New survey data reveals that between April and August 2022, 98% of Canadian adults had antibodies to SARS-CoV-2

OTTAWA, ON, March 27, 2023 /CNW/ - Today, Statistics Canada is releasing results from the second cycle of the Canadian COVID-19 Antibody and Health Survey (CCAHS). This survey provides a nationally representative measure of the population with antibodies to SARS-CoV-2, the virus that causes COVID-19. Between April and August 2022, 54% of Canadian adults – or about 16.4 million Canadians – had antibodies indicating a past infection to SARS-CoV-2. That is more than 20 times higher than the 2.6% observed in early 2021. In addition, by the same time, four out of ten Canadians were unaware that they ever had COVID-19.

Statistics Canada partnered with the Public Health Agency of Canada (PHAC) and the COVID-19 Immunity Task Force (CITF) to conduct this survey to better understand the spread and longer-term impacts of COVID-19, including long-term symptoms following an infection. The CCAHS is the largest nationally comprehensive study on COVID-19 antibodies from Canadian adults. The data are based on dried blood spot (DBS) samples and survey results collected between April and August 2022.

Between April and August 2022, nearly all Canadian adults (98.1%) had antibodies against SARS-CoV-2, acquired through vaccination, a previous infection or both. The survey also suggests that while younger Canadians were more likely to have been infected since the start of the pandemic, older Canadians living in private dwellings were more likely to be unaware of their infection. Racialized, non-Indigenous Canadians (60.1%) were more likely to have antibodies from infection than non-racialized, non-Indigenous Canadians (51.8%).

Across all ten provinces, over 100,000 randomly selected Canadians aged 18 years and older received invitations from Statistics Canada to participate in the survey. Respondents received a kit in the mail. Among the items inside was a link to the online survey with questions related to their general health, any chronic symptoms and conditions, their COVID-19 history and related symptoms, vaccination status, access to the healthcare system and medication use.

In addition to the invitations to complete the online survey, respondents were provided with DBS test kits, with step-by-step instructions, to test for COVID-19 antibodies as well as a saliva test kit to test for current or recent infections. The DBS tests were used to estimate the number of Canadian adults who have infection-acquired and/or vaccine-induced antibodies to SARS-CoV-2. Respondents who chose to conduct the DBS test component received a personalized report of their results.

"We appreciate the participation of those who took part in this survey on COVID-19. Increasing our understanding of COVID-19, including its longer-term symptoms and effects, is key to addressing and recovering from the pandemic. Your involvement provided valuable insights to better understand the extent of COVID-19 across the country and help support those who are experiencing longer term symptoms."

 The Honourable Jean-Yves Duclos, Minister of Health

"These nationally representative results are complementary to results of the COVID-19 Immunity Task Force's seroprevalence modelling based on more than twenty studies and are an important additional dataset to integrate into our monthly estimates. These data also reaffirm findings that racialized Canadians have had a greater incidence of COVID-19 than non-racialized Canadians, pointing to systemic issues that must be addressed now."

Catherine Hankins, Co-Chair, COVID-19 Immunity Task Force

"We thank Canadians for continuing to participate in this unique survey. The results are used by our partners, the Public Health Agency of Canada, the COVID-19 Immunity Task Force, as well as health professionals, researchers and policy makers across the country to better understand the social, health and economic impacts of COVID-19 on the well-being of Canadians." 

Anil Arora, Chief Statistician of Canada

• CCAHS (Cycle 1) started in 2020 and found that few Canadians had antibodies against SARS-CoV-2 in early 2021.
  
  
• Over 100,000 Canadians aged 18 years and older across the ten provinces were randomly selected to create a representative sample and ensure that the results are generalizable to the Canadian adult population.
  
  
• The CCAHS (Cycle 2) Access to Health Care portion of the survey will provide further information in May 2023.
  
  
• A follow-up survey to the CCAHS (Cycle 2) will be launched in spring 2023.

• Canadian COVID-19 Antibody and Health Survey (CCAHS) 
  
  
• Coronavirus disease (COVID-19): Canada's response 
  
  
• Post COVID-19 condition 
  
  
• Longer-term symptoms among Canadian adults 
  
  
• Scientists use dried blood spot testing to study spread of COVID-19 in Canada
  
  
• COVID-19 Immunity Task Force

SOURCE Statistics Canada