Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study

BackgroundWe developed a questionnaire on a web application for analyzing COVID-19 contamination circumstances in France during the second wave of the pandemic. ObjectiveThis study aims to analyze the impact on contamination characteristics before and after the second partial lockdown in...

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Main Authors: Denis, Fabrice, Septans, Anne-Lise, Le Goff, Florian, Jeanneau, Stephan, Lescure, François-Xavier
Format: Article
Language:English
Published: JMIR Publications 2021-05-01
Series:Journal of Medical Internet Research
Online Access:https://www.jmir.org/2021/5/e26932
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author Denis, Fabrice
Septans, Anne-Lise
Le Goff, Florian
Jeanneau, Stephan
Lescure, François-Xavier
author_facet Denis, Fabrice
Septans, Anne-Lise
Le Goff, Florian
Jeanneau, Stephan
Lescure, François-Xavier
author_sort Denis, Fabrice
collection DOAJ
description BackgroundWe developed a questionnaire on a web application for analyzing COVID-19 contamination circumstances in France during the second wave of the pandemic. ObjectiveThis study aims to analyze the impact on contamination characteristics before and after the second partial lockdown in France to adapt public health restrictions to further prevent pandemic surges. MethodsBetween December 15 and 24, 2020, after a national media campaign, users of the sourcecovid.fr web application were asked questions about their own or a close relative’s COVID-19 contamination after August 15, 2020, in France. The data of the contamination’s circumstances were assessed and compared before and after the second partial lockdown, which occurred on October 25, 2020, during the second wave of the pandemic and was ongoing on December 24, 2020. ResultsAs of December 24, 2020, 441,000 connections on the web application were observed. A total of 2218 questionnaires were assessable for analysis. About 61.8% (n=1309) of the participants were sure of their contamination origin, and 38.2% (n=809) thought they knew it. The median age of users was 43.0 (IQR 32-56) years, and 50.7% (n=1073) were male. The median incubation time of the assessed cohort was 4.0 (IQR 3-5) days. Private areas (family’s or friend’s house) were the main source of contamination (1048/2090, 50.2%), followed by work colleagues (579/2090, 27.7%). The main time of day for the contamination was the evening (339/961, 35.3%) before the lockdown and was reduced to 18.2% (86/473) after the lockdown (P<.001). The person who transmitted the virus to the user before and after the lockdown was significantly different (P<.001): a friend (382/1317, 29% vs 109/773, 14.1%), a close relative (304/1317, 23.1% vs 253/773, 32.7%), or a work colleague (315/1317, 23.9% vs 264/773, 34.2%). The main location where the virus was transmitted to the users before and after the lockdown was significantly different too (P<.001): home (278/1305, 21.3% vs 194/760, 25.5%), work (293/1305, 22.5% vs 225/760, 29.6%), collective places (430/1305, 33% vs 114/760, 15%), and care centers (58/1305, 4.4% vs 74/760, 9.7%). ConclusionsModalities of transmissions significantly changed before and after the second lockdown in France. The main sources of contamination remained the private areas and with work colleagues. Work became the main location of contamination after the lockdown, whereas contaminations in collective places were strongly reduced. Trial RegistrationClinicalTrials.gov NCT04670003; https://clinicaltrials.gov/ct2/show/NCT04670003
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spelling doaj.art-9cc89f35c097466babf249083f2711b72022-12-22T04:11:07ZengJMIR PublicationsJournal of Medical Internet Research1438-88712021-05-01235e2693210.2196/26932Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational StudyDenis, FabriceSeptans, Anne-LiseLe Goff, FlorianJeanneau, StephanLescure, François-XavierBackgroundWe developed a questionnaire on a web application for analyzing COVID-19 contamination circumstances in France during the second wave of the pandemic. ObjectiveThis study aims to analyze the impact on contamination characteristics before and after the second partial lockdown in France to adapt public health restrictions to further prevent pandemic surges. MethodsBetween December 15 and 24, 2020, after a national media campaign, users of the sourcecovid.fr web application were asked questions about their own or a close relative’s COVID-19 contamination after August 15, 2020, in France. The data of the contamination’s circumstances were assessed and compared before and after the second partial lockdown, which occurred on October 25, 2020, during the second wave of the pandemic and was ongoing on December 24, 2020. ResultsAs of December 24, 2020, 441,000 connections on the web application were observed. A total of 2218 questionnaires were assessable for analysis. About 61.8% (n=1309) of the participants were sure of their contamination origin, and 38.2% (n=809) thought they knew it. The median age of users was 43.0 (IQR 32-56) years, and 50.7% (n=1073) were male. The median incubation time of the assessed cohort was 4.0 (IQR 3-5) days. Private areas (family’s or friend’s house) were the main source of contamination (1048/2090, 50.2%), followed by work colleagues (579/2090, 27.7%). The main time of day for the contamination was the evening (339/961, 35.3%) before the lockdown and was reduced to 18.2% (86/473) after the lockdown (P<.001). The person who transmitted the virus to the user before and after the lockdown was significantly different (P<.001): a friend (382/1317, 29% vs 109/773, 14.1%), a close relative (304/1317, 23.1% vs 253/773, 32.7%), or a work colleague (315/1317, 23.9% vs 264/773, 34.2%). The main location where the virus was transmitted to the users before and after the lockdown was significantly different too (P<.001): home (278/1305, 21.3% vs 194/760, 25.5%), work (293/1305, 22.5% vs 225/760, 29.6%), collective places (430/1305, 33% vs 114/760, 15%), and care centers (58/1305, 4.4% vs 74/760, 9.7%). ConclusionsModalities of transmissions significantly changed before and after the second lockdown in France. The main sources of contamination remained the private areas and with work colleagues. Work became the main location of contamination after the lockdown, whereas contaminations in collective places were strongly reduced. Trial RegistrationClinicalTrials.gov NCT04670003; https://clinicaltrials.gov/ct2/show/NCT04670003https://www.jmir.org/2021/5/e26932
spellingShingle Denis, Fabrice
Septans, Anne-Lise
Le Goff, Florian
Jeanneau, Stephan
Lescure, François-Xavier
Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study
Journal of Medical Internet Research
title Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study
title_full Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study
title_fullStr Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study
title_full_unstemmed Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study
title_short Analysis of COVID-19 Transmission Sources in France by Self-Assessment Before and After the Partial Lockdown: Observational Study
title_sort analysis of covid 19 transmission sources in france by self assessment before and after the partial lockdown observational study
url https://www.jmir.org/2021/5/e26932
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