Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Multicenter Study
. 2021 May 10;21(1):435.
doi: 10.1186/s12879-021-06002-0.

Epidemiological characteristics of the COVID-19 spring outbreak in Quebec, Canada: a population-based study

Rodolphe Jantzen  1   2 , Nolwenn Noisel  3   4 , Sophie Camilleri-Broët  5 , Catherine Labbé  3 , Thibault de Malliard  3 , Yves Payette  3 , Philippe Broët  3   4   6   7
Affiliations
Multicenter Study

Epidemiological characteristics of the COVID-19 spring outbreak in Quebec, Canada: a population-based study

Rodolphe Jantzen et al. BMC Infect Dis. .

Abstract

Background: By mid-July 2020, more than 108,000 COVID-19 cases had been diagnosed in Canada with more than half in the province of Quebec. In this context, we launched a study to analyze the epidemiological characteristics and the socio-economic impact of the spring outbreak in the population.

Method: We conducted an online survey of the participants of the CARTaGENE population-based cohort, composed of middle-aged and older adults. We collected information on socio-demographic, lifestyle, health condition, COVID-19 related symptoms and COVID-19 testing. We studied the association between these factors and two outcomes: the status of having been tested for SARS-CoV-2 and the status of having received a positive test. These associations were measured with univariate and multivariate analyses using a hybrid tree-based regression model.

Results: Among the 8,129 respondents from the CARTaGENE cohort, 649 were tested for COVID-19 and 41 were positive. Medical workers and individuals having a contact with a COVID-19 patient had the highest probabilities of being tested (32% and 42.4%, respectively) and of being positive (17.2% and 13.0%, respectively) among those tested. Approximately 8% of the participants declared that they have experienced at least one of the four COVID-19 related symptoms chosen by the Public Health authorities (fever, cough, dyspnea, anosmia) but were not tested. Results from the tree-based model analyses adjusted on exposure factors showed that the combination of dyspnea, dry cough and fever was highly associated with being tested whereas anosmia, fever, and headache were the most discriminant factors for having a positive test among those tested. During the spring outbreak, more than one third of the participants have experienced a decrease in access to health services. There were gender and age differences in the socio-economic and emotional impacts of the pandemic.

Conclusion: We have shown some discrepancies between the symptoms associated with being tested and being positive. In particular, the anosmia is a major discriminant symptom for positivity whereas ear-nose-throat symptoms seem not to be COVID-19 related. The results also emphasize the need of increasing the accessibility of testing for the general population.

Keywords: CARTaGENE; COVID-19; Coronavirus; Pandemic; Population-based cohort; SARS-CoV-2; Social factors; Tree-based model.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
GPLTR model for being tested (a), for being positive when tested (b)
Fig. 2
Fig. 2
Relationship between symptoms and positivity. Left panel: Probability of being positive given that the person has experienced a symptom. Right panel: Normalized Depth Deviance Importance Score of the symptoms
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Situation of the Coronavirus (COVID-19) in Québec. 2020. https://www.quebec.ca/en/health/health-issues/a-z/2019-coronavirus/situa.... Accessed 5 Aug 2020.
    1. Public Health Agency of Canada. 2020. https://www.canada.ca/en/public-health.html. Accessed 5 Aug 2020.
    1. Richardson S, Hirsch JS, Narasimhan M, Crawford JM, McGinn T, Davidson KW, and the Northwell COVID-19 Research Consortium. Barnaby DP, Becker LB, Chelico JD, Cohen SL, Cookingham J, Coppa K, Diefenbach MA, Dominello AJ, Duer-Hefele J, Falzon L, Gitlin J, Hajizadeh N, Harvin TG, Hirschwerk DA, Kim EJ, Kozel ZM, Marrast LM, Mogavero JN, Osorio GA, Qiu M, Zanos TP. Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area. JAMA. 2020;323(20):2052. doi: 10.1001/jama.2020.6775. - DOI - PMC - PubMed
    1. Docherty AB, Harrison EM, Green CA, Hardwick HE, Pius R, Norman L, Holden KA, Read JM, Dondelinger F, Carson G, Merson L, Lee J, Plotkin D, Sigfrid L, Halpin S, Jackson C, Gamble C, Horby PW, Nguyen-Van-Tam JS, Ho A, Russell CD, Dunning J, Openshaw PJ, Baillie JK, Semple MG. Features of 20 133 UK patients in hospital with Covid-19 using the ISARIC WHO Clinical Characterisation Protocol: Prospective observational cohort study. BMJ. 2020:m1985. 10.1136/bmj.m1985. - PMC - PubMed
    1. Zhou F, Yu T, Du R, Fan G, Liu Y, Liu Z, Xiang J, Wang Y, Song B, Gu X, Guan L, Wei Y, Li H, Wu X, Xu J, Tu S, Zhang Y, Chen H, Cao B. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: A retrospective cohort study. The Lancet. 2020;395(10229):1054–62. doi: 10.1016/S0140-6736(20)30566-3. - DOI - PMC - PubMed

Publication types

Grants and funding