Risk factors associated with the intensity of COVID-19 outbreaks in Canadian community settings: a retrospective analysis of outbreak-level surveillance data.

BACKGROUND: The severity of COVID-19 outbreaks is disproportionate across settings (e.g., long-term care facilities (LTCF), schools) across Canada. Few studies have examined factors associated with outbreak severity to inform prevention and response. Our study objective was to assess how outbreak severity, as measured using outbreak intensity and defined as number of outbreak-associated cases divided by outbreak duration, differed by setting and factors known to influence SARS-CoV-2 transmission. METHODS: We described outbreak intensity trends in 2021 using data from the Canadian COVID-19 Outbreak Surveillance System from seven provinces/territories, representing 93% of the Canadian population. A negative binomial fixed-effects model was used to assess for associations between the outcome, outbreak intensity, and characteristics of outbreaks: setting type, median age of cases, number at risk, and vaccination coverage of at least 1 dose. Also included were variables previously reported to influence SARS-CoV-2 transmission: stringency of non-pharmaceutical interventions (NPI) and the predominant SARS-CoV-2 variant detected by surveillance. RESULTS: The longest outbreaks occurred in LTCF (mean = 25.4 days) and correctional facilities (mean = 20.6 days) which also reported the largest outbreaks (mean = 29.6 cases per outbreak). Model results indicated that outbreak intensity was highest in correctional facilities. Relative to correctional facilities (referent), the second highest adjusted intensity ratio was in childcare centres (intensity ratio = 0.58 [95% CI: 0.51-0.66]), followed by LTCF (0.56 [95% CI: 0.51-0.66]). Schools had the lowest adjusted intensity ratio (0.46 [95% CI: 0.40-0.53]) despite having the highest proportion of outbreaks (37.5%). An increase in outbreak intensity was associated with increases in median age, the number at risk, and stringency of NPI. Greater vaccination coverage with at least 1 dose was associated with reduced outbreak intensity. CONCLUSION: Descriptive and multivariable model results indicated that in Canada during 2021, outbreak intensity was greatest in closed congregate living facilities: correctional facilities and LTCF. Findings from this study support the importance of vaccination in reducing outbreak intensity when vaccines are effective against infection with circulating variants, which is especially important for closed congregate living facilities where NPIs are more challenging to implement.

Post-licensure deployment of oral cholera vaccines: a systematic review.

OBJECTIVE: To describe and analyse the characteristics of oral cholera vaccination campaigns; including location, target population, logistics, vaccine coverage and delivery costs. METHODS: We searched PubMed, the World Health Organization (WHO) website and the Cochrane database with no date or language restrictions. We contacted public health personnel, experts in the field and in ministries of health and did targeted web searches. FINDINGS: A total of 33 documents were included in the analysis. One country, Viet Nam, incorporates oral cholera vaccination into its public health programme and has administered approximately 10.9 million vaccine doses between 1997 and 2012. In addition, over 3 million doses of the two WHO pre-qualified oral cholera vaccines have been administered in more than 16 campaigns around the world between 1997 and 2014. These campaigns have either been pre-emptive or reactive and have taken place under diverse conditions, such as in refugee camps or natural disasters. Estimated two-dose coverage ranged from 46 to 88% of the target population. Approximate delivery cost per fully immunized person ranged from 0.11-3.99 United States dollars. CONCLUSION: Experience with oral cholera vaccination campaigns continues to increase. Public health officials may draw on this experience and conduct oral cholera vaccination campaigns more frequently.

Responding to and managing multijurisdictional outbreaks of COVID-19 in Canadian industrial worksite/work camp settings.

SETTING: Early in the COVID-19 pandemic, the Public Health Agency of Canada (PHAC) and provincial/territorial (P/T) public health identified the need for a coordinated response to complex multijurisdictional COVID-19 outbreaks. The first large multijurisdictional industrial worksite COVID-19 outbreak highlighted the risk of transmission within these congregate work settings, the risk of transmission to the broader community(ies), and the need to develop setting-specific outbreak response frameworks. INTERVENTION: PHAC assembled a team to provide national outbreak support for multijurisdictional COVID-19 outbreaks in May 2020. The COVID-19 Outbreak Response Unit (ORU) worked with P/T partners to develop guiding principles for outbreak response and outbreak investigation processes, guidance documents, and investigation tools (e.g., minimum data elements and questionnaires). OUTCOMES: The ORU, P/T partners, and onsite industrial worksite health and safety staff leveraged outbreak investigation guidelines, industrial worksite outbreak process documents (including minimum data elements), and enhanced case questionnaires to respond to multiple COVID-19 outbreak investigations in industrial worksites. Clear roles/responsibilities and processes, along with standardized data, allowed for more efficient outbreak investigations and earlier implementation of mitigation measures. IMPLICATIONS: Multijurisdictional COVID-19 outbreaks highlighted the importance of public health collaboration with industry partners onsite. The assembly of a national outbreak response team was important to facilitate information sharing and provide technical support. Lessons learned and recommendations on outbreak preparation, detection, management, and communication are included to enhance a response framework applicable to future emerging or re-emerging pathogens with epidemic and/or pandemic potential.

RéSUMé: CONTEXTE: Au début de la pandémie de COVID-19, l'Agence de la santé publique du Canada (ASPC) et les autorités provinciales/territoriales de santé publique ont reconnu la nécessité d'une réponse coordonnée en cas d'éclosions complexes multi-juridictionnelles de COVID-19. La première grande éclosion multi-juridictionnelle de COVID-19 dans un chantier industriel a mis en évidence le risque de transmission dans ces milieux de travail collectifs, le risque de transmission à l'ensemble de la (des) communauté(s) et la nécessité d'élaborer des cadres d'intervention en cas d'éclosion spécifiques aux types de milieux. INTERVENTION: L'ASPC a formé une équipe chargée de soutenir la réponse nationale contre les éclosions multi-juridictionnelles de COVID-19 en mai 2020. L'Unité d'intervention en cas d'éclosion (UIE) de COVID-19 a collaboré avec des partenaires provinciaux et territoriaux pour élaborer des principes de référence pour la lutte contre les éclosions de COVID-19 et des processus d'enquête sur les éclosions, des documents d'orientation et des outils d'enquête (p.ex. des éléments de données minimales et des questionnaires). RéSULTATS: L'UIE, les provinces et territoires et le personnel chargé de la santé et sécurité du travail sur le site se sont appuyés sur des principes de référence aux enquêtes sur les éclosions, les documents de processus d'enquête sur les éclosions dans les sites industriels, y compris les éléments de données minimales et le questionnaire détaillé sur les cas, pour répondre à multiples enquêtes d'éclosions de COVID-19 dans les sites industriels. Des rôles/responsabilités et des processus clairs, ainsi que des données standardisées, ont permis de mener des enquêtes plus efficaces sur les éclosions et de mettre en œuvre plus rapidement des mesures d'atténuation. IMPLICATIONS: Les éclosions multi-juridictionnelles de COVID-19 ont mis en évidence l'importance de la collaboration entre les autorités de santé publique et les partenaires industriels sur site. La constitution d'une équipe nationale d'intervention en cas d'éclosion a été importante pour faciliter le partage des informations et fournir un soutien technique. Les connaissances acquises et les recommandations sur la préparation, la détection, la gestion et la communication des éclosions sont incluses afin d'améliorer le cadre de réponse aux futurs agents pathogènes émergents ou ré-émergents ayant un potentiel épidémique et/ou pandémique.

Canadian COVID-19 Outbreak Surveillance System: implementation of national surveillance during a global pandemic.

SETTING: Early in the SARS-CoV-2 pandemic, the need to develop systematic outbreak surveillance at the national level to monitor trends in SARS-CoV-2 outbreaks was identified as a priority for the Public Health Agency of Canada (PHAC). The Canadian COVID-19 Outbreak Surveillance System (CCOSS) was established to monitor the frequency and severity of SARS-CoV-2 outbreaks across various community settings. INTERVENTION: PHAC engaged with provincial/territorial partners in May 2020 to develop goals and key data elements for CCOSS. In January 2021, provincial/territorial partners began submitting cumulative outbreak line lists on a weekly basis. OUTCOMES: Eight provincial and territorial partners, representing 93% of the population, submit outbreak data on the number of cases and severity indicators (hospitalizations and deaths) for 24 outbreak settings to CCOSS. Outbreak data can be integrated with national case data to supply information on case demographics, clinical outcomes, vaccination status, and variant lineages. Data aggregated to the national level are used to conduct analyses and report on outbreak trends. Evidence from CCOSS analyses has been useful in supporting provincial/territorial outbreak investigations, informing policy recommendations, and monitoring the impact of public health measures (vaccination, closures) in specific outbreak settings. IMPLICATIONS: The development of a SARS-CoV-2 outbreak surveillance system complemented case-based surveillance and furthered the understanding of epidemiological trends. Further efforts are required to better understand SARS-CoV-2 outbreaks for Indigenous populations and other priority populations, as well as create linkages between genomic and epidemiological data. As SARS-CoV-2 outbreak surveillance enhanced case surveillance, outbreak surveillance should be a priority for emerging public health threats.

RéSUMé: CONTEXTE: Au début de la pandémie de SRAS-CoV-2, l'Agence de la santé publique du Canada (ASPC) a déterminé comme priorité la nécessité de développer un système de surveillance systématique des éclosions à l'échelle nationale afin de suivre les tendances des éclosions de SRAS-CoV-2. Le système canadien de surveillance des éclosions de COVID-19 (SCSEC) a été établi pour surveiller la fréquence et la gravité des éclosions de SRAS-CoV-2 dans différents milieux communautaires. INTERVENTION: L'ASPC s'est engagée avec les partenaires provinciaux et territoriaux en mai 2020 pour élaborer des objectifs et des éléments de données clés pour le SCSEC. En janvier 2021, les partenaires provinciaux et territoriaux ont commencé à transmettre des listes d'éclosions cumulatives hebdomadaires. RéSULTATS: Huit partenaires provinciaux et territoriaux, représentant 93 % de la population, transmettent au SCSEC des données sur les éclosions sur le nombre de cas et les indicateurs de gravité (les hospitalisations et les décès) pour 24 types de milieux. Les données sur les éclosions peuvent être intégrées avec les données nationales sur les cas pour obtenir des informations sur la démographie des cas, les résultats cliniques, le statut vaccinal et les lignées de variants. Les données agrégées à l'échelle nationale sont utilisées pour effectuer des analyses et faire rapport des tendances sur les éclosions. Les résultats des analyses du SCSEC ont été utiles pour soutenir les enquêtes provinciales/territoriales sur les éclosions, informer les recommandations politiques et surveiller l'impact des mesures de santé publique (la vaccination, les fermetures) dans des milieux d'éclosions spécifiques. IMPLICATIONS: Le développement d'un système de surveillance des éclosions de SRAS-CoV-2 a permis de complémenter la surveillance des cas et d'approfondir notre compréhension des tendances épidémiologiques. Des efforts supplémentaires sont nécessaires pour mieux comprendre les éclosions de SRAS-CoV-2 chez les populations autochtones et d'autres populations minoritaires, ainsi que pour créer des liens entre les données génomiques et les données épidémiologiques. Comme la surveillance des éclosions de SRAS-CoV-2 a enrichi la surveillance des cas, la surveillance des éclosions devrait être une priorité pour les menaces émergentes pour la santé publique.

COVID-19 outbreak trends in Canada, 2021.

Background: In January 2021, the Public Health Agency of Canada launched an outbreak surveillance system, the Canadian COVID-19 Outbreak Surveillance System (CCOSS), with the goal of monitoring incidence and severity of coronavirus disease 2019 (COVID-19) outbreaks across various community settings and complementing case surveillance. Methods: Seven provinces were included in this report; these provinces submitted weekly cumulative COVID-19 outbreak line lists to CCOSS in 2021. Data includes administrative variables (e.g. date outbreak declared, date outbreak declared over, outbreak identifier), 24 outbreak settings, and number of confirmed cases and outcomes (hospitalization, death). Descriptive analyses for COVID-19 outbreaks across Canada from January 3, 2021, to January 1, 2022, were performed examining trends over time, severity, and outbreak size. Results: Incidence of outbreaks followed similar trends to case incidence. Outbreaks were most common in school and childcare settings (39%) and industrial/agricultural settings (21%). Outbreak size ranged from 2 to 639 cases per outbreak; the median size was four cases per outbreak. Correctional facilities had the largest median outbreak size with 18 cases per outbreak, followed by long-term care facilities with 10 cases per outbreak. During periods of high case incidence, outbreaks may be under-ascertained due to limited public health capacity, or reporting may be biased towards high-risk settings prioritized for testing. Outbreaks reported to CCOSS were dominated by jurisdictions with the largest populations. Conclusion: The trends illustrate that COVID-19 outbreaks in 2021 were reported most frequently in community settings such as schools; however, the largest outbreaks occurred in congregate living settings. The information gathered from outbreak surveillance complemented case incidence trends and furthered understanding of COVID-19 in Canada.

The burden of acute respiratory infections in crisis-affected populations: a systematic review.

Crises due to armed conflict, forced displacement and natural disasters result in excess morbidity and mortality due to infectious diseases. Historically, acute respiratory infections (ARIs) have received relatively little attention in the humanitarian sector. We performed a systematic review to generate evidence on the burden of ARI in crises, and inform prioritisation of relief interventions. We identified 36 studies published since 1980 reporting data on the burden (incidence, prevalence, proportional morbidity or mortality, case-fatality, attributable mortality rate) of ARI, as defined by the International Classification of Diseases, version 10 and as diagnosed by a clinician, in populations who at the time of the study were affected by natural disasters, armed conflict, forced displacement, and nutritional emergencies. We described studies and stratified data by age group, but did not do pooled analyses due to heterogeneity in case definitions. The published evidence, mainly from refugee camps and surveillance or patient record review studies, suggests very high excess morbidity and mortality (20-35% proportional mortality) and case-fatality (up to 30-35%) due to ARI. However, ARI disease burden comparisons with non-crisis settings are difficult because of non-comparability of data. Better epidemiological studies with clearer case definitions are needed to provide the evidence base for priority setting and programme impact assessments. Humanitarian agencies should include ARI prevention and control among infants, children and adults as priority activities in crises. Improved data collection, case management and vaccine strategies will help to reduce disease burden.