COVID-19 Delta-driven fourth wave could decline in the coming weeks in Canada

Tuesday, 12 October 2021 10:32.AM

The Public Health Agency of Canada (PHAC) continues to monitor COVID-19 epidemiological indicators to quickly detect, understand and communicate emerging issues of concern. The following is a summary of the latest national numbers and trends. Today, I presented an update on national epidemiology and modelling. The following is a brief summary of the modelling results and the latest national numbers and trends.

The updated longer-range modelling forecast suggests that at current levels of transmission, the Delta-driven fourth wave could decline in the coming weeks if we maintain vaccine uptake and existing public health measures. This is a significant improvement over the previous trajectory presented in early September, when a large resurgence was forecast. The re-introduction of public health measures in heavily impacted areas has helped slow overall epidemic growth, nationally. Although several jurisdictions are still facing considerable challenges, this update reaffirms that by achieving a strong foundation of protection, with over 82% of eligible Canadians fully vaccinated, and applying public health measures, epidemic growth can be managed.

Even at current levels of vaccination coverage, the importance of core public health and personal protective measures like mask-wearing and limiting contacts continue to be important for managing epidemic growth and to reduce the risk of overwhelming healthcare capacity. As we head into Thanksgiving weekend, Canadians are urged to keep gatherings small and follow public health advice based on the local epidemiological situation. Keeping up with best practices in all our interactions this weekend and in the months ahead will help protect our progress and keep us safer, including by helping to prevent other respiratory infections during the winter months.

During this fourth wave of the COVID-19 pandemic in Canada, infections and severe outcomes have several key features:

- Nationally, the highly contagious Delta Variant of Concern (VOC), accounts for the majority of recently reported cases, is associated with increased severity, and may reduce the effectiveness of vaccines
- Most reported cases, hospitalizations and deaths are occurring among unvaccinated people
- Virus spread in areas with low vaccination coverage presents an ongoing risk for emergence of and replacement by new VOCs, including a risk of VOCs with the ability to evade vaccine protection.

Since the start of the pandemic, there have been 1,651,236 cases of COVID-19 and 28,141 deaths reported in Canada. These cumulative numbers tell us about the overall burden of COVID-19 illness to date, while the number of active cases, now at 41,549, and 7-day moving averages indicate current disease activity and severity trends.

Updated surveillance data show ongoing regional variation in disease activity, but overall, public health measures re-applied in heavily impacted areas have slowed acceleration of the epidemic nationally. The latest national 7-day average of 3,745 new cases reported daily (Oct 1-7) is a decrease of 14% over the previous week. Unfortunately, hospitalisation and critical care admission trends, primarily involving unvaccinated people, are still elevated, nationally. Together with prolonged hospital stays this continues to place a heavy strain on local healthcare resources, particularly where infection rates are high and vaccination rates are low. The latest provincial and territorial data show that an average of 2,513 people with COVID-19 were being treated in Canadian hospitals each day during the most recent 7-day period (Oct 1-7), which is 2.5% higher than last week. This includes, on average, 769 people who were being treated in intensive care units (ICU), 3.2% less than last week and an average of 38 deaths were reported daily (Oct 1-7). It is hoped that maintaining strengthened control measures in heavily impacted areas will begin to reduce severe illness trends and ease the strain on the health system in the weeks to come.

Regardless of which SARS-CoV-2 variant is predominating in an area, we know that vaccination, in combination with public health and individual measures, continue to work to reduce disease spread and severe outcomes. In particular, evidence continues to demonstrate that a complete two-dose series of Health-Canada approved COVID-19 vaccines provides substantial protection. Based on the latest data from 12 provinces and territories for the eligible population, 12 years or older:

- From December 14, 2020 to September 18, 2021, 0.16% of fully vaccinated people became infected, with the majority of recent cases and hospitalizations occurring in unvaccinated or partially vaccinated people.
- In recent weeks (August 22 – September 18, 2021):
-- -- the average weekly rate of new COVID-19 cases in unvaccinated people was 10 times higher than in the fully vaccinated.
-- -- the average weekly rate of hospitalized cases in unvaccinated people was 36 times higher compared to fully vaccinated people.

As of October 7, 2021, provinces and territories have administered over 56 million doses of COVID-19 vaccines, with the latest provincial and territorial data indicating that over 88% of people aged 12 years or older have received at least one dose of COVID-19 vaccine and over 82% are now fully vaccinated. Age-specific vaccine coverage data, as of October 2nd 2021, show that over 86% of people 40 years or older have at least one dose and over 80% are fully vaccinated, while 82% of younger adults aged 18-39 years have at least one dose and 72%-74% are fully vaccinated.

As more of our activities move indoors, this fall and winter, we must strive to have as many eligible people as possible fully vaccinated against COVID-19 as quickly as possible to protect ourselves and others, including those who may not mount a strong immune response or who cannot get vaccinated. Implementing timed and targeted public health measures and maintaining individual protective practices will be crucial for slowing COVID-19 infection rates and reducing the impact on healthcare capacity. While our protection against COVID-19 has been bolstered by vaccines, we also need to think about the return of other respiratory infections. We can stay healthier by getting up-to-date with recommended vaccines, such as influenza and other routine vaccines for children and adults and maintaining basic precautions that help slow the spread of COVID-19 as well as other respiratory infections.

While COVID-19 is still circulating in Canada and internationally, core public health practices remain crucial: stay home/self-isolate if you have symptoms; be aware of risks associated with different settings; follow local public health advice and maintain individual protective practices. In particular, physical distancing and properly wearing a well-fitted and well-constructed face mask provide additional layers of protection that further reduce your risk in all settings, as well as getting the best ventilation possible in indoor spaces. Canadians are advised to continue avoiding non-essential travel outside of Canada; if you must travel, be aware of the requirements for visiting other countries and for returning to Canada.

For additional information regarding vaccination in your area, reach out to your local public health authorities, healthcare provider, or other trusted and credible sources, such as Canada.ca and Immunize.ca. Canada.ca provides a broad range of COVID-19 information and resources to help Canadians understand the benefits of being vaccinated against COVID-19 and find guidance on life after vaccination.

Canadians can also go the extra mile by sharing credible information on COVID-19 risks and prevention practices and measures to reduce COVID-19 in communities. Read my backgrounder to access more COVID-19 Information and Resources on ways to reduce the risks and protect yourself and others, including information on COVID-19 vaccination.

SOURCE: Public Health Agency of Canada