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. 2021 Feb 10;21(1):169.
doi: 10.1186/s12879-021-05864-8.

Incidence and risk factors of COVID-19-like symptoms in the French general population during the lockdown period: a multi-cohort study

Fabrice Carrat  1   2 , Mathilde Touvier  3 , Gianluca Severi  4   5 , Laurence Meyer  6   7 , Florence Jusot  8 , Nathanael Lapidus  9   10 , Delphine Rahib  11 , Nathalie Lydié  11 , Marie-Aline Charles  12 , Pierre-Yves Ancel  13   14 , Alexandra Rouquette  5   6 , Xavier de Lamballerie  15 , Marie Zins  16   17 , Nathalie Bajos  18 ; SAPRIS study group
Collaborators, Affiliations

Incidence and risk factors of COVID-19-like symptoms in the French general population during the lockdown period: a multi-cohort study

Fabrice Carrat et al. BMC Infect Dis. .

Abstract

Background: Our main objectives were to estimate the incidence of illnesses presumably caused by SARS-CoV-2 infection during the lockdown period and to identify the associated risk factors.

Methods: Participants from 3 adult cohorts in the general population in France were invited to participate in a survey on COVID-19. The main outcome was COVID-19-Like Symptoms (CLS), defined as a sudden onset of cough, fever, dyspnea, ageusia and/or anosmia, that lasted more than 3 days and occurred during the 17 days before the survey. We used delayed-entry Cox models to identify associated factors.

Results: Between April 2, 2020 and May 12, 2020, 279,478 participants were invited, 116,903 validated the questionnaire and 106,848 were included in the analysis. Three thousand thirty-five cases of CLS were reported during 62,099 person-months of follow-up. The cumulative incidences of CLS were 6.2% (95% Confidence Interval (95%CI): 5.7%; 6.6%) on day 15 and 8.8% (95%CI 8.3%; 9.2%) on day 45 of lockdown. The risk of CLS was lower in older age groups and higher in French regions with a high prevalence of SARS-CoV-2 infection, in participants living in cities > 100,000 inhabitants (vs rural areas), when at least one child or adolescent was living in the same household, in overweight or obese people, and in people with chronic respiratory diseases, anxiety or depression or chronic diseases other than diabetes, cancer, hypertension or cardiovascular diseases.

Conclusion: The incidence of CLS in the general population remained high during the first 2 weeks of lockdown, and decreased significantly thereafter. Modifiable and non-modifiable risk factors were identified.

Keywords: COVID-19; Cohort; General population; Incidence; Risk factors; SARS-CoV-2.

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Conflict of interest statement

Prof Fabrice Carrat, Mathilde Touvier, Prof Gianluca Severi, Prof Laurence Meyer, Prof Florence Jusot, Nathanael Lapidus, Delphine Rahib, Nathalie Lydié, Marie-Aline Charles, Prof Pierre-Yves Ancel, Alexandra Rouquette, Claude Martin, Prof Xavier de Lamballerie, Prof Marie Zins, Nathalie Bajos declare no competing interest.

Figures

Fig. 1
Fig. 1
Participants Flow chart
Fig. 2
Fig. 2
Daily incidence (/1000) of COVID-19-Like Symptoms (> 3 days) in participants between March 16, 2020 (first day of the lockdown in France) and April 30, 2020 - unweighted estimates. Error bars indicate 95% confidence intervals
See this image and copyright information in PMC

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