December 2021 Board of Health Meeting - COVID-19 Surveillance and Epidemiology Information Report

Meeting Document Type
Information Report
COVID-19 Surveillance and Epidemiology


Epidemiology and Evaluation Department


December, 2021


COVID-19 Surveillance and Epidemiology



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 assists in the development of timely interventions to limit further spread in the community.


In the month of November (2021), the health unit reported 1,391 confirmed cases of COVID-19. This is a 72.2% increase in case counts compared to the previous month of October (2021). Similarly, the monthly case rate for November was 321.8 cases per 100,000 population, which is higher compared to the monthly rate in October (187.0 cases per 100,000 population). In Ontario, during the month of November, the case rate was 125.0 cases per 100,000 population. This is approximately 2.6 times lower compared to the rate of Windsor-Essex County.

Age and Gender

Approximately 52% (729) of the cases were among females and 47% among males. A disproportionately (21.9%) higher number of cases, in November 2021,  were reported among those 0 to 18 years of age, followed by 15.6% among those 30 to 39 years of age, and 15.5% in the 40 to 49 year age group. Comparatively, from the onset of the pandemic locally (March 1, 2020 to November 30, 2021), approximately 16% of our cases were in the 0 to 19 age group.

Municipal Distribution

The Town of Leamington had the highest case rates (548.7 cases per 100,000 population), followed by Amherstburg (469.0 cases per 100,000 population), Tecumseh (461.3 cases per 100,000 population), and Essex (433.7 cases per 100,000 population). However, looking at the distribution of cases, 46% of cases were from the City of Windsor, 12% from Leamington, 8% from Tecumseh and 8% from Essex.

Risk Factors

For the month of November 2021, the top three risk factors reported were being an elementary or secondary student (15.6%), being a healthcare worker (2.4%) and being an educational staff (2.2%).

Variants of Concern (VOCs)

Of the 1,391 cases reported in the month of November, genomic sequencing results were available for 528 cases (38% of cases). Overall, 36% of cases reported were due to the Delta variant (B.1.617.2).

Source of Acquisition

Approximately, 33% of cases in November (2021) acquired COVID-19 from an unknown source (no epi-link identified), 29% from a household contact, 20% from a close contact outside of their household, 8% due to being related to an outbreak, and 1.6% from travel-related outside of the province (e.g., to another province and/or outside of Canada).

Outcome Status

Of the 1,391 cases reported in November (2021), 51% (706) had their infection resolved, 574 cases (45%) were active and being followed by the health unit, and 2.4% (21) of cases were lost to follow-up. Six deaths were reported in November (2021) due to COVID-19.

Vaccination Status

36,141 doses were administered to Windsor-Essex County residents in the month of November (2021) compared to over 21,889 doses in the month of October. This represents a 65% increase for the month of November (2021). Approximately 57% of the doses administered were third doses/boosters, 23% were first doses to individuals who were previously unvaccinated, and 20% were among those completing their vaccination series (fully vaccinated).

Among the 1,391 cases reported in November (2021), 49% were fully vaccinated, 46% were unvaccinated, 4.5% were partially protected with one dose, and 1% were not yet protected after receiving the first dose. Among the 636 unvaccinated cases, approximately 42% were among those 0 to 18 years of age which includes children who were ineligible to receive the vaccine.


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

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