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BACKGROUND: There are few reports of longitudinal serologic responses in children following Sars-CoV-2 infection and vaccination. This study describes longitudinal SARS-CoV-2 antibody responses following infection, vaccination, or both (hybrid immunity) in a cohort of Canadian children. The objectives of our study were to compare antibody levels following SARS-CoV-2 infection, vaccination, and hybrid immunity and to examine antibody decline after final antigen exposure. METHODS: The Alberta Childhood COVID-19 Cohort (AB3C) study was a prospective longitudinal cohort study conducted from July 2020 to September 2022 with repeat sampling across 5 visits. Children under 18 years of age were enrolled for serial measurement of antibody responses to SARS-CoV-2 virus vaccine and infection. RESULTS: The final sample size was 919; participants were 50.5% female, 48.2% were > 12 years and 88.5% were white ethnicity. The median peak spike IgG level of those with only infection was not different from those with no vaccination or infection (233 AU/mL (IQR: 99-944 AU/mL) vs. 3 AU/mL (IQR: 1-5 AU/mL; P = 0.1765). Participants with infections after vaccination had higher IgG levels than those where infection preceded vaccination (median: 36,660 (IQR: 22,084 - 40,000 AU/mL) vs. 17,461 AU/mL (IQR: 10,617 - 33,212 AU/mL); P < 0.0001). In a linear mixed methods model, children with infection-only had low levels of antibody that stayed stable over the study duration without further antigen exposures. Those with infection after vaccination had the slowest rate of antibody decline over time at 4% (95%CI: 2-5%) per week, compared with children where infection preceded vaccine 7% (95%CI: 6-8%) per week. CONCLUSIONS: Children with hybrid immunity conferred through vaccination (2 + doses) followed by a SARS-CoV-2 infection had the highest and longest lasting antibody levels, compared to children who had an infection followed by vaccination, vaccination-only, or infection-only. The longer-term clinical importance of these findings, related to prevention of repeated infections and severe outcomes and need for further vaccine doses, is not yet known.
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Anticuerpos Antivirales , Formación de Anticuerpos , Vacunas contra la COVID-19 , COVID-19 , Inmunoglobulina G , SARS-CoV-2 , Vacunación , Humanos , Femenino , Masculino , COVID-19/inmunología , COVID-19/prevención & control , Niño , Anticuerpos Antivirales/sangre , SARS-CoV-2/inmunología , Estudios Longitudinales , Adolescente , Estudios Prospectivos , Vacunas contra la COVID-19/inmunología , Vacunas contra la COVID-19/administración & dosificación , Inmunoglobulina G/sangre , Alberta , Preescolar , Lactante , CanadáRESUMEN
SETTING: In Canada's federated healthcare system, 13 provincial and territorial jurisdictions have independent responsibility to collect data to inform health policies. During the COVID-19 pandemic (2020-2023), national and regional sero-surveys mostly drew upon existing infrastructure to quickly test specimens and collect data but required cross-jurisdiction coordination and communication. INTERVENTION: There were 4 national and 7 regional general population SARS-CoV-2 sero-surveys. Survey methodologies varied by participant selection approaches, assay choices, and reporting structures. We analyzed Canadian pandemic sero-surveillance initiatives to identify key learnings to inform future pandemic planning. OUTCOMES: Over a million samples were tested for SARS-CoV-2 antibodies from 2020 to 2023 but siloed in 11 distinct datasets. Most national sero-surveys had insufficient sample size to estimate regional prevalence; differences in methodology hampered cross-regional comparisons of regional sero-surveys. Only four sero-surveys included questionnaires. Sero-surveys were not directly comparable due to different assays, sampling methodologies, and time-frames. Linkage to health records occurred in three provinces only. Dried blood spots permitted sample collection in remote populations and during stay-at-home orders. IMPLICATIONS: To provide timely, high-quality information for public health decision-making, routine sero-surveillance systems must be adaptable, flexible, and scalable. National capability planning should include consortiums for assay design and validation, defined mechanisms to improve test capacity, base documents for data linkage and material transfer across jurisdictions, and mechanisms for real-time communication of data. Lessons learned will inform incorporation of a robust sero-survey program into routine surveillance with strategic sampling and capacity to adapt and scale rapidly as a part of a comprehensive national pandemic response plan.
RéSUMé: CONTEXTE: Au Canada, où le système de santé est fédéré, les 13 juridictions provinciales et territoriales ont la responsabilité individuelle de recueillir les données qui leur permettent d'élaborer leurs politiques de santé. Lors de la pandémie de COVID-19 (20202023), pour réaliser les enquêtes de séroprévalence à l'échelle régionale et nationale, les autorités ont principalement utilisé l'infrastructure existante pour pouvoir analyser les échantillons et recueillir des données rapidement, mais cela a également nécessité de la communication et de la coordination entre les différentes juridictions. INTERVENTION: Au Canada, il y a eu quatre enquêtes nationales et sept enquêtes régionales sur la séroprévalence du SARS-CoV-2 dans la population générale. Les méthodologies utilisées différaient selon la méthode de sélection des participants, le choix des tests d'analyses et les structures de rapports. Nous avons analysé la façon dont ces enquêtes avaient été réalisées afin d'en dégager des éléments essentiels qui permettront de planifier pour les futures pandémies. RéSULTATS: Entre 2020 et 2023, plus d'un million d'échantillons, répartis en 11 ensembles de données distincts, ont été analysés afin de rechercher la présence d'anticorps au SARS-CoV-2. Dans la plupart des enquêtes nationales, la taille de l'échantillon était insuffisante pour pouvoir estimer la prévalence à l'échelle régionale. La disparité des méthodologies utilisées a entravé la comparaison des enquêtes régionales. Seules quatre enquêtes fournissaient les données recueillies à partir des questionnaires. Il a été impossible de comparer les enquêtes entre elles en raison de la diversité des tests d'analyse utilisés, des méthodes d'échantillonnage et de la durée des enquêtes. Seules trois provinces avaient couplé leurs données avec les archives médicales. Pour réaliser les enquêtes dans les populations éloignées et lors des périodes de confinement, la méthode d'analyse sur gouttes de sang séché a été utilisée. CONCLUSION: Afin de pouvoir fournir, en temps et en heure, des données de haute qualité pour la prise de décisions en matière de santé publique, un système de sérosurveillance continuelle doit être adaptable, modulable et évolutif. En cas de pandémie, un plan national doit prévoir des consortiums pour la conception et la validation des tests d'analyse, des moyens d'amélioration de la capacité de dépistage, des documents de base pour le couplage des données, un mode de transfert du matériel entre les différentes juridictions et des moyens pour une communication en temps réel des données. Les leçons tirées de cette analyse permettront de mettre en place un solide programme d'enquêtes de séroprévalence au sein des systèmes de sérosurveillance continuelle, et que ce programme sera accompagné d'une stratégie d'échantillonnage et d'un plan d'intervention national, rapide et complet en cas de pandémie.
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COVID-19 , Pandemias , Humanos , COVID-19/epidemiología , Canadá/epidemiología , Estudios Seroepidemiológicos , Vigilancia de la Población/métodos , Prueba Serológica para COVID-19 , SARS-CoV-2RESUMEN
Omicron has become the dominant SARS-CoV-2 variant globally since December 2021, with distinct waves being associated with separate Omicron sublineages. Rapid detection of BA.1, BA.2, BA.4, and BA.5 was accomplished in the province of Alberta, Canada, through the design and implementation of real-time reverse transcriptase PCR assays targeting S:N501Y, S:ins214EPE, S:H69/V70, ORF7b:L11F, and M:D3N. Using the combination of results for each of these markers, samples could be designated as belonging to sublineages within BA.1, BA.2, BA.4, or BA.5. The analytical sensitivity of these markers ranged from 132 to 2229 copies/mL and in-laboratory accuracy was 98.9-100%. A 97.3% agreement using 12,592 specimens was demonstrated for the assays compared to genome sequencing. The use of these assays, combined with genome sequencing, facilitated the surveillance of SARS-CoV-2 lineages throughout a BA.5-dominated period.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , ADN Polimerasa Dirigida por ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alberta , Prueba de COVID-19RESUMEN
The targeted screening and sequencing approaches for COVID-19 surveillance need to be adjusted to fit the evolving surveillance objectives which necessarily change over time. We present the development of variant screening assays that can be applied to new targets in a timely manner and enable multiplexing of targets for efficient implementation in the laboratory. By targeting the HV69/70 deletion for Alpha, K417N for Beta, K417T for Gamma, and HV69/70 deletion plus K417N for sub-variants BA.1, BA.3, BA.4, and BA.5 of Omicron, we achieved simultaneous detection and differentiation of Alpha, Beta, Gamma, and Omicron in a single assay. Targeting both T478K and P681R mutations enabled specific detection of the Delta variant. The multiplex assays used in combination, targeting K417N and T478K, specifically detected the Omicron sub-variant BA.2. The limits of detection for the five variants of concern were 4-16 copies of the viral RNA per reaction. Both assays achieved 100% clinical sensitivity and 100% specificity. Analyses of 377 clinical samples and 24 wastewater samples revealed the Delta variant in 100 clinical samples (nasopharyngeal and throat swab) collected in November 2021. Omicron BA.1 was detected in 79 nasopharyngeal swab samples collected in January 2022. Alpha, Beta, and Gamma variants were detected in 24 wastewater samples collected in May-June 2021 from two major cities of Alberta (Canada), and the results were consistent with the clinical cases of multiple variants reported in the community.
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BACKGROUND: During the first year of the COVID-19 pandemic, the proportion of reported cases of COVID-19 among Canadians was under 6%. Although high vaccine coverage was achieved in Canada by fall 2021, the Omicron variant caused unprecedented numbers of infections, overwhelming testing capacity and making it difficult to quantify the trajectory of population immunity. METHODS: Using a time-series approach and data from more than 900 000 samples collected by 7 research studies collaborating with the COVID-19 Immunity Task Force (CITF), we estimated trends in SARS-CoV-2 seroprevalence owing to infection and vaccination for the Canadian population over 3 intervals: prevaccination (March to November 2020), vaccine roll-out (December 2020 to November 2021), and the arrival of the Omicron variant (December 2021 to March 2023). We also estimated seroprevalence by geographical region and age. RESULTS: By November 2021, 9.0% (95% credible interval [CrI] 7.3%-11%) of people in Canada had humoral immunity to SARS-CoV-2 from an infection. Seroprevalence increased rapidly after the arrival of the Omicron variant - by Mar. 15, 2023, 76% (95% CrI 74%-79%) of the population had detectable antibodies from infections. The rapid rise in infection-induced antibodies occurred across Canada and was most pronounced in younger age groups and in the Western provinces: Manitoba, Saskatchewan, Alberta and British Columbia. INTERPRETATION: Data up to March 2023 indicate that most people in Canada had acquired antibodies against SARS-CoV-2 through natural infection and vaccination. However, given variations in population seropositivity by age and geography, the potential for waning antibody levels, and new variants that may escape immunity, public health policy and clinical decisions should be tailored to local patterns of population immunity.
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COVID-19 , SARS-CoV-2 , Humanos , COVID-19/epidemiología , Pandemias , Estudios Seroepidemiológicos , Alberta , Anticuerpos AntiviralesRESUMEN
Wastewater-based surveillance is a valuable approach for monitoring COVID-19 at community level. Monitoring SARS-CoV-2 variants of concern (VOC) in wastewater has become increasingly relevant when clinical testing capacity and case-based surveillance are limited. In this study, we ascertained the turnover of six VOC in Alberta wastewater from May 2020 to May 2022. Wastewater samples from nine wastewater treatment plants across Alberta were analysed using VOC-specific RT-qPCR assays. The performance of the RT-qPCR assays in identifying VOC in wastewater was evaluated against next generation sequencing. The relative abundance of each VOC in wastewater was compared to positivity rate in COVID-19 testing. VOC-specific RT-qPCR assays performed comparatively well against next generation sequencing; concordance rates ranged from 89% to 98% for detection of Alpha, Beta, Gamma, Omicron BA.1 and Omicron BA.2, with a slightly lower rate of 85% for Delta (p < 0.01). Elevated relative abundance of Alpha, Delta, Omicron BA.1 and BA.2 were each associated with increased COVID-19 positivity rate. Alpha, Delta and Omicron BA.2 reached 90% relative abundance in wastewater within 80, 111 and 62 days after their initial detection, respectively. Omicron BA.1 increased more rapidly, reaching a 90% relative abundance in wastewater after 35 days. Our results from VOC surveillance in wastewater correspond with clinical observations that Omicron is the VOC with highest disease burden over the shortest period in Alberta to date. The findings suggest that changes in relative abundance of a VOC in wastewater can be used as a supplementary indicator to track and perhaps predict COVID-19 burden in a population.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiología , Aguas Residuales , Monitoreo Epidemiológico Basado en Aguas Residuales , Prueba de COVID-19RESUMEN
INTRODUCTION: We determined adverse events after 4 doses of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine in those with inflammatory bowel disease (IBD), associations between antibodies and injection site reactions (ISR), and risk of IBD flare. METHODS: Individuals with IBD were interviewed for adverse events to SARS-CoV-2 vaccine. Multivariable linear regression assessed the association between antibody titers and ISR. RESULTS: Severe adverse events occurred in 0.03%. ISR were significantly associated with antibody levels after the fourth dose (geometric mean ratio = 2.56; 95% confidence interval 1.18-5.57). No cases of IBD flare occurred. DISCUSSION: SARS-CoV-2 vaccines are safe for those with IBD. ISR after the fourth dose may indicate increased antibodies.
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Vacunas contra la COVID-19 , COVID-19 , Enfermedades Inflamatorias del Intestino , Humanos , Anticuerpos Antivirales , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Reacción en el Punto de Inyección , SARS-CoV-2 , VacunaciónRESUMEN
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.
Historique: En mai 2022, l'Organisation mondiale de la Santé a déclaré une flambée multinationale d'infection par le virus de la variole simienne (MPXV). Le 2 juin 2022, la province de l'Alberta, dans l'Ouest canadien, a recensé son premier cas de MPXV chez un voyageur de retour de l'étranger. Les chercheurs ont entrepris un exercice de dépistage rétrospectif pour évaluer la possibilité que le MPXV ait circulé auparavant dans la province. Méthodologie: Les chercheurs ont extrait de l'entreposage les écouvillons des lésions cutanées (génitales et non génitales) et muqueuses soumis en vue de dépister le virus herpès simplex (VHS), le virus varicelle-zona (VZV) et le virus de la syphilis des patients de sexe masculin qui avaient fréquenté les cliniques d'infections transmises sexuellement de la province de l'Alberta entre le 28 janvier et le 30 mai 2022. Ils ont sélectionné la population soumise au dépistage en fonction de l'épidémiologie de la flambée multinationale de MPXV en 2022. Les écouvillons ont été soumis à l'extraction et au test des acides nucléiques viraux pour dépister la présence d'ADN de l'Orthopoxvirus au moyen d'un test commercial d'amplification en chaîne par polymérase (PCR). RÉsultats: Les chercheurs ont extrait un total de 392 échantillons (représentant 341 personnes uniques d'un âge médian de 31 ans). De ce nombre, 349 (89,0 %) avaient été soumis au test PCR du VHS, du VZV et de la syphilis, 13 (3,3 %), du VHS et du VZV seulement et 30 (7,7 %), de la syphilis seulement. Aucun des 392 échantillons n'a donné de résultat positif à l'ADN de l'Orthopoxvirus. Conclusions: D'après les résultats de la présente étude, il est peu probable que le MPXV ait circulé dans la population plus vulnérable de l'Alberta avant la détection du premier cas. Les chercheurs recommandent que les autres provinces et territoires examinent leur épidémiologie locale, le contexte et les ressources avant de procéder à des études de ce type.
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BACKGROUND: Measurement of SARS-CoV-2 antibody seropositivity is important to accurately understand exposure to infection and/or vaccination in specific populations. This study aimed to estimate the serologic response to SARS-CoV-2 virus infection and vaccination in children in Calgary, Alberta over a two-year period. METHODS: Children with or without prior SARS-CoV-2 infections, were enrolled in Calgary, Canada in 2020. Venous blood was sampled 4 times from July 2020 to April 2022 for SARS-CoV-2 nucleocapsid and spike antibodies. Demographic and clinical information was obtained including SARS-CoV-2 testing results and vaccination records. RESULTS: 1035 children were enrolled and 88.9% completed all 4 visits; median age 9 years (IQR: 5,13); 519 (50.1%) female; and 815 (78.7%) Caucasian. Before enrolment, 118 (11.4%) had confirmed or probable SARS-CoV-2. By April 2022, 39.5% of previously uninfected participants had a SARS-CoV-2 infection. Nucleocapsid antibody seropositivity declined to 16.4% of all infected children after more than 200 days post diagnosis. Spike antibodies remained elevated in 93.6% of unvaccinated infected children after more than 200 days post diagnosis. By April 2022, 408 (95.6%) children 12 years and older had received 2 or more vaccine doses, and 241 (61.6%) 5 to 11 year-old children had received 2 vaccine doses. At that time, all 685 vaccinated children had spike antibodies, compared with 94/176 (53.4%) of unvaccinated children. CONCLUSIONS: In our population, after the first peak of Omicron variant infections and introduction of COVID-19 vaccines for children, all vaccinated children, but just over one-half of unvaccinated children, had SARS-CoV-2 spike antibodies indicating infection and/or vaccination, highlighting the benefit of vaccination. It is not yet known whether a high proportion of seropositivity at the present time predicts sustained population-level protection against future SARS-CoV-2 transmission, infection or severe COVID-19 outcomes in children.
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COVID-19 , SARS-CoV-2 , Niño , Femenino , Humanos , Preescolar , Masculino , Alberta/epidemiología , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19 , Formación de Anticuerpos , Prueba de COVID-19 , Estudios Seroepidemiológicos , Vacunación , Anticuerpos AntiviralesRESUMEN
Introduction. Starting in December, 2020, the ID NOW was implemented throughout the province of Alberta, Canada (population 4.4 million) in various settings.Gap statement. ID NOW's test performance with SARS-CoV-2 Omicron variant BA.1 is unknown.Aim. To assess the ID NOW performance among symptomatic individuals during the BA.1 Omicron wave and compare it to previous SARS-CoV-2 variant waves.Methodology. The ID NOW was assessed in two locations among symptomatic individuals: rural hospitals and community assessment centres (AC) during the period 5-18 January 2022. Starting 5 January, Omicron represented >95â% of variants detected in our population. For every individual tested, two swabs were collected: one for ID NOW testing and the other for either reverse-transcriptase polymerase chain reaction (RT-PCR) confirmation of negative ID NOW results or for variant testing of positive ID NOW results.Results. A total of 3041 paired samples were analysed (1139 RT-PCR positive). From this, 1873 samples were from 42 COVID-19 AC and 1168 from 69 rural hospitals. ID NOW sensitivity for symptomatic individuals presenting to community AC and rural hospitals was 96.0â% [95â% confidence interval (CI) 94.5-97.3â%, n=830 RT-PCR positive], and 91.6â% (95â% CI 87.9-94.4â%, n=309 RT-PCR positive), respectively. SARS-CoV-2 positivity rate was very high for both populations (44.3â% at AC, 26.5â% in hospital).Conclusions. Sensitivity of ID NOW SARS-CoV-2, compared to RT-PCR, is very high during the BA.1 Omicron wave, and is significantly higher when compared to previous SARS-CoV-2 variant waves.
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COVID-19 , Humanos , COVID-19/diagnóstico , COVID-19/epidemiología , SARS-CoV-2/genética , Canadá , HospitalesRESUMEN
OBJECTIVE: Diagnostic evaluation of the ID NOW coronavirus disease 2019 (COVID-19) assay in various real-world settings among symptomatic and asymptomatic individuals. METHODS: Depending on the setting, the ID NOW testing was performed using oropharyngeal swabs (OPSs) taken from patients with symptoms suggestive of COVID-19, asymptomatic close contacts, or asymptomatic individuals as part of outbreak point prevalence screening. From January to April 2021, a select number of sites switched from using OPS to combined oropharyngeal and nasal swab (O + NS) for ID NOW testing. For every individual tested, two swabs were collected by a health care worker: one swab (OPS or O + NS) for ID NOW testing and a separate swab (OPS or nasopharyngeal swab) for RT-PCR. RESULTS: A total of 129 112 paired samples were analysed (16 061 RT-PCR positive). Of these, 81 697 samples were from 42 COVID-19 community collection sites, 16 924 samples were from 69 rural hospitals, 1927 samples were from nine emergency shelters and addiction treatment facilities, 23 802 samples were from six mobile units that responded to 356 community outbreaks, and 4762 O + NS swabs were collected from three community collection sites and one emergency shelter. The ID NOW assay sensitivity was the highest among symptomatic individuals presenting to community collection sites (92.5%; 95% CI, 92.0-93.0%) and the lowest for asymptomatic individuals associated with community outbreaks (73.9%; 95% CI, 69.8-77.7%). Specificity was >99% in all populations tested. DISCUSSION: The sensitivity of ID NOW severe acute respiratory syndrome coronavirus 2 testing is the highest when used in symptomatic community populations not seeking medical care. Sensitivity and positive predictive value drop by approximately 10% when tested on asymptomatic populations. Using combined oropharyngeal and nasal swabs did not improve the performance of ID NOW assay.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/diagnóstico , COVID-19/epidemiología , Prueba de COVID-19 , Técnicas de Laboratorio Clínico , Estudios Prospectivos , Manejo de Especímenes , Sensibilidad y Especificidad , NasofaringeRESUMEN
With a unique and large size of testing results of 1,842 samples collected from 12 wastewater treatment plants (WWTP) for 14 months through from low to high prevalence of COVID-19, the sensitivity of RT-qPCR detection of SARS-CoV-2 RNA in wastewater that correspond to the communities was computed by using Probit analysis. This study determined the number of new COVID-19 cases per 100,000 population required to detect SARS-CoV-2 RNA in wastewater at defined probabilities and provided an evidence-based framework of wastewater-based epidemiology surveillance (WBE). Input data were positive and negative test results of SARS-CoV-2 RNA in wastewater samples and the corresponding new COVID-19 case rates per 100,000 population served by each WWTP. The analyses determined that RT-qPCR-based SARS-CoV-2 RNA detection threshold at 50%, 80% and 99% probability required a median of 8 (range: 4-19), 18 (9-43), and 38 (17-97) of new COVID-19 cases /100,000, respectively. Namely, the positive detection rate at 50%, 80% and 99% probability were 0.01%, 0.02%, and 0.04% averagely for new cases in the population. This study improves understanding of the performance of WBE SARS-CoV-2 RNA detection using the large datasets and prolonged study period. Estimated COVID-19 burden at a community level that would result in a positive detection of SARS-CoV-2 in wastewater is critical to support WBE application as a supplementary warning/monitoring system for COVID-19 prevention and control.
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COVID-19 , Humanos , COVID-19/epidemiología , SARS-CoV-2/genética , Aguas Residuales/análisis , ARN Viral/genética , ARN Viral/análisis , Alberta/epidemiologíaRESUMEN
To assess the burden of respiratory virus coinfections with severe acute respiratory coronavirus virus 2 (SARS-CoV-2), this study reviewed 4,818 specimens positive for SARS-CoV-2 and tested using respiratory virus multiplex testing. Coinfections with SARS-CoV-2 were uncommon (2.8%), with enterovirus or rhinovirus as the most prevalent target (88.1%). Respiratory virus coinfection with SARS-CoV-2 remains low 1 year into the coronavirus disease 2019 (COVID-19) pandemic.
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COVID-19 , Coinfección , Infecciones por Enterovirus , Humanos , SARS-CoV-2 , Coinfección/epidemiología , Alberta , PandemiasRESUMEN
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.
HISTORIQUE: 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. MÉTHODOLOGIE: 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 (n = 30) et des États-Unis (n = 1). Ils ont invité les laboratoires participants à fournir de l'information détaillée sur les dosages diagnostiques utilisés, les plateformes sur lesquelles les dosages étaient exécutés et les résultats obtenus pour chaque échantillon. Les chercheurs ont demandé aux laboratoires participants de fournir de l'information détaillée sur les dosages diagnostiques utilisés, les plateformes sur lesquelles les dosages ont été effectués, et les résultats obtenus à l'égard de chaque échantillon. Les laboratoires ont mené les études à l'insu des résultats escomptés. RÉSULTATS: 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 %). CONCLUSION: 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.
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The correlations between SARS-CoV-2 RNA levels in wastewater from 12 wastewater treatment plants and new COVID-19 cases in the corresponding sewersheds of 10 communities were studied over 17 months. The analysis from the longest continuous surveillance reported to date revealed that SARS-CoV-2 RNA levels correlated well with temporal changes of COVID-19 cases in each community. The strongest correlation was found during the third wave (r = 0.97) based on the population-weighted SARS-CoV-2 RNA levels in wastewater. Different correlations were observed (r from 0.51 to 0.86) in various sizes of communities. The population in the sewershed had no observed effects on the strength of the correlation. Fluctuation of SARS-CoV-2 RNA levels in wastewater mirrored increases and decreases of COVID-19 cases in the corresponding community. Since the viral shedding to sewers from all infected individuals is included, wastewater-based surveillance provides an unbiased and no-discriminate estimation of the prevalence of COVID-19 compared with clinical testing that was subject to testing-seeking behaviors and policy changes. Wastewater-based surveillance on SARS-CoV-2 represents a temporal trend of COVID-19 disease burden and is an effective and supplementary monitoring when the number of COVID-19 cases reaches detectable thresholds of SARS-CoV-2 RNA in wastewater of treatment facilities serving various sizes of populations.
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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.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Vacuna BNT162 , COVID-19/diagnóstico , Vacunas contra la COVID-19 , Ácido Edético , Humanos , Inmunoglobulina G , Glicoproteína de la Espiga del Coronavirus , Organización Mundial de la SaludRESUMEN
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: Longitudinal surveillance of SARS-CoV-2 seropositivity with data linkage is valuable for decision-making during the pandemic.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anciano de 80 o más Años , Alberta/epidemiología , Anticuerpos Antivirales , COVID-19/epidemiología , COVID-19/prevención & control , Humanos , Inmunoglobulina G , Pandemias , VacunaciónRESUMEN
In order to detect the SARS-CoV-2 variants of concern (VOCs), five real-time reverse transcriptase PCR (rRT-PCR) assays were designed to target the critical discriminatory mutations responsible for the following amino acid changes in the spike protein: two Δ69-70 + N501Y + E gene triplexes (one optimized for Alpha [B.1.1.7] and one optimized for Omicron [B.1.1.529]), a K417N + 242-244 wild-type duplex, a K417T + E484K duplex, and a L452R + P681 + E484Q triplex. Depending on the assay, sensitivity was 98.97-100% for the detection of known VOC-positive samples, specificity was 97.2-100%, limit of detection was 2-116 copies/reaction, intra- and interassay variability was less than 5%, and no cross-reactivity with common respiratory pathogens was observed with any assay. A subset of rRT-PCR- positive VOC samples were further characterized by genome sequencing. A comparison of the lineage designation by the VOC rRT-PCR assays and genome sequencing for the detection of the Alpha, Beta, Gamma, Delta and Omicron variants showed clinical sensitivities of 99.97-100 %, clinical specificities of 99.6-100 %, positive predictive values of 99.8-100%, and negative predictive values of 99.98-100 %. We have implemented these rRT-PCR assays targeting discriminatory single nucleotide polymorphisms for ongoing VOC screening of SARS-CoV-2 positive samples for surveillance purposes. This has proven extremely useful in providing close to real-time molecular surveillance to monitor the emergence of Alpha, the replacement of Alpha by Delta, and the replacement of Delta by Omicron. While the design, validation and implementation of the variant specific PCR targets is an ever-evolving approach, we find the turn-around-time, high throughput and sensitivity to be a useful complementary approach for SARS-CoV-2 genome sequencing for surveillance purposes in the province of Alberta, Canada.