Clinical Considerations

Clinical Considerations

Vulnerable populations

Most people who get COVID-19 will experience mild to moderate symptoms. However, as the evidence rolls in, some groups of our population are at higher risk for more serious illness, complications and death. These groups include:1,2,3,4

  • Older adults (>60 years old)
  • Chronic or pre-existing conditions (i.e., heart disease, hypertension, diabetes, chronic respiratory disease, cancer)
  • Individuals with a compromised immune system

Socio-economic factors can also contribute to increasing vulnerability of individuals to COVID-19, increasing their risk of negative health outcomes. This includes people who use substances, are unsheltered, employed in precarious work, live in isolated communities, all of whom may face additional challenges in applying preventive strategies or gaining access to necessary resources.5,6 The Public Health Agency of Canada (PHAC) provides some guidance on how organizations and health-care providers can support vulnerable populations.


There is considerable evidence to indicate that many people infected with COVID-19 may have little or no symptoms at all. For those who do develop symptoms, they may take up to 14 days to appear, though the average is 5-6 days from exposure to symptom onset. PHAC notes that there is research being conducted to confirm if the virus can be transmitted while an infected individual is asymptomatic. This is believed to be possible, but not confirmed.7

Evidence from China, Italy, South Korea and Germany indicates that significant numbers of patients with confirmed COVID-19 have anosmia, or loss of smell. In South Korea, many patients with otherwise mild COVID-19 disease had anosmia as their main presenting symptom. This is not currently considered a symptom of COVID-19, and research is continuing in this area. Globally, there has been discussion that requiring those with anosmia to self-quarantine may help to limit spread.8,9

Detection and reporting

Diagnosis of COVID-19 is made through a combination of examining clinical presentation, epidemiology, and lab confirmation. Specimens are usually tested locally/provincially and then sent to the National Microbiology Laboratory (NML) for confirmation. Several provinces are now able to do confirmatory testing themselves. NML conducts confirmatory testing on all specimens, where confirmatory testing is not yet available in province.

Important information on diagnosis and reporting from the Public Health Agency of Canada:10

Familiarize yourself with the guidance on the public health management of cases and contacts associated with COVID-19.

As testing may vary by province, we encourage you to seek specific information from the jurisdiction in which you reside or practise.

* Denotes provinces with the capacity to do their own confirmatory testing at time of writing

Knowledge/resource/practice gaps

While the position of the WHO related to COVID-19 identification and containment is “test, test, test,” that is currently not the practice in Canada. Nationally, there are recommendations for who should be tested, though that may vary by province. At the outset of the outbreak in Canada, the majority of provinces/territories were only testing symptomatic persons with a positive travel history, close contacts of confirmed cases, and hospitalized persons with severe illness consistent with COVID-19. Testing of those without travel history or known close contact was not widely done, though that appears to be changing, as some provinces are shifting to test community clusters. Asymptomatic individuals are not being tested, as per current recommendations.

At the time of writing, there are significant barriers to broad testing, including resource availability. Test kits, reagents and lab capacity issues are themes we are hearing across the country. These challenges mean that testing remains more conservative than we may see in other countries, and as such, the true number of cases and true rate of community transmission is not known.

Case and contact management

Management of cases and contacts may vary by province. PHAC’s recommendations on case and contact management focuses on the following:

Contact management

  • As per PHAC, the purpose of contact management is twofold:
    • To identify contacts and support containment, reducing transmission to others in the community
    • To gain more information/understanding about SARS CoV 2
  • Depending on exposure level risk assessment, contacts are placed into either high, medium, or low risk categories, and managed according to the corresponding recommendations for that risk level.

Case management

  • Reporting and notification
  • Lab testing
  • Clinical management/treatment
  • Case management in home and co-living situations
  • Public health monitoring of cases and persons under investigation (PUIs)

1 The Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. (2020). The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19) — China, 2020. Retrieved from

2 Public Health Agency of Canada. (2020, March). Vulnerable populations and COVID-19. Retrieved from

3 Centers for Disease Control and Prevention. (2020, March, 22). People who are at higher risk for severe illness. Retrieved from

4 British Columbia Centre for Disease Control. (n.d.). Vulnerable populations. Retrieved from

5 Ibid.

6 Public Health Agency of Canada. (2020, March). Vulnerable populations and COVID-19. Retrieved from