Search

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.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 (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 of93%, 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%).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.Les dosages sérologiques conçus pour dépister les anticorps anti-SRAS-CoV-2 sont utilisés dans les études sérologiques et d’autres applications spécialisées. Par conséquent, et pour s’assurer que leurs résultats respectent des normes de qualité, il faut procéder à des évaluations de leur performance et de la compétence des laboratoires à les effectuer.Les chercheurs ont obtenu une batterie de 60 prélèvements de plasma et de sérum chez des donneurs dont l’amplification en chaîne par polymérase après transcription inverse (RT-PCR) avait confirmé des infections par le SRAS-CoV-2 et de 21 prélèvements dont les résultats étaient négatifs au SRAS-CoV-2 et les ont distribués aux laboratoires intéressés du Canada (Les divers dosages avaient une excellente exécution, les plateformes à haut débit de Roche, d’Ortho et de Siemens démontrant une sensibilité de 100 %. La plupart des autres plateformes à haut débit avaient des sensibilités de plus de 93 %, à l’exception des dosages des IgG faisant appel à l’analyseur ARCHITECT d’Abbott, dont la sensibilité moyenne était de seulement 87 %. La majorité des plateformes à haut débit avaient également une très bonne spécificité (plus de 97 %).La présente étude de compétence démontre que la plupart des dosages sérologiques du SRAS-CoV-2 évalués dans des laboratoires sanitaires provinciaux ou les laboratoires hospitaliers du Canada possèdent une sensibilité acceptable et une excellente spécificité.

Background: A multi-country outbreak of monkeypox virus (MPXV) infections was identified by the World Health Organization in May 2022. The western Canadian province of Alberta identified its first case of MPXV in a returning traveller on June 2, 2022. We undertook a retrospective testing exercise to evaluate whether MPXV may have been circulating in the province earlier. Methods: Skin (genital and non-genital) and mucosal lesion swabs submitted for herpes simplex virus (HSV)/varicella zoster virus (VZV)/syphilis testing from male patients attending sexually-transmitted infection clinics across the province of Alberta from January 28 to May 30, 2022 were retrieved from storage. The population tested was selected based on the epidemiology of the current 2022 multi-country MPXV outbreak. Samples underwent viral nucleic acid extraction and testing for the presence of Orthopoxvirus DNA using a commercial real-time polymerase chain reaction (PCR) kit. Results: A total of 392 samples (representing 341 unique individuals of median age 31 years) were retrieved. Of them, 349 (89.0%) samples were submitted for HSV/VZV/syphilis testing, 13 (3.3%) for HSV/VZV only, and 30 (7.7%) for syphilis PCR only. None of the 392 samples tested were found to be positive for Orthopoxvirus DNA. Conclusions: The results of this study indicate that circulation of MPXV in a higher-risk population in Alberta, prior to the first case, was less likely. We recommend that other provinces/territories review their local epidemiology, context and resources prior to conducting similar studies.

OBJECTIVE We evaluated the incidence of influenza and non-influenza respiratory viruses (NIRVs) pre-/post-implementation of public health (PH) measures aimed to decrease COVID-19 transmission using population-based surveillance data. We hypothesized that such measures could reduce the burden of respiratory viruses (RVs) transmitting via the same routes. PATIENTS AND METHODS An interrupted time-series analysis of RV surveillance data in Alberta, Canada from May 2017 – July 2020 was conducted. The burden of influenza and NIRVs before and after intervention initiation at week 11, 2020 was compared. The analysis was adjusted for seasonality, over-dispersion, and autocorrelation. RESULTS During the study period, an average of 708 and 4056 weekly respiratory multiplex molecular panels were conducted pre-/post-intervention respectively. We found significant reductions in test positivity rates in the post-intervention period for influenza (-94.3%; 95% CI -93.8 to 97.4%, p CONCLUSION The implementation of COVID-19 PH measures likely resulted in reduced transmission of common RVs. While drastic lockdowns are unlikely to be required given widespread COVID-19 vaccination, targeted implementation of such measures can lower RV disease burden. Studies to evaluate relative contributions of individual interventions are warranted.

Influenza strains circulating among swine populations can cause outbreaks in humans. In October 2020, we detected a variant influenza A subtype H1N2 of swine origin in a person in Alberta, Canada. We initiated a public health, veterinary, and laboratory investigation to identify the source of the infection and determine whether it had spread. We identified the probable source as a local pig farm where a household contact of the index patient worked. Phylogenetic analysis revealed that the isolate closely resembled strains found at that farm in 2017. Retrospective and prospective surveillance using molecular testing did not identify any secondary cases among 1,532 persons tested in the surrounding area. Quick collaboration between human and veterinary public health practitioners in this case enabled a rapid response to a potential outbreak.

Autochthonous leprosy was reported in the Southern USA in 2011 and has comprised an average of 34% of new cases from 2015 to 2020 in that country. We report a similar case in a patient from Western Canada. A 50-year old male patient presented with a four-year history of a chronic rash. Pathology stains revealed acid-fast bacilli prompting specialist referral. Examination was suspicious for leprosy, which was confirmed on slit skin smears and molecular testing. The patient responded well to treatment. Genotypic testing mapped the organism to the 3I-2 SNP type, which is of European origin and is the type found in implicated armadillo species in North America.

Wastewater-based SARS-CoV-2 surveillance enables unbiased and comprehensive monitoring of defined sewersheds. We performed real-time monitoring of hospital wastewater that differentiated Delta and Omicron variants within total SARS-CoV-2-RNA, enabling correlation to COVID-19 cases from three tertiary-care facilities with2100 inpatient beds in Calgary, Canada. RNA was extracted from hospital wastewater between August/2021 and January/2022, and SARS-CoV-2 quantified using RT-qPCR. Assays targeting R203M and R203K/G204R established the proportional abundance of Delta and Omicron, respectively. Total and variant-specific SARS-CoV-2 in wastewater was compared to data for variant specific COVID-19 hospitalizations, hospital-acquired infections, and outbreaks. Ninety-six percent (188/196) of wastewater samples were SARS-CoV-2 positive. Total SARS-CoV-2 RNA levels in wastewater increased in tandem with total prevalent cases (Delta plus Omicron). Variant-specific assessments showed this increase to be mainly driven by Omicron. Hospital-acquired cases of COVID-19 were associated with large spikes in wastewater SARS-CoV-2 and levels were significantly increased during outbreaks relative to non-outbreak periods for total SARS-CoV2, Delta and Omicron. SARS-CoV-2 in hospital wastewater was significantly higher during the Omicron-wave irrespective of outbreaks. Wastewater-based monitoring of SARS-CoV-2 and its variants represents a novel tool for passive COVID-19 infection surveillance, case identification, containment, and potentially to mitigate viral spread in hospitals. This article is protected by copyright. All rights reserved.

BACKGROUND: In response to a facility-wide COVID-19 outbreak, our tertiary acute care hospital implemented an evidence-based bundle of infection control practices including the use of audits and trained observers "dofficers" to provide real-time constructive feedback. METHODS: We trained furloughed staff to perform the role of dofficer. They offered support and corrective feedback on proper PPE use and completed 21-point audits during a 4-week intervention period. Audits tracked appropriate signage, placement and availability of supplies (equipment), correct PPE use, enhanced environmental cleaning, along with cohorting and social distancing rates. Audit data was used to provide weekly quality improvement reports to units. RESULTS: Nine hundred and sixty two separate audits recorded 36,948 observations, over 7,696 observer-hours. The most common errors were with environmental cleaning and PPE use; the least common were with regards to equipment availability and cohorting and social distancing. Mean error rates decreased from 9.81% to 2.88% (P < .001). The largest reduction, 22.57%, occurred in the category of PPE doffing errors. CONCLUSIONS: Dofficer led audits effectively identified areas for improvement. Feedback through weekly reports and real-time correction of PPE errors by dofficers led to statistically significant improvements; however, error rates remained high. Further research is needed establish if these relationships are causal.

The accurate measurement of serological response to SARS-CoV-2 vaccination is needed to correlate responses with effective protective immunity. The World Health Organization (WHO) has created an international standard to allow harmonization of immune response assessment to an arbitrary unit across different commercial assays; however, the accuracy of reporting of SARS-CoV-2 spike antibody titers in international standard units (BAU or IU/mL) from commercial assays is not well studied. Here, we report the performance comparison of four quantitative commercial assays testing for SARS-CoV-2 spike immunoglobins using the WHO's international standard. Sera, EDTA-plasma and heparinized plasma collected from individuals who are vaccine naïve or received BNT162b2 (Pfizer/BioNTech), mRNA-1273 (Moderna) or ChAdOx1-S (Oxford-AstraZeneca) were tested using Abbott Architect AdviseDx SARS-CoV-2 IgG II, DiaSorin LIAISON SARS-CoV-2 TrimericS IgG, Roche Elecsys Anti-SARS-CoV-2 S and GenScript cPass SARS-CoV-2 surrogate virus neutralization assays. The sensitivities ranged from 90% to 100%, and specificities from 88% to 100%. These four assays had excellent agreement (0.79-0.93) and correlation (0.87-0.97); however, Passing-Bablok regression analysis indicated that data generated by these assays were not comparable. Our data suggests that natural SARS-CoV-2 infection elicited a greater antibody response compared to vaccines, evident by a significantly higher neutralizing antibody titer in unvaccinated individuals who seroconverted.

Background SARS-CoV-2 infection can present with a broad clinical differential that includes many other respiratory viruses; therefore, accurate tests are crucial to distinguish true COVID-19 cases from pathogens that do not require urgent public health interventions. Co-circulation of other respiratory viruses is largely unknown during the COVID-19 pandemic but would inform strategies to rapidly and accurately test patients with respiratory symptoms. Methods This study retrospectively examined 298,415 respiratory specimens collected from symptomatic patients for SARS-CoV-2 testing in the three months since COVID-19 was initially documented in the province of Alberta, Canada (March-May, 2020). By focusing on 52,285 specimens that were also tested with the Luminex Respiratory Pathogen Panel for 17 other pathogens, this study examines the prevalence of 18 potentially co-circulating pathogens and their relative rates in prior years versus since COVID-19 emerged, including four endemic coronaviruses. Results SARS-CoV-2 was identified in 2.2% of all specimens. Parallel broad multiplex testing detected additional pathogens in only 3.4% of these SARS-CoV-2-positive specimens: significantly less than in SARS-CoV-2-negative specimens (p p Conclusions Broad respiratory pathogen testing rarely detected additional pathogens in SARS-CoV-2-positive specimens. While helpful to understand co-circulation of respiratory viruses causing similar symptoms as COVID-19, ultimately these broad tests were resource-intensive and inflexible in a time when clinical laboratories face unprecedented demand for respiratory virus testing, with further increases expected during influenza season. A transition from broad, multiplex tests toward streamlined diagnostic algorithms targeting respiratory pathogens of public health concern could simultaneously reduce the overall burden on clinical laboratories while prioritizing testing of pathogens of public health importance. This is particularly valuable with ongoing strains on testing resources, exacerbated during influenza seasons.

The landscape of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostic testing is rapidly evolving. While serology testing has limited diagnostic capacity for acute infection, its role in providing population-based information on positivity rates and informing evidence-based decision making for public health recommendations is increasing. With the global availability of vaccines, there is increasing pressure on clinical laboratories to provide antibody screening and result interpretation for vaccinated and non-vaccinated individuals. Here we present the most up-to-date data on SARS-CoV-2 antibody timelines, including the longevity of antibodies, and the production and detection of neutralizing antibodies. Additionally, we provide practical guidance for clinical microbiology laboratories to both verify commercial serology assays and choose appropriate testing algorithms for their local populations.

The COVID-19 pandemic has necessitated the need to rapidly make public health decisions. We systematically evaluated SARS-CoV-2 seropositivity to understand local COVID-19 epidemiology and support evidence-based public health decision making. Residual blood samples were collected for SARS-CoV-2 receptor binding domain (RBD) IgG testing over a 1–5 day period monthly from 26 February 2021–9 July 2021 from six clinical laboratories across the province of Alberta, Canada. Monthly crude and adjusted (for age and gender) seropositivity were calculated. Results were linked to provincial administrative, laboratory, and vaccine databases. 60,632 individual blood samples were tested. Vaccination data were available for 98.8% of samples. Adjusted RBD IgG positivity rose from 11.9% (95% confidence interval [CI] 11.9–12.0%) in March 2021 to 70.2% (95% CI 70.2–70.3%) in July 2021 (p < .0001). Seropositivity rose from 9.4% (95% CI 9.3–9.4%) in March 2021 to 20.2% (95% CI 20.1–20.2%) in July 2021 in unvaccinated Albertans. Unvaccinated seropositive individuals were from geographic areas with significantly (p < .001) lower median household income, lower proportion of married/common-law relationships, larger average household size and higher proportions of visible minorities compared to seronegative unvaccinated individuals. In July 2021, the age groups with the lowest and highest seropositivity in unvaccinated Albertans were those ≥80 years (12.0%, 95% CI 5.3–18.6%) and 20–29 years (24.2%, 95% CI 19.6–28.8%), respectively. Of seropositive unvaccinated individuals, 50.2% (95% CI 45.9–54.5%) had no record of prior SARS-CoV-2 molecular testing. Longitudinal surveillance of SARS-CoV-2 seropositivity with data linkage is valuable for decision-making during the pandemic.

We read with interest the highly impactful CLARITY IBD study that demonstrated a diminished serological response to SARS-CoV-2 in individuals with IBD receiving infliximab as compared with those receiving vedolizumab.1 We assessed the prevalence of antibodies to SARS-CoV-2 in patients with IBD and evaluated whether serological response to SARS-CoV-2 wanes over time following infection. Individuals with IBD from Calgary, Canada, were recruited from October 2020 to April 2021 and stratified into two cohorts: (1) serosurveillance (n=279) defined as those who were not previously diagnosed with COVID-19; and (2) COVID-19 recovered (n=45), defined as those with a molecular-confirmed diagnosis of SARS-CoV-2 infection via PCR. Serum was analysed using the Abbott Architect SARS-CoV-2 IgG antibody to the nucleocapsid protein. A positive antibody test was defined as an index signal/cut-off ≥1.4. The assay has been validated with 95% sensitivity and >99% specificity 12 days following symptom onset and correlates to neutralising antibodies.2 We assessed the proportion, with 95% CIs, of individuals with IBD who mounted an antibody response among those undergoing serosurveillance and following infection with SARS-CoV-2. In those diagnosed with COVID-19, we calculated the days from diagnosis to serological testing and developed a logistic regression model that assessed the effect of time from COVID-19 diagnosis to serology testing (before vs after 90 days) on nucleocapsid positive versus negative antibody; adjusted for age, sex and anti-tumour necrosis factor (TNF) usage. The baseline characteristics of the two cohorts are summarised in table 1. Among the serosurveillance cohort, 1.08% (95% CI 0.22 to …

We present a case of coronavirus disease 2019 (COVID-19) with an initial medical presentation of keratoconjunctivitis, the first such reported case in North America. The patient's primary symptom was a red eye with watery discharge, though she did have mild respiratory symptoms, without fever. She was diagnosed with keratoconjunctivitis; evolving corneal findings were characterized through repeat visits to ophthalmology. A conjunctival swab of the affected eye was positive for the SAR-CoV-2 virus. This case emphasizes the importance of ensuring that first-line health care providers, including ophthalmologists, optometrists, emergency physicians, and family physicians, consider COVID-19 on the differential for any patient with recent travel who presents with acute conjunctivitis. Having a high index of suspicion with this presentation would allow for appropriate precautions to be taken to prevent further spread of COVID-19.

BackgroundIndividuals with inflammatory bowel disease (IBD) who are immunocompromised may have a reduced serological response to the SARS-CoV-2 vaccine. We investigated serological responses following 1st, 2nd, and 3rddoses of SARS-CoV-2 vaccination in those with IBD.MethodsA prospective cohort study of persons with IBD (n= 496) assessed serological response 1–8 weeks after 1stdose vaccination, 1–8 weeks after 2nddose, 8 or more weeks after 2nddose, and at least 1 week after 3rddose. Seroconversion and geometric mean titer (GMT) with 95% confidence intervals (CI) were assessed for antibodies to the SARS-CoV-2 spike protein. Multivariable linear regression models assessed the adjusted fold change (FC) in antibody levels.ResultsSeroconversion and GMT increased from post-1stdose to 1–8 weeks post-2nddose (81.6%, 1814 AU/mL vs. 98.7%, 9229 AU/mL,pnddose (94.9%, 3002 AU/mL,prddose (99.6%, 14639 AU/mL,prd-dose vaccination (FC: 0.07 [95% CI: 0.02, 0.20]). Antibody levels steadily decline following the 2nd(FC: 0.92 [95% CI: 0.90, 0.94] per week) and 3rddose (FC: 0.88 [95% CI: 0.84, 0.92] per week) of the SARS-CoV-2 vaccine.ConclusionA three-dose regimen of vaccination to SARS-CoV-2 yields a robust antibody response for those with IBD across all classes of IBD therapies except for prednisone. The decaying antibody levels following the 3rddose of the vaccine should be monitored in future studies.

SARS-CoV-2 can cause outbreaks in community- and hospital-based settings. The aim of this study was to provide a detailed epidemiologic account of a hospital-wide SARS-CoV-2 outbreak and provide a description of case evaluations, transmission networks and the interventions implemented to stem the outbreak.We conducted a retrospective descriptive study of a hospital-wide SARS-CoV-2 outbreak at the Misericordia Community Hospital (Edmonton) from June 21 to Aug. 14, 2020. We reviewed hospital chart, public health and occupational health records to determine demographics, case type (community- or hospital-acquired), need for critical care and outcome for each case linked to the outbreak (patients, hospital staff, and community and patient visitors). We developed detailed transmission networks using epidemiologic data to determine what variables may have contributed to transmission.Fifty-eight cases of SARS-CoV-2 infection were linked to this hospital outbreak (31 patients, 25 staff members and 2 visitors; 66% female, age range 19-97 years). One patient required critical care, and 11 deaths were recorded (all among inpatients). Most cases were hospital-acquired (91%), and 28% were asymptomatic at the time of diagnosis. The outbreak was composed of 2 clusters driven by protective equipment breaches, premature removal of precautions, transmission in small staff quarters and infection of a staff member after exposure to a wandering patient with dementia and asymptomatic, undetected SARS-CoV-2 infection.A detailed epidemiologic review of this hospital-wide outbreak shows that a SARS-CoV-2 outbreak can involve complex transmission chains and clusters. Multipronged bundled approaches, aggressive contact tracing, and patient and staff prevalence screening are important to help bring such outbreaks under control, along with ongoing vigilance in detecting delayed cases.

Coronavirus disease 2019 (COVID-19) has caused significant global morbidity and mortality. The serology test that detects antibodies against the disease causative agent, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has often neglected value in supporting immunization policies and therapeutic decision-making. The ELISA-based antibody test is time-consuming and bulky. This work described a gold micro-interdigitated electrodes (IDE) biosensor for COVID antibody detection based on Electrochemical Impedance Spectroscopy (EIS) responses. The IDE architecture allows easy surface modification with the viral structure protein, Spike (S) protein, in the gap of the electrode digits to selectively capture anti-S antibodies in buffer solutions or human sera. Two strategies were employed to resolve the low sensitivity issue of non-faradic impedimetric sensors and the sensor fouling phenomenon when using the serum. One uses secondary antibody-gold nanoparticle (AuNP) conjugates to further distinguish anti-S antibodies from the non-specific binding and obtain a more significant impedance change. The second strategy consists of increasing the concentration of target antibodies in the gap of IDEs by inducing an AC electrokinetic effect such as dielectrophoresis (DEP). AuNP and DEP methods reached a limit of detection of 200 ng/mL and 2 μg/mL, respectively using purified antibodies in buffer, while the DEP method achieved a faster testing time of only 30 min. Both strategies could qualitatively distinguish COVID-19 antibody-positive and -negative sera. Our work, especially the impedimetric detection of COVID-19 antibodies under the assistance of the DEP force presents a promising path toward rapid, point-of-care solutions for COVID-19 serology tests.

The processing of swabs for respiratory virus detection involves vortexing while still in the viral transport medium (VTM). The effect of not vortexing swabs prior to analysis has not been studied extensively for SARS-CoV-2 detection, and presents an opportunity to improve pre-analytic laboratory workflow. We aimed to assess the impact of not vortexing nasopharyngeal/throat swabs submitted in VTM for SARS-CoV-2 testing. To assess the impact of not vortexing swabs, 277 swab samples were tested for SARS-CoV-2 RNA in paired vortexed and non-vortexed aliquots using eight routine nucleic acid amplification assays. We compared the qualitative (positive/negative) and semi-quantitative (cycle threshold, Ct) results. Following discordant analysis, all but one non-vortexed sample had the same qualitative result as the vortexed sample. 27.4 % of samples were SARS-CoV-2 positive. Comparison of Ct values revealed an apparent reduction in human cellular nucleic acid in the non-vortexed samples (mean Ct values of 24.0 and 26.5 for vortexed and non-vortexed samples, respectively, p < 0.0001) and increased Ct values for non-vortexed samples using a laboratory-developed SARS-CoV-2 assay (mean Ct values of 4.1 and 4.2 for vortexed and non-vortexed samples, respectively; p < 0.0001), but this was not observed for a more automated commercial SARS-CoV-2 assay (mean Ct values of 15.2 for both vortexed and non-vortexed samples, respectively; p = 0.68). While vortexing swabs appears to improve the recovery of cellular material, it does not have an appreciable impact on the qualitative sensitivity of SARS-CoV-2 nucleic acid tests, which may support omission of this step and simplification of front-end sample processing.

We systematically evaluated SARS-CoV-2 IgG positivity in a provincial cohort to understand the local epidemiology of COVID-19 and support evidence-based public health decisions. Residual blood samples were collected for serology testing over 5-day periods monthly from June 2020 to January 2021 from six clinical laboratories across the province of Alberta, Canada. A total of 93,993 individual patient samples were tested with a SARS-CoV-2 nucleocapsid antibody assay with positives confirmed using a spike antibody assay. Population-adjusted SARS-CoV-2 IgG seropositivity was 0.92% (95% confidence interval [CI]: 0.91 to 0.93%) shortly after the first COVID-19 wave in June 2020, increasing to 4.63% (95% CI: 4.61 to 4.65%) amid the second wave in January 2021. There was no significant difference in seropositivity between males and females (1.39% versus 1.27%; P = 0.11). Ages with highest seropositivity were 0 to 9 years (2.71%, 95% CI: 1.64 to 3.78%) followed by 20 to 29 years (1.58%, 95% CI: 1.12 to 2.04%), with the lowest rates seen in those aged 70 to 79 (0.79%, 95% CI: 0.65 to 0.93%) and >80 (0.78%, 95% CI: 0.60 to 0.97%). Compared to the seronegative group, seropositive patients inhabited geographic areas with lower household income ($87,500 versus $97,500; P

SARS-CoV-2 variants of concern (VOCs) have emerged as a global threat to the COVID-19 pandemic response. We implemented a combined approach to quickly detect known VOCs while continuously monitoring for evolving mutations of the virus. To rapidly detect VOCs, two real-time reverse transcriptase PCR assays were designed and implemented, targeting the spike gene H69/V70 deletion and the N501Y mutation. The H69/V70 deletion and N501Y mutation assays demonstrated accuracies of 98.3% (95% CI 93.8 to 99.8) and 100% (95% CI 96.8 to 100), limits of detection of 1,089 and 294 copies/ml, and percent coefficients of variation of 0.08 to 1.16% and 0 to 2.72% for the two gene targets, respectively. No cross-reactivity with common respiratory pathogens was observed with either assay. Implementation of these tests allowed the swift escalation in testing for VOCs from 2.2% to ∼100% of all SARS-CoV-2-positive samples over 12 January to 9 February 2021, and resulted in the detection of a rapid rise of B.1.1.7 cases within the province of Alberta, Canada. A prospective comparison of the VOC assays to genome sequencing for the detection of B.1.1.7, combined detection of P.1 and B.1.351, and wild-type (i.e., non-VOC) lineages showed sensitivities of 98.2 to 100%, specificities of 98.9 to 100%, positive predictive values of 76.9% to 100%, and negative predictive values of 96 to 100%. Variant screening results inform sampling strategies for regular surveillance by genome sequencing, thus allowing rapid identification of known VOCs while continuously monitoring the evolution of SARS-CoV-2 in the province. IMPORTANCE Different strains, or variants, of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus that causes COVID-19) have emerged that have higher levels of transmission, less susceptibility to our immune response, and possibly cause more severe disease than previous strains of the virus. Rapid detection of these variants of concern is important to help contain them and prevent them from spreading widely within the population. This study describes two newly developed tests that are able to identify and differentiate the variants of concern from regular strains of SARS-CoV-2. These tests are faster and simpler than the main, gold standard method of identifying variants of concern (genome sequencing). These tests also demonstrated a high correlation with genome sequencing and allowed for the rapid and accurate detection of the rise of B.1.1.7 (one of the variants of concern) in the province of Alberta, Canada.

IntroductionThe COVID-19 pandemic has an excessive impact on residents in long-term care facilities (LTCF), causing high morbidity and mortality. Early detection of presymptomatic and asymptomatic COVID-19 cases supports the timely implementation of effective outbreak control measures but repetitive screening of residents and staff incurs costs and discomfort. Administration of vaccines is key to controlling the pandemic but the robustness and longevity of the antibody response, correlation of neutralising antibodies with commercial antibody assays, and the efficacy of current vaccines for emerging COVID-19 variants require further study. We propose to monitor SARS-CoV-2 in site-specific sewage as an early warning system for COVID-19 in LTCF and to study the immune response of the staff and residents in LTCF to COVID-19 vaccines.Methods and analysisThe study includes two parts: (1) detection and quantification of SARS-CoV-2 in LTCF site-specific sewage samples using a molecular assay followed by notification of Public Health within 24 hours as an early warning system for appropriate outbreak investigation and control measures and cost–benefit analyses of the system and (2) testing for SARS-CoV-2 antibodies among staff and residents in LTCF at various time points before and after COVID-19 vaccination using commercial assays and neutralising antibody testing performed at a reference laboratory.Ethics and disseminationEthics approval was obtained from the University of Alberta Health Research Ethics Board with considerations to minimise risk and discomforts for the participants. Early recognition of a COVID-19 case in an LTCF might prevent further transmission in residents and staff. There was no direct benefit identified to the participants of the immunity study. Anticipated dissemination of information includes a summary report to the immunity study participants, sharing of study data with the scientific community through the Canadian COVID-19 Immunity Task Force, and prompt dissemination of study results in meeting abstracts and manuscripts in peer-reviewed journals.

Frequent screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among asymptomatic populations using antigen-based point-of-care tests (APOCTs) is occurring globally with limited clinical performance data. The positive predictive value (PPV) of two APOCTs used in the asymptomatic screening of SARS-CoV-2 among health care workers (HCWs) at continuing care (CC) sites across AB, Canada, was evaluated. Between 22 February and 2 May 2021, CC sites implemented SARS-CoV-2 voluntary screening of their asymptomatic HCWs. On-site testing with Abbott Panbio or BD Veritor occurred on a weekly or twice-weekly basis. Positive APOCTs were confirmed with a real-time reverse transcriptase PCR (rRT-PCR) reference method. A total of 71,847 APOCTs (17,689 Veritor and 54,158 Panbio) were performed among 369 CC sites. Eighty-seven (0.12%) APOCTs were positive, of which 39 (0.05%) were confirmed as true positives using rRT-PCR. Use of the Veritor and Panbio resulted in 76.6% and 30.0% false-positive detection, respectively (P < 0.001). This corresponded to PPVs of 23.4 and 70.0% for the Veritor and Panbio, respectively. Frequent screening of SARS-CoV-2 among asymptomatic HCWs in CC, using APOCTs, resulted in a very low detection rate and a high rate of detection of false positives. Careful assessment of the risks versus benefits of APOCT programs and the prevalence of infection in this population needs to be thoroughly considered before implementation.

Hepatitis B virus (HBV) vaccination starting at birth is approximately 95% effective in preventing mother-to-child transmission to infants born to HBV-infected mothers. A higher risk of transmission is associated with birth to a highly viremic mother, often due to transplacental exposure, while later horizontal transmission is much less common, particularly following complete vaccination. This study reports a case of infection in an older child despite appropriate immunoprophylaxis starting at birth and an apparent protective immune response post-vaccination. Two immune escape mutations within the antigenic determinant of the surface antigen-coding region were observed in the child's dominant HBV sequence, whereas the maternal HBV variant lacked mutations at both sites. Ultra-deep sequencing confirmed the presence of 1 mutation at low levels within the maternal HBV quasispecies population, suggesting early exposure to the child followed by viral evolution resulting in immunoprophylaxis escape and chronic infection.

OBJECTIVESFrequent screening of SARS-CoV-2 among asymptomatic populations using antigen-based point of care tests (APOCT) is occurring globally with limited clinical performance data. The positive predictive value (PPV) of two APOCT used in the asymptomatic screening of SARS-CoV-2 among healthcare workers (HCW) at continuing care (CC) sites across Alberta, Canada was evaluated.METHODSBetween February 22 and May 2, 2021, CC sites implemented SARS-CoV-2 voluntary screening of their asymptomatic HCW. Onsite testing with Abbott Panbio or BD Veritor occurred on a weekly or twice weekly basis. Positive APOCT were confirmed with a real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) reference method.RESULTSA total of 71,847 APOCT (17,689 Veritor and 54,158 Panbio) were performed among 369 CC sites. Eighty-seven (0.12%) APOCT were positive, of which 39 (0.05%) confirmed as true positives using rRT-PCR. Use of the Veritor and Panbio resulted in a 76.6% and 30.0% false positive detection, respectively (pCONCLUSIONSFrequent screening of SARS-CoV-2 among asymptomatic HCW in CC, using APOCT, resulted in a very low detection rate and a high detection of false positives. Careful assessment between the risks vs benefits of APOCT programs in this population needs to be thoroughly considered before implementation.

The first case of coronavirus disease 2019 (COVID-19) in Alberta, Canada, was confirmed on March 5, 2020. Because the virus testing criteria had changed significantly over this time period, we wanted to ascertain whether previous cases of COVID-19 had been missed in the province.Our aim was to retrospectively evaluate specimens submitted for respiratory virus testing from December 1, 2019, through March 7, 2020, for undetected severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections before the first confirmed case.Testing of 23,517 samples (representing 23,394 patients) identified 1 patient positive for SARS-CoV-2. This specimen was collected on February 24, 2020, from a patient with symptoms consistent with COVID-19 who had recently returned from the western United States. Phylogenetic analysis confirmed this viral isolate belonged to lineage B.1. The epidemiology of this case is consistent with those of other early cases before sustained community transmission, which included a travel history outside of Canada.This exercise provides support that local public health pandemic planning was satisfactory and timely.Le premier cas de maladie à coronavirus 2019 (COVID-19) en Alberta, au Canada, a été confirmé le 15 mars 2020. Puisque les critères de dépistage ont beaucoup évolué pendant cette période, les chercheurs voulaient vérifier si des cas antérieurs de COVID-19 avaient été omis dans la province.Les chercheurs ont procédé à l’évaluation rétrospective d’échantillons soumis en vue du dépistage d’un virus respiratoire entre le 1Le dépistage de 23 517 échantillons (représentant 23 394 patients) a fait ressortir un patient positif au SARS-CoV-2. Le prélèvement avait été effectué le 24 février 2020 chez un patient éprouvant des symptômes correspondant à la COVID-19 revenu récemment de l’ouest des États-Unis. L’analyse phylogénétique a confirmé que l’isolat viral appartenait à la lignée B.1. L’épidémiologie de ce cas est compatible avec celle des autres premiers cas précédant une transmission communautaire soutenue, qui incluait un voyage à l’extérieur du Canada.Cet exercice appuie la pertinence et la rapidité de la planification sanitaire locale de la pandémie.

PURPOSEWith rapid approval of SARS-CoV-2 vaccines, the ability of clinical laboratories to detect vaccine-induced antibodies with available high-throughput commercial assays is unknown. We aimed to determine if commercial serology assays can detect vaccine-induced antibodies (VIAs) and understand the vaccination response.METHODSThis cohort study recruited healthcare workers and residents of long-term care facilities (receiving the BNT162b2 and mRNA-1273 products, respectively) who underwent serum collection pre-vaccination (BNT162b2 group), 2-weeks post vaccination (both groups), and pre-2nddose (both groups). Sera were tested for the presence of SARS-CoV-2 IgG using four commercial assays (Abbott Architect SARS-CoV-2 IgG, Abbott Architect SARS-CoV-2 IgG II Quant, DiaSorin Liaison Trimeric S IgG, and GenScript cPASS) to detect VIAs. Secondary outcomes included description of post-vaccination antibody response and correlation with neutralising titers.RESULTS225 participants (177 receiving BNT162b2 and 48 receiving mRNA-1273) were included (median age 41 years,; 66-78% female). Nucleocapsid IgG was found in 4.1% and 21.9% of the BNT162b2 (baseline) and mRNA-1273 (2-weeks post first dose). All anti-spike assays detected antibodies post-vaccination, with an average increase of 87.2% (range 73.8-94.3%; BNT162b2), and 25.2% (range 23.8-26.7%; mRNA-1273) between the first and last sampling time points (all pCONCLUSIONAnti-spike vaccine-induced SARS-CoV-2 IgG are detectable by commercially available high-throughput assays and increases over time. Prior to second dose of vaccination, neutralising antibodies are detectable in 73-89% of individuals, suggesting the majority of individuals would have some degree of protection from subsequent infection.

BACKGROUND: With rapid approval of SARS-CoV-2 vaccines, the ability of clinical laboratories to detect vaccine-induced antibodies with available high-throughput commercial assays is unknown. We aimed to determine if commercial serology assays can detect vaccine-induced antibodies (VIAs) and understand the vaccination response. METHODS: This cohort study recruited healthcare workers and residents of long-term care facilities (receiving the BNT162b2 and mRNA-1273 products, respectively) who underwent serum collection pre-vaccination (BNT162b2 group), 2-weeks post vaccination (both groups), and pre-2nd dose (both groups). Sera were tested for the presence of SARS-CoV-2 IgG using four commercial assays (Abbott SARS-CoV-2 IgG, Abbott SARS-CoV-2 IgG II Quant, DiaSorin Trimeric S IgG, and GenScript cPASS) to detect VIAs. Secondary outcomes included description of post-vaccination antibody response and correlation with neutralizing titers. RESULTS: 225 participants (177 receiving BNT162b2 and 48 receiving mRNA-1273) were included (median age 41 years; 66-78% female). Nucleocapsid IgG was found in 4.1% and 21.9% of the BNT162b2 (baseline) and mRNA-1273 (2-weeks post first dose). All anti-spike assays detected antibodies post-vaccination, with an average increase of 87.2% (range 73.8-94.3%; BNT162b2), and 25.2% (range 23.8-26.7%; mRNA-1273) between the first and last sampling time points (all p

Many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology tests have proven to be less accurate than expected and do not assess antibody function as neutralizing, correlating with protection from reinfection. A new assay technology measuring the interaction of the purified SARS-CoV-2 spike protein receptor binding domain (RBD) with the extracellular domain of the human angiotensin-converting enzyme 2 (hACE2) receptor detects these important antibodies., Many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology tests have proven to be less accurate than expected and do not assess antibody function as neutralizing, correlating with protection from reinfection. A new assay technology measuring the interaction of the purified SARS-CoV-2 spike protein receptor binding domain (RBD) with the extracellular domain of the human angiotensin-converting enzyme 2 (hACE2) receptor detects these important antibodies. The cPass surrogate virus neutralization test (sVNT), compared directly with eight SARS-CoV-2 IgG serology and two live-cell neutralization tests, gives similar or improved accuracy for qualitative delineation between positive and negative individuals in a fast, scalable, and high-throughput assay. The combined data support the cPass sVNT as a tool for highly accurate SARS-CoV-2 immunity surveillance of infected/recovered and/or vaccinated individuals as well as drug and convalescent-phase donor screening. The data also preview a novel application for the cPass sVNT in calibrating the stringency of live-cell neutralization tests and its use in longitudinal testing of recovered and/or vaccinated patients.

The COVID-19 pandemic has led to the influx of immunoassays for the detection of antibodies towards severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the global market. The Canadian Public Health Laboratory Network Serology Task Force undertook a nationwide evaluation of twelve laboratory and 6 point-of-care based commercial serological assays for the detection of SARS-CoV-2 antibodies. We determined that there was considerable variability in the performance of individual tests and that an orthogonal testing algorithm should be prioritized to maximize the accuracy and comparability of results across the country. The manual enzyme immunoassays and point-of-care tests evaluated had lower specificity and increased coefficients of variation compared to automated enzyme immunoassays platforms putting into question their utility for large-scale sero-surveillance. Overall, the data presented here provide a comprehensive approach for applying accurate serological assays for longitudinal sero-surveillance and vaccine trials while informing Canadian public health policy.

Coronavirus disease (COVID) serological tests are essential to determine the overall seroprevalence of a population and to facilitate exposure estimates within that population. We performed a head-to-head assessment of enzyme immunoassays (EIAs) and point-of-care lateral flow assays (POCTs) to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. Demographics, symptoms, comorbidities, treatment, and mortality of patients whose sera were used were also reviewed. Six EIAs (Abbott, Affinity, Bio-Rad, DiaSorin, Euroimmun, and Roche) and six POCTs (BTNX, Biolidics, Deep Blue, Genrui, Getein BioTech, and Innovita) were evaluated for the detection of SARS-CoV-2 antibodies in known COVID-19-infected individuals. Sensitivity of EIAs ranged from 50 to 100%, with only four assays having overall sensitivities of >95% after 21 days after symptom onset. Notably, cross-reactivity with other respiratory viruses (parainfluenza virus [PIV-4] [n = 5], human metapneumovirus [hMPV] [n = 3], rhinovirus/enterovirus [n = 1], CoV-229E [n = 2], CoV-NL63 [n = 2], and CoV-OC43 [n = 2]) was observed; however, overall specificity of EIAs was good (92 to 100%; all but one assay had specificity above 95%). POCTs were 0 to 100% sensitive >21 days after onset, with specificity ranging from 96 to 100%. However, many POCTs had faint banding and were often difficult to interpret. Serology assays can detect SARS-CoV-2 antibodies as early as 10 days after symptom onset. Serology assays vary in their sensitivity based on the marker (IgA/IgM versus IgG versus total) and by manufacturer; however, overall only 4 EIAs and 4 POCTs had sensitivities of >95% >21 days after symptom onset. Cross-reactivity with other seasonal coronaviruses is of concern. Serology assays should not be used for the diagnosis of acute infection but rather in carefully designed serosurveys to facilitate understanding of seroprevalence in a population and to identify previous exposure to SARS-CoV-2.

Background:: HIV transmission during pregnancy and breastfeeding among serodiscordant heterosexual couples represents an ongoing barrier to the elimination of vertical transmission of HIV-1 infection in Canada. Objective:: To report a case of vertical HIV transmission during breastfeeding and examine the prevalence of risk factors for HIV transmission in the pregnancy and postpartum periods among serodiscordant couples where the male partner is HIV positive and female partner HIV negative. Methods:: Case report and retrospective chart review of HIV-serodiscordant pregnant couples over an eight-year period in Edmonton, Canada. Results:: We report a case of maternal primary HIV infection during the postpartum period and vertical transmission to a nursing infant that went undetected until the infant presented with AIDS. We also report a series of 41 serodiscordant pregnant couples identified by our public health nurse between 2008 and 2016. Among HIV-infected male partners, 20 (49%) had a detectable viral load (VL) during their partner’s pregnancy and during breastfeeding, with median peak VL 4,700 copies/mL (range 49-120,000) and 5,100 copies/mL (range 40-120,000) during pregnancy and breastfeeding, respectively. None of the female partners seroconverted during pregnancy, but three seroconverted at 1.8, 2.4, and 6.9 years after delivery. No vertical transmission occurred. Conclusion:: Despite concerted attempts to minimize HIV transmission during pregnancy and breastfeeding in our well-resourced setting, residual transmission risk remains due to non-suppressed viral load within many HIV-serodiscordant pregnant couples.