Lessons learned from the investigation of a COVID-19 cluster in Creil, France: effectiveness of targeting symptomatic cases and conducting contact tracing around them - Archive ouverte HAL Access content directly
Journal Articles BMC Infectious Diseases Year : 2021

Lessons learned from the investigation of a COVID-19 cluster in Creil, France: effectiveness of targeting symptomatic cases and conducting contact tracing around them

(1, 2, 3) , (3) , (2, 3, 1) , (3) , (2, 3) , (2, 3) , (3) , (2, 3) , (3) , (3) , (4) , (3) , (3) , (5) , (6, 7, 8) , (3) , (9, 3) , (9, 3) , (3)
1
2
3
4
5
6
7
8
9

Abstract

This study presents the methods and results of the investigation into a SARS-CoV-2 outbreak in a professional community. Due to the limited testing capacity available in France at the time, we elaborated a testing strategy according to pre-test probability. Methods The investigation design combined active case finding and contact tracing around each confirmed case with testing of at-risk contact persons who had any evocative symptoms ( n = 88). One month later, we performed serology testing to test and screen symptomatic and asymptomatic cases again ( n = 79). Results Twenty-four patients were confirmed (14 with RT-PCR and 10 with serology). The attack rate was 29% (24/83). Median age was 40 (24 to 59), and the sex ratio was 15/12. Only three cases were asymptomatic (= no symptoms at all, 13%, 95% CI, 3–32). Nineteen symptomatic cases (79%, 95% CI, 63–95) presented a respiratory infection, two of which were severe. All the RT-PCR confirmed cases acquired protective antibodies. Median incubation was 4 days (from 1 to 13 days), and the median serial interval was 3 days (0 to 15). We identified pre-symptomatic transmission in 40% of this cluster, but no transmission from asymptomatic to symptomatic cases. Conclusion We report the effective use of targeted testing according to pre-test probability, specifically prioritizing symptomatic COVID-19 diagnosis and contact tracing. The asymptomatic rate raises questions about the real role of asymptomatic infected people in transmission. Conversely, pre-symptomatic contamination occurred frequently in this cluster, highlighting the need to identify, test, and quarantine asymptomatic at-risk contact persons (= contact tracing). The local lockdown imposed helped reduce transmission during the investigation period.
Fichier principal
Vignette du fichier
s12879-021-06166-9.pdf (660.78 Ko) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

hal-03304654 , version 1 (03-08-2021)

Licence

Attribution - CC BY 4.0

Identifiers

Cite

Franck de Laval, Anaïs Grosset-Janin, François Delon, Alexandre Allonneau, Christelle Tong, et al.. Lessons learned from the investigation of a COVID-19 cluster in Creil, France: effectiveness of targeting symptomatic cases and conducting contact tracing around them. BMC Infectious Diseases, 2021, 21 (1), pp.457. ⟨10.1186/s12879-021-06166-9⟩. ⟨hal-03304654⟩
696 View
33 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More