Tweet
Commun Med (Lond)
. 2026 May 4.
doi: 10.1038/s43856-026-01543-4. Online ahead of print.
Implications for distancing measures on in-person school and work attendance from Italian post-pandemic social contact data
Lorenzo Lucchini # 1 , Valentina Marziano # 2 , Filippo Trentini 3 , Chiara Chiavenna 1 4 , Elena D'Agnese 1 5 6 , Vittoria Offeddu 1 , Mattia Manica 2 , Piero Poletti 2 , Duilio Balsamo 1 4 , Giorgio Guzzetta 2 , Marco Ajelli 7 , Alessia Melegaro 8 9 , Stefano Merler 2
Affiliations
Background: The collection of updated post-COVID-19 data on social contacts is critical for future epidemiological assessment and evaluation of non-pharmaceutical interventions.
Methods: We conducted two waves of an online survey in Italy (March 2022 and March 2023), collecting representative data on direct (verbal/physical) and indirect (indoor co-location) contacts. Using a generalised linear mixed model, we analysed social contact determinants and the impact of work-from-home and distance learning on reducing a pathogen's reproduction number (R). Additionally, we calibrated an age-structured model to the 2023-2024 influenza A epidemic in Italy to explore the impact of alternative in-person attendance scenarios on infection attack rates.
Results: We find that in-person attendance significantly increases contacts: adults attending in person have 1.69 times (95%CI: 1.55-1.83) more contacts than those staying home, while children/adolescents 2.36 (95%CI: 1.96-2.84). Limiting in-person work alone marginally affects R, whereas combining work-from-home with distance learning (from primary school onwards) reduces R by up to 23.2% (95%CI: 13.7-30.1%), with minimal additional benefit from suspending early childcare. In the influenza A case study, seasonal infection attack rates range from 14.7% (95%PI: 12.8-16.5%) under full in-person attendance to <0.2% under the most restrictive scenario. Moderate interventions (suspension of tertiary education and work-from-home) reduce attack rates by up to one fourth among adults (15-64 years) and one sixth among older individuals.
Conclusions: This study provides post-pandemic contact matrices for Italy, essential for modelling transmission of respiratory pathogens, and quantitative evidence on the epidemiological impact of targeted physical distancing measures, thereby supporting future policy design.
Plain language summary
Respiratory viruses spread through everyday contacts between people. Understanding how human interactions changed after the COVID-19 pandemic is important for preparing for future outbreaks. We conduct two online surveys in Italy in 2022 and 2023 to measure the number of social contacts across different age groups. We explore factors associated with higher numbers of contacts and find that people attending work or school in person report substantially more contacts than others. We estimate how combining work-from-home and distance learning could reduce the transmission potential of respiratory viruses, using seasonal influenza to illustrate the impact on a real-world epidemic. These findings provide updated estimates of social contacts and can
. 2026 May 4.
doi: 10.1038/s43856-026-01543-4. Online ahead of print.
Implications for distancing measures on in-person school and work attendance from Italian post-pandemic social contact data
Lorenzo Lucchini # 1 , Valentina Marziano # 2 , Filippo Trentini 3 , Chiara Chiavenna 1 4 , Elena D'Agnese 1 5 6 , Vittoria Offeddu 1 , Mattia Manica 2 , Piero Poletti 2 , Duilio Balsamo 1 4 , Giorgio Guzzetta 2 , Marco Ajelli 7 , Alessia Melegaro 8 9 , Stefano Merler 2
Affiliations
- PMID: 42082766
- DOI: 10.1038/s43856-026-01543-4
Background: The collection of updated post-COVID-19 data on social contacts is critical for future epidemiological assessment and evaluation of non-pharmaceutical interventions.
Methods: We conducted two waves of an online survey in Italy (March 2022 and March 2023), collecting representative data on direct (verbal/physical) and indirect (indoor co-location) contacts. Using a generalised linear mixed model, we analysed social contact determinants and the impact of work-from-home and distance learning on reducing a pathogen's reproduction number (R). Additionally, we calibrated an age-structured model to the 2023-2024 influenza A epidemic in Italy to explore the impact of alternative in-person attendance scenarios on infection attack rates.
Results: We find that in-person attendance significantly increases contacts: adults attending in person have 1.69 times (95%CI: 1.55-1.83) more contacts than those staying home, while children/adolescents 2.36 (95%CI: 1.96-2.84). Limiting in-person work alone marginally affects R, whereas combining work-from-home with distance learning (from primary school onwards) reduces R by up to 23.2% (95%CI: 13.7-30.1%), with minimal additional benefit from suspending early childcare. In the influenza A case study, seasonal infection attack rates range from 14.7% (95%PI: 12.8-16.5%) under full in-person attendance to <0.2% under the most restrictive scenario. Moderate interventions (suspension of tertiary education and work-from-home) reduce attack rates by up to one fourth among adults (15-64 years) and one sixth among older individuals.
Conclusions: This study provides post-pandemic contact matrices for Italy, essential for modelling transmission of respiratory pathogens, and quantitative evidence on the epidemiological impact of targeted physical distancing measures, thereby supporting future policy design.
Plain language summary
Respiratory viruses spread through everyday contacts between people. Understanding how human interactions changed after the COVID-19 pandemic is important for preparing for future outbreaks. We conduct two online surveys in Italy in 2022 and 2023 to measure the number of social contacts across different age groups. We explore factors associated with higher numbers of contacts and find that people attending work or school in person report substantially more contacts than others. We estimate how combining work-from-home and distance learning could reduce the transmission potential of respiratory viruses, using seasonal influenza to illustrate the impact on a real-world epidemic. These findings provide updated estimates of social contacts and can