Early chains of transmission of COVID-19 in France, January to March 2020
Eurosurveillance·
- DOI
- 10.2807/1560-7917.es.2022.27.6.2001953
- PMID
- 35144724
- PMCID
- PMC8832523
- OpenAlex
- W4211086680
- Study type
- Journal article
- Publisher
- European Centre for Disease Control and Prevention (ECDC)
- Article type
- journal-article
- Integrity
- current
Publication version
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Open linked preprint →Why this research matters now
The findings highlight the importance of superspreading events in early COVID-19 transmission and demonstrate that household settings posed higher transmission risk than workplace or healthcare settings. These insights informed contact-tracing priorities and outbreak control strategies during the pandemic's initial phase.
Structured evidence summary
Research question
The study aimed to characterize SARS-CoV-2 transmission patterns using contact-tracing data from the initial phase of the COVID-19 pandemic in France.
Study design
This was a retrospective analysis of contact-tracing and epidemiological investigation data collected in France from January 24 to March 30, 2020. The study assessed secondary clinical attack rates, characterized transmission chains, and estimated key spread parameters including serial intervals.
Population and setting
The study analyzed 6,082 contacts of 735 confirmed COVID-19 cases in France during the early pandemic period. Contacts included family members, co-workers, friends, and nosocomial (healthcare-associated) contacts.
Main findings
The overall secondary clinical attack rate was 4.1% and increased with the age of both index cases and contacts. Family contacts had double the risk of becoming cases compared to co-workers or friends, while nosocomial contacts had lower risk. The distribution of secondary cases was highly over-dispersed, with 80% of secondary transmissions caused by only 10% of cases. The mean serial interval was 5.1 days in contact-tracing pairs and 6.8 days in retrospectively investigated pairs.
Public-health relevance
The findings highlight the importance of superspreading events in early COVID-19 transmission and demonstrate that household settings posed higher transmission risk than workplace or healthcare settings. These insights informed contact-tracing priorities and outbreak control strategies during the pandemic's initial phase.
Important limitations
This summary relies on the supplied single-article abstract and metadata. The serial interval estimates from contact-tracing pairs may be affected by censoring of late transmission events. Full interpretation of study limitations requires access to the complete published article.
GIDS interpretation
This peer-reviewed journal article was published in Eurosurveillance in February 2022 and is classified under outbreak investigation, surveillance, and transmission dynamics topics for COVID-19 and SARS in France. The study provides retrospective epidemiological evidence from the early pandemic period rather than real-time surveillance data.
Related GIDS surveillance
Literature context does not validate, explain, or change a surveillance signal. Exact and contextual relationships are shown separately.
Evidence relationships
This article has 9 auditable classifier relationships to diseases, places, topics, and study design.