TT risk from donors travelling to areas affected by disease outbreaks: Fiji (DENV), Bali (DENV), Phuket (DENV), Indonesia (CHIKV) and French Polynesia (ZIKV).

RESULTS

We predict minimal risk from travel, with the annual unmitigated risk of an infected component being released varying from 1 in 1·43 million to <1 in one billion and the risk of severe consequences ranging from 1 in 130 million to <1 in one billion.

CONCLUSION

The predicted unmitigated likelihood of infection in blood components manufactured from donors travelling to the above-mentioned areas was very low, with the possibility of severe consequences in a transfusion recipient even smaller. Given the increasing demand for plasma products in Australia, the current strategy of restricting donors returning from select infectious disease outbreak areas to source plasma collection provides a simple and effective risk management approach.

Advances in hepatitis E - II: Epidemiology, clinical manifestations, treatment and prevention

INTRODUCTION

Infection with hepatitis E virus (HEV) is the commonest cause of acute hepatitis worldwide. This infection, with fecal-oral transmission, was previously thought to be limited to humans residing in developing countries with poor sanitation, spreading via contaminated drinking water. In recent years, our understanding of epidemiology and clinical spectrum of this infection have changed markedly.

AREAS COVERED

This article reviews the epidemiology, including routes of transmission, and clinical manifestations of HEV infection around the world. In addition, recent findings on transmission-associated HEV infection, extrahepatic manifestations of hepatitis E and chronic infection with HEV, and treatment and prevention of this infection are discussed. Expert commentary: HEV infection has two distinct epidemiologic forms and clinical patterns of disease: (i) acute epidemic or sporadic hepatitis caused by fecal-oral (usually water-borne) transmission of genotype 1 and 2 HEV from a human reservoir in areas with poor hygiene and frequent water contamination, and (ii) infrequent sporadic hepatitis E caused by zoonotic infection, possibly from an animal source through ingestion of undercooked animal meal, of genotype 3 or 4 virus. In disease-endemic areas, pregnant women are at a particular risk of serious disease and high mortality. In less-endemic areas, chronic infection with HEV among immunosuppressed persons is observed. HEV can also be transmitted through Transfusion of blood and blood products. Ribivirin treatment is effective in chronic hepatitis E. Two efficacious vaccines have been tried in humans; one of these has received marketing approval in its country of origin.

Implications of a switch to a 100% apheresis platelet supply for patients and for blood donors: a risk benefit analysis

BACKGROUND

A 100% apheresis platelet supply is considered to increase transfusion safety by lowering donor exposures for transfusion recipients. We performed a risk benefit analysis to contrast the reduction of donor exposures and the risk of contaminated blood products in the nation-wide inventory with the donor risks associated with a switch to a 100% apheresis platelet supply in Germany.

METHODS

Donor exposures and the number of contaminated blood products resulting from HIV-like, HBV-like, HCV-like pathogens and two theoretical agents with infection rates of 10 and 1000 in 100 000, respectively, were calculated for a 100% apheresis platelet supply in Germany based on the 2006-2012 hemovigilance reports. These numbers were compared with the current mixed platelet supply of pooled and apheresis platelets. Moreover, additional donation time and apheresis donor complications resulting from a 100% apheresis platelet supply were estimated.

RESULTS

Per million total blood products (red cells, platelets, fresh frozen plasma), a 100% apheresis platelet supply would reduce donor exposures by 87 100 and the number of contaminated blood products ranging from 0·8 to 871·1. On the other hand, this requires additional 29 478 apheresis donations, 3·4 years additional donor time, and would be associated with 58 additional donor complications, respectively.

CONCLUSIONS

A 100% apheresis platelet supply would reduce donor exposures and the number of contaminated blood products in the inventory, but would increase apheresis complications in donors. Potential risks for patients must be carefully weighed against the risks for donors, dependent on the specific pathogen scenario.

Transfusion practices and infectious risks

Transfusion-transmitted infections remain among the most-feared complications of allogeneic blood transfusion. Thanks to several strategies including donor screening and deferral, blood testing and pathogen inactivation, their risks have reached all-time low levels, particularly in developed nations. Nonetheless, new and emerging infections remain a threat that is likely to exacerbate in the coming years with continued globalization and climate change. More effective strategies of pathogen inactivation and more vigilant horizon screening are hoped to abate the risk. Additionally, allogeneic transfusion has repeatedly been shown to be associated with worsening of outcomes in patients, including the documented increased risk of infections (often nosocomial) in recipients of transfusions. The underlying mechanism is likely to be related to immunosuppressive effects of allogeneic blood, iron content, and bacterial contamination. This issue is best addressed by more judicious and evidence-based use of allogeneic blood components to ensure the potential benefits outweigh the risks.

Genomic Assays for Identification of Chikungunya Virus in Blood Donors, Puerto Rico, 2014

A newly developed transcription-mediated amplification assay was used to detect chikungunya virus infection in 3 of 557 asymptomatic donors (0.54%) from Puerto Rico during the 2014–2015 Caribbean epidemic. Viral detection was confirmed by using PCR, microarray, and next-generation sequencing. Molecular clock analysis dated the emergence of the Puerto Rico strains to early 2013.

Look-back study on recipients of Parvovirus B19 (B19V) DNA-positive blood components

BACKGROUND AND OBJECTIVES

To assess the relevance of Parvovirus B19 (B19V) DNA at low to intermediate concentrations in blood donors for the recipients of their blood components.

MATERIAL AND METHODS

We studied recipients of B19V DNA-positive blood components [red blood cell concentrates (RBCs), pooled platelet concentrates and fresh frozen plasma]. This included archived pretransfusion samples as well as follow-up samples investigated by ELISA or NAT and genome sequence analysis.

RESULTS

In 132 out of 424 recipients, we could detect no anti-B19V IgG before transfusion. In 67 out of 132 sero-negative recipients, a follow-up sample was available. Sixty-five of these received blood components from donors with <10(4) IU B19V DNA/ml plasma and had no evidence of transfusion-transmitted (TT)-B19V infection. Homology in genome sequences in donor and recipient provided evidence for a TT-B19V infection in two recipients. Both patients received RBC containing 3.4 × 10(6) and 1.8 × 10(4) IU B19V DNA/ml plasma, respectively. The anti-B19V IgG titres in the donors were 2 and 76 IU/ml plasma, respectively. The antibodies in the second donor were directed against capsid proteins and are thus considered as potential neutralizing antibodies.

CONCLUSIONS

TT-B19V infections through blood components with low (<10(4) IU/ml plasma) B19V DNA concentrations did not occur in our study. One of the TT-B19V infections occurred from RBC with intermediate B19V DNA concentration despite the presence of potential neutralizing antibodies in the donor, but its clinical significance was low.

Estimation of the infectious viral load required for transfusion-transmitted human T-lymphotropic virus type 1 infection (TT-HTLV-1) and of the effectiveness of leukocyte reduction in preventing TT-HTLV-1

BACKGROUND AND OBJECTIVES

The risk of transfusion-transmitted human T-lymphotropic virus type 1 infection (TT-HTLV-1) after prestorage leucocyte reduction (LR) remains unknown, as the proviral load in the blood component that would cause TT-HTLV-1 is undetermined. On the basis of the distribution of HTLV-1 proviral load among HTLV-1-sero-positive blood donors, we attempted to estimate the proviral load for transfusion-related infectivity. We also discuss the effectiveness of LR in preventing TT-HTLV-1.

MATERIALS AND METHODS

The HTLV-1 proviral load in 300 HTLV-1-sero-positive blood donors was determined by real-time polymerase chain reaction analysis. The proviral load required for transfusion-related infectivity was estimated using historical TT-HTLV-1 frequency data from a retrospective study on patients who had received blood from HTLV-1-sero-positive blood donors and the distribution pattern of HTLV-1 proviral load among blood donors.

RESULTS

HTLV-1 proviral loads ranged between < 0.01 and 25.0 copies per 100 leucocytes. Historical data showed TT-HTLV-1 frequency to be 80%. Assuming that 80% of the 300 sero-positive samples are infectious, it is estimated that the transfer of ≥ 9 × 10(4) cells containing the HTLV-1 provirus is required to establish TT-HTLV-1.

CONCLUSION

The residual number of HTLV-1-infected cells after LR is substantially lower than the viral load necessary for TT-HTLV-1. LR therefore appears to be effective in minimizing the incidence of TT-HTLV-1.

Automated nucleic acid amplification testing in blood banks: An additional layer of blood safety

CONTEXT

A total of 30 million blood components are transfused each year in India. Blood safety thus becomes a top priority, especially with a population of around 1.23 billion and a high prevalence rate of human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) in general population. Nucleic acid amplification testing (NAT) in blood donor screening has been implemented in many developed countries to reduce the risk of transfusion-transmitted viral infections (TTIs). NAT takes care of the dynamics of window period of viruses and offers the safest blood pack for donation.

AIMS

The aim of this study is to show the value of NAT in blood screening.

SETTINGS AND DESIGN

Dhanavantari Blood Bank, Rajahmundry, Andhra Pradesh, India.

SUBJECTS AND METHODS

Over a period of 1 year from January 2012 to December 2012, a total number of 15,000 blood donor samples were subjected to tests for HIV, HBV, and HCV by enzyme-linked immunosorbent assay (ELISA) method and 8000 ELISA nonreactive samples were subjected for NAT using multiplex polymerase chain reaction technology.

RESULTS

Of the 15,000 donors tested, 525 were seroreactive. In 8000 ELISA negative blood samples subjected to NAT, 4 donor samples were reactive for HBV. The NAT yield was 1 in 2000.

CONCLUSIONS

NAT could detect HIV, HBV, and HCV cases in blood donor samples those were undetected by serological tests. NAT could interdict 2500 infectious donations among our approximate 5 million annual blood donations.

Psychrobacter arenosus bacteremia after blood transfusion, France

We report a case of transfusion-associated bacteremia caused by Psychrobacter arenosus. This psychrotolerant bacterium was previously isolated in 2004 from coastal sea ice and sediments in the Sea of Japan, but not from humans. P. arenosus should be considered a psychrotolerant bacterial species that can cause transfusion-transmitted bacterial infections.

Residual risk of transfusion-transmitted infection with human immunodeficiency virus, hepatitis C virus, and hepatitis B virus in Korea from 2000 through 2010

BACKGROUND

Despite screening blood donations with advanced technologies and improved donor screening, the risk of transfusion-transmitted infections persists. This risk is mainly due to blood donations collected during the window period. A precise estimate of the transfusion risk of viral infection will help to determine the effect of new and current safety measures and to prioritize and allocate limited resources. Therefore, we estimated the risk of transfusion-transmitted viral infection in blood donations collected in Korea from 2000 to 2010.

METHODS

Blood donations collected at 16 blood centers were tested for HIV, HCV, and HBV to estimate the residual risk of transfusion-transmitted viral infection. The residual risk was calculated in two-year periods using the incidence/window model. The incidence rates for HIV/HCV and the confirmed positive rate for HIV/HCV in first-time and repeat donors were compared.

RESULTS

The residual risks for HIV in 2004/2005 and 2009/2010 were 1 in 1,080,244 and 1 in 1,356,547, respectively. The risks for HCV in 2000/2001 and 2009/2010 were 1 in 81,431 and 1 in 2,984,415, and the risks for HBV in 2000/2001 and 2009/2010 were 1 in 45,891 and 1 in 43,666. These estimates indicate that the residual risks for HCV in Korea have declined 36.6-fold, and those for HIV and HBV have not improved significantly, compared to previous estimates. The odds ratios for HCV and HBV positivity in first-time donors compared to repeat donors were 11.8 and 19.6, respectively.

CONCLUSIONS

The residual risk of HCV declined over the last decade due to improved screening reagents, implementation of the nucleic acid amplification test, and tight application of strict donor selection procedures. Current residual risk estimates for HIV and HCV in Korea are extremely low, but the risk for HBV is still high; therefore, urgent measures should focus on decreasing the residual risk of HBV. Despite the introduction of more sensitive assays in blood screening, several other factors may influence the actual residual risk of transfusion-transmitted infection. A continuous monitoring of residual risk of transfusion-transmitted infection is crucial in managing blood safety.

Reducing the risk of hepatitis B virus transfusion-transmitted infection

Before 1970, approximately 6% of multi-transfused recipients acquired a transfusion-transmitted Hepatitis B virus (HBV) infection. The safety improvements since then have been tremendous. From a level of a few infections per 1000 donations, the risk today, depending on the screening algorithm and additional measurements performed, has decreased to around 1:500,000 to 1:1,000,000, an improvement greater than 1000-fold compared to 50 years ago. This enormous gain in safety has been achieved through many factors, including development of increasingly more sensitive Hepatitis B antigen (HBsAg) assays; the adoption in some countries of hepatitis B core antibody (anti-HBc) screening; an improved donor selection procedure; HBV vaccination programs; and finally the introduction of HBV nucleic acid testing (NAT). Because there is a tendency in transfusion medicine to add one safety measure on top of another to approach the ultimate goal of zero risks, costs become increasingly a matter of debate. It is obvious that any new measure in addition to existing methods or measures will have very poor cost effectiveness. Therefore each country needs to perform its own calculation based on the country’s own epidemiology, resources, political and public awareness of the risks, in order to choose the correct and most cost-efficient measures. Ideally, each country would make decisions regarding implementation of additional blood safety measures in the context of both the perceived benefit and the allocation of overall health care resources.

Theoretically estimated risk of severe acute respiratory syndrome transmission through blood transfusion during an epidemic in Shenzhen, Guangdong, China in 2003

BACKGROUND

Severe acute respiratory syndrome (SARS) is a newly recognized infectious disease that caused an outbreak in south China in 2003. The cause of SARS was identified as a novel coronavirus (CoV). The existence of asymptomatic seroconvertors and the detection of the SARS-CoV RNA in plasma during the course of infection all suggest that SARS could, as least theoretically, be transmitted by transfusion. An estimate of the risk of SARS transmission through blood transfusion will contribute to decisions concerning blood safety monitoring and may be useful in the design of strategies to decrease the risk of transfusion-transmitted infections.

STUDY DESIGN AND METHODS

Case onset dates from the 2003 Shenzhen SARS epidemic and investigational results from Taiwan on viremia in humans are used to estimate the number of cases that were viremic throughout the epidemic. Estimates of the asymptomatic-to-clinically confirmed SARS-CoV infection ratio, the proportion of asymptomatic infections reported in a seroprevalence survey in Hongkong, and the population size of Shenzhen are used to infer the SARS-CoV transfusion-transmission risk. Statistical resampling methods are used.

RESULTS

Based on data from Shenzhen, Hongkong and Taiwan, the maximum and mean risk (per million) of SARS-CoV transmission from donors in Shenzhen were estimated as 23.57 (95% CI: 6.83-47.69) and 14.11 (95% CI: 11.00-17.22), respectively. The estimated risk peaked on April 02, 2003.

CONCLUSIONS

Although there are currently no confirmed reports of the transmission of SARS-CoV from asymptomatic individuals, recent research data indicate that transfusion-transmitted SARS-CoV is at least theoretically possible. Although the risk is low, with its rapid spread of the disease, appearance of alarmingly high infectivity and high fatality rate, public health authorities need to consider strategies for blood donor recruitment and virus inactivation during an epidemic to further ensure blood safety.