Cluster of Coronavirus Disease 2019 (COVID-19) in the French Alps, February 2020
Kostas Danis, Olivier Épaulard, Thomas Bénet, Alexandre Gaymard, Séphora Campoy, Élisabeth Botelho-Nevers, Maude Bouscambert‐Duchamp, Guillaume Spaccaferri, Florence Ader, Alexandra Mailles, Zoubida Boudalaa, Violaine Tolsma, Julien Berra, Sophie Vaux, E. Forestier, Caroline Landelle, Erica Fougère, A. Thabuis, P. Berthelot, Raphaël Veil, D Lévy-Brühl, Christian Chidiac, Bruno Lina, B. Coignard, C. Saura, Investigation Team, Élise Brottet, Delphine Casamatta, Yves Gallien, Scarlett George, Delphine Viriot, Fatima Aït El Belghiti, Sibylle Bernard-Stoecklin, Jean‐Claude Desenclos, Coralie Giese, Didier Ghislain, Magali Gounon, N. Grangeret, Cécile Marie, Bruno Morel, Muriel Deher, Anne-Sophie Ronnaux Baron, Geneviève Courbis, Nathalie Ragozin, M. Wolska, Eric Serange, Delphine Mercatello, Soraya Aiouaz, Martine Valette, Émilie Frobert, Laurence Josset, Vanessa Escuret, Florence Morfin, Geneviève Billaud, Myriam Blanc, Julie Arata-Bardet, Marie Froidure, Marion Le Maréchal, Patricia Pavèse, Isabelle Pierre, Agathe Becker, Pierre Chauvelot, Anne Conrad, Tristan Ferry, Patrick Miailhes, Thomas Perpoint, Cécile Pouderoux, Sandrine Roux, Florent Valour, Marie-France Lutz, Anne Pouvaret, Virginie Vitrat, Mylène Maillet, C. Janssen, Emilie Piet, Alexie Bosch, Anne-Laure Destrem, Margaux Isnard, Thibault Challan-Belval, C. Wackenheim, Alice Couturier, Gael Gheno, T Roupioz, Nicolas Lucet, Stéphane Ayouni, Mireille Vincent, Servicio de Epidemiología, Dirección General de Salud Pública del Gover Balear, Virginie Masserey Spicher, C Bourquin, Jeanine Stoll, P. Chaud, Anne-Laure Mounayar
Abstract
BACKGROUND: On 7 February 2020, French Health authorities were informed of a confirmed case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in an Englishman infected in Singapore who had recently stayed in a chalet in the French Alps. We conducted an investigation to identify secondary cases and interrupt transmission. METHODS: We defined as a confirmed case a person linked to the chalet with a positive reverse-transcription polymerase chain reaction sample for SARS-CoV-2. RESULTS: The index case stayed 4 days in the chalet with 10 English tourists and a family of 5 French residents; SARS-CoV-2 was detected in 5 individuals in France, 6 in England (including the index case), and 1 in Spain (overall attack rate in the chalet: 75%). One pediatric case, with picornavirus and influenza A coinfection, visited 3 different schools while symptomatic. One case was asymptomatic, with similar viral load as that of a symptomatic case. Seven days after the first cases were diagnosed, 1 tertiary case was detected in a symptomatic patient with from the chalet a positive endotracheal aspirate; all previous and concurrent nasopharyngeal specimens were negative. Additionally, 172 contacts were monitored; all contacts tested for SARS-CoV-2 (N = 73) were negative. CONCLUSIONS: The occurrence in this cluster of 1 asymptomatic case with similar viral load as a symptomatic patient suggests transmission potential of asymptomatic individuals. The fact that an infected child did not transmit the disease despite close interactions within schools suggests potential different transmission dynamics in children. Finally, the dissociation between upper and lower respiratory tract results underscores the need for close monitoring of the clinical evolution of suspected cases of coronavirus disease 2019.