Abstract
Importance Accurate understanding of COVID pandemic during the first viral wave in Canada could help prepare for future epidemic waves.
Objective To track the early course of the pandemic by examining self-reported COVID symptoms over time before testing became widely available.
Design Adults from the nationally representative Angus Reid Forum were randomly invited to complete an online survey in May/June 2020. The study is a part of the Action to Beat Coronavirus antibody testing study.
Setting A 20-item internet survey.
Participants 14,408 adults age 18 years of age.
Exposures The months that respondents and any household members first experienced various respiratory, neurological, sleep, skin or gastric symptoms.
Main Outcomes and Measure “COVID symptom-positive,” defined as fever (or fever with hallucinations) plus at least one of difficulty breathing, a dry severe cough, loss of smell or “COVID toe.”
Results In total, 14,408 panel members (48% male and 52% female) completed the survey. Despite overrepresentation of higher levels of education, the prevalence of obesity, smoking, diabetes and hypertension were similar to national census and health surveys. A total of 811 (5.6%) were COVID symptom-positive; highest rates were at ages 18-44 years (8.3% among), declining at older ages. Females had higher odds of reporting COVID symptoms (OR = 1.32, 95%CI 1.11 – 1.56) as did visible minorities (OR = 1.74, 1.29 – 2.35). COVID symptom positivity for respondents and their household members peaked in March (OR = 1.93, 95% CI = 1.59 – 2.34 compared to earlier months).
Conclusions and Relevance This study enhances our current understanding of the progression of the COVID epidemic in Canada, with few laboratory-confirmed cases in January and February, peaking in April. The results suggest substantial viral transmission in March, before widespread testing began, and a gradual decline in cases since May.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
This work was supported by the Canadian Institutes of Health Research Foundation grant (grant number FDN 154277); and Pfizer Canada (grant number 61608943). PJ is a Canada Research Chair and Dalla Lana Chair of Global Health at the University of Toronto, and received the above grants.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The Unity Health Toronto Research Ethics Board approved this study (REB# 20-107).
All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
Yes
I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.
Yes
Data Availability
The data that support the findings of the Ab-C Study are available on request from the corresponding author PJ. The request is also subject to the approval of the Unity Health Toronto Research Ethics Board.