Since the World Health Organization (WHO) declared an emergency of international concern in January 2020, COVID-19 has required unprecedented public health action to protect population health. Initially, the impact of the pandemic was measured by deaths, hospitalizations, and intensive care unit admissions. However, growing population immunity through vaccination and infection, emergence of less virulent variants, and availability of new treatments for acute SARS-CoV-2 infections contributed to the WHO declaring COVID-19 no longer an emergency of international concern in May 2023.
Despite this declaration, COVID-19 continues to cause significant health concerns for the Canadian population. As of June 2023, most Canadians had been infected by SARS-CoV-2. Most people recover from their symptoms. However, for many others, symptoms persist for months or years, often impacting their ability to work and quality of life.
Long-term symptoms of COVID-19 refer to the presence of symptoms three or more months after a confirmed or suspected SARS-CoV-2 infection that could not be explained by anything else. Symptoms may be new onset, following initial recovery from an acute COVID-19 episode, or persist from the initial illness. Symptoms may also fluctuate or relapse over time.
This study examined COVID-19 infections, including reinfections, long-term symptoms and their impact on the Canadian adult population more than three years since the beginning of the pandemic. The study is based on data from the 2023 Canadian COVID-19 Antibody and Health Survey – Follow-up Questionnaire.
Key findings of the study include:
- As of June 2023, about two-thirds of Canadian adults reported at least one confirmed or suspected COVID-19 infection, with one in five having been infected multiple times.
- Multiple infections were more commonly reported among certain racialized groups. Black Canadians were most likely to report multiple infections compared to other racialized groups.
- About one in nine (3.5 million) of all Canadian adults have experienced long-term COVID-19 symptoms. About 2.1 million reported they were still experiencing symptoms as of June 2023. Almost half of those still experiencing symptoms reported they had not seen any improvement in symptoms over time.
- Those reporting two known or suspected COVID-19 infections were 1.7 times more likely to report prolonged symptoms than those reporting only one known or suspected infection, and those with three or more infections were 2.6 times more likely.
- Long-term symptoms commonly reported included fatigue (65%), brain fog (39%), and shortness of breath (28%).
- About seven in ten Canadian adults with long-term symptoms experienced them on a daily or nearly daily basis.
- Among Canadians who were in school or employed and dealing with long-term symptoms, more than one in five missed days of school or work, missing 24 days on average.
- About 40% of those with long-term symptoms who sought healthcare about their symptoms reported difficulties with access.
- Two-thirds of Canadian adults who sought healthcare services for their long-term symptoms reported not receiving adequate care for any of their symptoms.
- Adults with chronic conditions and senior adults were more likely to have been vaccinated in the six months prior to June 2023.
Although there is an observed association between the number of COVID-19 infections and long-term symptom risk in this study, there is not enough evidence to demonstrate a causal relationship in either direction. More research is required to explain the association between reinfection and the likelihood of developing long-term symptoms.
