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.

A registry-based population study of the HLA in Québec, Canada

As part of the worldwide effort to better characterize HLA diversity in populations, we have studied the population of Québec in Canada. This province has been defined by a complex history with multiple founder effects and migration patterns. We analyzed the typing data of 3806 individuals registered in Héma-Québec's Registry, which covered most administrative regions in Québec. Typing information was resolved at the second field level of resolution by next-generation sequencing (NGS) or by Sanger sequencing. We used the HLA-net.eu GENE[RATE] tools to estimate allele and two-locus haplotype frequencies for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1, as well as Hardy-Weinberg equilibrium (HWE), selective neutrality, and linkage disequilibrium. The chord genetic distance was also calculated between administrative regions and was visualized using non-metric multidimensional scaling (NMDS) analysis. While most individual regions were in HWE, HWE was rejected for the province considered as a whole. Some regions exhibited signatures of selection, mostly toward an excess of heterozygotes. Allele and haplotype frequencies revealed outlier regions that strongly differed from the other regions. NMDS plots also showed differences between regions. The administrative regions of the province of Québec displayed heterogeneity in their HLA profiles. This heterogeneity was attributable to differing allele and haplotype specificities by region. In particular, regions 02-Saguenay-Lac-Saint-Jean and 01-Bas-St-Laurent diverged from the rest of the regions. The urban regions 06-Montréal and 13-Laval were very diversified in their HLA profiles. Together, these results will help optimize donor recruitment strategies in Québec.

Relevance of haemoglobin monitoring in apheresis plasma donors: A retrospective cohort study in Québec, Canada

BACKGROUND AND OBJECTIVES

Systematically measuring pre-donation haemoglobin (Hb) levels might be overly cautious for apheresis plasma donation, since plasmapheresis entails a small loss of red blood cells. We explored the association between the frequency of apheresis plasma donation and capillary blood Hb levels.

MATERIALS AND METHODS

This retrospective cohort study included donors who gave apheresis plasma at least twice between 24 October 2020 and 23 October 2022 in Québec, Canada. Results were stratified by sex and analysed with linear repeated-measure mixed models with random intercepts.

RESULTS

In total, 9535 men (mean age = 46.7 years) and 9409 women (mean age = 41.1 years) made ≥2, but no more than 16 apheresis plasma donations. Over an average of 9.2 months of observation, men maintained Hb levels well above the Hb deferral threshold, and their Hb levels decreased by only 0.17 g/dL between the 1st and 15th donation return (p < 0.0001). Over an average of 9.0 months of observation, women also maintained adequate Hb levels, and their Hb levels decreased by 0.08 g/dL between the 1st and 15th donation return.

CONCLUSION

The frequency of apheresis plasma donation was not associated with clinically meaningful changes in Hb levels, neither in men nor in women. This evidence questions the relevance of systematically monitoring Hb for apheresis plasma donation, at least for donation frequencies of ≤7-8 times per year. However, an adverse impact of plasmapheresis on Hb levels cannot be ruled out for individuals donating more frequently or for longer than ~9 months.

Associated criteria used in investigating suspected septic transfusion reactions: A scoping review

BACKGROUND AND OBJECTIVES

Septic transfusion reactions (STRs) occur as a result of bacterial contamination of blood or blood products, resulting in sepsis. This scoping review aimed to identify, explore and map the available literature on the STR criteria triggering the investigation of STR.

MATERIALS AND METHODS

Four electronic databases (MEDLINE, Web of Science, Science Direct, Embase) were searched to retrieve scientific literature reporting such criteria, published from 1 January 2000 to 5 May 2022. Grey literature was also searched from open web sources.

RESULTS

Of 1052 references identified, 43 (21 peer-reviewed and 22 grey literature) met the eligibility criteria for inclusion and data extraction after full article screening. Of them, most (27/43, 62.79%) were found to report a single set of criteria, and only two reported four or more sets of criteria. The analysis of 66 sets of criteria collected from the selected references revealed 57 different sets. A few sets of criteria used only one sign and symptom (s/s) (12.12%, n = 8), whereas 16 sets used 7-15 s/s (n = 16/66; 24.24%). Of the total 319 occurrences of s/s associated with the 66 sets of criteria, post-transfusion hyperthermia, body temperature increase and hypotension were the most common s/s categories. Of all the literature available, only one study tested the diagnostic accuracy of the STR criteria.

CONCLUSION

This scoping review revealed a substantial variation in criteria used to identify suspected STR. Consequently, conducting further studies to enhance the diagnostic accuracy of these criteria, which trigger STR investigations, is imperative for advancing clinical practice.

Two-phase Bayesian latent class analysis to assess diagnostic test performance in the absence of a gold standard: COVID-19 serological assays as a proof of concept

BACKGROUND AND OBJECTIVES

In this proof-of-concept study, which included blood donor samples, we aimed to demonstrate how Bayesian latent class models (BLCMs) could be used to estimate SARS-CoV-2 seroprevalence in the absence of a gold standard assay under a two-phase sampling design.

MATERIALS AND METHODS

To this end, 6810 plasma samples from blood donors who resided in Québec (Canada) were collected from May to July 2020 and tested for anti-SARS-CoV-2 antibodies using seven serological assays (five commercial and two non-commercial).

RESULTS

SARS-CoV-2 seroprevalence was estimated at 0.71% (95% credible interval [CrI] = 0.53%-0.92%). The cPass assay had the lowest sensitivity estimate (88.7%; 95% CrI = 80.6%-94.7%), while the Héma-Québec assay had the highest (98.7%; 95% CrI = 97.0%-99.6%).

CONCLUSION

The estimated low seroprevalence (which indicates a relatively limited spread of SARS-CoV-2 in Quebec) might change rapidly-and this tool, developed using blood donors, could enable a rapid update of the prevalence estimate in the absence of a gold standard. Further, the present analysis illustrates how a two-stage BLCM sampling design, along with blood donor samples, can be used to estimate the performance of new diagnostic tests and inform public health decisions regarding a new or emerging disease for which a perfect reference standard does not exist.

Highly pathogenic avian influenza: Unprecedented outbreaks in Canadian wildlife and domestic poultry

Canada experienced a wave of HPAI H5N1 outbreaks in the spring of 2022 with millions of wild and farmed birds being infected. Seabird mortalities in Canada have been particularly severe on the Atlantic Coast over the summer of 2022. Over 7 million birds have been culled in Canada, and outbreaks continue to profoundly affect commercial bird farms across the world. This new H5N1 virus can and has infected multiple mammalian species, including skunks, foxes, bears, mink, seals, porpoises, sea lions, and dolphins. Viruses with mammalian adaptations such as the mutations PB2-E627K, E627V, and D701N were found in the brain of various carnivores in Europe and Canada. To date this specific clade of H5N1 virus has been identified in less than 10 humans. At the ground level, awareness should be raised among frontline practitioners most likely to encounter patients with HPAI.

Transfusion-transmitted Babesia spp.: a changing landscape of epidemiology, regulation, and risk mitigation

Babesia spp. are tick-borne parasites with a global distribution and diversity of vertebrate hosts. Over the next several decades, climate change is expected to impact humans, vectors, and vertebrate hosts and change the epidemiology of Babesia. Although humans are dead-end hosts for tick-transmitted Babesia, human-to-human transmission of Babesia spp. from transfusion of red blood cells and whole blood-derived platelet concentrates has been reported. In most patients, transfusion-transmitted Babesia (TTB) results in a moderate-to-severe illness. Currently, in North America, most cases of TTB have been described in the United States. TTB cases outside North America are rare, but case numbers may change over time with increased recognition of babesiosis and as the epidemiology of Babesia is impacted by climate change. Therefore, TTB is a concern of microbiologists working in blood operator settings, as well as in clinical settings where transfusion occurs. Microbiologists play an important role in deploying blood donor screening assays in Babesia endemic regions, identifying changing risks for Babesia in non-endemic areas, investigating recipients of blood products for TTB, and drafting TTB policies and guidelines. In this review, we provide an overview of the clinical presentation and epidemiology of TTB. We identify approaches and technologies to reduce the risk of collecting blood products from Babesia-infected donors and describe how investigations of TTB are undertaken. We also describe how microbiologists in Babesia non-endemic regions can assess for changing risks of TTB and decide when to focus on laboratory-test-based approaches or pathogen reduction to reduce TTB risk.

Risk of variant Creutzfeldt-Jakob disease in a simulated cohort of Canadian blood donors

BACKGROUND AND OBJECTIVES

No transfusion-associated cases of variant Creutzfeldt-Jakob disease (vCJD) have occurred in more than 20 years. Yet, many countries have maintained blood donor deferral criteria for vCJD. We developed a risk simulation model to reassess the need for vCJD-related deferral criteria in Canada.

MATERIALS AND METHODS

The model provides results separately for Héma-Québec (HQ) and Canadian Blood Services (CBS). The model used a Monte Carlo simulation approach to estimate the risk of having a vCJD-contaminated blood donation ('risk of vCJD') in a simulated cohort of 10 million donors followed for up to 85 years. The model assumed current deferral criteria for vCJD were lifted, which would allow new 'at-risk' donors to give blood. The model accounted for disease prevalence, donors' travel/immigration history, PRNP genotype at codon 129, demographics and the type of labile blood product.

RESULTS

In the base case, the risk of vCJD was estimated at zero at both blood services. In the most pessimistic scenario, the risk of vCJD was 6.4 × 10-9 (i.e., 1 in 157 million donations) at HQ, or ≤1 in 77 million based on the upper bound of the 95% confidence interval (CI). At CBS, this risk was 4.8 × 10-8 (i.e., 1 in 21 million donations), or ≤1 in 16 million based on the upper bound of the 95% CI.

CONCLUSION

vCJD poses minimal risks to the Canadian blood supply. Current vCJD deferral criteria may, therefore, be lifted with virtually no impact on safety, while significantly expanding the donor base.

Identifying Clinical Criteria for an Expanded Targeted Approach to Screening for Congenital Cytomegalovirus Infection-A Retrospective Study

Targeted screening for congenital CMV infection (cCMV), which entails CMV testing of infants who fail newborn hearing screening (NBHS), has become common practice. However, this strategy misses nearly all infected infants with normal hearing at birth who are nonetheless at high risk of subsequent hearing loss and would benefit from timely cCMV diagnosis. The objective of this study was to identify expanded criteria predictive of cCMV to increase the scope and utility of targeted newborn CMV screening. In this retrospective study, 465 newborns were tested for cCMV at a single tertiary care center with a targeted screening program between 2014 and 2018. Twenty-two infants were diagnosed with cCMV, representing 0.2% of the 12,189 births over this period and 4.7% of the infants tested. The highest prevalence of cCMV infection was among infants tested because of primary maternal CMV infection (8/42, 19%), followed by failed initial NBHS (10/88, 11.4%), maternal HIV infection (3/137, 2.2%), and clinical suspicion alone (5/232, 2.2%). The symptoms with the highest prevalence of infection among all infants tested included an enlarged liver and/or spleen (33.3%) (3/9), followed by petechiae (33.3%), microcephaly (9.4%), direct hyperbilirubinemia (7.7%), thrombocytopenia (6%), and growth impairment (4.3%). In addition to CMV screening of newborns who fail the NBHS, these data suggest that certain clinical signs of cCMV-in particular: thrombocytopenia, growth impairment, and HIV exposure in pregnancy-should be additional criteria for expanded targeted newborn CMV screening, where universal screening is not yet the standard of care.

Transmission of Variant Creutzfeldt-Jakob Disease Through Blood Transfusion and Plasma-Derived Products: A Narrative Review of Observed and Modeled Risks

Secondary transmission of variant Creutzfeldt-Jakob disease (vCJD) can occur through blood transfusion or receipt of plasma-derived products. However, published reviews on this topic are outdated, focused on a single country or product type, or did not comprehensively review modeling studies on the risk of transfusion-transmission. We reviewed existing data on observed and modeled risks of transfusion-transmission of vCJD. To date, five patients are suspected to have acquired clinical vCJD or a vCJD infection after receiving a blood or plasma-derived product from a donor who later developed clinical vCJD. All of these cases received a nonleukodepleted blood-derived product in the United Kingdom between 1994 and 1999. Thus, all transfusion-associated cases occurred before the adoption of universal leukodepletion in 1999, which supports the preferential tropism of vCJD for leukocytes. In descriptive cohort studies, no cases of clinical vCJD were observed over ∼13 years of follow-up. In modeling studies, the risk of collecting a contaminated donation was generally <23 per million donations, that of infection was generally <10 per million transfusions or doses, and that of clinical vCJD was generally <2 per million transfusions or doses. These low risk estimates and the two-decade long absence of new cases of transfusion-associated vCJD suggest vCJD poses minimal risks to the safety of the blood supply. Furthermore, despite concerns of a second wave driven by individuals harboring a non-MM genotype at codon 129 of PRNP, there has been only 1 autopsy-confirmed case of clinical vCJD in an MV individual in 2016. The current trend to reassess or (in some countries) fully withdraw the blood donation criteria related to vCJD therefore seems justified, safe, and may significantly expand the donor base.

Evaluation of anti-nucleocapsid level variation to assess SARS-CoV-2 seroprevalence in a vaccinated population

BACKGROUND

Serosurveys have been key to public health decision-making since the beginning of the SARS-CoV-2 pandemic. However, several studies have uncovered that vaccination blunts the anti-nucleocapsid (N) response to a subsequent infection, which hinders the ability of serologic assays (including commercial ones) to detect recent infections. We therefore developed a new analytical approach to increase the sensitivity of detection of infection in vaccinated individuals.

METHODS

Two samples were obtained from 248 SARS-CoV-2-positive (PCR-confirmed), vaccinated donors: one before the infection (reference sample) and one after (test sample). All samples were tested using an in-house, anti-N enzyme-linked immunosorbent assay (ELISA) which had a sensitivity of 98.1% before the mass vaccination campaign. Instead of applying a seropositivity threshold based on a single absorbance value (i.e. conventional approach), seropositivity was determined based on the ratio between the anti-N absorbance of the test and reference samples.

RESULTS

The sensitivity of the new approach to detect infection in vaccinated individuals was 95.2% using a cut-off of 1.5 for the anti-N ratio, whereas that of the conventional approach was 63.3%.

CONCLUSION

The new analytical approach described herein captured a significantly greater proportion of vaccinated individuals with a known history of SARS-CoV-2 infection than the conventional approach used in most serosurveys.

Concordance in COVID-19 serology, bone mineralization, and inflammatory analytes between venous and self-collected capillary blood samples exposed to various pre-analytical conditions

BACKGROUND

The COVID-19 has led to a significant increase in demand for remote blood sampling in clinical trials. This study aims to ascertain the concordance between venous versus capillary samples, processed immediately or exposed to various pre-analytical conditions.

METHODS

Participants (≥12 years old) provided a venous blood sample (processed immediately) and capillary samples allocated to one of the following conditions: processed immediately or exposed to 12-, 24-, or 36-h delays at room temperature or 36-h delays with a freeze-thaw cycle. The analytes of interest included SARS-CoV-2 IgG, 25-hydroxy vitamin D (25(OH)D), alkaline phosphate (ALP), calcium (Ca), phosphate (Ph), and c-reactive protein (CRP). Paired samples were considered interchangeable if they met three criteria: minimal within-subject mean difference, 95% of values within desirable total errors, and inter-class correlation (ICC) > 0.90.

RESULTS

90 participants (44.1% male) were enrolled. When comparing rapidly processed venous with capillary samples, 25(OH)D, ALP, and CRP met all three criteria; SARS-CoV-2 IgG met two criteria (mean difference and ICC); and Ca and Ph met one criterion (mean difference). When considering all three criteria, concentrations of 25(OH)D, CRP, and ALP remained unchanged after delays of up to 36 h; SARS-CoV-2 IgG met two criteria (mean difference and ICC); Ca and Ph met one criterion (mean difference).

CONCLUSION

These findings suggest that remote blood collection devices can be used to measure anti-SARS-CoV-2 IgG, 25(OH)D, CRP, and ALP. Further analysis is required to evaluate the interchangeability between venous and capillary testing in Ca and Ph levels, which are more sensitive to pre-analytical conditions.

Cohort profile: A Québec-based plasma donor biobank to study COVID-19 immunity (PlasCoV)

PURPOSE

The long-term humoral immunity to COVID-19 is not well understood owing to the continuous emergence of new variants of concern, the evolving vaccine-induced and infection-induced immunity, and the limited duration of follow-up in previous studies. As the sole blood service in Québec (Canada), Héma-Québec established a COVID-19-focused biobank ('PlasCoV') in April 2021.

PARTICIPANTS

As of January 2022, the biobank included 86 483 plasma samples from 15 502 regular donors (age range=18-84 years, females=49.7%), for an average of 5.6 donations per donor. Nearly two-thirds (65.6%) of biobank donors made at least two donations, with many donors having provided samples prevaccination and postvaccination (3061 (19.7%)) or preinfection and postinfection (131 (0.8%)), thus allowing for longitudinal studies on vaccine-induced and infection-induced immunity.

FINDINGS TO DATE

A study that used PlasCoV samples revealed that previously infected individuals who received a single dose of the BNT162b2 COVID-19 vaccine exhibited the strongest immune response. By contrast, SARS-CoV-2-naïve individuals required two vaccine doses to produce a maximal immune response. Furthermore, the results of a four-phase seroprevalence study indicated that the antinucleocapsid (N) response wanes rapidly, so that up to one-third of previously infected donors were seronegative for anti-N.

FUTURE PLANS

Donations from individuals who consented to participate before 1 October 2022 will be collected up until 31 March 2023. This plasma biobank will facilitate the conduct of longitudinal studies on COVID-19 immunity, thus helping to provide valuable insights into the anti-SARS-CoV-2 immune response and its persistence, and the effects of vaccination and variants on the specificity of the anti-SARS-CoV-2 immune response.

Pre-donation water and salty snacks to prevent vasovagal reactions among blood donors

BACKGROUND

Minimizing the risk of vasovagal reactions (VVRs) can prevent donor harms and improve donor return. We report the results of a program to reduce VVR rates.

STUDY DESIGN AND METHODS

The program was implemented on June 11, 2017 and consisted in drinking water and eating a salty snack before donating blood, plasma, or platelets. All donations made during the "pre-program period" (October 11, 2015-June 10, 2017) and "post-program period" (June 11, 2017-May 11, 2019) were included. Study outcomes comprised VVRs (any severity) and syncopal VVRs, whether employee- or donor-reported. An interrupted time series (ITS) analysis proxied causality based on the "pre-program trend," the "immediate trend" (i.e., immediately before versus after the program), and the "post-program trend". The relative risk (RR) of VVR (along with confidence intervals [CIs]) was reported, overall and stratified by subgroups based on age, sex, donor type (i.e., first-time versus repeat), and donation type (i.e., whole blood versus apheresis).

RESULTS

The monthly VVR rate (any severity) dropped from 4.6% in the pre-program period to 4.3% in the post-program period, and never reached its pre-program level. The ITS analysis revealed a statistically significant and increasing pre-program trend (RR [95% CI] = 1.011 [1.002-1.020]), a statistically significant and decreasing immediate trend (RR [95% CI] = 0.848 [0.743-0.969]), and a non-statistically-significant and stable post-program trend (RR [95% CI] = 0.999 [0.993-1.006]). Similar trends were observed for nearly all high- and low-risk subgroups. No statistically significant trend was observed for syncopal VVRs.

DISCUSSION

These results suggest that the herein-described program durably reduced the incidence of VVRs (any severity) by ~15%.

Validation of new, gender-neutral questions on recent sexual behaviors among plasma donors and men who have sex with men

BACKGROUND AND OBJECTIVES

Several blood services might eventually interview donors with gender-neutral questions on sexual behaviors to improve the inclusivity of blood donation. We tested two ways (i.e., "scenarios") of asking donors about their recent sexual behaviors.

MATERIALS AND METHODS

The study comprised 126 regular source plasma donors and 102 gay, bisexual, and other men who have sex with men (gbMSM), including 73 cis-gbMSM (i.e., the "cis-gbMSM subgroup," which excluded nonbinary, genderqueer, and trans individuals). In Scenario 1, participants were asked if, in the last 3 months, they "have […] had a new sexual partner or more than one sexual partner." In Scenario 2, they were asked "Have you had a new sexual partner?" and "have you had more than one sexual partner?". Validation questions included more specific questions on the type of partners and sexual activity.

RESULTS

Among plasma donors, sensitivity was 100.0% for both scenarios; specificity was 100.0% and 99.1% for Scenarios 1 and 2, respectively. Among gbMSM, sensitivity was 74.5% and 82.9% for Scenarios 1 and 2, respectively; specificity was 100.0% for both scenarios. Among cis-gbMSM, sensitivity was 88.6% and 100.0% for Scenarios 1 and 2, respectively; specificity was 100.0% for both scenarios. The area under the receiver operating characteristic curve of Scenario 2 was significantly higher than that of Scenario 1 among gbMSM and in the cis-gbMSM subgroup (all p < .05).

CONCLUSION

Scenario 2 questions performed well among plasma donors and cis-gbMSM, but less so in the broader gbMSM population.

Research partnerships between blood services and public health authorities: An international, cross-sectional survey

BACKGROUND AND OBJECTIVES

The COVID-19 pandemic has brought to the fore how blood services can partner with public health (PH) authorities to inform decisions. Yet the scope of partnerships between blood services and PH authorities is inadequately documented. We explored how blood services partner with PH authorities outside the scope of COVID-19.

MATERIALS AND METHODS

On 19 January 2022, survey was sent to employees of blood services located throughout the world. Survey questions mainly pertained to partnerships with PH authorities, including how blood specimens are used and collected.

RESULTS

Twenty-seven recipients-4 (14.8%) in Africa, 3 (11.1%) in Asia, 9 (33.3%) in Europe, 6 (22.2%) in North America, 2 (7.4%) in Oceania and 3 (11.1%) in South America-completed the survey. Fifteen recipients (55.6%) indicated their blood service was directly or indirectly supervised by PH authorities. Twenty-four recipients (88.9%) indicated currently using or planning to use blood donor data or samples for PH research or pathogen surveillance. A substantial proportion of respondents reported using samples or results from non-routine tests for the surveillance of non-transfusion-transmitted infectious disease pathogens (n = 13 [48.1%]); samples or results of non-routine tests for PH research unrelated to pathogens (n = 10 [37.0%]); donor data for PH research unrelated to pathogens (n = 12 [44.4%]) and donor data for PH research unrelated to transfusion safety (n = 11 [40.7%]). Fourteen (51.9%) had established (or planned to establish) longitudinal cohorts and 19 (70.4%) biobanks.

CONCLUSION

The majority of responding blood services were already involved in or planned to be involved in PH research or pathogen surveillance.

Epstein–Barr virus seroprevalence and viral load at disease onset in children with inflammatory bowel disease

Background and Aim

Patients with inflammatory bowel disease (IBD) are at increased risk for life‐threatening complications of Epstein–Barr virus (EBV), including lymphoproliferative diseases. These complications are likely related to inherent immune dysfunction and immunomodulating therapies often used. We aimed to determine the seroprevalence of EBV at diagnosis in our population, its impact on disease at onset, and the risk of active EBV infection.

Methods

We included patients newly diagnosed with IBD for whom an EBV serology was performed over a 2‐year period. Demographic information and data on disease characteristics were collected retrospectively. Stored serum from the time of diagnosis was retrieved when available for the patients with positive EBV serology, and quantitative polymerase chain reaction testing was performed to assess the pre‐treatment viral load of EBV.

Results

One hundred twenty patients were included in the study. Fifty‐three patients (44.2%) had positive EBV serology at diagnosis. Stratified by age group, the prevalence of seropositive patients was for 0 to <10 years 35%, 10 to <17 years 46%, and ≥17 years 50%. Overall, therapies started within 6 months of diagnosis were similar in both the seropositive and seronegative groups. Within the seropositive group, 66% received systemic corticosteroids, 32.1% infliximab, 5.7% adalimumab, and 5.7% azathioprine.

Conclusion

EBV seroprevalence is high in pediatric patients with IBD. EBV seropositivity did not seem to influence the severity of disease at onset or initial choice of therapy.

Evaluation of the performance of multiple immunoassay diagnostic platforms on the National Microbiology Laboratory SARS-CoV-2 National Serology Panel

BACKGROUND

Serological assays designed to detect SARS-CoV-2 antibodies are being used in serological surveys and other specialized applications. As a result, and to ensure that the outcomes of serological testing meet high quality standards, evaluations are required to assess the performance of these assays and the proficiency of laboratories performing them.

METHODS

A panel of 60 plasma/serum samples from blood donors who had reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed SARS-CoV-2 infections and 21 SARS-CoV-2 negative samples were secured and distributed to interested laboratories within Canada (n = 30) and the United States (n = 1). Participating laboratories were asked to provide details on the diagnostic assays used, the platforms the assays were performed on, and the results obtained for each panel sample. Laboratories were blinded with respect to the expected outcomes.

RESULTS

The performance of the different assays evaluated was excellent, with the high-throughput platforms of Roche, Ortho, and Siemens demonstrating 100% sensitivity. Most other high-throughput platforms had sensitivities of >93%, with the exception of the IgG assay using the Abbott ARCHITECT which had an average sensitivity of only 87%. The majority of the high-throughput platforms also demonstrated very good specificities (>97%).

CONCLUSION

This proficiency study demonstrates that most of the SARS-CoV-2 serological assays utilized by provincial public health or hospital laboratories in Canada have acceptable sensitivity and excellent specificity.

Prevalence, incidence, and risk factors associated with cytomegalovirus infection in healthcare and childcare worker: a systematic review and meta-analysis

BACKGROUND

Cytomegalovirus (CMV) is transmitted by direct contact with body fluids from infected individuals. Transmission of CMV in households, particularly those with young children, contributes significantly to CMV infection in the general population. However, little is known about the contribution of occupational healthcare or childcare exposure to risk of CMV infection.

OBJECTIVES

To determine CMV seroprevalence, incidence of primary infection, and associated risk factors in healthcare and childcare workers.

METHODS

Six electronic databases were searched systematically for publications on CMV infection in healthcare and childcare workers until March 7, 2022. Two authors independently evaluated the literature for quality and inclusion in our analyses. The pooled results for seroprevalence, incidence, and relative risk (RR) were determined using a random effects model. Heterogeneity among studies was quantified and further investigated in subgroup analysis and meta-regression. Publication bias was assessed using funnel plot. Statistical analyses were preformed using R version 4.05.

RESULTS

Forty-eight articles were included in this meta-analysis (quality assessment: 18 good, 14 fair, and 16 poor). Pooled CMV seroprevalence was 59.3% (95% CI: 49.8-68.6) among childcare workers and 49.5% (95% CI: 40.3-58.7) among healthcare workers, and pooled incidences of primary CMV infection per 100 person-years were respectively 7.4 (95% CI: 3.9-11.8) and 3.1 (95% CI: 1.3-5.6). RR for primary infection compared to controls were 3.4 (95% CI: 1.3-8.8) and 1.3 (95% CI: 0.6-2.7) for healthcare and childcare workers, respectively. The odds of CMV seropositivity were 1.6 (95% CI: 1.2-2.3) times higher for childcare workers compared to controls, but not significantly different between healthcare workers and controls (0.9; 95% CI: 0.6-1.2). CMV seropositivity in both groups was significantly associated with having one or more children residing at home, marital status, ethnicity, and age.

CONCLUSIONS

Childcare workers, but not healthcare workers, have an increased risk of prevalent and incident CMV infection, a risk that is further increased with the presence of at least one child living at home. These findings suggest that enforcing simple, conventional hygienic measures in childcare settings could help reduce transmission of CMV, and that special precautionary measures for preventing CMV infection may not be required for pregnant healthcare workers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020139756.

Risk of transfusion-related acute lung injury and human immunodeficiency virus associated with donations from trans donors in Quebec, Canada

BACKGROUND AND OBJECTIVES

Blood operator must establish selection criteria according to the populations at risk of blood-related infections and complications. Therefore, this study aimed to assess the risks of transfusion-related acute lung injury (TRALI) and human immunodeficiency virus (HIV) associated with donations from trans persons.

MATERIALS AND METHODS

Donor screening data from Héma-Québec were used. The risks of TRALI and HIV were estimated based on internal data and assumptions derived from the literature. The risk was assessed under four scenarios: a most likely scenario, an optimistic scenario and two pessimistic scenarios. All scenarios assumed no prior screening for trans donors.

RESULTS

The trans population comprised 134 donors, including 94 (70.1%) trans men. Of the 134 donors, 58 (43.3%) were deferred from donating a blood-derived product because of an ongoing gender-affirming genital surgery, and the remaining 76 (56.7%) were eligible donors. The risk of having a TRALI-causing donation, given that it comes from a trans man, was estimated at one every 115-999 years for all scenarios. The risk of having an HIV-contaminated donation, given that it comes from a trans woman, was estimated at one every 1881-37,600 years for all scenarios.

CONCLUSION

This study suggests that donations from trans persons are associated with a negligible risk of TRALI and HIV.

Seroprevalence of SARS-CoV-2 antibodies among blood donors in Québec: an update from a serial cross-sectional study

Objectives

We previously estimated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies following the first pandemic wave at 2.23% in Québec, Canada. Following the much bigger second wave in fall 2020 and early 2021, we estimated the seroprevalence of anti-SARS-CoV-2 in Québec during the first months of 2021.

Methods

Blood samples from regular, asymptomatic (for ≥ 14 days) donors were collected between January 25, 2021 and March 11, 2021. Anti-SARS-CoV-2 seropositivity was assessed using an enzyme-linked immunosorbent assay that captures antibodies directed against the receptor binding domain of the SARS-CoV-2 spike (and hence cannot discriminate between infection- and vaccine-induced seropositivity). Seroprevalence estimates were adjusted for regional distribution, age, and sex.

Results

Samples from 7924 eligible donors were analyzed, including 620 (7.8%) vaccinated donors and 7046 (88.9%) unvaccinated donors (vaccination status unknown for 258 (3.3%) donors). Overall, median age was 51 years; 46.4% of donors were female. The adjusted seroprevalence was 10.5% (95% CI = 9.7–11.3) in the unvaccinated population and 14.7% (95% CI = 13.8–15.6) in the overall population. Seroprevalence gradually decreased with age and was higher among donors who self-identified as having a racial/ethnic background other than white, both in the overall and in the unvaccinated populations.

Conclusion

The seroprevalence of SARS-CoV-2 antibodies significantly increased in Québec since spring 2020, with younger persons and ethnic minorities being disproportionately affected. When compared with the cumulative incidence rate reported by public health authorities (i.e., 3.3% as of March 11, 2021), these results suggest that a substantial proportion of infections remain undetected despite improvements in access to COVID-19 testing.

Supplementary Information

The online version contains supplementary material available at 10.17269/s41997-022-00622-y.

Cost-effectiveness of pathogen reduction technology for plasma and platelets in Québec: A focus on potential emerging pathogens

BACKGROUND

The last economic evaluation of pathogen reduction technology (PRT) in Canada was conducted in 2007. We reassessed the cost-effectiveness of PRT in the province of Québec (which has its own blood supplier) and included an evaluation of the potential impact of emerging pathogens on cost-effectiveness.

STUDY DESIGN AND METHODS

Decision analytic Markov models were developed to simulate the costs and quality-adjusted life-years (QALY) associated with PRT as an addition to existing safety measures for plasma and platelet products (except for bacterial culture). Models accounted for several infectious and noninfectious transfusion reactions, recipients' productivity losses ensuing from these reactions, and the impact of PRT on platelet function. Scenario analyses were conducted to evaluate the impact of a new highly contagious human immunodeficiency virus (HIV)-like or West Nile virus (WNV)-like pathogen, assuming various epidemiological scenarios.

RESULTS

In the base case, the incremental cost-effectiveness ratio (ICER) of PRT was estimated at $8,088,974/QALY gained. Assuming the presence of an HIV-like pathogen, the ICER was $265,209/QALY gained in the "average transmission" scenario, $1,274,445/QALY gained in the "rapid testing scenario," and $123,063/QALY gained in the "highly contagious" scenario. Assuming the presence of a WNV-like pathogen, the ICER was $7,469,167/QALY gained in the "average transmission" scenario and $6,652,769/QALY gained in the "highly contagious" scenario.

CONCLUSION

The cost-effectiveness of PRT may substantially improve in the event of a new, blood-borne pathogen. Given their significant impact on cost-effectiveness, the emergence of new pathogens should be considered when deciding whether to adopt PRT.

Reported non-compliance with pre-donation screening among blood donors in Québec, Canada: A focus on the 3-month deferral for men who have sex with men

BACKGROUND AND OBJECTIVES

In Québec (Canada), the donation deferral for men who have sex with men (MSM) has recently been shortened to 3 months. Whether this change impacted compliance with pre-donation screening is unknown. We assessed compliance with the disclosure of male-to-male sex and other behavioural risk factors for HIV amid this change.

MATERIALS AND METHODS

Québec residents who donated from 14 July 2020 to 30 November 2020 were invited to participate in an online survey. Donors were informed that the survey was optional and anonymous. Survey questions were those used for routine pre-donation screening. Rates of reported non-compliance were weighted based on several characteristics.

RESULTS

Of 21,918 contacted donors, 7113 (32.45%) participated. Among male participants (N = 3347), six (0.27% [95% confidence interval (CI) = 0.09%-0.44%]) were not compliant with a 3-month MSM deferral. Among female participants (N = 3766), two (0.06% [95% CI = 0.00%-0.13%]) were not compliant with a 3-month deferral for sex with a man who had male-to-male sex ≤12 months. Other risk factors exhibited similar or lower rates of reported non-compliance.

CONCLUSION

Reported non-compliance with a 3-month MSM deferral and the disclosure of other HIV behavioural risk factors was low. These results warrant the investigation of behavioural donor risk assessment approaches to further improve the inclusiveness of blood donation.

Study protocol of associated criteria used in investigating septic transfusion reactions (STRs): A scoping review about available evidence

Background and objective

Assessment criteria for septic transfusion reactions (STRs) are variable around the world. A scoping review will be carried out to find out, explore and map existing literature on STRs associated criteria.

Methods

This scoping review will include indexed and grey literatures available in English or French language from January 1, 2000, to December 31, 2021. Literature search will be conducted using four electronic databases (i.e., MEDLINE via PubMed, Web of Science, Science Direct, and Embase via Ovid), and grey literatures accompanying the research questions and objectives. Based on the inclusion criteria, studies will be independently screened by two reviewers for title, abstract, and full text. Extracted data will be presented in tabular form followed by a narrative description of inputs corresponding to research objectives and questions.

462. Differences in the Humoral Response to SARS-CoV-2 Infection in Children vs. Adult

Background

One of the most striking observations of the COVID-19 pandemic has been the difference in infection among children vs. adults. Overall, children with SARS-CoV-2 infection generally had milder disease compared to adults, though the cause is not clear.

The objective of this study was to compare the humoral response to infection in children vs. adults of a same family.

Methods

We performed a prospective cohort study at Sainte-Justine University Health Center in Montreal, Canada from July 2020 to March 2021. Children with a positive SARS-CoV-2 PCR were recruited from the COVID-19 clinic (index case), enrollment was offered to all household members. Serum IgG against SARS-CoV-2 native S1/S2 spike proteins was measured using the Diasorin (Liaison XL) assay, 4-6 months following a positive PCR. A mean antibody threshold of 15 Arbitrary unit per ml (AU/ml) was considered seropositive, with 94.4% positive agreement to plaque reduction neutralization tests (PRNT90) at a 1:40 ratio. Antibody titer was compared between children and adults.

Results

111 participants (52 adults and 59 children) were recruited from 50 separate families. Characteristic of participants and their clinical symptoms are described in Table 1. Among all participants, 76.3% children were SARS-CoV-2 seropositive vs. 51.9% of adults (p=0.007). Median antibody titer was significantly higher in children vs. adults (82.8 AU, [IQR: 18.4-130], vs 17.0 AU, [IQR: 6.8-77.8], p=0.006); findings were similar among SARS-CoV-2 PCR positive participants only. Overall, 13 participants were PCR positive but seronegative, 7 were PCR negative and seropositive, while 61 were both PCR positive and seropositive. Older participants and those with any comorbidity. Among the PCR positive group, the seropositive participants were younger (median age 31±17 vs 19±17 years, p=0.003) and more likely to have comorbidity (69% vs 29%, p=0.007).

Conclusion

These results suggest that children have a stronger antibody response to SARS-CoV-2 infection than adults, and that older age and presence of comorbidity are associated with a less robust humoral response. Further work on the differences in response between children and adults may help elucidate mechanisms underlying the severity of disease

Disclosures

Olivier Drouin, MDCM MsC MPH, Covis Pharma (Research Grant or Support)

Active seeking of post-donation information to minimize a potential threat to transfusion safety: A pilot programme in the context of the COVID-19 pandemic

BACKGROUND AND OBJECTIVES

Early in the pandemic, the transmissibility of coronavirus disease-19 (COVID-19) by transfusion was unknown. We piloted a systematic, post-donation outreach programme to contact blood donors and inquired about symptoms post-donation.

MATERIALS AND METHODS

Persons who donated on on May 1 and 2, 2020 were contacted 3 days post-donation, by phone to assess COVID-19-related symptoms. Half of the donors were administered a short questionnaire, consisting of only three questions. Others were questioned using a longer, more specific questionnaire. If symptoms were reported, products were quarantined until donors were contacted again by a trained nurse who more thoroughly assessed the likelihood of COVID-19. Blood products were withdrawn if symptoms indicative of COVID-19 were identified.

RESULTS

Of 654 donors, 609 (93.1%) were successfully contacted. Of 310 donors who answered the short questionnaire and 299 who answered the long questionnaire, 19 (6.1%) and 8 (2.7%) had one or more symptoms, respectively. Based on the nurses' assessment, two donations (0.3%) had to be withdrawn.

CONCLUSION

These results suggest that actively seeking post-donation information might be feasible to mitigate emerging, unqualified transfusion risks.

Frequency, timing and risk factors for primary maternal cytomegalovirus infection during pregnancy in Quebec

INTRODUCTION

Maternal Cytomegalovirus (CMV) infection in the first trimester (T1) of pregnancy is a public health concern, as it increases the risk of severe neurodevelopmental outcomes associated with congenital infection compared to infections occurring later during pregnancy.

OBJECTIVES

To determine CMV seroprevalence in T1 of pregnancy, its trend, risk factors and the incidence rate of primary infection during pregnancy.

METHODS

Using the biobank of the prospective cohort "Grossesse en Santé de Québec" collected between April 2005 and March 2010 at the Québec-Laval Hospital, Québec, Canada, maternal CMV serology was determined using Abbott Architect Chemiluminescence microparticle immunoassays for immunoglobulin G(IgG), immunoglobulin M(IgM) titration and IgG avidity testing. Changepoint detection analysis was used to assess temporal trends. Risk factors associated with seropositivity were determined by multivariable logistic regression.

RESULTS

CMV seroprevalence in T1 of pregnancy was 23.4% (965/4111, 95% CI, 22.1-24.7%). The incidence rate for CMV primary infection during pregnancy was 1.8 (95% CI, 1.2-2.6) per 100 person-years. No changepoint was identified in the maternal CMV-seroprevalence trend. Multivariable analyses showed that T1 maternal CMV seropositivity was associated with having one child OR 1.3 (95% CI, 1.10-1.73) or two or more children OR 1.5 (95%CI, 1.1-2.1), ethnicity other than Caucasian OR 2.1 (95% CI, 1.1-3.8) and country of birth other than Canada and the USA OR 2.8 (95% CI, 1.5-4.9).

CONCLUSIONS

In this cohort, maternal seroprevalence in T1 of pregnancy and seroconversion rate were low. This information and identified risk factors could help guide the development and implementation of preventive actions and evidence-based health policies to prevent CMV infection during pregnancy.

Perspectives of women on screening and prevention of CMV in pregnancy

OBJECTIVE

To assess the choice and attitude of pregnant women regarding CMV serological screening and CMV prevention behaviors in pregnancy.

STUDY DESIGN

In this cross-sectional study, pregnant women were recruited in a single center during routine prenatal screening tests at 11-16 weeks. Participants filled out a questionnaire assessing knowledge about congenital CMV (cCMV) infection, risk perception and willingness to have CMV serological screening as well as their attitude toward CMV prevention behaviors.

RESULTS

Among 234 pregnant women, 74.4 % (95 % confidence interval: 68.8-80.0 %) wanted CMV serological screening in pregnancy. The factors significantly associated with the desire for screening were perceived risk and perceived severity of cCMV. An informed choice regarding CMV screening (value-consistent, based on good knowledge and deliberated) was performed by 54 % of women who chose the screening and 30 % of women who declined the screening (p = 0.039). The median scores regarding attitudes toward CMV prevention behaviors were 3.7/5 for avoiding sharing behaviors and 4.0/5 for not kissing a child on the lips.

CONCLUSION

The majority of pregnant women want to have CMV serological screening once informed about congenital CMV infection. New tools need to be developed to allow for informed choice regarding CMV serological screening in pregnancy.

Humoral responses to the measles, mumps and rubella vaccine are impaired in Leigh Syndrome French Canadian patients

Leigh Syndrome French Canadian (LSFC) is a rare autosomal recessive metabolic disorder characterized by severe lactic acidosis crises and early mortality. LSFC patients carry mutations in the Leucine Rich Pentatricopeptide Repeat Containing (LRPPRC) gene, which lead to defects in the respiratory chain complexes and mitochondrial dysfunction. Mitochondrial respiration modulates cellular metabolic activity, which impacts many cell types including the differentiation and function of immune cells. Hence, we postulated that, in addition to neurological and metabolic disorders, LSFC patients may show impaired immune activity. To gain insight into the quality of the immune response in LSFC patients, we examined the response to the measles, mumps and rubella (MMR) vaccine by measuring antibody titers to MMR in the plasma. In a cohort of eight LSFC patients, the response to the MMR vaccine was variable, with some individuals showing antibodies to all three viruses, while others had antibodies to two or fewer viruses. These results suggest that the mutations in the LRPPRC gene present in LSFC patients may affect the immune response to vaccines. Monitoring vaccine response in this fragile population should be considered to ensure full protection against pathogens.

Enteroviral and herpes simplex virus central nervous system infections in infants < 90 days old: a Paediatric Investigators' Collaborative Network on Infections in Canada (PICNIC) study

Background

The relative contribution of viruses to central nervous system (CNS) infections in young infants is not clear. For viral CNS infections, there are limited data on features that suggest HSV etiology or on predictors of unfavorable outcome.

Methods

In this cross-sectional retrospective study, seven centers from the Pediatric Investigators Collaborative Network on Infections in Canada identified infants < 90 days of age with CNS infection proven to be due to enterovirus (EV) or herpes simplex virus (HSV) January 1, 2013 through December 31, 2014.

Results

Of 174 CNS infections with a proven etiology, EV accounted for 103 (59%) and HSV for 7 (4%). All HSV cases and 41 (40%) EV cases presented before 21 days of age. Four HSV cases (57%) and 5 EV cases (5%) had seizures. Three (43%) HSV and 23 (23%) EV cases lacked cerebrospinal fluid (CSF) pleocytosis. HSV cases were more likely to require ICU admission (p = 0.010), present with seizures (p = 0.031) and have extra-CNS disease (p < 0.001). Unfavorable outcome occurred in 12 cases (11% of all EV and HSV infections) but was more likely following HSV than EV infection (4 (57%) versus 8 (8%); p = 0.002).

Conclusions

Viruses accounted for approximately two-thirds of proven CNS infections in the first 90 days of life. Empiric therapy for HSV should be considered in suspected CNS infections in the first 21 days even in the absence of CSF pleocytosis unless CSF parameters are suggestive of bacterial meningitis. Neurodevelopmental follow-up should be considered in infants whose course of illness is complicated by seizures.

Prenatal findings, neonatal symptoms and neurodevelopmental outcome of congenital cytomegalovirus infection in a university hospital in Montreal, Quebec

Background Outcome of congenital cytomegalovirus (cCMV) infection in the absence of routine CMV screening and third-trimester scan in North America is scarcely documented. The aim of this study was to assess the severe outcomes related to cCMV according to the indication for screening. Methods This was a retrospective study of 84 mother-child pairs followed for cCMV between 2003 and 2017 at CHU Sainte-Justine in Montreal, Canada. Prenatal ultrasound, neonatal symptoms, neuroimaging and severe outcomes (cerebral palsy, severe cognitive impairment, bilateral hearing loss or neonatal death) were reviewed. Results Among 38 cases with abnormal prenatal ultrasound, 41.9% of live-born infants developed severe outcomes. Sixteen (42.1%) were detected in the third trimester. Among 16 cases diagnosed prenatally because of maternal history, all had normal prenatal ultrasound, and none developed severe outcomes. Among cases diagnosed postnatally because of neonatal symptoms, 25% developed severe outcomes. All infants who developed severe outcomes had moderate/severe neonatal symptoms. Conclusion Outcome of cCMV infection varies according to the reason for screening and timing of diagnosis. Any prenatal ultrasound anomaly might indicate a risk of severe outcome, and warrants a detailed ultrasound scan. However, late detection, or postnatal diagnosis, represented more than half of the cases, and awareness of this will help ensuring optimal management.

A247 VIRAL LOAD OF EPSTEIN-BARR VIRUS IN PEDIATRIC PATIENTS WITH NEW ONSET IBD AT DIAGNOSIS AND ON FOLLOW UP: AN OBSERVATIONAL STUDY

Background

Patients with Inflammatory Bowel Disease are at increased risk for complications associated with Epstein-Barr Virus, such as uncontrolled infection, colitis mimicking IBD, and lymphoproliferative disease. These complications may be due to inherent immune dysfunction or effects of immunomodulating therapies used. We have previously identified that the seroprevalence of EBV in our cohort of IBD patients at time of diagnosis was 44.2%, with prevalence stratified by age as follows: 0 to &lt;10 years 36%, 10 to &lt;17 years 46%, and 17 + years 50%.

Aims

Our objective is to assess the risk of EBV reactivation in this population, to determine whether patients treated with immunomodulators should be more closely monitored for EBV viral load.

Methods

Retrospective chart review was done for all patients with new-onset IBD diagnosed at CHU Sainte-Justine over a two-year period, from Jan. 2016 to Dec. 2017. Serum from time of diagnosis was retrieved from the microbiology laboratory for patients with positive EBV serology, and quantitative PCR was performed to assess viral load at diagnosis. 47 of 53 seropositive patients had available serum at time of retrieval. EBV PCR was subsequently performed on serum drawn one to two years after start of immunosuppressants.

Results

53 patients were EBV positive at time of diagnosis (EBNA/VCA IgG). Two patients were IgM positive, suggesting recent or active infection. The viral load as measured by quantitative PCR on serum drawn at diagnosis was negative in all retroactively tested patients. Of the two IgM-positive patients, one had known positive quantitative PCR at time of diagnosis. PCR previously tested in clinical follow-up of two seropositive, PCR-negative patients became positive at 7 and 17 months from diagnosis, suggesting viral reactivation. Both patients had received anti-TNF’s and systemic corticosteroids. Viral loads on follow-up are to be assessed for the rest of the cohort. Overall, therapies started within 6 months of diagnosis were similar in the seropositive and seronegative groups, the majority receiving some form of immunosuppression. Within the seropositive group: 66% received corticosteroids, 32.1% Infliximab, 5.7% Adalimumab, and 5.7% Azathioprine.

Conclusions

Only one patient had active EBV infection with positive PCR at time of diagnosis. All other patients had no sign of active infection based on retroactive PCR’s. While a majority of patients, regardless of EBV serology, receive immunomodulating agents, we currently do not routinely screen for seroconversion in seronegative patients, or for viral load in seropositive patients. We will be assessing viral loads after start of immunomodulation to better understand the potential impact of these agents on disease progression.

Funding Agencies

None

Maternal infections

Congenital infections are infections transmitted from mother to child during pregnancy (transplacentally) or delivery (peripartum). They have the potential to adversely affect fetal development and long-term neurodevelopmental outcome through inflammatory, destructive, developmental, or teratogenic lesions of the brain. Because the fetal/neonatal brain has a limited capacity to respond to injury, early inflammatory changes may be difficult to visualize and only manifest as neurocognitive disability later in life. Teratogenic effects, which may include aberrations of neuronal proliferation and migration, are more easily visible on imaging, but may be equally difficult to use to predict long-term neurocognitive outcomes. This chapter reviews the general pathophysiology of congenital infection and describes the epidemiology, the antenatal and postnatal diagnosis, and the treatment of congenital infections as well as the long-term neurodevelopmental outcomes.

Pregnancies Among the First Generation of Survivors of Perinatal HIV Infection

OBJECTIVE

Little is known about pregnancy outcomes among women who have acquired human immunodeficiency virus (HIV) through perinatal infection and survived into adulthood. The objectives of this study were to describe pregnancy outcomes among women with perinatal HIV infection (PHIV) in Canada and to identify potential challenges in the prevention of perinatal HIV transmission in this population.

METHODS

A retrospective review of all pregnancies among women with PHIV who were previously followed as children at two tertiary care centres in Montréal, Québec, was conducted. Data were extracted from pediatric and obstetrical records.

RESULTS

There were 21 pregnancies among 11 women, and 18 of these pregnancies were unintentional. Mean age at first pregnancy was 19.5 years (range 15-29 years). At the first prenatal visit, 79% had a detectable viral load, 36% were immunosuppressed (CD4 T cell count <200 mm³), and only 36% were receiving antiretroviral therapy (ART). At the time of delivery, although all were prescribed ART, 50% of these women still had a detectable viral load, and 36% remained immunosuppressed. All of the women harboured mutations conferring drug resistance to zidovudine and lamivudine, and the majority (73%) were also resistant to nevirapine. None of the infants were HIV infected, although all received prophylaxis with agents to which their mother's virus was resistant.

CONCLUSION

Unplanned pregnancies, difficulties with adherence to ART, and drug resistance were identified challenges in the management of pregnancies among women with PHIV. This study highlights a gap in the reproductive counselling of adolescents with PHIV and the need for close follow-up and adherence support during pregnancy in this population.

Blood viral load in the diagnostic workup of congenital cytomegalovirus infection

BACKGROUND

There is limited data on the role of cytomegalovirus (CMV) blood quantitative polymerase chain reaction (qPCR) in the diagnostic workup of congenital CMV (cCMV) infection.

OBJECTIVES

The objective of this study was to determine if CMV blood qPCR at the time diagnosis could differentiate between symptomatic and asymptomatic infants according to the recent consensus classification.

STUDY DESIGN

Retrospective study of children diagnosed with cCMV infection at CHU Sainte-Justine, Montreal, Canada, between 2008 and 2016. Cases for whom qPCR was done at baseline (<4 weeks of age) alongside a complete diagnostic workup were included. The association between CMV blood viral load (VL) and clinical severity group was determined. The probability of having moderate to severe symptoms was assessed using univariate logistic regression analysis.

RESULTS

Forty-seven patients were included in the analysis. Median VL was significantly higher among infants with moderate to severely symptomatic disease vs. those asymptomatic or asymptomatic with isolated sensorineural hearing loss (SNHL) (13 736 vs. 1876 copies/ml, p = 0.004), infants with moderate to severe disease or asymptomatic with isolated SNHL vs. asymptomatic (17 736 vs. 1496 copies/ml, p < 0.001), and in infants with baseline neurological involvement vs. those without (17 317 vs. 2641 copies/ml, p = 0.03). Using logistic regression, an infant would have a >75 % probability of being moderate to severely symptomatic above 18 770 copies/ml, with a threshold of 100 000 copies/ml approaching a 100 % probability.

CONCLUSIONS

Our baseline assessment of CMV blood VL suggests that that the level of CMV viremia correlates with symptom severity.

Reevaluating immunization delays after red blood cell transfusion

BACKGROUND

Current American and Canadian guidelines recommend delaying live vaccine immunization by 5 to 6 months after transfusion of red blood cells (RBCs) due to potential interference by serum antibodies. Due to lack of data, the recommendations may be unfounded and prevent valuable vaccination opportunities for children with frequent blood transfusions. The primary aim of this study was to determine measles, mumps, rubella (MMR) vaccine immunogenicity in patients chronically transfused with RBCs. A secondary aim was to quantify vaccine antibodies in RBC donations.

STUDY DESIGN AND METHODS

MMR-specific antibodies were quantified in 25 pediatric patients who received both doses of MMR vaccine while on a chronic RBC transfusion program (median, 6.6 years after vaccination). MMR antibodies were also quantified in 30 samples of supernatants from RBC donations.

RESULTS

Immunity to each of the MMR components was 68% to 76%. In blood donors born before 1976 (pre-MMR vaccine), 67% of MMR serologies in the supernatants of RBC donations were at the immune level versus 7% in blood donors born after 1976.

CONCLUSION

This is the first study of the impact of RBC transfusions on MMR vaccine immunogenicity. Although lower than in the literature (immunity rates, ≥90%), the results show a high rate of immunogenicity of the MMR vaccine in chronically transfused patients. Additionally, results suggest that MMR antibody content in transfusions will continue to decrease with time. Weighing the risks and benefits of disease prevention in a vulnerable population, a reevaluation of immunization delays after RBC transfusions is called for.

Head ultrasound, CT or MRI? The choice of neuroimaging in the assessment of infants with congenital cytomegalovirus infection

Background

Despite growing interest in universal screening for congenital CMV infection (cCMV), and data to support treatment for cases with central nervous system (CNS) involvement, there is limited regarding the optimal imaging modalities to identify CNS involvement. The objective of this study was to assess the concordance between head ultrasound (US) and magnetic resonance imaging (MRI) or computed tomography (CT), in identifying neurological abnormalities in infants with cCMV infection, and to determine whether the addition of advanced neuroimaging after US had an impact on clinical management.

Methods

Retrospective review of infants with cCMV infection, referred to the Centre d’Infectiologie Mère-Enfant (CIME) at Sainte-Justine Hospital Center in Montreal, between 2008 and 2016. Only patients who underwent head US followed by and brain MRI or CT scan were included in this analysis.

Results

Of 46 cases of cCMV identified during the study period, 34 (74%) had a head US followed by MRI (n = 28, 61%), or CT scan (n = 6, 13%). In the majority of cases (n = 24, 71%), both images were concordant (11 both reported abnormal, 13 both reported normal). In 5 cases, US was reported normal and subsequent imaging (MRI = 4, CT = 1); reported abnormal. In all 5 cases patients were clinically symptomatic and met treatment criteria even in the absence of neuroimaging findings. In 5 cases, US was reported abnormal with a subsequent normal MRI (4) or CT (1); in 2 of these cases, patients were clinically symptomatic and met treatment criteria regardless of neuroimaging findings. However, in 3 cases, the patients were clinically asymptomatic, and in 2 of these cases, treated based only on the abnormal US findings.

Conclusions

In this study, we found that that sequential US and MRI were concordant in the majority (71%) of cases in detecting abnormalities potentially associated with cCMV infection. While the addition of MRI to baseline head ultrasound did not influence the decision to treat in clinically symptomatic infants, the addition of MRI to infants with abnormal HUS imaging who are clinically asymptomatic could help refine treatment decisions in these cases.