I?bl Publ'c Health Agenoe de la sant? I Agerlicy of Canada publique du Canada Canada in Canada: Modelling Update April 28, 2020 PROTECTING AND EMPOWERING CANADIANS TO IMPROVE THEIR HEALTH 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, and  preventing importation of infection from other countries. 2 Reminder of our strategy for this phase of the epidemic: Control epidemic, increase health care system capacity Number of new cases Control the epidemic Increase health care capacity Measures to reduce the number of people a person infects to < 1 to end onward transmission (e.g., physical distancing, travel restrictions, self isolation) Measures to increase the health care hard assets (e.g., ventilators) and health human resources Health Care System Capacity Time 3 If each person infects fewer than one person on average, the epidemic dies out Where we’ve been Where we are now Today, stronger controls Prior to stronger public health measures, each infected person including physical distancing and (case) in Canada infected 2.19 self-isolation are helping to reduce the average number of people each other people on average case infects to just above 1 Where we want to be Goal: Each person infects fewer than one person on average; epidemic dies out 4 Epidemiology THE PANDEMIC IN CANADA TODAY National overview, by province/territory, age and gender Median age 52 years (<1 to 111) Females 55% Males 45% Other gender <1% Age and gender available for 26,650 and 26,650 cases, respectively Deaths Data as of April 27, 2020: 11:00 Source: Provincial and Territorial websites 2,617 (5.5%) Hospitalisations 2,795 (17.1%)* ICU Admissions 692 (4.2%)* *Of 16,348 detailed case reports for which hospitalization status was available 6 Older Canadians and males are at greater risk of severe outcomes • Individuals aged ≥ 60 years comprise: Distribution of COVID-19 cases by age group • 1,018 (95%) of 1,072 deaths* • 1,811 (66%) of 2,747 hospital admissions* • 429 (63%) of 679 ICU admissions* • 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 70.0% 60.0% Percentage* • 2,012 (79%) of 2,561 deaths are linked to long-term care and seniors’ homes (as of April 26) 80.0% 50.0% 40.0% General population Cases Hospitalizations ICU admissions Deaths 30.0% 20.0% 10.0% 0.0% <19 • 74% of hospitalized cases reported one or more underlying health condition, but no one is immune to severe outcomes of COVID-19 Data as of April 27, 2020: 15:30 20-39 40-59 60-79 80+ Age group *Age information available for 26,340 cases, 2,747 hospitalizations, 679 ICU admissions and 1,072 deaths 7 Canada has several regional epidemics Epidemic growth has levelled off in several provinces Cases in Quebec, Ontario and Alberta 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 Data as of April 27, 2020: 15:30 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 9 Canada’s epidemic growth is slower than many international partners 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 Data as of April 27, 2020: 15:30 The number of cases in Canada is doubling every 16 days Looking Forward MODELLING SCENARIOS Canada’s approach to modelling • Models cannot predict what will happen, but 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) 12 Forecasting the short-term epidemic trajectories 53,196 to 66,835 cases by May 5 Date 3,277 to 3,883 deaths by May 5 Date 13 Modelled scenarios show the 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 1% to 10% infected Weaker controls (delay and reduce the peak) • low degree of physical distancing • low % of cases and their contacts traced and isolated or quarantined No control effort 70% to 80% infected Number of new cases Stronger epidemic control • high degree of physical distancing • high % of cases and their contacts traced and isolated or quarantined 25% to 50% infected Spring Fall Summer Winter Spring 2021 2020 Time 14 Our ambition: Early and rapid epidemic control Reduce importation and transmission spring summer fall winter With early epidemic control, responses to outbreaks will likely continue to be required over time 15 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 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 16 >szx Impr?I 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. Disease Stages 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 Exacerbating 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. Model includes factors that increase transmission, i.e., the movement of infectious (symptomatic / asymptomatic) people, where contacts take place (e.g., school, work, etc.). 18 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: Weaker control models include: • A high degree of physical distancing • A low degree of physical distancing • A high proportion of cases identified and isolated • A low proportion of cases identified and isolated • A high proportion of contacts traced and quarantined • A low proportion of contacts traced and quarantined 19 Cumulative deaths under different scenarios over the course of pandemic 400,000 No controls Number of deaths 350,000 300,000 250,000 Weaker controls 200,000 150,000 Stronger epidemic control 100,000 50,000 - 1% 2.50% 5% 10% 25% Percentage of population infected 50% 70% 80% 20 Scenarios show a range of impact for Canada over the course of the pandemic Overall % of the population infected 1% 2.5% 5% 10% 25% 50% 70% 80% All cases 376,000 940,000 1,879,000 3,759,000 9,397,000 18,795,000 26,312,000 30,071,000 Hospitalized 29,000 73,000 146,000 292,000 730,000 1,461,000 2,045,000 2,337,000 ICU 9,000 23,000 46,000 92,000 229,000 459,000 642,000 734,000 Deaths 4,000 11,000 22,000 44,000 111,000 222,000 311,000 355,000 Stronger epidemic controls Weaker controls No controls • 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 21