Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study

Abstract Background During the SARS-CoV-2 pandemic, Germany employed several nonpharmaceutical interventions (NPIs) to reduce social contacts and decelerate the virus’s spread. Associations between demographics and other factors, e.g. perceived pandemic threat level, might help explain variations in...

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Main Authors: Huynh Thi Phuong, Antonia Bartz, Andrzej K. Jarynowski, Berit Lange, Christopher I. Jarvis, Nicole Rübsamen, Rafael T. Mikolajczyk, Stefan Scholz, Tom Berger, Torben Heinsohn, Vitaly Belik, André Karch, Veronika K. Jaeger
Format: Article
Language:English
Published: BMC 2025-04-01
Series:BMC Infectious Diseases
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Online Access:https://doi.org/10.1186/s12879-025-10917-3
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author Huynh Thi Phuong
Antonia Bartz
Andrzej K. Jarynowski
Berit Lange
Christopher I. Jarvis
Nicole Rübsamen
Rafael T. Mikolajczyk
Stefan Scholz
Tom Berger
Torben Heinsohn
Vitaly Belik
André Karch
Veronika K. Jaeger
author_facet Huynh Thi Phuong
Antonia Bartz
Andrzej K. Jarynowski
Berit Lange
Christopher I. Jarvis
Nicole Rübsamen
Rafael T. Mikolajczyk
Stefan Scholz
Tom Berger
Torben Heinsohn
Vitaly Belik
André Karch
Veronika K. Jaeger
author_sort Huynh Thi Phuong
collection DOAJ
description Abstract Background During the SARS-CoV-2 pandemic, Germany employed several nonpharmaceutical interventions (NPIs) to reduce social contacts and decelerate the virus’s spread. Associations between demographics and other factors, e.g. perceived pandemic threat level, might help explain variations in social contact behaviours. We aimed to estimate contact numbers during the pandemic in Germany and assess factors associated with changes therein. Methods Between 04/2020 and 12/2021, we conducted an online contact survey (COVIMOD) with 33 waves in Germany. We calculated the mean and 95% confidence interval of daily reported contacts (“people who you met in person and with whom you exchanged at least a few words, or with whom you had physical contact”) using bootstrapping. The effects of different factors on the number of contacts were determined by fitting generalized additive models (GAMs). Results The COVIMOD survey recorded 59,585 responses from 7,851 participants across Germany. The overall mean number of daily social contacts during the study period was 3.30 (95%CI: 3.23–3.38), with the number of non-household contacts being twice as high as the number of contacts with household members. The lowest overall number of contacts (2.11, 95%CI: 2.01–2.22) was reported during Germany's strongest contact reduction campaigns (end of 04/2020), when the number of household contacts was three times higher than non-household contacts. The highest number of contacts (6.38, 95%CI: 5.67–7.15) was observed during periods of relaxed measures (June 2020), when household contacts were four times fewer than non-household contacts. The work and school contacts shaped the overall variation of contact patterns in Germany during the pandemic. In participants under 18 years, partially/fully closing schools reduced school contacts by 83% (95%CI: 80–85%) and overall contacts by 39% (95%CI: 36–42%). Higher risk perceptions regarding COVID-19 were associated with 11% (95% CI: 2–17%) more social contacts among all participants and 66% (95%CI: 32–108%) more work contacts in the adult participants. Conclusions Our study revealed fluctuations in the number of social contacts during the SARS-CoV-2 pandemic in Germany, with substantial variations influenced by NPIs and individual factors. Understanding these factors affecting social contacts is vital for refining disease transmission models and informing future pandemic response strategies.
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spelling doaj-art-e60bd0b7da13477d81405e0d7cd5515f2025-08-20T02:19:58ZengBMCBMC Infectious Diseases1471-23342025-04-0125111310.1186/s12879-025-10917-3Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD studyHuynh Thi Phuong0Antonia Bartz1Andrzej K. Jarynowski2Berit Lange3Christopher I. Jarvis4Nicole Rübsamen5Rafael T. Mikolajczyk6Stefan Scholz7Tom Berger8Torben Heinsohn9Vitaly Belik10André Karch11Veronika K. Jaeger12Institute of Epidemiology and Social Medicine, University of MünsterInstitute of Epidemiology and Social Medicine, University of MünsterSystem Modelling Group, Institute of Veterinary Epidemiology and Biostatistics, Freie Universität BerlinDepartment of Epidemiology, Helmholtz Centre for Infection Research, Brunswick, Germany & German Centre for Infection Research, TI BBDLondon School of Hygiene and Tropical MedicineInstitute of Epidemiology and Social Medicine, University of MünsterInstitute for Medical Epidemiology, Biometrics, and Informatics (IMEBI), Interdisciplinary Center for Health Sciences, Medical Faculty of the Martin Luther University Halle-WittenbergMedical Faculty of the Martin Luther University Halle-Wittenberg, Halle, Germany, until 01/2022 Immunization Unit, Infectious Disease Epidemiology, Robert Koch-InstituteInstitute of Epidemiology and Social Medicine, University of MünsterDepartment of Epidemiology, Helmholtz Centre for Infection Research, Brunswick, Germany & German Centre for Infection Research, TI BBDSystem Modelling Group, Institute of Veterinary Epidemiology and Biostatistics, Freie Universität BerlinInstitute of Epidemiology and Social Medicine, University of MünsterInstitute of Epidemiology and Social Medicine, University of MünsterAbstract Background During the SARS-CoV-2 pandemic, Germany employed several nonpharmaceutical interventions (NPIs) to reduce social contacts and decelerate the virus’s spread. Associations between demographics and other factors, e.g. perceived pandemic threat level, might help explain variations in social contact behaviours. We aimed to estimate contact numbers during the pandemic in Germany and assess factors associated with changes therein. Methods Between 04/2020 and 12/2021, we conducted an online contact survey (COVIMOD) with 33 waves in Germany. We calculated the mean and 95% confidence interval of daily reported contacts (“people who you met in person and with whom you exchanged at least a few words, or with whom you had physical contact”) using bootstrapping. The effects of different factors on the number of contacts were determined by fitting generalized additive models (GAMs). Results The COVIMOD survey recorded 59,585 responses from 7,851 participants across Germany. The overall mean number of daily social contacts during the study period was 3.30 (95%CI: 3.23–3.38), with the number of non-household contacts being twice as high as the number of contacts with household members. The lowest overall number of contacts (2.11, 95%CI: 2.01–2.22) was reported during Germany's strongest contact reduction campaigns (end of 04/2020), when the number of household contacts was three times higher than non-household contacts. The highest number of contacts (6.38, 95%CI: 5.67–7.15) was observed during periods of relaxed measures (June 2020), when household contacts were four times fewer than non-household contacts. The work and school contacts shaped the overall variation of contact patterns in Germany during the pandemic. In participants under 18 years, partially/fully closing schools reduced school contacts by 83% (95%CI: 80–85%) and overall contacts by 39% (95%CI: 36–42%). Higher risk perceptions regarding COVID-19 were associated with 11% (95% CI: 2–17%) more social contacts among all participants and 66% (95%CI: 32–108%) more work contacts in the adult participants. Conclusions Our study revealed fluctuations in the number of social contacts during the SARS-CoV-2 pandemic in Germany, with substantial variations influenced by NPIs and individual factors. Understanding these factors affecting social contacts is vital for refining disease transmission models and informing future pandemic response strategies.https://doi.org/10.1186/s12879-025-10917-3Contact behaviourHeterogeneityModellingPandemicSARS-CoV-2
spellingShingle Huynh Thi Phuong
Antonia Bartz
Andrzej K. Jarynowski
Berit Lange
Christopher I. Jarvis
Nicole Rübsamen
Rafael T. Mikolajczyk
Stefan Scholz
Tom Berger
Torben Heinsohn
Vitaly Belik
André Karch
Veronika K. Jaeger
Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study
BMC Infectious Diseases
Contact behaviour
Heterogeneity
Modelling
Pandemic
SARS-CoV-2
title Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study
title_full Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study
title_fullStr Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study
title_full_unstemmed Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study
title_short Changes in social contact patterns in Germany during the SARS-CoV-2 pandemic – an analysis based on the COVIMOD study
title_sort changes in social contact patterns in germany during the sars cov 2 pandemic an analysis based on the covimod study
topic Contact behaviour
Heterogeneity
Modelling
Pandemic
SARS-CoV-2
url https://doi.org/10.1186/s12879-025-10917-3
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