Hepatitis B virus genotype surveillance in Canadian blood donors and a referred patient population, 2016-2021.

BACKGROUND AND OBJECTIVES: Hepatitis B virus (HBV) genotypes (A-H) have a distinct geographic distribution and are highly associated with the country of birth. Canada has experienced increased immigration over the past decade, primarily from regions where HBV is endemic. This study investigated the proportions and trends of HBV genotypes within blood donor and clinical populations of Canada over the period 2016-2021. MATERIALS AND METHODS: Study samples involved two cohorts: (1) Canadian blood donors (n = 246) deferred from donation due to HBV test positivity and (2) chronic HBV patients from across Canada (clinically referred population, n = 3539). Plasma or serum was extracted, and the surface antigen and/or polymerase-coding region was amplified and sequenced to determine genotype by phylogenetic analysis. RESULTS: Six (A-E, G) and eight (A-H) HBV genotypes were detected among deferred blood donors and the clinically referred population, respectively. Differences in HBV genotype proportions between the two cohorts were observed across Canada. Males comprised most of the referred population among genotypes A-E (p < 0.0001), except for genotypes B and C. The median age was younger among blood donors (36 years [range 17-72]) compared with the referred population (41 years [range 0-99]). Distinct trends of increasing (E, referred; B, blood donor) and decreasing genotype prevalence were observed over the study period. CONCLUSION: HBV genotypes in Canada are highly diverse, suggesting a large immigrant population. Observed trends in genotype prevalence and proportional differences among cohorts imply shifts among the HBV-infected population of Canada, which warrants continued surveillance.

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

BACKGROUND AND OBJECTIVES: Blood donors are increasingly being recognized as an informative resource for surveillance. We aimed to review severe acute respiratory syndrome coronavirus 2 seroprevalence studies conducted among blood donors to investigate methodological biases and provide guidance for future research. MATERIALS AND METHODS: We conducted a scoping review of peer-reviewed and preprint publications between January 2020 and January 2021. Two reviewers used standardized forms to extract seroprevalence estimates and data on methodology pertaining to population sampling, periodicity, assay characteristics, and antibody kinetics. National data on cumulative incidence and social distancing policies were extracted from publicly available sources and summarized. RESULTS: Thirty-three studies representing 1,323,307 blood donations from 20 countries worldwide were included (sample sizes ranged from 22 to 953,926 donations). The majority of the studies (79%) reported seroprevalence rates <10% (ranging from 0% to 76% [after adjusting for waning antibodies]). Overall, less than 1 in 5 studies reported standardized seroprevalence rates to reflect the demographics of the general population. Stratification by age and sex were most common (64% of studies), followed by region (48%). A total of 52% of studies reported seroprevalence at a single time point. Overall, 27 unique assay combinations were identified, 55% of studies used a single assay and only 39% adjusted seroprevalence rates for imperfect test characteristics. Among the nationally representative studies, case detection was most underrepresented in Kenya (1:1264). CONCLUSION: By the end of 2020, seroprevalence rates were far from reaching herd immunity. In addition to differences in community transmission and diverse public health policies, study designs and methodology were likely contributing factors to seroprevalence heterogeneity.

Implementation of measures to reduce vasovagal reactions: Donor participation and results.

BACKGROUND: There are several strategies to reduce donor reactions. We report donor participation and reaction rates before and after implementing multiple measures at Canadian Blood Services. STUDY DESIGN AND METHODS: We introduced a structured program of 500 mL of water and a salty snack pre-donation and applied muscle tension (AMT) during donation. Donors were not deferred for out of range blood pressure (BP); however, BP was measured in first time donors. Time on the donation chair post-donation was decreased from 5 to 2 min for repeat donors. We assessed participation rates using our quarterly survey of 10,000 recent donors. We extracted vasovagal reactions with loss of consciousness (LOC) from our operational database and compared pre-implementation (Oct 12,018-March 31,2019) and post-implementation (Oct 12,019-March 31,2020) periods. RESULTS: Survey response rates varied from 11% to 16%. The percentage of donors who drank the water and ate the salty snack increased from 58% to 82% and 44% to 70% over 4 quarters; those performing AMT increased from 24% to 41%. Reactions decreased from 19.07 per 10,000 (744 reactions in 390,123 donations) to 14.04 per 10,000 (537 in 382,382 donations) (p < .0001). No first-time donors with high BP (n = 684) but 5 with low BP (n = 718) had reactions, CI were very large. CONCLUSIONS: Achieving optimal participation was challenging. After implementation of a donor wellness initiative based on best practice, rates of vasovagal reactions with LOC decreased by 25%. A larger dataset is necessary to assess the safety contribution of BP deferrals when other mitigation measures are in place.

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

BACKGROUND AND OBJECTIVES: Access to large pools of healthy adult donors advantageously positions blood component providers to undertake anti-SARS-CoV-2 seroprevalence studies. While numerous seroprevalence reports have been published by blood operators during the COVID-19 pandemic, details on the assay used has not been well documented. The objectives of this study were to evaluate the diversity of assays being used by blood operators and assess how this may affect seroprevalence estimates. MATERIALS AND METHODS: We surveyed 49 blood component providers from 39 countries. Questionnaire included information on the number and identity of assays used, the detected immunoglobulin(s) and target antigen, and performance characteristics (sensitivity, specificity). RESULTS: Thirty-eight of the 49 contacted blood suppliers provided at least partial responses. The results indicate that 19 commercial and five in-house serology assays have been used by surveyed blood operators. The Abbott SARS-CoV-2 IgG assay was the most commonly used kit and utilized by 15 blood suppliers. Two assays did not detect IgG, but detected either IgM/IgA or IgM. 68·2% of assays targeted the spike protein and 50% the nucleocapsid protein, while 18·2% targeted both viral proteins. The sensitivity and specificity of IgG-specific assays ranged from 71·9% to 100% and from 96·2% to 100%, respectively. As of 18 October 2020, the seroprevalence was below 5% in 10 of 14 countries reporting. CONCLUSION: Our results highlight the diversity of assays being used. Analyses comparing blood donor seroprevalence across countries should consider assay characteristics with optimization of signal/cut-off ratios and consistent methodology to adjust for waning antibody.

Evaluation of a pre-exposure prophylaxis (PrEP)/post-exposure prophylaxis (PEP) deferral policy among blood donors.

BACKGROUND: The use of pre-/post-exposure prophylaxis (PrEP/PEP) may interfere with routine HIV screening. As a result, blood services worldwide have adopted a variety of deferral policies to mitigate increased residual risk. In this study, we evaluated the operational impact of modifying the donor health questionnaire (DHQ) to include explicit questions to assess PrEP/PEP exposure. STUDY DESIGN AND METHODS: We conducted a retrospective study between June 2019 and October 2020 of all blood donors attempting to donate at Canadian Blood Services. Sixteen-months post-implementation, we summarized self-reported PrEP/PEP rates and their indications for use. We also assessed deferral rates and the sensitivity of using existing risk questions to defer people exposed to PrEP/PEP. RESULTS: Of 1,122,075 donations, 89 people (eight per 100,000 donations) reported PrEP (64%)/PEP (34%) use in the last 4 months. People exposed to PrEP were more likely to be men (94%) and taking PrEP for lifestyle reasons (87%). In contrast, indications for PEP use included occupational exposure (50%) and sexual assault (27%). Most donors who answered affirmatively to PrEP/PEP exposure were deferred (96%). If potential donors were not directly asked about their PrEP/PEP use, the majority would not have been deferred for any other reasons (PrEP 32/57 (56%) and PEP 15/30 (50%)). CONCLUSION: Not all blood services have adopted direct questions to identify PrEP/PEP exposure; some rely on existing DHQ questions. In Canada, despite DHQ questions such as medication use in the last 3-days, more than half of people exposed to PrEP/PEP would not have been identified and deferred.

Research initiatives of blood services worldwide in response to the covid-19 pandemic.

BACKGROUND AND OBJECTIVES: While coronavirus (COVID-19) is not transfusion-transmitted, the impact of the global pandemic on blood services worldwide is complex. Convalescent plasma may offer treatment, but efficacy and safety are not established. Measuring seroprevalence in donors would inform public health policy. Here, we survey blood services around the world to assess the different research programmes related to COVID-19 planned or in progress. MATERIALS AND METHODS: Blood collection services were surveyed in June 2020 to determine whether they were participating in serosurveys or convalescent plasma collection and clinical trials. RESULTS: A total of 48 countries (77% of those contacted) responded. Seroprevalence studies are planned or in progress in 73% of countries surveyed and in all continents, including low- and middle-income countries. Most aimed to inform public health policy. Convalescent plasma programmes have been initiated around the globe (79% of surveyed), about three quarters as clinical trials in high-, middle- and low-income countries. CONCLUSION: Blood services around the world have drawn upon their operational capacity to provide much-needed seroprevalence data to inform public health. They have rapidly implemented preparation of potential treatment when few treatments are available and mostly as clinical trials. At the same time, they must continue to provide blood products for recipients despite challenges of working in a state of emergency. It is important to track and coordinate research efforts across jurisdictions to gain a composite evidence-based view that will influence future practice and preparative strategies.

Two-year follow-up of donors in a large national study of ferritin testing.

BACKGROUND: We assessed donor return rates, donation frequency, and factors related to the evolution of ferritin levels 2 years after entering donors into a large operational study of ferritin testing. STUDY DESIGN AND METHODS: Ferritin testing was done on donors from representative clinics (n = 12,595). Low-ferritin donors (<25 µg/L) were informed and not called for 6 months to book a donation. Approximately 37% of donors had ferritin retested on a return donation. Return rate and donation frequency were monitored, and a logistic regression model was constructed. RESULTS: The return rate was lower in low-ferritin donors (67% vs. 78%), particularly in women who were first-time donors (36% vs. 61%). Returning low-ferritin donors made fewer donations in the 2 years after notification compared to the 2 years prenotification (4.5 vs. 7.5 for men, 3.0 vs. 5.0 for women), while donation frequency was lower and increased slightly for normal-ferritin donors (4.7 vs. 4.4 for men, 3.6 vs. 3.1 for women). An increased number of donations, shorter interdonation intervals, female sex, and younger age are associated with low ferritin levels on initial and repeat testing. Some recovery of ferritin occurred, but most low-ferritin donors continued to have low or borderline levels on retesting. CONCLUSION: Informing donors of low ferritin results had a long-lasting impact on return rates and donation frequency, requiring recruitment efforts to maintain adequacy of supply. Increasing the interdonation interval leads to some improvement in ferritin levels; more sustained efforts to encourage donors to improve iron intake are needed to achieve long-term benefit.

Variant Creutzfeldt-Jakob disease deferral in Canada: impact of stop dates.

BACKGROUND: To reduce the risk of variant Creutzfeldt-Jakob disease (vCJD) transmission via blood transfusion in Canada, potential donors who spent a cumulative time in the United Kingdom, Western Europe or Saudi Arabia are deferred. "Stop dates" for accumulated time were later implemented for 3 months spent in the United Kingdom or France (1980-1996) and for 5 years elsewhere in Western Europe (1980-2007); Saudi Arabia deferral was implemented with the "stop date" (1980-1996). We evaluated the long-term impact of these deferrals and "stop dates", as well as the consistency of donors' answers to post-implementation screening questions. MATERIALS AND METHODS: The monthly deferral rate was monitored from 2003-2015. Time series methods (ARIMA) were used with interruption when "stop dates" were implemented. A telephone survey of 1,000 donors (250 first-time, 500 repeat deferred donors, 250 non-deferred control donors) assessed travel history (response rate 62%). An anonymous mail survey of 40,000 donors assessed compliance with deferral (response rate 45.3%). RESULTS: When the "stop date" for UK/France travel was implemented, the deferral rate decreased for first-time (2.1% to 1.1%, p<0.0001) and repeat (0.2% to 0.03%, p<0.0001) donors. The deferral rate increased after Saudi Arabia was included (mean increase of 0.4% first-time, 0.02% repeat, p<0.0001). After the Western Europe "stop date" the deferral rate was unchanged in first-time donors (1.0% to 1.1%, p=0.5) but decreased in repeat donors (0.03% to 0.02%, p<0.002). In the telephone survey, 94% of deferred donors confirmed deferrable travel history. In the anonymous survey 0.3% of donors were non-compliant with the UK/France deferral. DISCUSSION: Donors, particularly first-time ones, continue to be lost due to vCJD travel deferral, but most deferrals are correctly applied and non-compliance is rare. The application of a "stop date" reduced deferrals for UK/France travel, but it may be too early to see the full impact of the "stop date" for Western Europe.

A large national study of ferritin testing in Canadian blood donors.

BACKGROUND: We assessed risk groups for iron deficiency and the feasibility and efficacy of ferritin testing in a large blood center. STUDY DESIGN AND METHODS: Donors were informed of possible testing in the predonation pamphlet. Plasma ferritin was measured on retention samples (n = 12,595) from representative clinics. Low-ferritin donors (<25 µg/L) were sent a letter and information sheet and not called for 6 months. Ferritin testing was repeated on 25% of donors; donor return rate and frequency were monitored. RESULTS: Low-ferritin donors represented 2.9% of first-time and reactivated (no donation in past 12 months) male donors, 32.2% of first-time and reactivated female donors, 41.6% of repeat male donors, and 65.1% of repeat female donors. A mean of 11.7 months after index donation, the return rate was 76% for normal and 58% for low-ferritin donors; returning low-ferritin donors had made approximately one fewer donation. Ferritin increased by 16.3 and 12.1 µg/L in male and female low-ferritin donors and decreased by 17 µg/L in male and female normal-ferritin donors. CONCLUSION: The minimum hemoglobin level will be increased to 130 g/L for male donors and the minimum interdonation interval changed to 84 days (four donations yearly) for female donors based on iron deficiency risk groups. Large-scale ferritin testing was feasible. Donors informed of low-ferritin results had a lower return rate, donated less often, and had an increase in ferritin on return, approximately 1 year after initial testing, compared to donors with normal ferritin results.

Impact of informing donors of low ferritin results.

BACKGROUND: Informing donors of their ferritin status is one possible mitigating strategy to reduce iron deficiency in donors. STUDY DESIGN AND METHODS: We evaluated the impact of informing donors of their ferritin status on their donation frequency, understanding of iron needs, and actions to improve iron intake 2 years after their inclusion in a prospective observational cohort study. RESULTS: Informing donors of low ferritin results decreased return rate in first-time and repeat donors, and the median number of donations declined from three to two donations/year in returning donors with low ferritin on index donation compared to an increase from 1.5 to 2.5 donations/year in donors with normal ferritin. An electronic questionnaire demonstrated that approximately 60% of low ferritin donors saw their primary medical practitioner, and half of this group started iron. Qualitative interviews revealed suboptimal understanding of iron needs and poor compliance with iron supplementation. CONCLUSION: Providing donors with results of ferritin testing may reduce return rates and donation frequency in the 2 years after testing. Simply providing donors with ferritin results and an information sheet is often inadequate to improve donors' understanding of iron needs and may not lead to a substantive increase in iron intake over time.

Iron deficiency in Canadian blood donors.

BACKGROUND: The adequacy of communication and knowledge of donors and physicians regarding iron needs and the relationship between hemoglobin (Hb) and iron stores require evaluation to address donor iron deficiency. STUDY DESIGN AND METHODS: A prospective cohort study was performed on 550 successful donors and 50 donors deferred for low Hb (<125 g/L on repeat fingerstick). Donors participated in an on-clinic interview and had serum ferritin measured. They were mailed their results and recontacted regarding follow-up. RESULTS: Most donors are unaware of possible health impacts of donation and do not discuss donation with their physician. In successful donors, mean ferritin levels were 37 and 131 µg/L in first-time and reactivated (no donation for 2 years) females and males and 19 and 29 µg/L in frequent repeat females and males, respectively (p < 0.0001), with infrequent donors having intermediate results. Mean ferritin was 12 µg/L in donors deferred for low Hb. Twenty of 22 donors failing initial Hb testing and passing on repeat testing had ferritin below 25 µg/L. On follow-up, 63 of 164 donors (38%) with low ferritin were taking iron supplements 2 months postdonation. CONCLUSION: Iron deficiency is frequent, particularly in female donors and frequent donors. A fail on initial Hb testing followed by a pass on repeat testing is likely to be due to iron deficiency and borderline anemia. Donors and physicians need to be more aware of iron needs associated with blood donation and appropriate treatment for low iron stores.

Impact of changes to policy for Mexican risk travel on Canadian blood donor deferrals.

BACKGROUND: Travel to malaria risk areas such as Mexico is a common source of donor deferral in Canada. On February 21st, 2011 the deferrable regions in Mexico were revised to permit donation if donors travelled to the state of Quintana Roo, Mexico, a popular ocean-side resort area. MATERIALS AND METHODS: Canadian travel data and malaria deferral rates since 2007 were plotted to examine trends. Deferral records in one centre were accessed from January to April, 2011 to tabulate travel destinations of deferred donors immediately before and after the change. RESULTS: Travel to Mexico and the Caribbean accounts for 63% of general population travel, and travel to Mexico has been increasing (P <0.05). Deferral for short-term malaria risk travel has a strong seasonal trend with peaks in the winter and troughs in the summer. Approximately 36,000 fewer donations were lost following the change, a reduction of 37% from the previous year. Deferrals in one centre increased for Caribbean/Central America after the change (P <0.05) consistent with the seasonal trend, but decreased for Mexico (P <0.05). DISCUSSION: Deferrals for malaria risk travel are substantial. Careful revision and refinement of risk areas of travel can significantly reduce the burden of deferral.

Hepatitis C virus: the role of molecular mimicry in response to interferon treatment.

Chronic hepatitis C virus (HCV) infection is one of the major causes of chronic liver disease worldwide. In order for HCV to persist, the virus must escape immune recognition or inhibit the host immune response. The NS5A protein contains the interferon sensitivity-determining region (ISDR) and is able to repress dsRNA-dependent protein kinase (PKR) thus influencing the response to interferon (IFN) therapy. Patients who respond to IFN therapy have stronger antibody reactivity against the NS5A compared to IFN non-responders. Therefore, given the possible role for the ISDR in IFN resistance and differential antibody reactivity, it is possible that variation in ISDR may be involved in viral immune escape and development of persistent HCV infection employing aspects of host mimicry. In this study, pre-treatment samples obtained from HCV infected patients were used to investigate the effect of different NS5A ISDR variants on the IFN antiviral response and their involvement in immune evasion. The NS5A was identified as a homologue of the variable region of immunoglobulins (Ig). The IFN resistant genotypes had higher levels of similarity to Ig compared to IFN sensitive genotypes. Expression of NS5A-6003 (HCV genotype 1b) and NS5A-6074 (HCV genotype 2a) was able to rescue vesicular stomatitis virus (VSV) from IFN inhibition and restore luciferase activity. A correlation between Ig-like NS5A structure and also antibody response with the outcome of IFN treatment was observed.

Validation and implementation of a new hemoglobinometer for donor screening at Canadian Blood Services.

BACKGROUND: Hemoglobin (Hgb) determination is an essential part of donor qualification. We assessed and implemented a new spectrophotometer for donor Hgb determination. STUDY DESIGN AND METHODS: Precision, accuracy, and ease of use were assessed on a prototype DiaSpect analyzer (DiaSpect Medical, GmBH, Sailauf, Germany). A protocol to qualify the analyzer was developed and executed preimplementation. Samples were developed for periodic quality control (QC). Postimplementation performance was assessed based on QC results and trending of deferral rates. RESULTS: Precision was excellent, with a coefficient of variation of 0.53%-1.14% per sample. The correlation coefficient between capillary DiaSpect and venous laboratory autoanalyzer measurements was 0.736. After 169 out of 223 analyzers failed to qualify on our initial protocol, all were successfully qualified with the use of a modified protocol, adjusted to avoid sources of variability. Because commercial controls proved inadequate, in-house samples were developed for periodic QC. Postimplementation, all analyzers had adequate QC results. Deferral rates decreased from 10.1 to 8.1% (p < 0.0001) for female donors and from 0.8 to 0.6% for male donors (p < 0.0001). The system was faster and easier to use compared with our previous two-step process. CONCLUSION: We successfully implemented a new spectrophotometer, which resulted in greater efficiency, improved ease of use, and decreased deferrals.

Clinical outcome of frequent exposure to Torque Teno virus (TTV) through blood transfusion in thalassemia patients with or without hepatitis C virus (HCV) infection.

As a consequence of the high prevalence of TorqueTeno virus (TTV) in blood donors, thalassemia patients frequently acquire various genotypes of this virus through therapeutic blood transfusions. At present, the clinical consequences of TTV infection remain indeterminate for these patients. Here, several hundred thalassemia patients were tested for the presence of TTV and its genotypes using a combination of PCR and clone-based DNA sequencing. Approximately 10% (12/118) of the patients aged 2-20 years remained negative for TTV including eight genotypes of SENV. Ferritin, aspartate-aminotransferase (AST) and alanine-aminotransferase (ALT) levels were invariably lower in TTV-negative patients (P = 0.02, <0.01, and 0.06, respectively) than in TTV-positive patients. Patients with TTV-HCV co-infection showed elevated ferritin and ALT levels compared with patients with TTV infection alone (P < 0.02 and P < 0.01). AST and ALT levels were within the normal range for all TTV-negative patients, whereas abnormal levels of AST and ALT were seen in a significant proportion of TTV-positive patients (30.7% and 33.6%, respectively) and patients with TTV-HCV co-infections (70.0% and 56.6%, respectively). Only TTV-positive patients (28.0%) and patients with TTV-HCV co-infections (36.3%) had hyper-ferritin levels (> or =3,000 ng/ml). The genotype(s) of TTV responsible for the liver dysfunction could not be determined. However, high levels of AST and ALT were found to be correlated with detection of a higher number of TTV genotypes in the patients. The data suggests that frequent and persistent TTV infection through blood transfusion is associated with hepatic dysfunction and/or damage in transfusion dependent thalassemia patients.