SUBMITTED BY:
Ramsey D’Souza, Manager of Epidemiology and Evaluation
DATE:
October 2021
SUBJECT:
COVID-19 Surveillance and Epidemiology
BACKGROUND
Overview
The Epidemiology & Evaluation department conducts on-going population health assessment and surveillance. The data and surveillance for COVID-19 plays an integral role in understanding and managing the pandemic locally. The evidence provides information on how the pandemic has and is evolving, assessing the risk and severity, and develop timely interventions to limit further spread in the community.
Trends
In the month of September 2021, the health unit reported 1,542 confirmed cases of COVID-19. This is a 14% decrease in case counts compared to the previous month of August 2021. Similarly, the monthly case rate for September was 356.8 cases per 100,000 population, which is lower compared to the monthly rate in August (312.1 cases per 100,000 population). In Ontario, during the month of September, the case rate was 139.6 cases per 100,000 population. This is approximately 2.6 times lower compared to the rate of Windsor-Essex County.
Age and Gender
Approximately 51% (793) of the cases were among females and 48% among males. A disproportionately (26%) higher number of cases, in September 2021, were reported among those 0 to 18 years of age, followed by 19% among those 19 to 29 years of age, and 17% in the 30 to 39 year age group. Comparatively, from the onset of the pandemic locally (March 1, 2020 to September 30, 2021), 14% of our cases were in the 0 to 19 age group.
Municipal Distribution
The Town of Leamington had the highest case rates (447.1 cases per 100,000 population), followed by the Town of Kingsville (443.0 cases per 100,000 population) and the City of Windsor (376.0 cases per 100,000 population). However, looking at the distribution of cases, 58% of cases were from the City of Windsor, 9% from Leamington and 8% from Lakeshore.
Risk Factors
For the month of September 2021, the top five risk factors reported were an elementary or secondary student (11.2%), farm worker (3.2%), healthcare worker (2.4%), resident of a congregate living setting (1.8%) and a student in a childcare setting (1.4%).
Variants of Concern (VOCs)
Of the 1,542 cases reported in the month of September, genomic sequencing results were available for 1,391 cases (90% of cases). Overall, 78% of cases reported were due to the Delta variant (B.1.617.2), 12% of cases reported results without a variant, and 10% were not sequenced to identify a mutation or a VOC.
Source of Acquisition
Approximately, 32% of cases in September 2021 acquired COVID-19 from their household contact, 17% from a close contact outside of their household, 7% due to being related to an outbreak, and 3% from travel-related outside of the province (e.g., to another province and/or outside of Canada).
Outcome Status
Of the 1,542 cases reported in September 2021, 76% (1,175) had their infection resolved, 268 cases (18%) were active and being followed by the health unit, and 5.4% (83) of cases were lost to follow-up. Seventeen deaths were reported in September 2021 due to COVID-19.
Vaccination Status
Over 34,500 doses were administered to Windsor-Essex County residents in the month of September compared to 31,700 doses in the month of August. This represents a 9% increase for the month of September 2021. Approximately 51% of the doses administered were second doses to complete a vaccination, 39% were first doses to individuals who were previously unvaccinated, and 10% among those in the highest risk priority groups (e.g., residents of long-term care and retirement homes).
Among the 1,542 cases reported in September 2021, 66% were unvaccinated (or not eligible to receive a vaccine), 23% were fully vaccinated, 6% were partially protected with one dose, and 4% were not yet protected after receiving the first dose. Among the 775 unvaccinated cases, approximately 48% were among those 0 to 18 years of age which includes children who were ineligible to receive the vaccine.
CURRENT INITIATIVES
The health unit will continue to monitor and provide epidemiological expertise on COVID-19 to internal leadership, community partners, and residents to support evidence-informed decision-making. This includes daily epidemiological updates, weekly epidemiological presentations to the community and supporting policy decisions through data driven approaches.
CONSULTATION:
The following individuals were contributed to this report: Bridget Irwin, Scott Miller, Karanveer Banipal, Anum Khan, Noor Al-Azary