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Text Descriptions: COVID Data and Modelling

On April 9th, the Government of Canada released a "Technical Briefing for Canadians" entitled "COVID-19 in Canada: Using data and modelling to inform public health action." This PDF document, available for download (download COVID-19 in Canada: Using data and modelling to inform public health action), includes a number of graphs and figures, which NNELS accessibility testers have described.

Forecasting the short-term epidemic trajectory

Extrapolation based on recent trends using a forecasting model (with ranges of uncertainty). Text description based on a line graph shared in the document, “using-data-modelling-inform-eng.pdf”, from April 9, 2020. https://www.canada.ca/content/dam/phac-aspc/documents/services/diseases/2019-novel-coronavirus-infection/using-data-modelling-inform-eng.pdf

This is a line graph with several curves illustrating ranges of uncertainty based on recent trends. The X-axis shows dates ranging from March 1 to April 16. Visually, the days on the X-axis are labeled for every other day, starting on March 1.  However, there are markers for the days that are not labeled. The Y-axis is labeled “Cumulatively Reported Cases” ranging from 0 to 30000 in increments of 5000.

There is one line on the graph labeled “Cumulatively Reported Cases” beginning on March 1 to April 6, and three branching lines showing projections from April 6 to April 16. These lines are labeled as “Lower 95% Prediction Limit, “Prediction to April 16,” and “Upper 95% Prediction Limit” respectively.

The “cumulatively reported cases” line starts out flat on the baseline, all the way to March 13. From March 13, the line curves upwards gradually to March 22, with approximately 1000 cases. From March 22, the line rises steeply, almost at a 45-degree angle, all the way to April 6, where it ends at a point that indicates approximately 17000 cases.  The other three lines described above, begin at this point.

The line indicating the “Lower 95% Prediction Limit” goes from April 6 to April 16. This curve continues to increase in an upwards direction but gradually flattens until it is almost horizontal ending with a prediction of 22580 cases.

The “Prediction to April 16” line goes from April 6 to April 16. This curve continues to increase steeply but at an angle about 10 to 15 degrees lower than compared to the “Upper 95% Prediction Limit line. This curve indicates that it is just beginning to flatten but is still increasing. It ends at April 16th with a prediction of 27215 cases.

The “Upper 95% Prediction Limit” line continues to rise steadily at the same rate, (approximately 45-degree angle), from April 6 to April 16, where the line ends with a prediction of approximately 31850 cases.

Modelled scenarios show impact of public health measures

Modelled scenarios show impact of public health measures. Text description based on a line graph shared in the document, “using-data-modelling-inform-eng.pdf”, from April 9, 2020. https://www.canada.ca/content/dam/phac-aspc/documents/services/diseases/2019-novel-coronavirus-infection/using-data-modelling-inform-eng.pdf.


Text Description:

A line graph with three colour-coded curves, each depicting a specific scenario over a period of time. The X-axis is labelled as “time” and the Y-axis is labelled as “Number of New Cases.” No numbers are shown on the Y-axis. The labels on the X-axis are, “Spring,” “Summer,” “Fall,” “Winter,” and “Spring.” The years “2020” and “2021” are beneath these labels to indicate the overall length of time. At the top of the graph are three textboxes, with a line ending in an arrow, starting at the text box and each pointing to one of the corresponding three curves.

First box reads:

“Stronger Epidemic Control = high degree of physical distancing + high % of cases and their contacts traced and isolated for quarantine.
“1% to 10% infected”
This Corresponds to the green line.

Second box reads:

“No control effort
70% to 80% infected”
This refers to the red line.

Third box reads:

“Weaker controls (delay and reduce the peak) = low degree of physical distancing + low % of cases and their contacts traced and isolated or quarantined
25 to 50% infected”
This refers to the blue line.

The green line begins in Spring and ends in the Fall of 2020. It peaks at 10% of the graph which corresponds to Summer. The shape of this line forms a shallow arch that gently rises to a rounded point before gently going back down, at the same rate.

The red line begins in Spring and ends in late Fall of 2020. It peaks at 80% of the graph which approximately corresponds to the middle of Summer.  The shape of this line is in the shape of a triangle with a rounded peak that forms a very steep curve that rises and falls back down at the same rate.

The blue line begins in Spring and ends in spring of 2021. It peaks at 40% of the graph which approximately corresponds to late Summer. The shape of this line forms a wide arch with a rounded peak that steeply rises and falls back down at the same rate.

The blue line which has the widest arch intersects the red line half-way up. The green line which has the shallowest arch touches the red and blue lines before it reaches its peak. It does not intersect any lines as it comes back down.

Cumulative deaths under different scenarios over the course of pandemic

Cumulative deaths under different scenarios over the course of pandemic. Text description based on a line graph shared in the document, “using-data-modelling-inform-eng.pdf”, from April 9, 2020. https://www.canada.ca/content/dam/phac-aspc/documents/services/diseases/2019-novel-coronavirus-infection/using-data-modelling-inform-eng.pdf

The X-axis is labelled as "Percentage of population infected” ranging from 0% to 80%. The labels on the X-axis are 1% 2.5%, 5%, 10%, 25% 50% 70% and 80%. The Y-axis is labeled as "Number of Deaths" Which range from 0 to 400000 in increments of 50000. There are 8 bars in total. From left to right, there are 4 green bars categorized as “Stronger epidemic control,” 2 blue bars indicating “Weaker controls,” and 2 red bars representing “No controls.” Values can be found in the table just below. Note that these are rough estimates based on what we can see in this graph.

Percentage of population infected

Number of Deaths

1 5,000
2.5 10,000
5 20,000
10 50,000
25 100,000
50 200,000
70 300,000
80 350,000

There is also a small table on the graph entitled “% of Population Infected” which indicates the following:

Categories

2.5% 5%
All cases 934,000 1,879,000
Hospitalizations 73,000 146,000
ICU 23,000 46,000
Deaths 11,000 22,000

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