SUBMITTED BY:
Epidemiology and Evaluation Department
DATE:
January, 2022
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 assists in the development of timely interventions to limit further spread in the community.
Due to the recent surge in Omicron cases and changes in eligibility for testing, testing capacity is limited and case, contact, and outbreak management has been modified to focus on high-risk settings. As a result, case counts in this report are an underestimate of the true number of individuals with COVID-19 in Windsor-Essex County and may impact data completeness. Please interpret these data accordingly.
Trends
In the month of December (2021), the health unit reported 3,811 confirmed cases of COVID-19. This is a 174.0% increase in case counts compared to the previous month of November (2021). Similarly, the monthly case rate for December was 881.8 cases per 100,000 population, which is higher compared to the monthly rate in November (321.8 cases per 100,000 population). In Ontario, during the month of December, the case rate was 935.7 cases per 100,000 population.
Age and Gender
Approximately 52% (1,971) of the cases were among females and 47% (1,828) among males. A disproportionately (22.0%) higher number of cases, in November 2021, were reported among those 20 to 29 years of age, followed by 20.9% among those 0 to 19 years of age, and 16.5% in the 30 to 39 year age group. Comparatively, from the onset of the pandemic locally (March 1, 2020 to December 31, 2021), approximately 16% of our cases were in the 0 to 19 age group.
Municipal Distribution
The Town of Tecumseh had the highest case rates (1184.3 cases per 100,000 population), followed by Amherstburg (976.8 cases per 100,000 population), Leamington (972.1 cases per 100,000 population), and Kingsville (925.1 cases per 100,000 population). However, looking at the distribution of cases, 53% of cases were from the City of Windsor, 9% from Lakeshore, 8% from Tecumseh and 8% from Leamington.
Risk Factors
For the month of December 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%).
Source of Acquisition
Approximately, 23.0% of cases in December (2021) acquired COVID-19 from an unknown source (no epi-link identified), 19.9% from a household contact and 12.9% from a close contact outside of their household. With the change in testing eligibility in the province in December alongside the high number of cases, approximately 29.7% of cases are still under investigation.
Outcome Status
Of the 3,811 cases reported in December (2021), 47.4% (1,808) had their infection resolved, 1,145 cases (30.0%) were active and being followed by the health unit, and 20.0% (764) of cases were lost to follow-up. Twenty-four deaths were reported in December (2021) due to COVID-19.
Vaccination Status
107,139 doses were administered to Windsor-Essex County residents in the month of December (2021) compared to over 36,141 doses in the month of November. This represents a 196.4% increase for the month of December (2021) due to the eligibility of 5 to 11 year olds and access for third dose boosters. Approximately 86.7% of the doses administered were third doses/boosters, 8.8% were first doses to individuals who were previously unvaccinated, and 4.5% were among those completing their vaccination series (fully vaccinated).
Among the 3,811 cases reported in December (2021), 64.0% were fully vaccinated, 29.6% were unvaccinated, 4.7% were partially protected with one dose, and 1.8% were not yet protected after receiving the first dose. Among the 1,129 unvaccinated cases, approximately 65.6% were among those 0 to 18 years of age, which includes children who were ineligible to receive the vaccine.
CURRENT INITIATIVES
With the changes in testing eligibility, and guidance with case, contact and outbreak management, the health unit is exploring other methods to conduct COVID-19 surveillance and epidemiological analyses. 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.