A national study of self-reported COVID symptoms during the first viral wave in Canada

  1. Xuyang Tang
  2. Hellen Gelband
  3. Teresa Lam
  4. Nico Nagelkerke
  5. Angus Reid
  6. Prabhat Jha
  7. for the Action to beat Coronavirus (Ab-C) Study Investigators

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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.

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  1. ScreenIT

    SciScore for 10.1101/2020.10.02.20205930: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: The Unity Health Toronto Research Ethics Board approved this study (REB# 20-107).
    RandomizationForum members were stratified by age, sex, education and province or territories of residence, and then randomly invited on a rolling basis to participate in the online survey portion of the Ab-C study, during which the respondents could opt in for later antibody testing.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    The study has certain limitations. Symptom positivity data are available only monthly rather than weekly, which would have given us a finer tuned look at the shape of the symptom curve. However, monthly data are less likely to be misreported retrospectively. Also, there is the potential for reporting biases. Overreporting, i.e., low specificity of symptoms for COVID, could result from time-varying knowledge and awareness of COVID effects. We examined household distribution of less common symptoms (e.g., loss of appetite, dizziness, disturbed sleep) to see whether participants and their household members simply noticed symptoms because of the pandemic or whether they truly experienced symptoms, using graphs similar to Figure 2. The shape of the graphs is generally consistent with Figure 2 which suggests that respondents may not have enhanced reporting of symptoms as they become more aware of COVID (data not shown). Naturally, self-reported symptoms may represent not just COVID but other conditions, including seasonal influenza. Symptoms also have low sensitivity for COVID as notable proportion of (infectious) COVID cases are asymptomatic.27 The next phase of the study will as combine survey responses with antibody testing results as well as examining the discordance of symptoms and antibodies in multi-person households. The antibody collection started in mid-June, which should allow for testing of at least IgG antibodies which have been shown to be stable for a few months afte...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2020.10.02.20205930v1 on medRxiv