NCCID Disease Debriefs provide Canadian public health practitioners and clinicians with up-to-date reviews of essential information on prominent infectious diseases for Canadian public health practice. Information is gathered from key sources including the Public Health Agency of Canada (PHAC), the USA Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and the European Centre for Disease Prevention and Control (ECDC).
This Disease Debrief provides quick links for public health and practitioner use.
***Une mise à jour des Points saillants sur COVID-19 est disponible en anglais (link). La mise à jour en français sera disponible d’ici 24 heures.
on “Prioritization of Initial Doses of COVID-19 Vaccine(s)” is now available online: Guidance on the Prioritization of Initial Doses of COVID-19 Vaccine(s)
The Coronavirus disease (COVID-19) is a global pandemic as announced by World Health Organization (WHO, March 11th 2020). It is caused by SARS-COV-2 coronavirus, a virus strain never previously identified in humans. The genetic sequence indicates that it is a betacoronavirus, closely linked to the SARS virus. The government of Canada has issued COVID-19 pandemic guidance for the health sector for federal, provincial and territorial health authorities.
A detailed epidemiologic summary and COVID-19 outbreak update for Canada is available from the Public Health Agency of Canada.
Government of Canada-Coronavirus disease (COVID-19)-For Health Professionals (English and French)
World Health Organization-Coronavirus (English and French)
Signs & symptoms
The most commonly observed symptoms of COVID-19 infection are fever, flu, fatigue, new or worsening cough, loss of appetite, loss of smell and/or taste, muscle and body ache, and headache. Gastrointestinal symptoms (abdominal pain, diarrhea, vomiting) can be less frequent. Shortness of breath is commonly reported in hospitalized patients. The symptoms in the geriatric population and in people with underlying health conditions may be subtle or atypical e.g., they could present without fever or respiratory symptoms. Overall, the frequency of symptoms is not well established, and symptoms may develop over time. This virus has an estimated incubation period from 1-14 days, with a median being 5-6 days, from exposure to symptom onset. Most individuals (97.5%) develop symptoms within 11.5 days of exposure. Recent research shows that transmission of the virus can occur from infected persons before they develop symptoms (pre-symptomatic transmission) and from infected persons who never develop symptoms (asymptomatic transmission).
Table I depicts the reported frequency of symptoms. Source: Government of Canada
|More frequent (>50%)||Less frequent (<50%)||Rare (<10%)|
|Fever (44-91%)||Sputum production (28-33%)||Confusion|
|Cough (57-74%)||Muscle aches (11-44%)||Runny nose|
|Shortness of breath (31-63%)||Chest pain (16-36%)||Fainting|
|Fatigue (31-70%)||Diarrhea (5-24%)||Skin manifestations|
|Loss of appetite (39-84%)||Nausea/vomiting (5-19%)|
|Loss of smell and /or taste (54-88%)||Headache (6-70%)|
|Sore throat (11-13%)|
Among children, most symptoms resemble those of adults (i.e. fever, cough, and shortness of breath); there may be gastrointestinal symptoms (diarrhea, abdominal pain, nausea, and vomiting) and skin rashes. A very rare complication associated with COVID-19 infection has been seen in children, severe multisystem inflammatory syndrome (MIS-C) which share features of typical or atypical Kawasaki disease or toxic shock syndrome.
Government of Canada- COVID-19 Symptoms and Treatment (English & French)
Canadian Pediatric Society-COVID-19 Information and Resources for Pediatricians (English and French)
World Health Organization-Coronavirus-Symptoms (English only)
Disease severity and risk factors for severe disease:
There is a range of COVID-19 disease severity, ranging from asymptomatic or mild, to moderate, severe and critical disease.
Data has constantly shown that older adults and those with some underlying medical conditions are at risk for serious illness. In Canada, where a clinical presentation of 74% reported one or more pre-existing conditions, where 60-year-old and over comprise 68% of hospital admissions, 64% of ICU admissions and 96% of deaths, these Canadian data being similar to those of other countries.
The most common comorbidities found in people with COVID-19 are shown in Table 2:
|More frequent (>40%)||Less frequent (<50%)||Rare (<10%)|
|Hypertension (17%-82%)||Chronic respiratory disease|
|Cardiovascular disease including heart failure (5%-55%)||Chronic renal disease (11-14%)||Atrial fibrillation/arrhythmia (3-6%)|
|Diabetes (4-40%)||Obesity (22-29%)||Gastrointestinal disease (5%)|
|Asthma (11%)||Chronic liver disease (2-3%)|
|Neurologic diseases, including dementia and stroke (8-13%)|
There is evidence of human re-infection with SARS-CoV-2, as documented by confirmed individuals who have been infected by different strains of the virus, but there are too few cases to determine the clinical presentation of the second infection and how it may differ. It is evident that after infection, people develop IgM and IgG antibodies in a few days or weeks after the appearance of symptoms, but even so the relationship between the levels of antibodies and the level of protection against reinfection remains undetermined, as well as the role of cellular immunity in the prevention of reinfection.
When serological testing for SARS-CoV-2 antibodies becomes more widely available, the results are expected to provide further insight regarding reinfection and immunity duration.
COVID-19 signs, symptoms and severity of disease: A clinician guide – Canada.ca (English and French)
The main mode of transmission in human-to-human spread of SARS CoV-2 is via respiratory droplets. Respiratory secretion from an infected person, through sneezing or coughing, reaches the mucous membrane of a healthy person, causing the spread of the virus. However, transmission can also occur if a person touches an infected surface and then touches their eyes, mouth, or nose though contribution of surfaces or objects in COVID-19 transmission is not completely understood.
The role of asymptomatic, pre-symptomatic and pauci-symptomatic COVID-19 cases in the transmission is still under investigation. There is uncertainty regarding the period of infectiousness of a COVID-19 infected person but the evidence shows that an individual may be infectious for up to three days before presenting any symptoms. It has been reported that during the course of the infection, viral shedding may occur but the exact extent is unknown so far. The viral load remains the same for both children and adults suggesting that children can be as infectious as adults.
Government of Canada-Signs-Symptoms and Severity of Disease-A Clinical Guide (English & French)
World Health Organization – Coronavirus Disease (COVID-19) (English and French)
Laboratory diagnostics and reporting
Health Canada regulates the sale and import of commercial testing devices relating to COVID-19. The majority of submissions received are for 2 types of commercial testing devices: nucleic acid-based testing and serology-based testing. There is a list of testing devices that have been authorized to date for use related to COVID-19.
The Public Health Agency of Canada (PHAC) recommends the following:
- The public health care professionals can use the interim national case definition for COVID-19 to consider the possibility of COVID-19 in persons with relevant clinical and exposure history.
- The public health care professionals can use the interim national COVID-19 case report form (PDF), to facilitate case reporting of confirmed and probable COVID-19 cases.
- Provincial and territorial public health authorities should report confirmed and probable COVID-19 cases to PHAC within 24 hours of their own notification.
- PHAC must report events that meet the requirements for International Health Regulations, Articles 6 and 7, to the WHO within 24 hours of assessment of public health information.
- Follow the guidance on the public health management of cases and contacts associated with COVID-19.
Government of Canada – Reporting (English and French)
Government of Canada Testing devices for COVID-19: Overview (English and French)
National case definitions
To aid in early detection and containment and to characterize the clinical and epidemiologic features of COVID-19, the Public Health Agency of Canada established a national case definition. Surveillance case definitions are provided for standardized case classification and reporting to the Public Health Agency of Canada. They are based on the current level of epidemiological evidence, uncertainty, and public health response goals. They are subject to change as new information becomes available.
Please refer to the documents below to obtain information for persons under investigation (PUI), probable and confirmed case definitions, and exposure criteria and mechanisms for reporting.
Government of Canada – Interim national case definition: Coronavirus (COVID-19) (English and French)
For additional information:
Infection prevention and control
The Government of Canada published interim guidance for acute healthcare settings. The Public Health Agency of Canada (the Agency) develops infection prevention and control (IPC) guidelines to provide evidence-based recommendations to complement provincial/territorial public health efforts in monitoring, preventing, and controlling healthcare-associated infections. Please read in conjunction with relevant provincial, territorial, and local legislation, regulations, and policies.
Currently available scientific evidence and expert opinion informs guidance and is subject to change as new information on transmissibility and epidemiology becomes available.
There are currently no vaccines available to protect against human 2019 novel Coronavirus infection.
For more information outside of Canada
European Centre for Disease Prevention and Control-Contact Tracing-Public health management of persons, including health care workers, having had contact with COVID-19 cases in the European Union (English only)
Second Interim guidance for clinical management of patients with COVID-19
The government of Canada has issued interim guidance for clinical management of patients with COVID-19 with an endorsement from the Canadian Critical Care Society and Association of Medical Microbiology & Infectious Diseases.
Government of Canada-Clinical management of patients with COVID-19-second interim guidance (updated August, 17, 2020) (English and French)
Canada’s response and risks to Canadians
PHAC activated the Health Portfolio Operations Centre to support effective coordination of federal, provincial, and territorial preparedness and response to the emergence of COVID-19. PHAC has also published the F/P/T public health response plan for biological events, which you can reference for more information.
Government of Canada – Coronavirus Disease (COVID-19): Canada’s Response (English & French)
Government of Canada – 2019 Novel Coronavirus: Prevention and Risks (English & French)
The government of Canada issued risk-informed decision-making guidelines for workplaces and businesses during the COVID-19 pandemic.
Vulnerable populations & COVID-19
Some Canadians are at higher risk of getting an infection and to develop severe complications associated with COVID-19 due to socio-economic and health status. The government of Canada has issued information on how organizations can support vulnerable populations during COVID-19. (English & French)
On March, 25th, 2020, the Canadian Pediatric Society issued current epidemiology and guidance for COVID-19 caused by SARS-COV-2 Virus, in children and on April, 20th, 2020 issued the acute management of pediatric coronavirus disease 2019 (COVID-19) (English & French)
Travel Advisory for Canadians
The Public Health Agency of Canada (PHAC) issued a Travel Health Notice level 3, outlining the potential dangers to Canadian travellers and the Canadian public. PHAC is recommending that Canadians should avoid all Non-essential travel outside of Canada. Self-isolation for 14 days is mandatory upon return from travel outside of Canada. Compliance with this order is subject to verification and enforcement. Those in violation may face transfer to a quarantine facility as well as fine or imprisonment. Any person experiencing fever, cough or difficulty in breathing, should continue to self-isolate and contact the local public health authority in their province or territory
Government of Canada-Coronavirus Disease (COVID-19): Travel advice (English & French)
Presently, “there are no drugs or vaccines authorized for COVID-19 treatment. However, Health Canada is closely monitoring all potential drugs and vaccines in the development phase in Canada and abroad by working with companies, academic research centres, and investigators to expedite the development and availability to Canadians”. According to Health Canada, in the case of hospitalized COVID-19 patients who require supplemental oxygen or mechanical ventilation, clinicians should strongly consider Intravenous Dexamethasone 6mg for 10 days (or until discharge if earlier) or equivalent glucocorticoid dose. Note: This guidance is not meant to replace clinical judgment or specialist consultation.