COVID-19 in Canada: Modelling update

On this page

• Technical briefing for Canadians
• Strategy: Action now determines our future
• Epidemiology: The pandemic in Canada today
• Looking forward: Modelling scenarios
• Annex

Strategy: Action now determines our future

Data and modelling are guiding Canada's response to COVID-19

• Earlier this month, we shared with Canadians information from our modelling work on COVID-19
• This presentation aims to provide an update on that important work
• The data continue to reinforce the critical message that the measures we are taking now remain essential to controlling Canada's COVID-19 epidemic:
  • physical (social) distancing
  • detection and isolation of cases
  • tracing and quarantine of contacts
  • preventing importation of infection from other countries

Reminder of our strategy for this phase of the epidemic: Control epidemic, increase health case system capacity

Control the epidemic

Measures to reduce the number of people a person infects to less than 1 to end onward transmission (e.g., physical distancing, travel restrictions, self isolation). Represented by the downward arrow in Figure 1.

Increase health care capacity

Measures to increase the healthcare hard assets (e.g., ventilators) and health human resources. Represented by the upward arrow in Figure 1.

Figure 1 - Long description

A blue line describes a bell curve that shows the number of new cases over time. A blue downward arrow represents “Control the epidemic”

A red horizontal dotted line indicating the capacity of the health care system cuts across the curve. A red upward arrow represents “Increase health care capacity”

If each person infects fewer than one person on average, the epidemic dies out

Figure 2 - Long description

Where we've been: Image 1 illustrates one person infecting 2.19 other people.

Where we are now: Image 2 illustrates one person infecting fewer than two people.

Where we want to be: Image 3 illustrates one person infecting less than one other person.

Where we've been

Prior to stronger public health measures, each infected person (case) in Canada infected 2.19 other people on average.

Where we are

Today, stronger controls including physical distancing and self-isolation are helping to reduce the average number of people each case infects to just above 1.

Where we want to be

Goal: Each person infects fewer than one person on average; epidemic dies out.

Epidemiology: The pandemic in Canada today

National overview, by province and territory, age and gender

Data as of April 27, 2020 at 11:00 am

Figure 3 - Long description

Table 1: Total number of confirmed and reported COVID-19 cases in Canada as of April 27, 2020 at 11:00 am

Province, territory or other	Number of total cases
Canada	47,327
Alberta	4,448
British Columbia	1,948
Manitoba	271
New Brunswick	118
Newfoundland and Labrador	258
Northwest Territories	5
Nova Scotia	873
Nunavut	0
Prince Edward Island	26
Quebec	24,107
Ontario	14,856
Saskatchewan	353
Yukon	11
Repatriated travellers	13

Note: The total number includes publicly reported confirmed and probable cases

Median age: 52 years old (cases from less than a year old to 111 years old)

Gender of reported cases

Gender	Proportion of casesFootnote a
Females	55%
Males	45%
Other gender	Les than 1%
Footnote Footnote a Age and gender available for 26,650 cases. Return to footnote a referrer

Severity indicator	Total number of reported cases	Proportion of cases
Deaths	2,617	5.5%
Hospitalization	2,795	17.1%Footnote b
Admissions to intensive care unit	692	4.2%Footnote b
Footnote Footnote b Of 16,348 detailed case reports for which hospitalization status was available Return to footnote b referrer

Older Canadians and males are at greater risk of severe outcomes

Data as of April 27, 2020 at 3:30 pm

Figure 4 - Long description

Distribution of COVID-19 cases by age group

Percentage of severity indicator	Less than 19	20-39	40-59	60-79	80+
General population	21.6%	27.4%	26.8%	19.9%	4.3%
Cases	4.7%	25.5%	32.5%	21.2%	16.1%
Hospitalisation	0.6%	7.5%	26.0%	40.6%	25.3%
ICU admissions	0.3%	5.4%	31.1%	52.3 %	10.9%
Deaths	0.0%	0.8%	4.2%	28.2%	66.8%

• Individuals aged ≥ 60 years comprise^{Footnote 1} :
  • 1,018 (95%) of 1,072 deaths
  • 1,811 (66%) of 2,747 hospital admissions
  • 429 (63%) of 679 ICU admissions
• 2,012 (79%) of 2,561 deaths are linked to long-term care and seniors’ homes (as of April 26)
• Males are more likely to be admitted to hospital
  • 20% of male vs. 14% of female cases are hospitalised
  • 6% of male vs. 3% of female cases are admitted to the ICU
• 74% of hospitalised cases reported one or more underlying health condition, but no one is immune to severe outcomes of COVID-19

Canada has several regional epidemics

Data as of April 27, 2020 at 3:30 pm

Figure 5 - Long description

Table: Cumulative number of COVID-19 cases by province or territory since the 100th reported case.

Days since 100th reported case	Canada	AB	BC	MB	NB	NL	NS	ON	QC	SK
1	103	146	103	103	101	102	110	103	121	104
2	141	195	186	127	103	120	122	145	139	134
3	179	226	271	167	105	135	127	177	221	134
4	199	259	271	182	108	148	147	189	221	175
5	253	301	424	194	111	152	173	258	628	184
6	341	358	424	203	112	175	193	311	1,013	193
7	440	419	472	204	112	183	207	377	1,339	206
8	597	486	617	217	114	183	236	425	1,629	220
9	873	542	659	221	116	195	262	503	2,021	231
10	1,004	542	725	224	116	217	293	588	2,498	249
11	1,371	621	725	230	117	226	310	688	2,840	253
12	1,471	690	884	243	117	228	342	858	3,430	260
13	2,091	754	884	242	117	232	373	993	4,162	271
14	2,792	754	960	246	118	236	407	993	4,611	278
15	3,409	968	970	246	118	239	428	1,355	5,518	285
16	4,043	1,075	1,066	246	118	241	445	1,706	6,101	289
17	4,689	1,075	1,121	250	118	242	474	1,966	6,997	298
18	5,425	1,250	1,174	250	118	244	517	2,392	7,944	300
19	6,258	1,348	1,203	253	118	244	549	2,793	8,580	301
20	7,437	1,373	1,203	253	118	247	579	3,255	9,340	304
21	8,548	1,423	1,266	254	118	252	606	3,630	10,031	305
22	9,613	1,451	1,291	255	118	256	649	4,038	10,912	307
23	11,283	1,500	1,336	257	118	257	675	4,347	11,677	313
24	12,537	1,569	1,370	262	n/a	257	721	4,726	12,292	315
25	13,904	1,651	1,410	263	n/a	257	737	5,276	12,846	316
26	15,512	1,732	1,445	267	n/a	257	772	5,759	13,557	320
27	16,667	1,870	1,445	271	n/a	256	827	6,237	14,248	326
28	17,897	1,996	1,490	272	n/a	256	850	6,648	14,860	331
29	19,289	2,158	1,517	n/a	n/a	256	865	7,049	15,857	341
30	20,765	2,397	1,561	n/a	n/a	257	873	7,470	16,798	349
31	22,148	2,562	1,561	n/a	n/a	258	900	7,953	17,521	353
32	23,318	2,562	1,575	n/a	n/a	258	n/a	8,447	18,357	365
33	24,383	2,908	1,618	n/a	n/a	n/a	n/a	8,961	19,319	n/a
34	25,680	3,095	1,618	n/a	n/a	n/a	n/a	9,525	20,126	n/a
35	27,063	3,401	1,699	n/a	n/a	n/a	n/a	10,010	20,965	n/a
36	28,381	3,720	1,724	n/a	n/a	n/a	n/a	10,578	21,838	n/a
37	30,092	4,017	1,795	n/a	n/a	n/a	n/a	11,184	22,616	n/a
38	31,884	4,233	1,824	n/a	n/a	n/a	n/a	11,735	23,267	n/a
39	33,354	4,480	1,853	n/a	n/a	n/a	n/a	12,245	24,107	n/a
40	34,786	4,696	1,948	n/a	n/a	n/a	n/a	12,879	24,982	n/a
41	36,831	n/a	1,948	n/a	n/a	n/a	n/a	13,519	n/a	n/a
42	38,422	n/a	1,998	n/a	n/a	n/a	n/a	13,995	n/a	n/a
43	40,190	n/a	n/a	n/a	n/a	n/a	n/a	14,432	n/a	n/a
44	42,110	n/a	n/a	n/a	n/a	n/a	n/a	14,856	n/a	n/a
45	43,888	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
46	45,354	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a

• Epidemic growth has levelled off in several provinces
• Cases in Quebec, Ontario, Alberta and Nova Scotia are driving recent national epidemic growth
• There is no community transmission occurring in Prince Edward Island, the Northwest Territories or the Yukon
• There have been no cases reported to date in Nunavut

Driving forces behind regional epidemics

• Outbreaks in long-term care and seniors' homes where older medically vulnerable adults reside
  • Driving recent epidemic growth in Quebec, Ontario and Nova Scotia currently
  • Responsible for the majority (79%) of deaths country-wide
• Outbreaks in other congregate living and work settings involving vulnerable populations with inadequate space for physical distancing including:
  • Shelters serving people experiencing homelessness in Toronto
  • Correctional facilities in British Columbia, Quebec and Ontario
  • Work settings and associated congregate housing for workers in Alberta and British Columbia

Canada's epidemic growth is slower than many international partners

Data as of April 27, 2020 at 3:30 pm

Figure 6 - Long description

Cumulative number of community cases (log scale)

Days since 500th case	Canada	China (Mainland)	France	Germany	Italy	Japan	South Korea	Spain	United Kingdom	United States
0	597	606	613	534	650	514	602	589	590	554
1	725	885	949	684	888	568	833	1,235	798	754
2	873	2,033	1,126	847	1,128	620	977	1,639	1,140	1,039
3	1,081	2,809	1,412	1,112	1,689	675	1,261	2,140	1,391	1,312
4	1,371	4,585	1,784	1,139	2,036	737	1,766	3,004	1,543	1,663
5	1,474	6,057	2,281	1,296	2,263	780	2,337	4,231	1,950	2,174
6	2,091	7,801	2,876	1,567	3,089	814	3,150	5,753	2,630	2,951
7	2,792	14,451	3,661	2,369	3,858	824	3,736	7,753	3,277	3,774
8	3,409	17,302	4,499	3,062	4,636	829	4,212	9,191	3,983	4,661
9	4,043	20,028	5,423	3,795	5,884	873	4,812	11,178	5,018	6,427
10	4,757	24,384	6,633	4,838	7,375	950	5,328	13,716	5,683	9,415
11	5,655	28,083	7,730	6,012	9,172	1,007	5,766	17,147	6,650	14,250
12	6,320	31,203	9,134	7,156	10,149	1,046	6,284	19,980	8,077	19,624
13	7,448	34,609	10,995	8,198	12,462	1,089	6,767	24,926	9,529	26,747
14	8,591	37,097	12,612	14,138	15,113	1,128	7,134	28,572	11,658	35,206
15	9,731	40,046	14,459	18,323	17,660	1,193	7,382	33,089	14,543	46,442
16	11,285	42,651	16,018	21,463	21,157	1,268	7,513	47,610	17,089	55,231
17	12,537	44,682	19,856	24,774	24,747	1,364	7,755	56,188	19,522	69,194
18	14,018	59,822	22,302	29,212	27,980	1,499	7,869	64,059	22,141	85,996
19	15,512	63,862	25,233	31,554	31,506	1,693	7,979	72,248	25,150	104,686
20	16,667	66,496	29,155	36,508	35,713	1,866	8,086	78,797	29,474	124,686
21	17,897	68,440	32,964	42,288	41,035	1,953	8,162	85,195	33,718	143,025
22	19,291	70,955	37,575	48,582	47,021	1,953	8,236	94,417	38,168	164,620
23	20,765	72,425	40,174	52,547	53,578	2,178	8,320	102,136	41,903	189,618
24	22,148	74,186	44,550	57,298	59,138	2,617	8,413	110,238	47,806	216,721
25	23,318	74,578	52,128	61,913	63,927	2,935	8,565	117,710	51,608	245,540
26	24,383	75,467	56,989	67,366	69,176	3,271	8,652	124,736	55,242	277,965
27	25,680	76,291	59,105	73,522	74,386	3,654	8,799	130,759	60,733	312,237
28	27,063	76,935	64,338	79,696	80,539	3,817	8,897	135,032	65,077	337,635
29	28,379	77,147	68,605	85,778	86,498	3,906	8,961	140,510	70,272	368,449
30	30,106	77,659	70,478	91,714	92,472	4,257	9,037	146,690	78,991	399,929
31	31,927	78,064	74,390	95,391	97,689	4,667	9,137	152,446	84,279	432,438
32	33,354	78,497	78,167	99,225	101,739	5,347	9,241	157,022	88,621	466,299
33	34,786	78,824	82,048	103,228	105,792	6,748	9,332	161,852	93,873	501,615
34	36,831	79,251	86,334	108,202	110,574	7,255	9,478	166,019	98,476	530,006
35	38,422	79,826	90,676	113,525	115,242	7,645	9,583	169,496	103,093	557,590
36	40,190	80,026	93,790	117,658	119,827	8,100	9,661	172,541	108,692	582,594
37	42,110	80,151	95,403	120,479	124,632	8,582	9,786	177,633	114,217	609,685
38	43,888	80,270	98,076	123,016	128,948	9,167	9,786	182,816	120,067	639,664
39	45,354	80,410	103,573	125,098	132,547	9,795	9,976	188,068	124,743	671,425
40	46,895	80,555	106,206	127,584	135,586	10,361	10,062	191,726	129,044	706,779
41	48,500	80,651	108,847	130,450	139,422	10,751	10,156	195,944	133,495	735,287
42	n/a	80,695	109,252	133,830	143,626	11,118	10,237	200,210	138,078	759,786
43	n/a	80,735	111,821	137,439	147,577	11,496	10,284	204,178	143,464	787,960
44	n/a	80,756	112,606	139,897	152,271	11,772	10,331	208,389	148,377	825,306
45	n/a	80,780	114,657	141,672	156,363	12,240	10,384	213,024	152,840	842,629
46	n/a	80,793	117,324	143,457	159,516	12,892	10,423	219,764	157,149	869,172
47	n/a	80,801	119,151	145,694	162,488	13,182	10,450	219,764	n/a	905,333
48	n/a	80,826	120,804	148,046	165,155	13,385	10,450	219,764	n/a	939,249
49	n/a	80,844	122,577	150,383	168,941	13,576	10,512	226,629	n/a	965,933
50	n/a	80,866	124,114	152,438	172,434	n/a	10,537	229,422	n/a	988,469
51	n/a	80,882	124,575	154,175	175,925	n/a	10,564	n/a	n/a	n/a
52	n/a	80,905	128,339	155,193	178,972	n/a	10,591	n/a	n/a	n/a
53	n/a	80,929	n/a	156,337	181,228	n/a	10,613	n/a	n/a	n/a
54	n/a	80,974	n/a	n/a	183,957	n/a	10,635	n/a	n/a	n/a
55	n/a	81,013	n/a	n/a	187,327	n/a	10,653	n/a	n/a	n/a
56	n/a	81,057	n/a	n/a	189,973	n/a	10,661	n/a	n/a	n/a
57	n/a	81,114	n/a	n/a	192,994	n/a	10,674	n/a	n/a	n/a
58	n/a	81,177	n/a	n/a	195,351	n/a	10,683	n/a	n/a	n/a
59	n/a	81,285	n/a	n/a	197,675	n/a	10,694	n/a	n/a	n/a

Comparable countries whose epidemics began earlier were chosen for this comparison.

Growth is declining across most comparison countries shown in the figure, likely due to strong public health and global measures.

Canada's epidemic growth is slowing. Although previously doubling every 3 days early in the epidemic, the number of cases in Canada is now doubling every 16 days.

Notes:

• Reported cases are impacted by the number of tests conducted, and changes in testing practices.
• These data are presented on a logarithm scale. Log scales show relative values instead of absolute ones

Looking forward: Modelling scenarios

Canada's approach to modelling

• Models cannot predict what will happen, but rather can help us understand what might happen to ensure we can plan for worst cases and drive public health action to achieve the best possible outcome
• Models can support decisions on public health measures and help the health care sector plan for the number of expected COVID-19 patients
• Reminder: Canada is using two modelling approaches:
  • Forecasting models use data to estimate how many new cases we might expect to see in the coming week
  • Dynamic models show how the epidemic might unfold over the coming months, using knowledge of how the virus behaves and of the potential impact of public health measures.
• Important to recognize that models have inherent limitations (e.g., simulate controlled scenarios, not real world)

Forecasting the short-term epidemic trajectory

Figure 7 - Long description

Extrapolation based on recent trends using a forecasting model (with ranges of uncertainty)

Current cases and deaths

Date	Cumulatively reported cases	Cumulative number of deaths
2020-04-17	32,849	1,365
2020-04-18	34,380	1,527
2020-04-19	36,016	1,636
2020-04-20	37,860	1,757
2020-04-21	39,392	1,909
2020-04-22	41,363	2,072
2020-04-23	43,227	2 232
2020-04-24	44,856	2,390

Table: Range of predicted cases and deaths from April 25 to May 5

	Predicted cases average (95% range)	Predicted deaths average (95% range)
2020-04-25	46,653 (46,236; 47,071)	2,527 (2,472; 2,581)
2020-04-26	48,360 (47,655; 49,065)	2,667 (2,594; 2,740)
2020-04-27	50,011 (48,903; 51,119)	2,801 (2,706; 2,896)
2020-04-28	51,592 (49,970; 53,215)	2,928 (2,809; 3,047)
2020-04-29	53,092 (50,857; 55,328)	3,047 (2,903; 3,191)
2020-04-30	54,501 (51,575; 57,428)	3,157 (2,986; 3,327)
2020-05-01	55,812 (52,139; 59,486)	3,258 (3,061; 3,456)
2020-05-02	57,020 (52,565; 61,475)	3,351 (3,127; 3,576)
2020-05-03	58,122 (52,872; 63,372)	3,435 (3,184; 3,687)
2020-05-04	59,120 (53,077; 65,162)	3,511 (3,234; 3,789)
2020-05-05	60,015 (53,196; 66,835)	3,579 (3,277; 3,883)

Two graphs showing an upward sloping curve representing actual cumulatively reported cases and deaths in Canada from March 1 to April 24, 2020. The line splits into 2 scenarios predicting data for May 5, 2020. Top line shows the upper 95% prediction limit. Lower line shows the lower 95% prediction limit.

• 53,196 to 66,835 cases by May 5, 2020
• 3,277 to 3,883 deaths by May 5, 2020

Modelled scenarios show impact of public health measures

Models help us identify which combinations of public health measures, applied with what intensity, are most likely to reinforce epidemic control.

Figure 8 - Long description

Graphic with 3 curves:

• Stronger epidemic control: Small shortest curve from Spring to Fall 2020, with a peak in Summer 2020
• No control effort: Tall short curve from Spring to Fall 2020, with a peak in Summer 2020
• Weaker controls (delays and reduce the peak): Medium long curve from Spring 2020 to Spring 2021, with a peak in Fall 2020

• Stronger epidemic control: high degree of physical distancing and high percentage of cases and their contacts traced and isolated or quarantined. 1% to 10% infected.
• No control effort: 70% to 80% infected.
• Weaker controls (delay and reduce the peak): low degree of physical distancing and low percentage of cases and their contacts traced and isolated or quarantined. 25% to 50% infected.

Our ambition: Early and rapid epidemic control

Figure 9 - Long description

On the left, a blue line describes a steep, high curve that begins in the spring and ends in the summer followed by a series of three low orange curves, representing smaller outbreaks in late summer, fall and winter. A final upward sloping orange line suggests a fourth small outbreak next year.

The four orange lines are labelled "Reduce importation and transmission."

With early epidemic control, responses to outbreaks will likely continue to be required over time.

Summary

• We continue to monitor the situation closely, and will evaluate, learn, and adapt as we go.
• Canada is making progress to slow the spread and bring the epidemic under control, thanks to the commitment of Canadians, who are following public health advice to protect themselves and others.
• It is critically important that we maintain our current public health measures, including physical distancing, until we have achieved epidemic control for the first wave.
• Relaxing controls too quickly could squander our collective efforts to date and put us at risk of future epidemic waves.

What we do together now to stop the spread of the virus will determine the overall impact of COVID-19 on the health of all Canadians

Annex

Dynamic models of scenarios

Model moves people through different states of infection. All start out as susceptible.

Individuals are then exposed. They either become infected, or remain susceptible.

Figure 10 - Long description

• Latent period
• Asymptomatic infectious period
• Symptomatic infectious period
• Outcome

The duration of each stage has an impact on the speed of spread of the disease. The models are run with different values for these periods.

Mitigating factors

Model includes factors that reduce transmission, with different scenarios for different levels of public health measures possible. Hospitalization in the models is also assumed to include no further transmission.

Exacerbating factors

Model includes factors that increase transmission, i.e., the movement of infectious (symptomatic / asymptomatic) people, where contacts take place (e.g., school, work, etc.).

Modelled scenarios—varied public health measures

• A series of models were used to generate a number of scenarios including three key scenarios: ‘no control', ‘weaker controls (delay and reduce the peak)', and ‘stronger epidemic control'. This lets us estimate the range of the population infected and the potential duration of the epidemic.
• Other interventions, such as border controls and domestic travel restrictions, have also been explored in modelling studies
• We continue to use models on an ongoing basis to help us identify which combinations of public health measures, applied with what intensity, are most likely to reinforce epidemic control

Stronger epidemic control models include

• A high degree of physical distancing
• A high proportion of cases identified and isolated
• A high proportion of contacts traced and quarantined

Weaker control models include

• A low degree of physical distancing
• A low proportion of cases identified and isolated
• A low proportion of contacts traced and quarantined

Cumulative deaths under different scenarios over the course of pandemic

Figure 11 - Long description

Potential number of deaths in Canada given different scenarios and percentages of the population infected.

Epidemic control	Percentage of the population affected	Number of deaths
Stronger epidemic control	1%	4,000
	2.5%	11,000
	5%	22,000
	10%	44,000
Weaker controls	25%	111,000
	50%	222,000
No controls	70%	311,000
	80%	355,000

Scenarios show a range of impact for Canada over the course of the pandemic

Table: Overall percentage of population infected according to different levels of epidemic control

Level of epidemic controls	Percentage	All cases	Hospitalized	ICU	Deaths
Stronger epidemic control	1%	376,000	29,000	9,000	4,000
Stronger epidemic control	2.5%	940,000	73,000	23,000	11,000
Stronger epidemic control	5%	1,879,000	146,000	46,000	22,000
Stronger epidemic control	10%	3,759,000	292,000	92,000	44,000
Weaker controls	25%	9,397,000	730,000	229,000	111,000
Weaker controls	50%	18,795,000	1,461,000	459,000	222,000
No controls	70%	26,312,000	459,000	642,000	311,000
No controls	80%	30,071,000	222,000	724,000	355,000

• Estimates are based on different attack rates obtained in model simulations with different levels of public health measures
• Assumptions: 7.8% of all cases are hospitalised; 2.4% of cases require ICU care; and 1.2% of all cases die (based on Imperial College London estimates of age-related variations in severity)
• Deaths for 25% to 80% scenarios are underestimates because the case fatality rate (proportion of cases who will die) is likely to rise as health care capacity is exceeded