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

Fabrice Denis, Anne-Lise Septans, Florian Le Goff, Stephan Jeanneau, François-Xavier Lescure, Fabrice Denis, Anne-Lise Septans, Florian Le Goff, Stephan Jeanneau, François-Xavier Lescure

Abstract

Background: We developed a questionnaire on a web application for analyzing COVID-19 contamination circumstances in France during the second wave of the pandemic.

Objective: This 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.

Methods: Between 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.

Results: As 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%).

Conclusions: Modalities 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 registration: ClinicalTrials.gov NCT04670003; https://ichgcp.net/clinical-trials-registry/NCT04670003.

Keywords: COVID-19; France; analysis; digital health; impact; lockdown; observational; public health; self-assessment; survey; transmission; web application.

Conflict of interest statement

Conflicts of Interest: All authors have completed and submitted the International Committee of Medical Journal Editors Form for Disclosure of Potential Conflicts of Interest. FD reports receiving personal fees from Astrazeneca, Ipsen, Kelindi, Pfizer, Chugai, and Roche. He is a cofounder of Kelindi. FLG is a cofounder of Kelindi. SJ is the founder of Adobis Group.

©Fabrice Denis, Anne-Lise Septans, Florian Le Goff, Stephan Jeanneau, François-Xavier Lescure. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 04.05.2021.

Figures

Figure 1
Figure 1
Impact of the partial lockdown on daily reverse transcription polymerase chain reaction positive tests. Red area: national partial lockdown period initiated on October 25, 2020.
Figure 2
Figure 2
Contamination circumstances before versus after the partial lockdown, which was triggered in France on October 25, 2020. Answer to the question “Who contaminated you or your close relative?” (P<.001).
Figure 3
Figure 3
Contamination circumstances before and after the partial lockdown, which was triggered in France on October 25, 2020. Answer to the question “When do you think the contamination occurred?” (P<.001).
Figure 4
Figure 4
Contamination circumstances before and after the partial lockdown, which was triggered in France on October 25, 2020. Answer to the question “Where do you think the contamination occurred?” (P<.001).
Figure 5
Figure 5
Main collective places concerned by contaminations before and after lockdown (P<.001); only principal location of collective area).

References

    1. Denis F, Basch E, Septans A, Bennouna J, Urban T, Dueck AC, Letellier C. Two-year survival comparing web-based symptom monitoring vs routine surveillance following treatment for lung cancer. JAMA. 2019 Jan 22;321(3):306–307. doi: 10.1001/jama.2018.18085.
    1. Basch E, Deal AM, Dueck AC, Scher HI, Kris MG, Hudis C, Schrag D. Overall survival results of a trial assessing patient-reported outcomes for symptom monitoring during routine cancer treatment. JAMA. 2017 Jul 11;318(2):197–198. doi: 10.1001/jama.2017.7156.
    1. Basch E. Patient-reported outcomes - harnessing patients' voices to improve clinical care. N Engl J Med. 2017 Jan 12;376(2):105–108. doi: 10.1056/NEJMp1611252.
    1. Galmiche S, Rahbe E, Fontanet A, Dinh A, Bénézit F, Lescure F, Denis F. Implementation of a self-triage web application for suspected COVID-19 and its impact on emergency call centers: observational study. J Med Internet Res. 2020 Nov 23;22(11):e22924. doi: 10.2196/22924.
    1. Denis F, Galmiche S, Dinh A, Fontanet A, Scherpereel A, Benezit F, Lescure F. Epidemiological observations on the association between anosmia and COVID-19 infection: analysis of data From a self-assessment web application. J Med Internet Res. 2020 Jun 11;22(6):e19855. doi: 10.2196/19855.
    1. Denis F, Fontanet A, Le Douarin YM, Le Goff F, Jeanneau S, Lescure FX. A self-assessment web-based app to assess trends of the COVID-19 pandemic in France: observational study. J Med Internet Res. 2021 Mar 12;23(3):e26182. doi: 10.2196/26182.
    1. . [2020-12-15]. .
    1. Goolsbee AC, Syverson C. Fear, lockdown, and diversion: comparing drivers of pandemic economic decline 2020. J Public Econ. 2021 Jan;193:104311. doi: 10.1016/j.jpubeco.2020.104311.
    1. Guan W, Ni Z, Hu Y, Liang W, Ou C, He J, Liu L, Shan H, Lei C, Hui DS, Du B, Li L, Zeng G, Yuen K, Chen R, Tang C, Wang T, Chen P, Xiang J, Li S, Wang J, Liang Z, Peng Y, Wei L, Liu Y, Hu Y, Peng P, Wang J, Liu J, Chen Z, Li G, Zheng Z, Qiu S, Luo J, Ye C, Zhu S, Zhong N. Clinical characteristics of coronavirus disease 2019 in China. N Engl J Med. 2020 Apr 30;382(18):1708–1720. doi: 10.1056/nejmoa2002032.
    1. Fisher KA, Tenforde MW, Feldstein LR, Lindsell CJ, Shapiro NI, Files DC, Gibbs KW, Erickson HL, Prekker ME, Steingrub JS, Exline MC, Henning DJ, Wilson JG, Brown SM, Peltan ID, Rice TW, Hager DN, Ginde AA, Talbot HK, Casey JD, Grijalva CG, Flannery B, Patel MM, Self WH, Network Investigators I, CDC COVID-19 Response Team Community and close contact exposures associated with COVID-19 among symptomatic adults ≥18 years in 11 outpatient health care facilities - United States, July 2020. MMWR Morb Mortal Wkly Rep. 2020 Sep 11;69(36):1258–1264. doi: 10.15585/mmwr.mm6936a5.
    1. Lu J, Gu J, Li K, Xu C, Su W, Lai Z, Zhou D, Yu C, Xu B, Yang Z. COVID-19 outbreak associated with air conditioning in restaurant, Guangzhou, China, 2020. Emerg Infect Dis. 2020 Jul;26(7):1628–1631. doi: 10.3201/eid2607.200764.
    1. Lei H, Xu X, Xiao S, Wu X, Shu Y. Household transmission of COVID-19-a systematic review and meta-analysis. J Infect. 2020 Dec;81(6):979–997. doi: 10.1016/j.jinf.2020.08.033.

Source: PubMed

Sponsoren und Mitarbeiter

Krankheiten

Drogeninterventionen

3
Abonnieren