Public Health Agency Of Canada Research Articles

Seroprevalence of Anti-SARS-CoV-2 Antibodies Among School and Daycare Children: Baseline Results From a Cohort Study in Montreal, Canada

Background: Montreal was one of the highest COVID-19 burdened cities in Canada during the first and second waves of the pandemic. We estimated the seroprevalence of SARS-CoV-2 in children and teenagers in four neighbourhoods of Montreal, Canada.Methods: All children attending selected schools and daycares within the four neighbourhoods were invited to participate in the study. Study participation included an online questionnaire that parents completed, followed by at-home dried blood spot (DBS) collection. Serological results were analyzed using a research-based ELISA assay. Statistical analyses included multivariable logistic regression models to calculate average marginal effects and robust standard errors to account for clustering by school or daycare. Several different sociodemographic differences were examined between the seronegative and seropositive children.Findings: There were 30 daycares, 22 primary schools, and 11 secondary schools that participated in the study with 1,632 participants having provided a DBS sample that was of sufficient quality for the serological analysis. The average seroprevalence was 5·8% (95%CI 4·6 to 7·0) but increased over time from 3·2% (95% CI 0·7 to 5·8) in October-November 2020 to 8.4% (95% CI 4·4 to 12·4) in March-April 2021. The children of visible minority parents were nearly twice as likely to be seropositive as children of non-visible minority parents (1·93, 95%CI 1·11 to 2·75). Interpretation: Our results provide a benchmark of the seroprevalence status in Canadian children and provide further evidence of COVID-19 inequities. It will be important to continue monitoring the serological status of children, particularly in the context of new COVID-19 variants of concern and in the absence of mass vaccination campaigns targeting young children.Funding Information: Public Health Agency of Canada through the COVID-19 Immunity Task Force.Declaration of Interests: All authors declare no competing interests.Ethics Approval Statement: All participants provided informed consent for the survey and ethics approval was received from the research ethics boards of the Université de Montréal and the Centre Hospitalier Universitaire Sainte-Justine.

Practical aspects of implementing the IRIDA system as a solution for One Health bioinformatics analyses

Managing sequence data, associated metadata, bioinformatics analyses and results can be challenging. In a One Health context, the challenge is even larger as there are many actors involved, many diverse types of results need to be produced, and the ensuing process data, such as software versions and options have to be tracked for auditing purposes. In addition, results must often be produced rapidly to be actionable, and non-bioinformaticians should be able to perform the the analyses. Therefore, a graphical user interface (preferably web system) with pipelines and visualization tools are needed to do these analyses. The Public Health Agency of Canada has together with other actors developed the web based system IRIDA (https://www.irida.ca) which uses Galaxy for analyses. IRIDA comes with a set of pipelines, visualization tools and a project based data management system that allows for fine grained data access control, which satisfies many of the requirements that a One Health bioinformatics platform dictates. However, as is often the case with a system meant to satisfy high demands, the platform is not trivial to set up and adapt for local use. In our setup, we are using two web servers, two database servers and one file server. The IRIDA web server provides the user interface. The Galaxy web server receives commands from IRIDA, executes the commands and returns results. Each web server has a database that keeps their respective metadata: user information, file locations and results. The actual files are stored on the fileserver. This spoke-and-wheel infrastructure was implemented to ensure minimum disruption of service if a component should go down. To get the necessary compute resources for this system, we are contracting with the Norwegian Research and Education Cloud (NREC), which offers Infrastructure as a Service (IaaS) services for Norwegian institutions and universities. NREC utilizes template VM images which can be instantiated according to need. The automated configuration and orchestration of images ensure that we can have dynamic access to resources according to need. This dynamic scaling is accomplished through collaboration with Elixir Norway. They have implemented the Pulse software which can check usage and instantiate and take down virtual machines as needed. At the Institute, we have spent close to two years on exploring and setting up this system. We have learned that it is important to not underestimate the amount compute resources needed to get a solid setup. However, having enough compute is irrelevant without knowledgeable staff. IRIDA comes with many features, which require considerable prior knowledge to adapt and set up in a local infrastructure. This includes knowledge on webservers, database systems, linux administration and Galaxy systems administration. The complexity dictates that these systems need to be set up and managed by in-house IT trained staff that will be able to tend the system along the way. It is also very important to maintain interactions with the users of the system, to ensure that the setup produces results that are useful to the users. To accomplish this, bioinformaticians are needed to develop pipelines and visualizations that give results that will on their own be easy for users to interpret in a biologically correct manner. Last but not least - such systems require a significant investment from the institution, thus it is important to showcase the benefits that the system will provide.

Web-Based Peer Support Interventions for Adults Living With Chronic Conditions: Scoping Review.

BackgroundGlobally, 1 in 3 adults live with multiple chronic conditions. Thus, effective interventions are needed to prevent and manage these chronic conditions and to reduce the associated health care costs. Teaching effective self-management practices to people with chronic diseases is one strategy to address the burden of chronic conditions. With the increasing availability of and access to the internet, the implementation of web-based peer support programs has become increasingly common.ObjectiveThe purpose of this scoping review is to synthesize existing literature and key characteristics of web-based peer support programs for persons with chronic conditions. MethodsThis scoping review follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) extension for scoping reviews guidelines. Studies were identified by searching MEDLINE, CINAHL, Embase, PsycINFO, and the Physiotherapy Evidence Database. Chronic diseases identified by the Public Health Agency of Canada were included. Our review was limited to peer support interventions delivered on the web. Peers providing support had to have the chronic condition that they were providing support for. The information abstracted included the year of publication, country of study, purpose of the study, participant population, key characteristics of the intervention, outcome measures, and results. ResultsAfter duplicates were removed, 12,641 articles were screened. Data abstraction was completed for 41 articles. There was a lack of participant diversity in the included studies, specifically with respect to the conditions studied. There was a lack of studies with older participants aged ≥70 years. There was inconsistency in how the interventions were described in terms of the duration and frequency of the interventions. Informational, emotional, and appraisal support were implemented in the studied interventions. Few studies used a randomized controlled trial design. A total of 4 of the 6 randomized controlled trials reported positive and significant results, including decreased emotional distress and increased health service navigation, self-efficacy, social participation, and constructive attitudes and approaches. Among the qualitative studies included in this review, there were several positive experiences related to participating in a web-based peer support intervention, including increased compassion and improved attitudes toward the individual’s chronic condition, access to information, and empowerment.ConclusionsThere is limited recent, high-level evidence on web-based peer support interventions. Where evidence exists, significant improvements in social participation, self-efficacy, and health-directed activity were demonstrated. Some studies incorporated a theoretical framework, and all forms of peer support—emotional, informational, and appraisal support—were identified in the studies included in this review. We recommend further research on web-based peer support in more diverse patient groups (eg, for older adults and chronic conditions outside of cancer, cardiovascular disease, and HIV or AIDS). Key gaps in the area of web-based peer support will serve to inform the development and implementation of future programs.

Older Age and Frailty Are Associated With Higher Mortality but Lower Intensive Care Unit Admission Among Adults Admitted to Canadian Hospitals With COVID-19: A Report From the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance Network

Background: We report characteristics and outcomes of adults admitted to Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network hospitals with COVID-19 in 2020. Methods: Adult patients with laboratory-confirmed COVID-19 admitted to eleven sites in Ontario, Quebec, Alberta and Nova Scotia up to December 31, 2020 were enrolled in this prospective observational cohort study. Age, sex, demographics, housing, exposure characteristics, Clinical Frailty Scale, comorbidities, and outcomes including length of stay, intensive care unit (ICU) admission, mechanical ventilation, and survival were conducted. Descriptive analyses and multivariable logistic regressions were conducted. Findings: Among 2011 patients, mean age was 71·0 (range 19-105) years. 45·7% were women and 74·0% were white. 21·5% were admitted from Assisted Living facilities, 8·2% from long term care, and 2·1% from homeless shelters. The full spectrum of frailty was represented in both younger and older age groups. The majority (61·7% of adults =65) had at least one underlying comorbidity and 27·2% had obesity. Mortality was 14·3% among those not admitted to ICU, and 24·6% for those admitted to ICU. Older age and higher frailty were associated with reduced ICU admission but increased mortality. Obesity was independently associated with ICU admission but not with death. Associations between underlying comorbidities and adverse outcomes were attenuated but persisted when adjusting for frailty.Interpretation: Frailty and age were independent predictors of lower ICU use and higher mortality; when accounting for frailty, obesity was not an independent predictor of mortality, and associations of comorbidities with mortality were weakened.Funding Statement: Funding was provided by the Public Health Agency of Canada and the Canadian Institutes of Health Research.Declaration of Interests: MKA reports grant funding from the Public Health Association of Canada, CIHR, Canadian Frailty Network, Sanofi Pasteur and GSK group of companies, and payments from Pfizer, Sanofi Pasteur and Seqirus outside the submitted work. AM reports payments from GSK, Seqirus and Sanofi Pasteur, outside the submitted work. JEM reports payments from RestorBio, Sanofi, GSK, Merck and Medicago outside of the submitted work. TFH reports grants from Pfizer and GSK. ML reports payments from Sanofi, Medicago, Sequirus, and Pfizer outside the submitted work. SAM reports grants and payments from Pfizer, GSK, Merck, Novartis and Sanofi, outside the submitted work. JG, JJL, GB, LV, ME, DM-C, AA, KW, ST, SS, AMc and KK report no conflicts of interest.Ethics Approval Statement: The protocol for active COVID-19 surveillance has been approved by each local site’s Research Ethics Board.

Studying the social determinants of COVID-19 in a data vacuum.

Race‐based and other demographic information on COVID‐19 patients is not being collected consistently across provinces in Canada. Therefore, whether the burden of COVID‐19 is falling disproportionately on the shoulders of particular demographic groups is relatively unknown. In this article, we first provide an overview of the available geographic and demographic data related to COVID‐19. We then make creative use of these existing data to fill the vacuum and identify key demographic risk factors for COVID‐19 across Canada's health regions. Drawing on COVID‐19 counts and tabular census data, we examine the association between communities’ demographic composition and the number of COVID‐19 infections. COVID‐19 infections are higher in communities with larger shares of Black and low‐income residents. Our approach offers a way for researchers and policymakers to use existing data to identify communities nationwide that are vulnerable to the pandemic in the absence of more detailed demographic and more granular geographic data.

How the Politics of Big Pharma Is Undermining COVID-19 Public Health Policy in Canada

In December 2020 a former NATO commander in Iraq appointed to lead vaccination logistics in the Public Health Agency of Canada announced that the country would adopt a “whole-of-nation” approach to achieve the goal of vaccinating all Canadians by the summer. Two months away from the summer, four into the announcement, and with 400 million doses procured to vaccinate 38 million people several times over, less than 3% of Canadians have received two doses of the leading, authorized products. A range of explanations have been proffered for the delay, including that the Liberal Trudeau Government is treating Big Pharma unfairly, thus causing unnecessary barriers to vaccine supplies. We argue that the assertion does not stand up to scrutiny. As our analysis will show, Canadian pharmaceutical policy is extremely corporate friendly and has been so for decades. This has led to both a predictably rocky vaccine effort and to the continuing failure by the government to guarantee equitable access to medically necessary drugs, prior to, during, and beyond the COVID-19 pandemic.

Correctional Work: Reflections Regarding Suicide.

The Public Health Agency of Canada declared suicide a public health problem in Canada (2016). Employees working in correctional services, researchers find, experience high rates of life-time suicidal ideation in comparison to other public safety professionals and the general population. Suicide behaviours (i.e., ideation, planning, attempts, death) are a multifactorial phenomenon, explained in part by the Interpersonal-Psychological Theory of Suicide that suggests attempted suicide is facilitated by perceived burdensomeness, a lost sense of belonging, a feeling of hopelessness, and a progressively reduced fear of death, as well as capacity and planning to engage a lethal attempt. In the current study, we unpack the factors that can influence suicide behaviours as reported by correctional workers. Our intent is to make explicit the experiences of a small sample (n = 25) of correctional workers in relation to suicidal behaviours, highlighting stories of recovery and acknowledging the importance of facilitating psychologically safe workplaces. Analysis entailed an inductive semi-grounded emergent theme approach. Participants identified certain risk factors as being able to induce suicidal ideation, such as marital or family problems as well as difficulties at work (i.e., bullying or difficult working conditions). Having children and a partner may act as factors preventing suicide for those with ideation. Participants sought help from professionals, such as their family doctor, a psychologist, or the Employee Assistance Program (EAP); however, the lack of perceived organisational supports and recognition of the issue of suicide by the employer are two elements that can hinder the search for help.

Measles surveillance in Canada, 2019.

The Public Health Agency of Canada (PHAC) has conducted enhanced measles surveillance since 1998, the year endemic measles transmission was eliminated in Canada. The objective of this annual national measles surveillance report is to provide an epidemiologic summary of measles activity reported in Canada for 2019 in order to provide evidence to support the continued verification of Canada's measles elimination status. Measles surveillance data are housed in the Canadian Measles and Rubella Surveillance System (CMRSS) database. Descriptive analyses of demographics and risk factors were performed. Outbreak characteristics were summarized and genotypic analyses conducted. Surveillance, laboratory and vaccine coverage data for 2019 were used to assess Canada's status against the Pan American Health Organization (PAHO) essential criteria for the verification of measles elimination. In 2019, 113 measles cases were reported in Canada (crude incidence rate of 3.0 cases per 1,000,000 population). Of these cases, 42 (37%) were imported into Canada, and of the imported cases, 12 (29%) resulted in further transmission. Infants younger than one year had the highest age-specific incidence rate at 13.1 cases per 1,000,000 population. Only 29% of cases had one or more documented doses of measles-containing vaccine. One-fifth (19%) of cases were hospitalized; no deaths were reported. Genotype information was available for 100% of outbreaks reported in 2019 and 90% of non-outbreak-related measles cases; of cases with genotype information available, 27% were B3 and 73% were D8. Despite meeting/partially meeting only three out of four of PAHO's essential criteria for measles elimination status, there is no evidence that endemic measles transmission has been reestablished in Canada.

Risk assessment of secondary metabolites produced by fungi in the genus Stemphylium.

The fungal genus Stemphylium (phylum Ascomycota, teleomorph Pleospora) includes plant pathogenic, endophytic, and saprophytic species with worldwide distributions. Stemphylium spp. produce prodigious numbers of airborne spores, so are a human health concern as allergens. Some species also produce secondary metabolites, such as glucosides, ferric chelates, aromatic polyketides, and others, that function as toxins that damage plants and other fungal species. Some of these compounds also exhibit a low level of mammalian toxicity. The high production of airborne spores by this genus can result in a high incidence of human exposure. Concern about toxin production appears to be the reason that Stemphylium vesicarium, which is a pathogen of several vegetable crops, was classified in Canada as a potential risk of harm to humans for many years. A detailed assessment of the risk of exposure was provided to the relevant regulatory body, the Public Health Agency of Canada, which then determined that Stemphylium spp. in nature or under laboratory conditions posed little to no risk to humans or animals, and the species was re-assigned as a basic (level 1) risk agent.

Nimble, efficient and evolving: the rapid response of the National Collaborating Centres to COVID-19 in Canada.

Since December 2019, there has been a global explosion of research on COVID-19. In Canada, the six National Collaborating Centres (NCCs) for Public Health form one of the central pillars supporting evidence-informed decision making by gathering, synthesizing and translating emerging findings. Funded by the Public Health Agency of Canada and located across Canada, the six NCCs promote and support the use of scientific research and other knowledges to strengthen public health practice, programs and policies. This paper offers an overview of the NCCs as an example of public health knowledge mobilization in Canada and showcases the NCCs' contribution to the COVID-19 response while reflecting on the numerous challenges encountered.

The use of an online survey for collecting food exposure information, Foodbook sub-study, February to April 2015.

During foodborne illness outbreak investigations, comparing food exposure frequencies of cases to those of a control population can help identify suspect food sources. The Public Health Agency of Canada (PHAC) conducted an online survey between February and April 2015 to collect seven-day food exposures from a convenience sample. The study period overlapped with a national, population-based exposure survey being conducted via telephone using random digit dialling. A subset of the food exposure questions from the telephone-based survey was included in the online survey. The online survey study objectives were to: 1) describe the survey methodology, survey respondents and response behaviour; and 2) determine if the online methodology is an appropriate alternative to telephone surveys by comparing food exposures. The online survey link was distributed via email to employees and public health partners, and was promoted on the PHAC website and social media channels. In total 2,100 surveys were completed. The majority of respondents were female, with high income and education, aged 30 to 39 years. The proportion reporting consuming the food items in the online survey was generally higher than those reported in the telephone survey, with a mean difference of 6.0% (95% CI: 4.2, 7.8). In an outbreak investigation, the 6.0% bias could make it more difficult to detect a difference between the case and control food exposures. Nevertheless, given the speed of response and lower resource expenditure of online surveys as well as the willing, able and convenient sample, a bias of 6.0% is considered small enough to be acceptable for future surveys.

HIV in Canada-surveillance report, 2019.

Human immunodeficiency virus (HIV) is a global public health issue. HIV has been nationally notifiable in Canada since 1985. The Public Health Agency of Canada (PHAC) monitors trends in new HIV diagnoses. The objective of this surveillance report is to provide an overview of the epidemiology of reported HIV cases in 2019 in Canada. The report highlights 10-year trends (2010-2019). Data on HIV diagnosed through Immigration Medical Exams (IME) and trends in perinatal transmission of HIV are also presented. PHAC monitors HIV through the HIV/AIDS Surveillance System, a passive, case-based system that collates non-nominal data submitted voluntarily by all Canadian provinces and territories. Descriptive analyses were conducted on national data. IME data were obtained from Immigration, Refugees and Citizenship Canada (IRCC), and data on HIV-exposed pregnancies were obtained through the Canadian Perinatal HIV Surveillance Program. In 2019, a total of 2,122 HIV diagnoses were reported in Canada (5.6 per 100,000 population). Saskatchewan reported the highest provincial diagnosis rate at 16.9 per 100,000 population. The 30 to 39-year age group had the highest HIV diagnosis rate at 12.7 per 100,000 population. While the rates for both males and females fluctuated in the past decade, since 2010 the rates among males decreased overall, while the rate among females increased slightly. As in previous years, the diagnosis rate for males in 2019 was higher than that for females (7.9 versus 3.4 per 100,000 population, respectively). The highest proportion of all reported adult cases with known exposure were gay, bisexual and other men who have sex with men (gbMSM, 39.7%), followed by cases attributed to heterosexual contact (28.3%) and among people who inject drugs (PWID, 21.5%). The number of migrants who tested positive for HIV during an IME conducted in Canada was 626. The one documented perinatal HIV transmission related to a mother who had not received antepartum or intrapartum antiretroviral therapy prophylaxis. The number and rate of reported HIV cases in Canada has remained relatively stable over the last decade, with minor year-to-year variations. As in previous years, the gbMSM and PWID populations represent a high proportion of HIV diagnoses, although a sizable number of cases were attributed to heterosexual contact. It is important to routinely monitor trends in HIV in light of pan-Canadian commitments to reduce the health impact of sexually transmitted and blood-borne infections by 2030.

A time-series analysis of testing and COVID-19 outbreaks in Canadian federal prisons to inform prevention and surveillance efforts.

Approximately 14,000 adults are currently incarcerated in federal prisons in Canada. These facilities are vulnerable to disease outbreaks and an assessment of coronavirus disease 2019 (COVID-19) testing and outcomes is needed. The objective of this study was to examine outcomes of COVID-19 testing, prevalence, case recovery and death within federal prisons and to contrast these data with those of the general population. Public time-series outcome data for prisoners and the general population were obtained on-line from the Correctional Service of Canada and the Public Health Agency of Canada, respectively, from March 30 to May 27, 2020. Prison, province and sex-specific frequency statistics for each outcome were calculated. A total of 50 facilities were included in this study. Of these 50 facilities, 64% reported fewer individuals tested per 1,000 population than observed in the general population and 12% reported zero tests in the study period. Testing tended to be reactive, increasing only once prisons had recorded positive tests. Six prisons reported viral outbreaks, with three recording over 20% cumulative COVID-19 prevalence among prisoners. Cumulatively, in prisons, 29% of individuals tested received a positive result, compared to 6% in the general population. Two of the 360 cases died (0.6% fatality). Four outbreaks appeared to be under control (more than 80% of cases recovered); however, sizeable susceptible populations remain at risk of infection. Female prisoners (5% of the total prisoner population) were over-represented among cases (17% of cases overall). Findings suggest that prison environments are vulnerable to widespread severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Gaps in testing merit public health attention. Symptom-based testing alone may not be optimal in prisons, given observations of widespread transmission. Increased sentinel or universal testing may be appropriate. Increased testing, along with rigorous infection prevention practices and the potential release of prisoners, will be needed to curb future outbreaks.

Indigenous Women’s Stress and Postpartum Depression: Discussions from the Canadian Maternity Experiences Survey and Indigenous Maternity Narratives


 
 
 This doctoral research highlights Indigenous women’s experiences of stress and postpartum depression (PPD) through secondary quantitative analysis of the Public Health Agency of Canada’s Canadian Maternity Experiences Survey (2009) and qualitative Indigenous maternity narratives. Indigenous women’s responses to the survey demonstrate that Indigenous women experience 1.9 times higher odds of PPD and are 1.5 times as likely to be diagnosed with depression prior to pregnancy, compared to Canadian women. Indigenous women are also 1.3 times as likely to experience higher levels of stress and 3.3 times as likely to experience three or more stressful life events. While the survey demonstrates higher rates of stress and PPD, it is not culturally or contextually relevant. Therefore, Indigenous maternity narratives from 10 Indigenous mothers in 2015 further contextualize experiences of stress and PPD to include narratives related to adverse social determinants of health and impacts of colonialism. The research includes a discussion on the limitations of previous maternity research and the limits of clinical-medical assessments and diagnosis of stress and PPD in Indigenous populations. The research concludes with recommendations for additional maternity experiences research and ways to support Indigenous women, infants and children, birth partners, families, and communities.
 
 

Simulating Preventative Testing of SARS-CoV-2 in Schools: Policy Implications

Background: School testing for SARS-CoV-2 infection has become an important policy and planning issue as schools are reopened after the summer season and as the COVID-19 pandemic continues. Decisions to test or not to test and, if testing, how many tests, how often and for how long, are complex decisions that need to be taken under uncertainty and conflicting pressures from various stakeholders.Method: We have developed an agent-based model and simulation tool that can be used to analyze the outcomes and effectiveness of different testing strategies and scenarios in schools with various number of classrooms and class sizes. We have applied a modified version of a standard SEIR disease transmission model that includes symptomatic and asymptomatic infectious populations, and that incorporates feasible public health measures. We also incorporated a pre-symptomatic phase for symptomatic cases. Every day, a random number of students in each class are tested. If they tested positive, they are placed in self-isolation at home when the test results are provided. Last but not least, we have included options to allow for full testing or complete self-isolation of a classroom with a positive case.Finding: We present sample simulation results for parameter values based on schools and disease related information, in the Province of Ontario, Canada. The findings show that testing can be an effective method in controlling the SARS-CoV-2 infection in schools if taken frequently, with expedited test results and self-isolation of infected students at home. Our findings show that while testing cannot eliminate the risk and has its own challenges, it can significantly control outbreaks when combined with other measures, such as masks and other protective measures.Funding Statement: Public Health Agency of Canada, Canadian Institute of Health Research, Ontario Research Funds, National Science and Engineering Research Council of Canada.Declaration of Interests: None to declare.

La réduction des complications de macrosomie, de déchirure périnéale et de césarienne à l’accouchement par la pratique d’activités physiques : état de la recherche

In Canada, there are more than 350,000 childbirths per year (Statistics Canada, 2019). In the final phase of pregnancy, women can have a birth with or without complications (WHO, 2018; Public Health Agency of Canada, 2018). According to several researchers, physical activity in several cases helps prevent some of these complications (Public Health Ontario, 2015 ; Government du Québec, 2019). The present study aimed to determine whether physical activity plays a part in reducing the etiological factors of three delivery complications: macrosomia, perineal tears as well as caesarean section and, through this analysis, determine whether physical activity acts as a preventative measure. The results obtained underline the key preventative role of a physical activity intervention and of leisure with regard to macrosomia and caesarean section. As for the contribution of physical activity in reducing the risk of perineal tears, more research is needed to determine if its role is significant.

Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines Against Symptomatic SARS-CoV-2 Infection and Severe COVID-19 Outcomes in Ontario, Canada

Background: We estimated the effectiveness of BNT162b2 and mRNA-1273 vaccines among residents of Ontario, Canada, where a policy to use an up to 16-week interval between doses was adopted in March 2021.Methods: We conducted a test-negative design study using linked province-wide laboratory, vaccination, and health administrative datasets. We included symptomatic individuals tested for SARS-CoV-2 by RT-PCR between 14 December 2020 and 19 April 2021. Study outcomes included symptomatic infection and associated severe outcomes (hospitalization or death). We estimated adjusted vaccine effectiveness (aVE) using multivariable logistic regression.Findings: Among 324,033 symptomatic tested individuals, 53,270 (16·4%) were positive for SARS-CoV-2 and 21,272 (6·6%) had received ≥1 dose of mRNA vaccine. Among test-positive cases, 2,479 (4·7%) had a severe outcome. aVE against symptomatic infection ≥14 days after receiving only 1 dose was 60% (95%CI, 57–64%), increasing from 48% (95%CI, 41–54%) at 14–20 days after the first dose to 71% (95%CI, 63–78%) at 35–41 days. aVE ≥7 days after receiving 2 doses was 91% (95%CI, 89–93%). Against severe outcomes, aVE ≥14 days after receiving 1 dose was 70% (95%CI, 60–77%) and aVE ≥7 days after receiving 2 doses was 98% (95%CI, 88–100%). We observed lower aVE against both outcomes after receiving 1 dose for adults aged ≥70 years, but aVE estimates for older adults were comparable to younger adults after 28 days. After 2 doses, we observed high aVE against E484K-positive variants.Interpretation: Our findings suggest that 2 doses of BNT162b2 and mRNA-1273 vaccines are highly effective against both symptomatic infection and associated severe outcomes for all circulating variants, with effectiveness lower after only a single dose, particularly for older adults shortly after the first dose.Funding Information: Canadian Institutes of Health Research, Public Health Agency of Canada, Ontario Ministries of Health and Long-Term Care.Declaration of Interests: KW is CEO of CANImmunize and serves on the data safety board for the Medicago COVID-19 vaccine trial. SMM has received unrestricted research grants from Merck, GlaxoSmithKline, Sanofi Pasteur, Pfizer, and Roche-Assurex for unrelated studies. SMM has received fees as an advisory board member for GlaxoSmithKline, Merck, Pfizer, Sanofi Pasteur, and Seqirus. CHR has received an unrestricted research grant from Pfizer for an unrelated study. The other authors declare no conflicts of interest.Ethics Approval Statement: ICES is a prescribed entity under Ontario’s Personal Health Information Protection Act (PHIPA). Section 45 of PHIPA authorizes ICES to collect personal health information, without consent, for the purpose of analysis or compiling statistical information with respect to the management of, evaluation or monitoring of, the allocation of resources to or planning for all or part of the health system. Projects that use data collected by ICES under section 45 of PHIPA, and use no other data, are exempt from REB review. The use of the data in this project is authorized under section 45 and approved by ICES’ Privacy and Legal Office.

Seroprevalence and Risk Factors for SARS-CoV-2 Among Incarcerated Adult Men in Quebec, Canada (2021): A Cross-Sectional Study

Background: People in prison are at increased risk of SARS-CoV-2 infection due to overcrowding and challenges in implementing infection prevention and control measures. We examined the seroprevalence of SARS-CoV-2 and associated risk factors among incarcerated adult men in Quebec, Canada.Methods: We conducted a cross-sectional seroprevalence study in 2021 in three provincial prisons, representing 45% of Quebec’s incarcerated male provincial population. The primary outcome was SARS-CoV-2 antibody seropositivity (Roche Elecsys® serology test). Participants completed self-administered questionnaires on sociodemographic, clinical, and carceral characteristics. The association of carceral variables with SARS-CoV-2 seropositivity was examined using Poisson regression models with robust standard errors. Crude and adjusted prevalence ratios (aPR) with 95% confidence intervals (95%CI) were calculated.Findings: Between January 19 and September 15, 2021, 246 of 1,100 (22%) recruited individuals tested positive across three prisons (range 15–27%). Seropositivity increased with time spent in prison since March 2020 (aPR 2·17, 95%CI 1·53–3·07 for “all” vs. “little time”), employment during incarceration (aPR 1·64, 95%CI 1·28–2·11 vs. not), shared meal consumption during incarceration (“with cellmates”: aPR 1·46, 95%CI 1·08–1.97 vs. “alone”; “with sector”: aPR 1·34, 95%CI 1·03–1·74 vs. “alone”), and incarceration post-prison outbreak (aPR 2·32, 95% CI 1·69–3·18 vs. “pre-outbreak”).Interpretation: The seroprevalence of SARS-CoV-2 among incarcerated individuals was high and varied between prisons. Several carceral factors were associated with seropositivity, underscoring the importance of decarceration and occupational safety measures, individual meal consumption, and enhanced infection prevention and control measures including vaccination during incarceration. Funding Information: The Public Health Agency of Canada funded this study (# 2021-HQ-000103). Declaration of Interests: CD, AH, SC, JS, HP, LDB, and SP declare no competing interests. NK reports research funding from Gilead Sciences, advisory fees from Gilead Sciences, ViiV Healthcare, Merck and Abbvie, and speaker fees from Gilead Sciences and Merck, all outside of the submitted work. MMG reports an investigator-sponsored research grant from Gilead Sciences Inc. MMG reports contractual arrangements with the World Health Organization, the Institut national de santé publique du Québec, and the Institut d’excellence en santé et services sociaux du Québec, all outside of the submitted work. MPC reports grants from the McGill Interdisciplinary Initiative in Infection and Immunity and from the Canadian Institutes of Health Research. MPC reports personal fees from GEn1E Lifesciences and form nplex biosciences, both outside the submitted work. MPC is the co-founder of Kanvas Biosciences, Inc. and owns equity in the company. MPC has a pending patent for Methods for detecting tissue damage, graft versus host disease, and infections using cell-free DNA profiling pending, and a pending patent for Methods for assessing the severity and progression of SARS-CoV-2 infections using cell-free DNA. JC has research funding from ViiV Healthcare and Gilead Sciences, and reports remuneration for advisory work (ViiV Healthcare, Gilead Sciences and Merck Canada), outside the submitted work.Ethics Approval Statement: Participants provided written informed consent and received an honorarium of $10 CAD for their study participation. This study was approved by the McGill University Health Centre Research Ethics Board (MUHC REB #2021–6888) and the Direction régionale des services correctionnels du Québec (#2020–12493).

Organizing a Mass Gathering Amidst a Rising COVID-19 Public Health Crisis: Lessons Learned From a Chinese Public Health Forum in Vancouver, BC.

IntroductionThe coronavirus disease 2019 (COVID-19) evolved from a rising public health concern to a pandemic over mere weeks. Before March 11, 2020, the Public Health Agency of Canada had not advised against any mass gatherings. Herein, we highlight practical precautions taken by event organizers to adapt to the rising public health threat from COVID-19 and maintain public safety when conducting a health forum for the Chinese community of Vancouver, British Columbia on February 22, 2020.Materials and MethodsIn the pre-forum phase, we advertised the availability of virtual conferencing for remote participation in the forum and also had an official communication from the Ministry of Health available regarding COVID-19 on our website. At the forum, we ensured that attendees sanitized their hands at registration and had access to sanitizers throughout the forum. Additionally, we provided translated health literature on COVID-19 to participants and had our health professional speakers address COVID-19-related questions.ResultsThis year, 231 older Chinese adults attended the forum in-person, while 150 participated remotely. The total number of 381 participants compares well to previous iterations of the forum, with twice the amount of participants on average attending online than before. Of the participants who attended the forum, 89% suggested that the forum would be effective in improving their overall health and 87% cited the forum’s utility in directing them to access community resources. None of the attendees had COVID-19 or are suspected to have contracted it at the forum.ConclusionConducting a mass gathering during a crisis required closely following guidance from local public health authorities, constant and clear communication with attendees, and employing practical risk mitigation strategies.

Application of a Sanger-Based External Quality Assurance Strategy for the Transition of HIV-1 Drug Resistance Assays to Next Generation Sequencing.

The National Institute of Allergy and Infectious Diseases (NIAID) Virology Quality Assurance (VQA) established a robust proficiency testing program for Sanger sequencing (SS)-based HIV-1 drug resistance (HIVDR) testing in 2001. While many of the lessons learned during the development of such programs may also apply to next generation sequencing (NGS)-based HIVDR assays, challenges remain for the ongoing evaluation of NGS-based testing. These challenges include a proper assessment of assay accuracy and the reproducibility of low abundance variant detection, intra- and inter-assay performance comparisons among laboratories using lab-defined tests, and different data analysis pipelines designed for NGS. In collaboration with the World Health Organization (WHO) Global HIVDR Laboratory Network and the Public Health Agency of Canada, the Rush VQA program distributed archived proficiency testing panels to ten laboratories to evaluate internally developed NGS assays. Consensus FASTA files were submitted using 5%, 10%, and 20% variant detection thresholds, and scored based on the same criteria used for SS. This small study showed that the SS External Quality Assurance (EQA) approach can be used as a transitional strategy for using NGS to generate SS-like data and for ongoing performance while using NGS data from the same quality control materials to further evaluate NGS assay performance.