COVID-19 for health professionals: Post COVID-19 condition

On this page

• About the condition
• Symptoms
• Prevention, diagnosis and treatment
• What Canada’s doing

About the condition

The World Health Organization (WHO) refers to symptoms lasting for weeks or months after a COVID-19 infection as post COVID-19 condition.

Some studies have reported later symptoms in patients with a severe COVID-19 infection. For example, those who were hospitalized or needed intensive care during recovery. However, post COVID-19 condition may also occur for people with mild or asymptomatic infection who were asked to isolate at home during the infectious phase.

Given the limited availability of testing capacity early in the pandemic, there are some patients experiencing post COVID-19 condition symptoms who were not formally tested and diagnosed with COVID-19.

Currently, the estimates on how often people experience post COVID-19 condition are inconsistent. This is due to differences in:

• how symptoms are measured
• what symptoms are examined
• the number of participants in the study
• the length of time the patients were followed
• which populations are included in the study (hospitalized versus outpatient versus undiagnosed)

Symptoms

Post COVID-19 condition is associated with a wide range of diverse symptoms across multiple organ systems.

The Public Health Agency of Canada recently released a review of the current international evidence (PDF). Over 100 symptoms or difficulties conducting usual activities of daily living were reported.

• Approximately 80% of adults reported 1 or more symptoms in the short term (4 to 12 weeks after their initial COVID-19 infection).
• Approximately 60% of adults reported 1 or more symptoms in the long term (more than 12 weeks after their initial COVID-19 infection).
• 10% of adult patients said they have been unable to return to work more than 12 weeks after their initial COVID-19 infection.

These estimates are likely to change in the future as the results of additional studies become available.

Post COVID-19 condition typically appears in adult patients. However, emerging evidence shows that children may also develop chronic, persisting symptoms after COVID-19 infection. More research is needed on the longer-term symptoms after a COVID-19 infection in children and adolescents.

Symptoms can fluctuate in intensity, and can sometimes disappear and reappear. Some patients report that mental and physical over-exertion may exacerbate the condition. Patients in Canada identify mental health issues as critically important symptoms that need to be prioritized in research and in the development of clinical practice guidelines.

Mental health

While it is normal to feel a range of emotions at this time, some feelings or symptoms may indicate your patient needs help. Patients should be encouraged to talk to their health care provider if they think they may be experiencing symptoms of anxiety, depression or posttraumatic stress disorder related to their illness.

Prevention, diagnosis and treatment

Ongoing research about what causes post COVID-19 condition and how to diagnose and treat it will help develop specific supports tailored to patients. The WHO and countries are working together to develop a harmonized way to define and diagnose post COVID-19 condition. This will help both patients and clinicians during the diagnostic process. The WHO is also inviting clinicians and patients to collect information in a systematic way through a case report form for post COVID-19 condition. This will help to expand our knowledge on the condition, and better support patient care and public health interventions.

Currently, there is no treatment for post COVID-19 condition as a whole. Sources of knowledge and support about the management of symptoms include:

• patient-led research
• patient-led initiatives
• emerging research on models of care (PDF)
• emerging guidelines from UK NICE and the Centers for Disease Control and Prevention

Post COVID-19 condition clinics have been established in countries around the world, including in Canada, with a clear focus on interdisciplinary care. As of April 2021, there are an estimated 11 public clinics and 39 private clinics across Canada.

Long COVID-19 clinics (PDF)

Clinics in Canada

What Canada’s doing

The Public Health Agency of Canada is maintaining a systematic review of published studies on post COVID-19 condition, including the:

• prevalence of symptoms
• proportion of individuals reporting difficulties in being able to carry out usual activities of daily living

In July 2021, 2 additional systematic reviews began, which focus on:

• examining the risk factors associated with the condition
• possible interventions to prevent the condition in those who were infected with COVID-19

We are also assessing a number of data sources for the purpose of tracking the condition and related symptoms in Canada, in partnership with:

• Statistics Canada
• academic organizations
• provinces and territories

We are also collaborating with other federal partners to continue gathering evidence, such as the:

• Canadian Institutes for Health Research
• Canadian Institute for Health Information