Time trends in social contacts before and during the COVID-19 pandemic: the CONNECT study

  1. Mélanie Drolet
  2. Aurélie Godbout
  3. Myrto Mondor
  4. Guillaume Béraud
  5. Léa Drolet-Roy
  6. Philippe Lemieux-Mellouki
  7. Alexandre Bureau
  8. Éric Demers
  9. Marie-Claude Boily
  10. Chantal Sauvageau
  11. Gaston De Serres
  12. Niel Hens
  13. Philippe Beutels
  14. Benoit Dervaux
  15. Marc Brisson

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Abstract

Background

Since the beginning of the COVID-19 pandemic, many countries, including Canada, have adopted unprecedented physical distancing measures such as closure of schools and non-essential businesses, and restrictions on gatherings and household visits. We described time trends in social contacts for the pre-pandemic and pandemic periods in Quebec, Canada.

Methods

CONNECT is a population-based study of social contacts conducted shortly before (2018/2019) and during the COVID-19 pandemic (April 2020 – February 2021), using the same methodology for both periods. We recruited participants by random digit dialing and collected data by self-administered web-based questionnaires. Questionnaires documented socio-demographic characteristics and social contacts for two assigned days. A contact was defined as a two-way conversation at a distance ≤ 2 m or as a physical contact, irrespective of masking. We used weighted generalized linear models with a Poisson distribution and robust variance (taking possible overdispersion into account) to compare the mean number of social contacts over time and by socio-demographic characteristics.

Results

A total of 1291 and 5516 Quebecers completed the study before and during the pandemic, respectively. Contacts significantly decreased from a mean of 8 contacts/day prior to the pandemic to 3 contacts/day during the spring 2020 lockdown. Contacts remained lower than the pre-COVID period thereafter (lowest = 3 contacts/day during the Christmas 2020/2021 holidays, highest = 5 in September 2020). Contacts at work, during leisure activities/in other locations, and at home with visitors showed the greatest decreases since the beginning of the pandemic. All sociodemographic subgroups showed significant decreases of contacts since the beginning of the pandemic. The mixing matrices illustrated the impact of public health measures (e.g. school closure, gathering restrictions) with fewer contacts between children/teenagers and fewer contacts outside of the three main diagonals of contacts between same-age partners/siblings and between children and their parents.

Conclusion

Physical distancing measures in Quebec significantly decreased social contacts, which most likely mitigated the spread of COVID-19.

Article activity feed

  1. Version published to 10.1186/s12889-022-13402-7
  2. Version published to 10.1101/2021.10.06.21264632v2 on medRxiv
  3. ScreenIT

    SciScore for 10.1101/2021.10.06.21264632: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsIRB: All CONNECT phases were approved by the ethics committee of the CHU de Québec research center (project 2016-2172) and we commissioned the market company Advanis for recruitment and data collection.
    Consent: All participants gave their consent to participate in the study during the recruitment phone call.
    Sex as a biological variablenot detected.
    RandomizationThe randomly generated landline and mobile phone number sample was provided by ASDE, a Canadian firm specialized in survey sampling (3).
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    However, CONNECT has some limitations. Firstly, previous data suggested that social contacts measured with survey methodology could underestimate the number of social contacts compared with a sensors methodology, particularly for contacts of short duration(22, 23). More specifically, parents participating in CONNECT reported difficulties in reporting contacts at school on behalf of their child. Secondly, although CONNECT is population-based with a random recruitment of the general population, volunteer participants may differ from those refusing to participate in the study and may be those adhering the most to the public health measures. However, we have collected a wealth of information regarding the participant’s characteristics and we are confident that the recruitment process was successful in providing a sample of participants generally representative of the Quebec general population (in terms of region, participation rate to education and employment, race, country of origin and mother tongue), and samples are comparable across the different phases of the study. Thirdly, given that public health measures undertaken aimed at limiting social contacts, social desirability may have contributed to an underestimation of contacts. Some participants may not have reported all their contacts, particularly contacts forbidden by public health measures. These three main limitations would likely bias our results towards an underestimation of social contacts. Nonetheless, changes in so...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a protocol registration statement.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  4. Version published to 10.1101/2021.10.06.21264632v1 on medRxiv