Coronavirus disease (COVID-19): For health professionals

What health professionals need to know

Health professionals in Canada have a critical role to play in identifying, reporting and managing potential cases of COVID-19.

COVID-19 is the disease caused by SARS-CoV-2 coronavirus, a new virus that was first recognized in December 2019. Genetic sequencing of the virus suggests that it is a betacoronavirus closely linked to the SARS virus. Coronaviruses are a large family of viruses. Some can infect animals, and some can infect humans.

The World Health Organization (WHO) declared COVID-19 a global pandemic in March 2020.

As we learn more about the virus, clinicians must remind Canadians to keep doing their part to prevent the spread of COVID-19. This includes following public health precautions, such as:

staying home when unwell
physical distancing
hand hygiene
respiratory etiquette
wearing masks when in closed indoor spaces
regularly cleaning and disinfecting common surfaces
self-monitoring for symptoms

The WHO is actively monitoring the situation and has issued:

updated information on the outbreak
advice on public health measures and infection prevention and control
enhanced surveillance

We are monitoring the COVID-19 situation closely, both in Canada and globally, and providing regular updates.

Causative agents

The coronavirus has been named SARS CoV-2.

Signs and symptoms

We have compiled a clinician guide for COVID-19. Based on scientific evidence, and informed by expert opinion, the guide outlines:

signs
symptoms
severity

This guidance is subject to change as new information emerges.

Clinical presentation and symptoms of COVID-19 vary in frequency and severity. Symptoms can take up to 14 days to appear after exposure to the virus.

People with COVID-19 may have few or no symptoms. Symptoms are often similar to other illnesses, particularly other respiratory viruses such as rhinovirus or influenza, amongst others. People can transmit the virus before they develop symptoms (pre-symptomatic transmission). Some infected people never develop symptoms, but can still transmit the virus (asymptomatic transmission). That is why everyone, even those who feel well, should follow measures to prevent the spread of COVID-19.

The true frequency of symptoms associated with COVID-19 is unknown. People with more severe symptoms may be overrepresented in published reports. Symptoms may also differ across care settings. More symptoms may develop as the disease progresses.

There is no validated list of symptoms with high specificity or sensitivity for the diagnosis of COVID-19. Clinical diagnosis should therefore always be confirmed by testing.

Encourage patients to seek medical consultation if they have new or worsening symptoms.

Transmission

The main mode of transmission for COVID-19 is person-to-person spread via respiratory droplets. The virus is contained in the droplets of an infected person. When the infected person coughs, sneezes, talks or breathes, their droplets can reach the mucous membrane of another person and infect them.

Infection can also occur when a person touches an infected surface and then touches their eyes, nose or mouth. We do not fully understand the contribution of surfaces or objects (also called fomites) in COVID-19 transmission.

The time period in which an individual with COVID-19 is infectious remains uncertain.

A person may be infectious for up to 3 days before showing symptoms (pre-symptomatic infectiousness).
Viral RNA levels appear to be highest just before or soon after symptom onset.

Incubation period

The incubation period ranges from 1 to 14 days. The median is 5 to 6 days between exposure and symptom onset. Most people (97.5%) develop symptoms within 11.5 days of exposure.

Re-infection

Further research is required to fully comprehend the relationship between positive antibody tests and protection against re-infection. There are now rare case reports of confirmed re-infection.

Currently, we don't know:

whether the presence of antibodies indicates immunity to re-infection, and if it does, how long that potential immunity lasts
the time period between a first and second infection
the potential severity of subsequent infections

As serological testing for antibodies expands, the results may provide insight into re-infection and duration of immunity.

Risk factors for severe disease

Coronaviruses can result in severe illness for some people in our communities. Those who are at risk of developing more severe disease or outcomes from COVID-19 are people:

who are an older adult (increasing risk with each decade, especially over 60 years)
of any age with chronic medical conditions, including:
- lung disease
- heart disease
- high blood pressure
- diabetes
- kidney disease
- liver disease
- dementia
- stroke
any age who are immunocompromised, including those:
- with an underlying medical condition, such as cancer
- taking medications which lower the immune system, such as chemotherapy
living with obesity (BMI of 40 or higher)

Learn more about disease severity and risk factors for severe disease in our clinician guide for health professionals.

Infection prevention and control

We have developed infection prevention and control guidance and strategies to prevent or limit COVID-19 transmission in health care settings, including:

There is an unprecedented demand and urgent need for products to help limit the spread of COVID-19. As a temporary measure, we are speeding up the authorization processes for personal protective equipment (PPE).

We are also allowing certain medical devices to be imported and sold that may not fully meet Canadian regulatory requirements. However, these devices are manufactured to comparable standards.

Learn more about strategies to address PPE shortages, including the reprocessing of N95 respirators.

Diagnosis

Our National Microbiology Laboratory (NML) helped develop and verify the laboratory tests used to identify COVID-19. NML has worked closely with provinces and territories through the Canadian Public Health Laboratory Network to advance testing capacity in Canada. Additionally, NML scientists continue to investigate novel technologies to detect COVID-19, which can potentially enhance access to testing and increase ease of collection.

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
serology-based testing

Consult the list of testing devices that have been authorized to date for use related to COVID-19.

Only testing devices authorized by Health Canada can be imported or sold in Canada. Unauthorized tests may not produce accurate results, leading to potential misdiagnosis. COVID-19 tests are confirmed to be well supported by evidence indicating they will provide accurate and reliable results.

Reporting

We do not accept reports from the public or individual health care providers. Reporting is completed by provincial or territorial health authorities.

The Public Health Agency of Canada (PHAC) collaborates with provincial and territorial public health partners to collect information on COVID-19 cases in Canada. A detailed epidemiologic summary is available.

Recommendations to public health care professionals

Use the interim national case definition for COVID-19 to consider the possibility of COVID-19 in persons with relevant clinical and exposure history.
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.

Treatment and vaccines

We are tracking all potential drugs and vaccines in development in Canada and abroad. To help expedite the development and availability of treatments to prevent and treat COVID-19, we are working with:

international partners
academic research centres
companies
investigators

Among hospitalized patients who have COVID-19 and require supplemental oxygen or mechanical ventilation, clinicians should strongly consider:

dexamethasone 6 mg IV for 10 days (or until discharge if earlier) or equivalent glucocorticoid dose

On July 27, 2020, Health Canada authorized with conditions the use of Veklury (remdesivir) to treat COVID-19 in adults and youth (12 years and older weighing at least 40 kg) with pneumonia requiring supplemental oxygen. Remdesivir is the first drug authorized to treat patients with severe symptoms of COVID-19 who have been hospitalized.

There are currently no vaccines authorized for COVID-19 in Canada.

Products that may ease symptoms such as fever and cough may be used to treat patients with COVID-19.

Together with a network of clinical experts, we have developed guidance for the clinical management of COVID-19 patients. This guidance is not meant to replace clinical judgment or specialist consultation.

Refer to the interim guidance on:

For more information on treatment under development, refer to the authorized clinical trials.

Guidance

Refer to our guidance for health professionals for clinical guidance on COVID-19, including:

infection prevention and control
signs, symptoms and severity of disease
clinical management of patients with COVID-19
care of residents in long-term care homes during the COVID-19 pandemic

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