Wastewater surveillance monitoring of SARS-CoV-2 variants of concern and dynamics of transmission and community burden of COVID-19.

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.

Number of COVID-19 cases required in a population to detect SARS-CoV-2 RNA in wastewater in the province of Alberta, Canada: Sensitivity assessment.

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.

Wastewater-Based Surveillance Is an Effective Tool for Trending COVID-19 Prevalence in Communities: A Study of 10 Major Communities for 17 Months in Alberta.

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.

SARS-CoV-2 outbreak in a Canadian suburban tertiary hospital necessitating full facility closure: a descriptive observational study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. INTERPRETATION: 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.

Ten Years of Diphtheria Toxin Testing and Toxigenic Cutaneous Diphtheria Investigations in Alberta, Canada: A Highly Vaccinated Population.

BACKGROUND: Respiratory diphtheria is a potentially fatal toxin-mediated disease that is rare among highly vaccinated populations. Cutaneous infections with toxigenic Corynebacterium diphtheriae are most commonly linked to travel to an endemic region. Corynebacterium ulcerans has emerged as a predominant, locally acquired cause of respiratory and cutaneous diphtheria in Western Europe. Recently, public health agencies from several highly vaccinated regions expanded their guidelines to investigate toxigenic cutaneous diphtheria regardless of travel history. With relatively unknown epidemiology of C diphtheriae in North America, and increasing diphtheria toxin testing over the last decade, this change could lead to substantial increases in public health investigations with unclear benefits. METHODS: This study examined the diagnostic and public health benefits of toxigenic cutaneous diphtheria investigations in the highly vaccinated population of Alberta, Canada, where travel history is not required for cutaneous diphtheria investigations. All C diphtheriae isolates collected between 2010 and 2019 were reviewed for specimen source, toxigenicity, biovar, and associated clinical and public health data. RESULTS: Of these, 5% of C diphtheriae isolates were toxigenic and 82% were isolated from cutaneous sites. Three cases of toxigenic cutaneous disease were identified, none from patients with recent travel. Contact tracing identified asymptomatic C diphtheriae colonization among 0%-26% of close contacts, with identical isolate profiles among colonized contacts and primary cases. CONCLUSIONS: Cutaneous diphtheria in nonendemic regions warrants public health investigation regardless of travel history and overall vaccination levels. This study underscores the importance of including C ulcerans in public health guidelines to assess the overall prevalence and epidemiology of toxigenic corynebacteria.

Early warning and rapid public health response to prevent COVID-19 outbreaks in long-term care facilities (LTCF) by monitoring SARS-CoV-2 RNA in LTCF site-specific sewage samples and assessment of antibodies response in this population: prospective study protocol.

INTRODUCTION: The 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 ANALYSIS: The 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 DISSEMINATION: Ethics 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.

First hospitalized case of laboratory-confirmed coronavirus disease 2019 (COVID-19) in Alberta, Canada.

As the pandemic of coronavirus disease 2019 (COVID-19) continues to evolve globally and within our Canadian borders, hospitals will begin to see an increasing number of confirmed or suspected cases at their doors. Although many patients can be managed at home, a reasonable proportion will experience progression of disease requiring hospitalization and potentially mechanical ventilation and intensive care. Herein, we report the presentation of the first case of COVID-19 admitted to hospital in Alberta. While The patient's course was mild, this case highlights a number of key points-namely the importance of widespread testing in the community to help inform emergency services (ambulance) workers and receiving front-line health care staff. Other important points include in-hospital monitoring and pharmacologic treatment.

Avec l'évolution de la pandémie de maladie à coronavirus 2019 (COVID-19) dans le monde et à l'intérieur des frontières du Canada, les hôpitaux verront un nombre croissant de patients au diagnostic confirmé ou présumé. De nombreux cas bénins peuvent être traités à la maison, mais dans une proportion raisonnable de cas, la maladie exigera une hospitalisation et peut-être une ventilation mécanique et une admission aux soins intensifs. Les auteurs rendent compte de la présentation du premier cas de COVID-19 hospitalisé en Alberta. Même si la maladie était bénigne, plusieurs éléments fondamentaux en sont ressortis, notamment l'importance de tests généralisés dans la population pour renseigner les services d'urgence (ambulance) et les travailleurs de la santé de première ligne. Le monitorage à l'hôpital et le traitement pharmacologique font partie des autres éléments importants.

Alberta's provincial take-home naloxone program: A multi-sectoral and multi-jurisdictional response to overdose.

SETTING: Alberta is a prairie province located in western Canada, with a population of approximately 4.3 million. In 2016, 363 Albertans died from apparent drug overdoses related to fentanyl, an opioid 50-100 times more toxic than morphine. This surpassed the number of deaths from motor vehicle collisions and homicides combined. INTERVENTION: Naloxone is a safe, effective, opioid antagonist that may quickly reverse an opioid overdose. In July 2015, a committee of community-based harm reduction programs in Alberta implemented a geographically restricted take-home naloxone (THN) program. The successes and limitations of this program demonstrated the need for an expanded, multi-sectoral, multi-jurisdictional response. The provincial health authority, Alberta Health Services (AHS), used previously established incident command system processes to coordinate implementation of a provincial THN program. OUTCOMES: Alberta's provincial THN program was implemented on December 23, 2015. This collaborative program resulted in a coordinated response across jurisdictional levels with wide geographical reach. Between December 2015 and December 2016, 953 locations, including many community pharmacies, registered to dispense THN kits, 9572 kits were distributed, and 472 reversals were reported. The provincial supply of THN kits more than tripled from 3000 to 10 000. IMPLICATIONS: Alberta was uniquely poised to deliver a large, province-wide, multi-sectoral and multi-jurisdictional THN program as part of a comprehensive response to increasing opioid-related morbidity and mortality. The speed at which AHS was able to roll out the program was made possible by work done previously and the willingness of multiple jurisdictions to work together to build on and expand the program.

Differentiating the wild from the attenuated during a measles outbreak.

In the midst of a local measles outbreak, a recently immunized child was investigated for a new-onset measles-type rash. Nucleic acid testing identified that a vaccine-type measles virus was being shed in the urine. Clinically differentiating measles from a nonmeasles rash is challenging, but can be supported by a thorough medical history evaluation. Rashes are expected to occur after immunization; nucleic acid testing can be used when it is difficult to differentiate between wild and attenuated strains.

Pendant une flambée locale de rougeole, un enfant récemment vacciné a subi des examens en raison d'une éruption rougeoleuse de novo. Le test d'acide nucléique a établi qu'un virus rougeoleux de type vaccinal était excrété dans l'urine. Il est difficile d'obtenir la différenciation clinique de la rougeole et d'une éruption non rougeoleuse, mais on peut l'étayer par une évaluation approfondie des antécédents médicaux. Des éruptions peuvent se produire après la vaccination. Le test d'acide nucléique peut être utile lorsqu'il est difficile de différencier les souches sauvages des souches atténuées.

Approaches to immunization data collection employed across Canada during the pandemic (H1N1) 2009 influenza vaccination campaign.

OBJECTIVES: A critical component of the 2009 H1N1 vaccination campaign was the collection of immunization data at the point of care. To meet reporting requirements and to ensure timely availability of coverage information, many jurisdictions across Canada employed new or modified approaches to vaccine data collection. The objective of this study was to observe and characterize the range of influenza immunization data collection approaches used across Canada. METHODS: As part of a multi-stage observational study, the research team visited immunization clinics at which tasks related to data collection and management were observed. Tasks included registration, medical history collection and review, vaccine record-keeping, proof of vaccination preparation, and data entry. Field notes were analyzed in order to understand the data collection mechanisms that comprised each information system as a whole. RESULTS: Data collection mechanisms were grouped into two categories: electronic systems (9/38), in which all data were captured on computer; and hybrid systems (29/38), comprised of computerized and paper-based data collection tasks. Observed systems included stand-alone databases, immunization registries, and electronic health records. Organizations incorporated magnetic card reader technology, telephone registration, and pre-populated fields into data collection approaches. Electronic systems captured a greater number of data elements. CONCLUSION: Canadian jurisdictions employed a range of data collection approaches during the H1N1 vaccination campaign. System characteristics can have important implications for on-site efficiency and organization as well as program planning and evaluation. The systems observed have been described in detail to allow vaccine providers and planners to learn from what has been done elsewhere.

Time and motion study to compare electronic and hybrid data collection systems during the pandemic (H1N1) 2009 influenza vaccination campaign.

During the pandemic (H1N1) 2009 vaccination campaign, vaccine providers collected immunization data using hybrid (paper-based and electronic methods) and electronic data systems. We measured staff time in seconds spent on data collection tasks to compare system efficiencies. The sample consisted of 38 organizations across nine Canadian provinces/territories. The total mean data collection times per client were 104 s (electronic system), 143 s (hybrid system with electronic registration) and 172 s (hybrid system with paper registration). Electronic registration and record keeping were faster than paper-based methods; these findings should be used to improve data collection for future influenza seasons.

Perceptions of immunization information systems for collecting pandemic H1N1 immunization data within Canada's public health community: a qualitative study.

BACKGROUND: Immunization information systems (IISs) are electronic registries used to monitor individual vaccination status and assess vaccine coverage. IISs are currently not widely used across Canada, where health jurisdictions employ a range of approaches to capture influenza immunization information. Conducted in advance of the 2009 H1N1 vaccination campaign, the objectives of this study were to understand the perceived value of individual-level data and IISs for influenza control, identify ideal system functions, and explore barriers to implementation. METHODS: In July and August 2009, semi-structured interviews were conducted with key informants engaged in vaccine delivery and/or pandemic planning at regional, provincial/territorial and federal levels across Canada. Key informants were recruited using a combination of convenience and snowball sampling methodologies. Qualitative analysis was used to extract themes from interview content. RESULTS: Patient management, assessment of vaccine coverage, and evaluation of safety and effectiveness were identified as public health priorities that would be achieved in a more timely manner, and with greater accuracy, through the use of an IIS. Features described as ideal included system flexibility, rapid data entry, and universality. Financial and human resource constraints as well as coordination between immunization providers were expressed as barriers to implementation. CONCLUSIONS: IISs were perceived as valuable by key informants for strengthening management capacity and improving evaluation of both seasonal and pandemic influenza vaccination campaigns. However, certain implementation restrictions may need to be overcome for these benefits to be achieved.

Transmission of pandemic influenza A (H1N1) 2009 within households: Edmonton, Canada.

BACKGROUND: In April 2009, a novel influenza A, subtype H1N1, now referred to as the Pandemic (H1N1) 2009 virus (pH1N1), began circulating in countries around the world. Describing the transmission characteristics of this novel influenza A virus is important to predict current, and future, disease spread. The Public Health response to the first wave of pH1N1 in Alberta focused on the identification and management of secondary cases within households. OBJECTIVES: The purpose of this study was to describe transmission characteristics of pH1N1 in households in Edmonton, the capital city of Alberta, during the first wave, and to identify the serial interval and secondary attack rate (SAR) in this setting. STUDY DESIGN: This is a prospective analysis of pH1N1 household transmission within 87 urban Canadian households between April 30 and June 9, 2009; with each household having at least one laboratory-confirmed case. The secondary attack rate was calculated in the 262 household contacts using a weighted average by number of susceptible individuals in each household. The serial interval, or time to illness in secondary cases, was analyzed using survival analysis with a Weibull model. RESULTS: Within the 87 households, 42 (48.3%) had no secondary cases develop; 25 (28.7%) had one secondary case develop; and 20 (22.9%) had more than one secondary case develop. The secondary attack rate did not decrease with increasing household size and households with two members exhibited the lowest secondary attack rate at 14.1%. Children under the age of 19, and individuals with an underlying medical condition, were at increased risk (p<0.05) of becoming a secondary case. The overall secondary attack rate among the 262 susceptible household contacts was 30.2% (95% CI: 12.6-52.2). The median serial interval for pH1N1 transmission was 3.4 days (95% CI: 2.9-3.9). CONCLUSIONS: The identified transmission characteristics of pH1N1 among Canadian households differ slightly from other previously reported North American estimates, but are in keeping with historical transmission rates of pandemic influenza viruses.

Pan-Canadian assessment of pandemic immunization data collection: study methodology.

BACKGROUND: The collection of individual-level pandemic (H1N1) 2009 influenza immunization data was considered important to facilitate optimal vaccine delivery and accurate assessment of vaccine coverage. These data are also critical for research aimed at evaluating the new vaccine's safety and effectiveness. Systems used to collect immunization data include manual approaches in which data are collected and retained on paper, electronic systems in which data are captured on computer at the point of vaccination and hybrid systems which are comprised of both computerized and manual data collection components. This study's objective was to compare the efficiencies and perceptions of data collection methods employed during Canada's pandemic (H1N1) 2009 influenza vaccination campaign. METHODS/DESIGN: A pan-Canadian observational study was conducted in a convenience sample of public health clinics and healthcare institutions during the H1N1 vaccination campaign in the fall of 2009. The study design consisted of three stages: Stage 1 involved passive observation of the site's layout, processes and client flow; Stage 2 entailed timing site staff on 20 clients through five core immunization tasks: i) client registration, ii) medical history collection, iii) medical history review, iv) vaccine administration record keeping and v) preparation of proof of vaccine administration for the client; in Stage 3, site staff completed a questionnaire regarding perceived usability of the site's data collection approach. Before the national study began, a pilot study was conducted in three seasonal influenza vaccination sites in Ontario, to both test that the proposed methodology was logistically feasible and to determine inter-rater reliability in the measurements of the research staff. Comparative analyses will be conducted across the range of data collection methods with respect to time required to collect immunization data, number and type of individual-level data elements collected, and clinic staff perceptions of the usability of the method employed at their site, using analysis of variance (ANOVA). DISCUSSION: Various data collection methods were employed at immunization sites across Canada during the pandemic (H1N1) 2009 influenza vaccination campaign. Our comparison of methods can facilitate planning an efficient, coordinated approach for collecting immunization data in future influenza seasons.

Population risk of syringe reuse: estimating the probability of transmitting bloodborne disease.

BACKGROUND: In 2008, the Medical Officer of Health at Alberta Health Services (Edmonton, Canada) was notified that, in some practice settings, a syringe was used to administer medication through the side port of an intravenous circuit and then the syringe, with residual drug, was used to administer medication to other patients in the same manner. This practice has been implicated in several outbreaks of bloodborne infection in hospital and clinic settings. METHODS: A risk assessment model was developed to predict the risk of a patient contracting a bloodborne viral infection from the practice. The risk of transmission was defined as the product of 5 factors: (1) the population prevalence of a specific bloodborne pathogen, (2) the probability of finding a viral bloodborne pathogen in an intravenous circuit, (3) the rate of syringe reuse, (4) the probability of causing disease given a bloodborne pathogen exposure, and (5) the susceptibility of the exposed person. RESULTS: The risk was modeled first with consistent use of the proximal port of the intravenous circuit. The risk of transmission of hepatitis B virus was approximately 12-53 transmission events per 1,000,000 exposure events for a range of practice probabilities (ie, frequency of the risk practice) from 20% to 80%, respectively. The risk of transmission of hepatitis C virus was approximately 1.0-4.3 transmission events per 1,000,000 exposure events for the same practice probability range, and the risk of transmission of human immunodeficiency virus was approximately 0.03-0.15 transmission events per 1,000,000 exposure events for the same practice probability range. The use of the distal port was associated with a 10-fold decrease in the risk. CONCLUSIONS: Practitioners must practice safe, aseptic injection techniques. The model presented here can be used to estimate the risk of disease transmission in situations where reuse has occurred and can serve as a framework for informing public health action.