Implementation of sexual risk behavior donor screening in Canada.

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.

Deferral of blood donors who have ever stayed in a Trypanosoma cruzi endemic area: An international survey.

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.

SARS-CoV-2 immunoassays in a predominantly vaccinated population: Performances and qualitative agreements obtained with two analytical approaches and four immunoassays.

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.

End of selection criteria based on sexual orientation: An international symposium on alternatives to donation deferral.

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.

Zika virus infection during pregnancy and vertical transmission: case reports and peptide-specific cell-mediated immune responses.

Zika virus (ZIKV) infection in pregnant women is associated with birth defects, which are more prevalent and severe the earlier in pregnancy the infection occurs. Pregnant women at risk of possible ZIKV exposure (n = 154) were screened using ELISA for ZIKV IgM and IgG. Nine of 154 (5.84%) pregnant women who underwent screening exhibited positive ZIKV serology. Of these, two maternal infections were confirmed by real-time RT-PCR and five were considered probable, but only three of those were retained for further analysis based on strict diagnostic criteria. Plaque reduction neutralization tests (PRNT) confirmed ZIKV infection in nine cases (5.84%). Two cases of vertical ZIKV transmission were confirmed by PCR. One infant showed no signs of congenital ZIKV syndrome and had a normal developmental profile despite first-trimester maternal infection. In the second case, pregnancy was terminated. Production of interferon γ (IFN-γ) by peripheral blood mononuclear cells obtained from pregnant women and umbilical cord blood was measured using enzyme-linked immunospot assay (ELISpot) after stimulation with panels of synthetic peptides derived from the sequence of ZIKV proteins. This analysis revealed that, among all peptide pools tested, those derived from the ZIKV envelope protein generated the strongest IFN-γ response.

Hepatitis E Virus in the United States and Canada: Is It Time to Consider Blood Donation Screening?

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world and can lead to severe complications in immunocompromised individuals. HEV is primarily transmitted through eating pork, which has led to an increased in anti-HEV IgG seropositivity in the general population of Europe in particular. However, it can also be transmitted intravenously, such as through transfusions. The growing evidence of HEV contamination of blood products and documented cases of transmission have given rise to practice changes and blood product screening of HEV in many European countries. This review covers the abundant European literature and focuses on the most recent data pertaining to the prevalence of HEV RNA positivity and IgG seropositivity in the North American general population and in blood products from Canada and the United States. Currently, Health Canada and the Food and Drug Administration do not require testing of HEV in blood products. For this reason, awareness among blood product prescribers about the possibility of HEV transmission through blood products is crucial. However, we also demonstrate that the province of Quebec has a prevalence of anti-HEV and HEV RNA positivity similar to some European countries. In light of this, we believe that HEV RNA blood donation screening be reevaluated with the availability of more cost-effective assays.

Incidence of SARS-CoV-2 during the Omicron wave: Results of a longitudinal serosurvey in Québec, Canada.

OBJECTIVES: Conventional serological approaches lack sensitivity for the detection of recent SARS-CoV-2 infections in vaccinated individuals, as these individuals exhibit a blunted anti-nucleocapsid (N) response. This limitation was recently addressed by the development of a "ratio-based approach", which compares longitudinally collected specimens. Here, we used this approach to estimate the incidence of SARS-CoV-2 infection and reinfection in Québec (Canada) during the Omicron wave. METHODS: Consenting plasma donors were included if they donated plasma before December 15, 2021 and during six consecutive periods of ~ 3 months between December 15, 2021 and July 7, 2023 (study period). Anti-N levels were measured with an enzyme-linked immunosorbent assay, and seroconversion was characterized by a ratio of ≥ 1.5 between the optical density of two consecutive samples. RESULTS: Among the 254 donors, the adjusted proportion of donors (95% confidence interval [CI]) with a new infection ranged between 18.1% (13.2‒23.0) and 24.2% (18.8‒29.7) over Periods 1-5 and fell to 7.9% (4.9‒11.0) during Period 6. During the study period, the proportion of newly infected donors decreased among those aged < 60 (Period 1 = 31.6%, Period 5 = 4.4%), but increased among those aged ≥ 70 (Period 1 = 0.3%, Period 6 = 10.3%). Throughout the study period, 72 (28.3%) reinfections occurred, including two seroconversion events in a single donor. Overall, 87.4% (95% CI = 82.7‒91.2) were infected by SARS-CoV-2 at least once during the study period. CONCLUSION: The vast majority of the Québec population may have been infected during the Omicron wave. This longitudinal survey demonstrates the usefulness of the "ratio-based approach" for identifying both new infections and reinfections in a vaccinated population.

RéSUMé: OBJECTIFS: Les approches sérologiques classiques démontrent un manque de sensibilité pour la détection des infections récentes par le SRAS-CoV-2 chez les personnes vaccinées, car ces dernières présentent une réponse anti-nucléocapside (N) peu élevée. Cette limitation a été récemment surmontée suite au développement d'une « approche basée sur les ratios ¼, qui compare des échantillons collectés de manière longitudinale. Nous avons utilisé cette approche pour estimer l'incidence de l'infection et de la réinfection par le SRAS-CoV-2 au Québec (Canada) pendant la vague Omicron. MéTHODES: Les donneurs de plasma consentants étaient inclus dans l'étude s'ils avaient donné du plasma avant le 15 décembre 2021 et pendant six périodes consécutives de 2 à 3 mois entre le 15 décembre 2021 et le 7 juillet 2023 (période d'étude). Les taux d'anti-N ont été mesurés par ELISA et la séroconversion a été caractérisée par un rapport ≥ 1,5 entre la densité optique de deux échantillons consécutifs. RéSULTATS: Parmi les 254 donneurs, le risque ajusté (IC 95 %) d'infection a varié entre 18,1 % (13,2‒23,0) et 24,2 % (18,8‒29,7) au cours des périodes 1 à 5 et a chuté à 7,9 % (4,9‒11,0) au cours de la période 6. Au cours de la période d'étude, le risque d'infection a diminué chez les donneurs âgés de moins de 60 ans (période 1 = 31,6 %, période 5 = 4,4 %), mais a augmenté chez ceux âgés de ≥ 70 ans (période 1 = 0,3 %, période 6 = 10,3 %). Tout au long de la période d'étude, 72 (28,3 %) réinfections se sont produites (c'est-à-dire deux événements de séroconversion chez un même donneur). Dans l'ensemble, 87,4 % (IC 95 % = 82,7‒91,2) ont été infectés par le SRAS-CoV-2 au moins une fois au cours de la période d'étude. CONCLUSION: La grande majorité de la population québécoise pourrait avoir été infectée lors de la vague Omicron. Cette enquête longitudinale démontre l'utilité de l'approche basée sur les ratios pour identifier les nouvelles infections et les réinfections dans une population vaccinée.

The Effect of Age and Comorbidities: Children vs. Adults in Their Response to SARS-CoV-2 Infection.

While children have experienced less severe coronavirus disease (COVID-19) after SARS-CoV-2 infection than adults, the cause of this remains unclear. The objective of this study was to describe the humoral immune response to COVID-19 in child vs. adult household contacts, and to identify predictors of the response over time. In this prospective cohort study, children with a positive SARS-CoV-2 polymerase chain reaction (PCR) test (index case) were recruited along with their adult household contacts. Serum IgG antibodies against SARS-CoV-2 S1/S2 spike proteins were compared between children and adults at 6 and 12 months after infection. A total of 91 participants (37 adults and 54 children) from 36 families were enrolled. Overall, 78 (85.7%) participants were seropositive for anti-S1/S2 IgG antibody at 6 months following infection; this was higher in children than in adults (92.6% vs. 75.7%) (p = 0.05). Significant predictors of a lack of SARS-CoV-2 seropositivity were age ≥ 25 vs. < 12 years (odds ratio [OR] = 0.23, p = 0.04), presence of comorbidities (vs. none, adjusted OR = 0.23, p = 0.03), and immunosuppression (vs. immunocompetent, adjusted OR = 0.17, p = 0.02).