Ontario COVID-19 Update (December 21st-22nd)
Public Health Ontario released its most recent COVID-19 wastewater data on December 21st, and their most recent update of the Respiratory Virus Tool on December 22nd.
Wastewater data was only released in chart form until June 2023, when an excel data set was made available with each update. This data set only provides data for the previous year, so this is why the data shown below begins in June 2022, the earliest data released in the first data set. Since the most recent data only includes data from December 2022, the charts below are created from a combination of weekly data sets, using the most recent available data for each reference week.
As of December 16th, the wastewater signal in Ontario was:
higher than ALL previous values since June 2022
25.4% higher than 1 week prior
51.8% higher than 2 weeks prior
71.1% higher than 3 weeks prior
86.2% higher than 4 weeks prior
116.1% higher than 5 weeks prior
164.3% higher than 6 weeks prior
199.0% higher than 7 weeks prior
211.6% higher than 8 weeks prior
As of December 16th, the wastewater signal in the Central East (excluding GTA) region was
higher than ALL previous values since June 2022
30.0% higher than 1 week prior
71.2% higher than 2 weeks prior
86.7% higher than 4 weeks prior
416.2% higher than 6 weeks prior
333.3% higher than 8 weeks prior
As of December 16th, the wastewater signal in the Central West (excluding GTA) region was
higher than ALL previous values since June 2022
4.8% higher than 1 week prior
20.7% higher than 2 weeks prior
96.4% higher than 4 weeks prior
425.8% higher than 6 weeks prior
302.5% higher than 8 weeks prior
As of December 16th, the wastewater signal in the Eastern region was
higher than 92.5% of previous values since June 2022
3.1% lower than 1 week prior
4.8% lower than 2 weeks prior
2.8% higher than 4 weeks prior
40.1% higher than 6 weeks prior
50.7% higher than 8 weeks prior
As of December 16th, the wastewater signal in the Greater Toronto Area (GTA) region was
higher than ALL previous values since June 2022
48.8% higher than 1 week prior
104.5% higher than 2 weeks prior
168.7% higher than 4 weeks prior
242.9% higher than 6 weeks prior
339.0% higher than 8 weeks prior
As of December 16th, the wastewater signal in the North East region was
higher than 86.3% of previous values since June 2022
20.7% lower than 1 week prior
35.0% lower than 2 weeks prior
29.3% lower than 4 weeks prior
38.3% higher than 6 weeks prior
47.7% higher than 8 weeks prior
As of December 16th, the wastewater signal in the North West region was
higher than 89.5% of previous values since June 2022
7.3% lower than 1 week prior
16.0% lower than 2 weeks prior
28.7% lower than 4 weeks prior
15.2% lower than 6 weeks prior
33.6% higher than 8 weeks prior
As of December 16th, the wastewater signal in the South West region was
higher than 93.7% of previous values since June 2022
1.8% lower than 1 week prior
9.0% lower than 2 weeks prior
17.3% lower than 4 weeks prior
35.0% higher than 6 weeks prior
86.2% higher than 8 weeks prior
Since COVID-19 testing was heavily restricted in Ontario in January 2022, presenting case figures alone is misleading. For this reason, I have chosen to chart weekly cases against weekly tests in Ontario. The y-axis scales differ, as there are many more tests than there are cases. At the current scales, there are 5x as many tests as there are cases where tests and cases appear equal.
Plotting cases alone might leave the impression that weekly cases have reduced drastically since the peaks of around 25,000 in Winter 2020-21, 31,000 in Spring 2021, and 102,000 in Winter 2021-22. But there were roughly 16 tests for every case at the peak of the Winter 2020-21 wave, 12 tests for every case at the peak of the Spring 2021 wave, and 4 tests for every case at the peak of the Winter 2021-22 wave.
In the most recent week, there were roughly 6 tests for every case.
This is slightly more promising than what was seen during the initial Omicron wave, but much worse than in the pre-Omicron waves.
The chart above shows weekly tests charted against percent positivity, and percent positivity tells a similar story to that noted above. Percent positivity was much lower than it is at present throughout 2020 and 2021, and was only higher than present values during the peak of the Winter 2021-22 wave.
*Note that percent positivity is often not exactly equal to the number of cases divided by the number of tests, due to details of methodology, though they are very close.
Hospital bed occupancy is also on the rise, though the recent peak around 1,700 is not as high as that seen in Spring 2021 and Winter 2021-22, and very close though not quite as high as that seen in Fall 2022. There has been a slight decrease in the 2 most recent reporting weeks. It is notable that current hospital occupancy is far higher than the peak in Spring 2020, when officials were urging the public to help “flatten the curve”. I continue to believe this is crucial advice, though governments appear to have abandoned this goal.
COVID-19 outbreaks have risen dramatically in Ontario since Summer 2023, peaking (for the time being) in late November/ early December. While the most recent peak round 200 is lower than several earlier peaks (around 300 in Winter 2021-22, 400 in Spring 2022, 700 in Winter 2021-22, 300 in Spring 2022 and in Summer 2022, and 250 in Fall 2022), the technical notes for this data include the following:
Outbreak definitions have changed over the course of the pandemic and outbreaks were declared based on the definitions in place at the time
As outbreak definitions have generally become less broad over time, this likely leads to lower numbers in more recent periods relative to that seen earlier in the pandemic. But even putting this issue aside, there are a significant number of outbreaks in recent weeks, at levels comparable to many earlier waves and much higher than the lows seen in Summer months.
I am continuing to experience ongoing health issues, so unfortunately I can not guarantee regular updates going forward. But I do hope to use my time off during the holidays to get caught up as much as possible.