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Background: In Canada, as many as 24% of mothers are deferred from cord blood (CB) donation due to risk factors for Zika virus (ZIKV). However, the ZIKV epidemic has waned considerably since 2016, and there has not been any report of ZIKV transmission by CB transplantation, which questions this policy. Thus, we performed an analysis of the risk of introducing ZIKV in the CB supply maintained by Héma‐Québec (HQ) and Canadian Blood Services (CBS). Study Design and Methods: This simulation considered the following parameters: the risk of travel exposure in a high‐risk ZIKV country, the duration of travel, the daily risk of acquiring ZIKV in a high‐risk country, the probability of materno‐fetal ZIKV transmission, the probability of asymptomatic fetal viremia, and the probability of sexual transmission. A hundred million Monte Carlo simulations were run. Results: In the most‐likely scenario (probability of traveling to a high‐risk ZIKV country while pregnant = 0.178), the risk was estimated at 0.9 ZIKV‐positive donations per million donations (95% confidence interval [CI] = 0.4–1.6)—or one every 868 years at HQ and one every 453 years at CBS. In the pessimistic model (probability of traveling to a high‐risk ZIKV country while pregnant = 0.240), the risk was estimated at 1.2 ZIKV‐positive donations per million donations (95% CI = 0.6–2.1)—or one every 644 years at HQ and one every 340 years at CBS. Discussion: We conclude that the risk of introducing ZIKV in the Canadian CB supply is too small to justify maintaining the current policy. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B core antibody (anti‐HBc) screening has been implemented in many blood establishments to help prevent transmission of hepatitis B virus (HBV), including from donors with occult HBV infection (OBI). We review HBV screening algorithms across blood establishments globally and their potential effectiveness in reducing transmission risk. Materials and Methods: A questionnaire on HBV screening and follow‐up strategies was distributed to members of the International Society of Blood Transfusion working party on transfusion‐transmitted infectious diseases. Screening data from 2022 were assimilated and analyzed. Results: A total of 30 unique responses were received from 25 countries. Sixteen respondents screened all donations for anti‐HBc, with 14 also screening all donations for HBV DNA. Anti‐HBc prevalence was 0.42% in all blood donors and 1.19% in new donors in low‐endemic countries; however, only 44% of respondents performed additional anti‐HBc testing to exclude false reactivity. 0.68% of anti‐HBc positive, HBsAg‐negative donors had detectable HBV DNA. Ten respondents did universal HBV DNA screening without anti‐HBc, whereas four respondents did not screen for either. Deferral strategies for anti‐HBc positive donors were highly variable. One transfusion‐transmission from an anti‐HBc negative donor was reported. Discussion: Anti‐HBc screening identifies donors with OBI but also results in the unnecessary deferral of a significant number of donors with resolved HBV infection and donors with false‐reactive anti‐HBc results. Whilst confirmation of anti‐HBc results could be improved to reduce donor deferral, transmission risks associated with anti‐HBc negative OBI donors must be considered. In high‐endemic areas, highly sensitive HBV DNA testing is required to identify infectious donors. [ABSTRACT FROM AUTHOR]

Babesia spp. are tickborne intraerythrocytic apicomplexan parasites responsible for the clinical infection babesiosis. Babesia microti, the leading cause of human babesiosis, is endemic in the northeastern and north-midwestern United States [...]

Background: Combining pathogen reduction technology (PRT) with blood screening may alleviate concerns over the risk of transfusion‐transmitted infections (TTI) and support changes in blood donor selection to potentially increase blood availability. This study aimed to estimate the residual risk of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) transfusion‐transmission in Canada after implementing PRT, while eliminating deferrals for sexual risk behaviors. Study Design and Methods: A probabilistic approach that combined Bayesian networks with Monte Carlo simulations was used to estimate the risk of transfusing HIV‐, HBV‐, or HCV‐contaminated blood components. Different scenarios were considered to compare the current residual risk after PRT implementation, with and without donor deferral criteria for sexual risk behaviors. Donor profiles and blood component outcomes were simulated based on a literature review including the prevalence and incidence of HIV, HBV, and HCV in the Canadian blood donor population; the use of current blood screening assays; and HIV, HBV, and HCV blood donor viral loads. Results: In the universal PRT scenario (i.e., with PRT/without deferral criteria), the estimated risks of HIV, HBV, and HCV transmission were significantly lower than those in the currently observed scenario (i.e., without PRT/with deferral criteria). Conclusions: This risk model suggests that PRT for platelets and plasma (and eventually for RBCs when available) significantly reduces the residual risks of HIV, HBV and HCV transfusion‐transmission and could enable the removal of blood donor deferral criteria for sexual risk behaviors. [ABSTRACT FROM AUTHOR]

Background and Objectives: There is a growing infectious syphilis outbreak in Western Canada. Although blood donors are screened for syphilis risks, some blood donors will still be confirmed test‐positive for syphilis. This study compares the characteristics of confirmed test‐positive syphilis donations in both Western Canada and Eastern Canada, November 2022–August 2023. Materials and Methods: Donors were defined as Western or Eastern Canadian. Blood donations were tested for syphilis using the PK‐TP assay (Beckman Coulter PK7300 Automated Microplate System). Confirmatory Treponema pallidum particle agglutination (TPPA) and rapid plasma reagin (RPR) assays were performed by one of two reference laboratories. An RPR titre ≥1:8 was used as a proxy for possible infectious syphilis. Results: Rates of laboratory‐confirmed syphilis were higher in Western (n = 43, 13.4/100,000 donations) versus Eastern donors (n = 19, 4.7/100,000 donations; Fisher's exact test, two‐sided, p ≤ 0.0001). Most syphilis confirmations were in first‐time donors (Western Canada n = 31/43, 72.1%, Eastern Canada 12/19, 63.2%). Conclusion: Although rates of laboratory‐confirmed syphilis were higher in Western versus Eastern donors, Western donors did not have higher rates of infectious syphilis. Further studies might assess whether donors with laboratory‐confirmed syphilis understood pre‐donation screening questions or were completely unaware of a past infection. [ABSTRACT FROM AUTHOR]

Background and Objectives: Data provided from blood donors have contributed to the understanding of public health epidemiology and policy decisions. A recent example was during the severe acute respiratory syndrome‐related coronavirus (SARS‐CoV‐2) pandemic when blood services monitored the seroprevalence in blood donors. Based on this experience, blood services have the opportunity to expand their role and participate in public health surveillance and research. The aim of this report is to share available resources to assist blood services in this area. Materials and Methods: The Surveillance, Risk Assessment and Policy (SRAP) Sub‐group of the International Society of Blood Transfusion (ISBT) Transfusion Transmitted Infectious Diseases (TTID) Working Party developed a Public Health Research Toolkit to assist blood services and researchers interested in expanding their role in public health research. Results: The ISBT Public Health Research Toolkit provides resources for what blood services can offer to public health, examples of donor research studies, the utility of donor data and website links to public health agencies. The toolkit includes a customizable template for those interested in establishing and managing a biobank. Conclusion: The ISBT Public Health Research Toolkit includes resources to increase the recognition of the role blood donors can play in public health and to help blood services gain commitment and funding from various agencies for new research and surveillance. [ABSTRACT FROM AUTHOR]

Background and Objectives: Trypanosoma cruzi is the etiologic agent of Chagas disease (CD), an anthropozoonosis from the American continent that progresses from an acute phase to an indeterminate phase, followed by a chronic symptomatic phase in around 30% of patients. In countries where T. cruzi is not endemic, many blood transfusion services test blood donors who have stayed in an endemic country ('at‐risk stay')—even if they do not present with other risk factors. However, the efficiency of this approach has been questioned. Materials and Methods: On 18 September 2023, a worldwide survey was distributed among employees of blood transfusion services. The questions mainly pertained to CD's endemicity in the blood services' region, the current testing policy for T. cruzi and the number of confirmed positive results among donors with a prior at‐risk stay alone (i.e., without other risk factors for T. cruzi infection). Results: Twenty‐six recipients completed the survey. Of the 22 (84.6%) blood services that operated in a non‐endemic region, 9 (42.9%) tested donors for T. cruzi, including 8 (88.9%) that considered the travel history or the duration of the stay (alone) in their testing algorithm ('study blood services'). Over 93 years of observation among all study blood services, 2 donations from donors with an at‐risk stay alone and 299 from those with other risk factors were confirmed positive for T. cruzi. Conclusion: The study findings question the utility of testing blood donors who have stayed in an endemic country without other risk factors. [ABSTRACT FROM AUTHOR]

Background: The two Canadian blood suppliers, Canadian Blood Services and Héma‐Québec, removed the time‐based deferral for men who have sex with men and adopted criteria assessing sexual risk behaviors. We report the impact of these changes on the safety and adequacy of the Canadian blood supply. Study Design and Methods: Since 2022, all donors are asked if (1) they have had a new partner and (2) more than one sexual partner in the last 3 months. Donors answering yes to either question are asked if they had anal sex in the last 3 months; if yes, they are deferred for 3 months. We followed HIV rates for the 18 months before and 14 (Héma‐Québec) or 18 months (Canadian Blood Services) post‐implementation and interviewed HIV‐positive whole blood donors. We assessed the number and characteristics of whole blood donors answering yes to the two first questions with or without deferral. Results: There were four HIV‐positive donations out of 1,492,355 donations pre‐implementation and four out of 1,447,772 post‐implementation (0.27/100,000 vs. 0.28/100,000, p = 1.00). Post‐implementation, one HIV‐positive donor was non‐compliant with multiple criteria, no risk factors were identified in the others. 3.2% of donors answered yes to questions (1) and/or (2); 0.17% were deferred for a new partner and/or more than one partner and anal sex. Deferral rates were highest in first time, younger donors, and similar in males and females. Conclusion: Implementation of sexual risk behavior donor screening resulted in unchanged HIV rates to date and a manageable deferral rate. [ABSTRACT FROM AUTHOR]

Background and Objectives: Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) serosurveys are typically analysed by applying a fixed threshold for seropositivity ('conventional approach'). However, this approach underestimates the seroprevalence of anti‐nucleocapsid (N) in vaccinated individuals—who often exhibit a difficult‐to‐detect anti‐N response. This limitation is compounded by delays between the onset of infection and sample collection. To address this issue, we compared the performance of four immunoassays using a new analytical approach ('ratio‐based approach'), which determines seropositivity based on an increase in anti‐N levels. Materials and Methods: Two groups of plasma donors and four immunoassays (Elecsys total anti‐N, VITROS total anti‐N, Architect anti‐N Immunoglobulin G (IgG) and in‐house total anti‐N) were evaluated. First‐group donors (N = 145) had one positive SARS‐CoV‐2 polymerase chain reaction (PCR) test result and had made two plasma donations, including one before and one after the PCR test (median = 27 days post‐PCR). Second‐group donors (N = 100) had made two plasma donations early in the Omicron wave. Results: Among first‐group donors (97.9% vaccinated), sensitivity estimates ranged from 60.0% to 89.0% with the conventional approach, compared with 94.5% to 98.6% with the ratio‐based approach. Among second‐group donors, Fleiss's κ ranged from 0.56 to 0.83 with the conventional approach, compared with 0.90 to 1.00 with the ratio‐based approach. Conclusion: With the conventional approach, the sensitivity of four immunoassays—measured in a predominantly vaccinated population based on samples collected ~1 month after a positive test result—fell below regulatory agencies requirement of ≥95%. The ratio‐based approach significantly improved the sensitivities and qualitative agreement among immunoassays, to the point where all would meet this requirement. [ABSTRACT FROM AUTHOR]

Background and Objectives: Until recently, gay, bisexual and other men who have sex with men (MSM) were deferred from donating blood for 3–12 months since the last male‐to‐male sexual contact. This MSM deferral has been discontinued by several high‐income countries (HIC) that now perform gender‐neutral donor selection. Materials and Methods: An international symposium (held on 20‐04‐2023) gathered experts from seven HICs to (1) discuss how this paradigm shift might affect the mitigation strategies for transfusion‐transmitted infections and (2) address the challenges related to gender‐neutral donor selection. Results: Most countries employed a similar approach for implementing a gender‐neutral donor selection policy: key stakeholders were consulted; the transition was bridged by time‐limited deferrals; donor compliance was monitored; and questions or remarks on anal sex and the number and/or type of sexual partners were often added. Many countries have now adopted a gender‐neutral approach in which questions on pre‐ and post‐exposure prophylaxis for human immunodeficiency virus (HIV) have been added (or retained, when already in place). Other countries used mitigation strategies, such as plasma quarantine or pathogen reduction technologies for plasma and/or platelets. Conclusion: The experience with gender‐neutral donor selection has been largely positive among the countries covered herein and seems to be acceptable to stakeholders, donors and staff. The post‐implementation surveillance data collected so far appear reassuring with regards to safety, although longer observation periods are necessary. The putative risks associated with HIV antiretrovirals should be further investigated. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Hepatitis B is transmitted sexually, by blood contact, and vertically from mother to child. Chronic hepatitis B is often seen in immigrants from higher-prevalence countries and their Canadian-born children. We assessed the relationship between hepatitis B and social determinants of health. Included were 1,539,869 first-time Canadian blood donors from April 2005 to December 2022. All donations were tested for hepatitis B markers. Logistic regression was fit with chronic hepatitis B as the dependent variable and age, sex, year, and ethnocultural composition and material deprivation quintiles as independent variables. Chronic hepatitis B prevalence was 47.5/100,000 (95% CI 41.5–53.5, years 2017–2022). Chronic hepatitis B prevalence was elevated in males, older age groups, and those living in more materially deprived and higher ethnocultural neighbourhoods. Of 212,518 donors from 2020 to 2022 with race/ethnicity data, chronic hepatitis B prevalence was highest in East Asians. The findings are consistent with infections in immigrants, acquired in their country of origin, in their Canadian-born children and in those with other risks. As blood donors are a low-risk population unaware of their infection and unlikely to seek testing, our results highlight the ongoing public health challenges of diagnosing chronic hepatitis B and treating it when appropriate. [ABSTRACT FROM AUTHOR]