Kostas Danis1, Olivier Epaulard2,3,4, Thomas Bénet5, Alexandre Gaymard6, Séphora Campoy7, Elisabeth Botelho-Nevers8,9, Maude Bouscambert-Duchamp6, Guillaume Spaccaferri5, Florence Ader10, Alexandra Mailles1, Zoubida Boudalaa7, Violaine Tolsma11, Julien Berra7, Sophie Vaux1, Emmanuel Forestier12, Caroline Landelle13,14, Erica Fougere5, Alexandra Thabuis5, Philippe Berthelot8,9, Raphael Veil15, Daniel Levy-Bruhl1, Christian Chidiac10,16, Bruno Lina6, Bruno Coignard1, Christine Saura5. 1. French National Public Health Agency, Department of Infectious Diseases, Saint-Maurice, France. 2. Infectious Diseases Department, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France. 3. Fédération d'infectiologie multidisciplinaire de l'Arc Alpin, Université Grenoble Alpes, Grenoble, France. 4. Unité Mixte de Recherche 5075 (UMR 5075), Institut de biologie structurale, Grenoble, France. 5. French National Public Health Agency, Auvergne-Rhône-Alpes Regional Office, Lyon, France. 6. Department of Virology, Infective Agents Institute, National Reference Center for Respiratory Viruses North Hospital Network, Lyon, France. 7. Regional Health Agency of Auvergne Rhône Alpes, Lyon, France. 8. Infectious Diseases Department, University Hospital of Saint-Etienne, Lyon, France. 9. Groupe Immunité des Muqueuses et Agents Pathogènes, Université Jean Monnet, Université de Lyon, St-Etienne, France. 10. Infectious and Tropical Disease Department, Croix-Rousse Hospital, University Hospital of Lyon, Lyon, France. 11. Infectious Diseases Unit, Centre Hospitalier Annecy Genevois, Annecy, France. 12. Infectious Disease Department, Centre Hospitalier Metropole Savoie, Chambery, France. 13. Service d'Hygiène Hospitalière et de Gestion des Risques, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France. 14. Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques, Applications, Grenoble, Unité Mixte de Recherche 5525 (TIMC-IMAG UMR5525), CNRS, Université Grenoble Alpes, Grenoble, France. 15. Public Health Emergency Operations Center, French Ministry of Health, Paris, France. 16. Maladies Infectieuses et Tropicales, Université Claude Bernard Lyon 1 (UCBL1), Unité de formation et de recherche (UFR) Lyon Sud-Charles Mérieux, Lyon, France.
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.
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 infectedchild 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.
Authors: Katy A M Gaythorpe; Sangeeta Bhatia; Tara Mangal; H Juliette T Unwin; Natsuko Imai; Gina Cuomo-Dannenburg; Caroline E Walters; Elita Jauneikaite; Helena Bayley; Mara D Kont; Andria Mousa; Lilith K Whittles; Steven Riley; Neil M Ferguson Journal: Sci Rep Date: 2021-07-06 Impact factor: 4.379