Assessment of an enhanced COVID-19 case and contact management protocol in controlling a SARS-CoV-2 Alpha (B.1.1.7) variant outbreak on a construction site.

BACKGROUND: To control the spread of SARS-CoV-2 variants of concern (VOCs), Kingston, Frontenac, and Lennox & Addington (KFL&A) Public Health implemented a more stringent COVID-19 case and contact management (CCM) protocol than what was used across Ontario at the time. We describe epidemiological data and public health measures employed during one of the largest COVID-19 outbreaks in the KFL&A region at the time, caused by the SARS-CoV-2 Alpha (B.1.1.7) VOC, to assess this enhanced protocol. METHODS: We obtained line lists of workers associated with the construction site outbreak, and subsequent cases and contacts from case investigators. Case testing, mutation status, and whole genome sequencing were conducted by Public Health Ontario Laboratories. RESULTS: From 409 high-risk contacts of the outbreak, 109 (27%) developed COVID-19. Three generations of spread were associated with the outbreak, affecting seven public health regions across three provinces. Using an enhanced approach to the CCM, KFL&A Public Health caught 15 cases that could have been missed by standard provincial protocols. CONCLUSIONS: Rapid initial spread within the construction site produced a relatively high attack rate among workers (26%) and their immediate contacts (34%). KFL&A Public Health's implementation of stringent CCM protocols and fast testing turn-around time effectively curbed the spread of the disease in subsequent generations - illustrated by the large reduction in attack rate (34%-14%) and cases (50-10) between the second and third generations. Lessons learned from this analysis may inform guidance on the CCM for future SARS-CoV-2 VOCs as well as other highly transmissible communicable diseases.

HISTORIQUE: Pour contrôler la propagation des variants inquiétants (VOC) du SRAS-CoV-2, la région sociosanitaire de Kingston, Frontenac, Lennox et Addington (KFL&A) a adopté un protocole plus rigoureux de gestion des cas et des contacts (GCC) qui était utilisé partout en Ontario à l'époque. Les auteurs décrivent les données épidémiologiques et les mesures sanitaires employées pendant l'une des plus grosses éclosions de COVID-19 de la région sociosanitaire de KFL&A, causée par le VOC Alpha (B.1.1.7) du SRAS-CoV-2, afin d'évaluer ce protocole amélioré. MÉTHODOLOGIE: Les auteurs ont obtenu les listes des lignes des travailleurs associés à l'éclosion sur le chantier de construction, ainsi que des cas et des contacts subséquents des enquêteurs de cas. Les Laboratoires de Santé publique Ontario ont procédé au dépistage des cas et ont vérifié l'état mutationnel et le séquençage du génome entier. RÉSULTATS: Des 409 contacts à haut risque de l'éclosion, 109 (27%) ont contracté la COVID-19. Trois générations de propagation étaient associées à l'éclosion et touchaient sept régions sociosanitaires réparties dans trois provinces. Au moyen d'une approche améliorée de la GCC, la région sociosanitaire de KFL&A a dépisté 15 cas qui auraient pu être omis par les protocoles provinciaux standards. CONCLUSIONS: Une propagation initiale rapide sur le chantier de construction a produit un taux d'attaque relativement élevé chez les travailleurs (26%) et leurs contacts immédiats (34%). Ladoption de protocoles rigoureux de GCC dans la région sociosanitaire de KFL&A et l'obtention rapide des résultats du dépistage ont enrayé la propagation de la maladie avec efficacité dans les générations suivantes, ce qui est démontré par une forte réduction du taux d'attaque (de 34% à 14%) et de cas (de 50 à 10) entre la deuxiéme génération et la troisiéme. Les leçons tirées de cette analyse pourraient éclairer les conseils sur la GCC des futurs VOC du SRAS-COV-2 et des autres maladies contagieuses hautement transmissibles.

COVID-19 Vaccine Uptake in Southeastern Ontario, Canada: Monitoring and Addressing Health Inequities.

CONTEXT: Implementation of a population-based COVID-19 vaccine strategy, with a tailored approach to reduce inequities in 2-dose coverage, by a mid-sized local public health agency in southeastern Ontario, Canada. PROGRAM: Coverage maps and crude and age-standardized coverage rates by material and social deprivation, urban/rural status, and sex were calculated biweekly and reviewed by local public health planners. In collaboration with community partners, the results guided targeted strategies to enhance uptake for marginalized populations. EVALUATION: The largest gaps in vaccine coverage were for those living in more materially deprived areas and rural residents-coverage was lower by 10.9% (95% confidence interval: -11.8 to -10.0) and 9.3% (95% confidence interval: -10.4 to -8.1) for these groups compared with living in less deprived areas and urban residents, respectively. The gaps for all health equity indicators decreased statistically significantly over time. Targeted strategies included expanding clinic operating hours and availability of walk-in appointments, mobile clinics targeted to marginalized populations, leveraging primary care partners to provide pop-up clinics in rural and materially and socially deprived areas, and collaborating with multiple partners to coordinate communication efforts, especially in rural areas. DISCUSSION: The scale and scope of monitoring and improving local vaccine uptake are unprecedented. Regular review of health equity indicators provided critical situational awareness for decision makers, allowing partners to align and tailor strategies locally and in collaboration with one another. Health care providers and pharmacies/pharmacists are key partners who require innovative support to increase uptake in marginalized groups. Continued engagement of other community partners such as schools, municipalities, and local service groups is also crucial. A "hyper local" approach is needed along with commitment from partners in all sectors and at all levels to reduce barriers to vaccination that lie further upstream for marginalized groups.

Limited Propagation of SARS-CoV-2 among Children in a Childcare Center, Canada, 2021.

An outbreak of severe acute respiratory syndrome coronavirus 2 with no definitive source and potential exposure to variants of concern was declared at a childcare center in Ontario, Canada, in March 2021. We developed a robust outbreak management approach to detect, contain, and interrupt this outbreak and limit propagation among children.

COVID-19 outbreak in a personal service setting in Kingston, Ontario, 2020.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, Ontario created a three-phase reopening framework for the economy. Outbreaks were expected at each phase. One week after Phase Two of reopening in the provincial public health administration region of Kingston, Frontenac, Lennox and Addington (KFL&A), a positive case was reported after three weeks of zero new COVID-19 cases. The objective of this report is to describe this COVID-19 outbreak, linked to a personal service setting (PSS), and the public health response to contain the outbreak. METHODS: The outbreak investigation included all COVID-19 cases in KFL&A between June 20, 2020 and July 3, 2020. Public health inspectors and nurses were rapidly deployed to inspect the PSS. A multimodal approach to high-volume testing involved fixed assessment centres, drive-through testing capacity and targeted testing at the outbreak site. Testing was conducted through a real-time polymerase chain reaction assay at the local Public Health Ontario laboratory. RESULTS: Thirty-seven cases were associated with the outbreak: 38% through direct PSS exposure; 32% through household contact; and 30% through social and workplace contact. A superspreading event contributed to 38% of total cases. The majority of cases were in the low to mid-quintiles when analyzed for material deprivation. Testing rates increased four-fold compared to the prior baseline weeks in response to media attention and public health messaging, resulting in a low percent positivity. CONCLUSION: The interplay of aggressive accessible testing, quick lab turnaround time, contact tracing within 24 hours of positive laboratory results as per provincial standards, frequent public communication, rapid inspections, mandatory self-isolation and face coverings were measures successful in halting the outbreak. Inspections or self-audits should be required at all PSSs prior to reopening and outbreak management must work with PSSs to reduce the possibility of superspreading events.

Phylogenomics reveals viral sources, transmission, and potential superinfection in early-stage COVID-19 patients in Ontario, Canada.

The emergence and rapid global spread of SARS-CoV-2 demonstrates the importance of infectious disease surveillance, particularly during the early stages. Viral genomes can provide key insights into transmission chains and pathogenicity. Nasopharyngeal swabs were obtained from thirty-two of the first SARS-CoV-2 positive cases (March 18-30) in Kingston Ontario, Canada. Viral genomes were sequenced using Ion Torrent (n = 24) and MinION (n = 27) sequencing platforms. SARS-CoV-2 genomes carried forty-six polymorphic sites including two missense and three synonymous variants in the spike protein gene. The D614G point mutation was the predominate viral strain in our cohort (92.6%). A heterozygous variant (C9994A) was detected by both sequencing platforms but filtered by the ARTIC network bioinformatic pipeline suggesting that heterozygous variants may be underreported in the SARS-CoV-2 literature. Phylogenetic analysis with 87,738 genomes in the GISAID database identified global origins and transmission events including multiple, international introductions as well as community spread. Reported travel history validated viral introduction and transmission inferred by phylogenetic analysis. Molecular epidemiology and evolutionary phylogenetics may complement contact tracing and help reconstruct transmission chains of emerging diseases. Earlier detection and screening in this way could improve the effectiveness of regional public health interventions to limit future pandemics.