Association of close-range contact patterns with SARS-CoV-2: a household transmission study
- National Health Laboratory Service, South Africa
- ISI Foundation, Italy
- University of the Witwatersrand, South Africa
- University of Turin, Italy
Abstract
Background: Households are an important location for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, especially during periods where travel and work was restricted to essential services. We aimed to assess the association of close-range contact patterns with SARS-CoV-2 transmission.
Methods: We deployed proximity sensors for two weeks to measure face-to-face interactions between household members after SARS-CoV-2 was identified in the household, in South Africa, 2020 - 2021. We calculated duration, frequency and average duration of close range proximity events with SARS-CoV-2 index cases. We assessed the association of contact parameters with SARS-CoV-2 transmission using mixed effects logistic regression accounting for index and household member characteristics.
Results: We included 340 individuals (88 SARS-CoV-2 index cases and 252 household members). On multivariable analysis, factors associated with SARS-CoV-2 acquisition were index cases with minimum Ct value <30 (aOR 10.6 95%CI 1.4-80.1) vs >35, and female contacts (aOR 2.4 95%CI 1.2-4.8). No contact parameters were associated with acquisition (aOR 1.0-1.1) for any of the duration, frequency, cumulative time in contact or average duration parameters.
Conclusion: We did not find an association between close-range proximity events and SARS-CoV-2 household transmission. Our findings may be due to study limitations, that droplet-mediated transmission during close-proximity contacts play a smaller role than airborne transmission of SARS-CoV-2 in the household, or due to high contact rates in households.
Funding: Wellcome Trust (Grant number 221003/Z/20/Z) in collaboration with the Foreign, Commonwealth and Development Office, United Kingdom.
Data availability
The contact network, selected individual characteristics and analysis script are available at https://github.com/crdm-nicd/sashts.git.
Article and author information
Author details
Funding
Wellcome Trust (221003/Z/20/Z)
- Cheryl Cohen
Horizon 2020 Framework Programme (101016233)
- Ciro Cattuto
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: The study protocol was reviewed and approved by University of the Witwatersrand Human Research Ethics Committee (Reference M2008114). The study was structured in accordance with the Declaration of Helsinki. Written informed consent was obtained from all household members aged {greater than or equal to}18 years; assent was obtained from children aged 7-17 years, and consent from a parent/ guardian of children aged <18 years. Informed consent was administered by a study team member who explained the study and requirements to participants, and shared an information leaflet with participants to keep. Consent included the enrolment into the study and all required procedures, as well as the anonymous processing of personal data for the final study report. Participants in follow-up received grocery store vouchers of USD 3 per visit to compensate for time required for specimen collection and interview, and an additional voucher once proximity sensors were returned with no visible damage.
Copyright
© 2023, Kleynhans et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Association of close-range contact patterns with SARS-CoV-2: a household transmission study
eLife 12:e84753.
https://doi.org/10.7554/eLife.84753
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