Eurosurv. COVID-19 outbreak among French firefighters, Marseille, France, 2020

[tetano]

• Guillaume André Durand[SUP]1,2[/SUP] , Franck de Laval[SUP]3,4[/SUP] , Albane de Bonet d’Oléon[SUP]3[/SUP] , François Xavier Le Flem[SUP]5[/SUP] , Yann Morin[SUP]3[/SUP] , Cyril Badaut[SUP]2,6[/SUP] , Gilda Grard[SUP]1,2[/SUP] , Constance Brossier[SUP]3[/SUP] , Marion Fossier[SUP]3[/SUP] , Aissata Dia[SUP]3[/SUP] , Flavie Letois[SUP]3[/SUP] , Manon Geulen[SUP]1,2[/SUP] , Géraldine Piorkowski[SUP]2[/SUP] , Jean-Baptiste Meynard[SUP]3[/SUP] , Frank Peduzzi[SUP]5[/SUP] , Isabelle Leparc-Goffart[SUP]1,2[/SUP] , Vincent Pommier de Santi[SUP]3,7,8[/SUP]

We investigated a COVID-19 outbreak at a fire station in Marseille, France. Confirmed cases were defined as individuals with positive SARS-CoV-2 reverse transcription (RT)-PCR and/or neutralising antibodies. All 85 firefighters at work during the outbreak period were included after questioning and sampled for RT-PCR and viral neutralisation assay. Twenty-three firefighters were confirmed positive, 19 of them were symptomatic, and four asymptomatic cases were confirmed by virus neutralisation. A total of 22 firefighters had specific neutralising antibodies against SARS-CoV-2. Neutralising antibodies were found in four asymptomatic and 18 symptomatic cases. Eleven symptomatic cases had high titres (≥ 1:80). The earliest detection of neutralising antibodies was 7 days after symptom onset, and 80% had neutralising antibodies 15 days after onset. One viral culture was positive 13 days after onset. The attack rate was 27%. We identified two introductions of the virus in this outbreak, through a presymptomatic and a paucisymptomatic case. Asymptomatic cases were not the source of a third generation of cases, although they worked without wearing a mask, indicating that asymptomatic cases did not play a significant role in this outbreak. Management and strategy based on early research of clinical signs associated with self-quarantine was effective.

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https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.41.2001676#html_fulltext