After estimating the number of Canadians who have developed antibodies following an infection or vaccination against COVID-19, in 2021, Statistics Canada is launching a second survey, which will aim in particular to assess the prevalence of post-COVID syndrome. as well as access to care during the pandemic.
Led by Statistics Canada, the Public Health Agency of Canada and the COVID-19 Immunity Task Force (TICG), this second phase of theCanadian COVID-19 Antibody and Health Survey (ECSAC) plans to interview 100,000 people aged 18 and over, randomly selected from the ten Canadian provinces. The persons solicited will be invited to answer an electronic questionnaire relating to their general state of health, the Covid infections they have had and the resulting symptoms, their vaccination status, as well as the difficulties they would have had in obtaining health care.
Respondents will also receive a dried blood spot test kit that detects the presence of SARS-CoV-2 antibodies that may have been produced as a result of an episode of COVID-19 or vaccination. “As we will know the dates of infection and / or administration of the different doses of vaccine, we will be able to see if the antibodies decline or not”, specifies the DD Catherine Hankins, co-chair of the GTIC.
“All information and biological data that will be provided by participants will be encrypted, secure, anonymized and therefore confidential. And the latter will be able to receive the results of the antibody tests and PCR screening, ”explains the DD Hankins.
The survey beginning this week will help estimate the prevalence of long-term COVID in the Canadian population, as at this time there is no idea how many people have it. “We will investigate whether respondents had difficulty accessing care for their persistent symptoms of COVID-19, but also for any other health conditions, given that telemedicine was prioritized and that some were afraid to go to the hospital. We want to get an idea of the impact of the pandemic on access to care,” says Dr.D Hankins.
Evaluate the sixth wave
On March 18, 33,333 letters of invitation were sent, including 5,166 to Quebec. Then the questionnaire and the analysis kit were mailed on 1er April.
During the second and third rounds of invitations, which should be launched in May (5633 in Quebec) and June (5633) respectively, a kit will be added to collect a saliva sample with which a PCR test will be carried out, which will allow detect the COVID-19 virus and thus count “active infections”. “This test will allow us to find, among other things, asymptomatic people who would probably never have had a screening test. This data will give us a better idea of the number of active infections [alors qu’on effectue de moins en moins de tests PCR] “, specifies the DD Hankins.
“Given that many vaccinated Canadians have only mild symptoms, if any, hospitalization rates do not give us a complete picture of COVID-19 in Canada. This survey will provide us with a good estimate of the number of Canadians who have already had COVID-19 or are acutely infected. This data will help us paint a better picture of this sixth wave and it will help governments make appropriate decisions in terms of public health strategies and measures such as maintaining masks,” said Dr.D Hankins.
While it has become difficult to estimate the number of infections in the population from the PCR test positivity rate, sick leave among healthcare workers and the number of hospitalizations and people in intensive care , the analysis of wastewater allows “very early detection” of the circulation of the virus, notes the DD Hankins. “Nearly 60% of the Canadian population is covered by this surveillance system, and we hope to increase it to 80% by the end of the year”, she indicates while emphasizing that this system “ warns very early that the virus is circulating and it tells us with what intensity and what variant it is. It gives us a signal even before people are declared positive and hospitalized”.
Each study participant will represent an entire population similar in age, gender and place of residence across the ten Canadian provinces. This will allow for comparisons (in terms of antibodies and active infections) between provinces.