On 07/02/2020, French Health authorities were informed of a confirmed case of SARS-CoV-2 coronavirus 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.
We defined as a confirmed case a person linked to the chalet with a positive RT-PCR sample for SARS-CoV-2.
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, one tertiary case was detected in a symptomatic patient with a positive endotracheal aspirate; all previous and concurrent nasopharyngeal specimens were negative. Additionally, 172 contacts were monitored, including 73 tested negative for SARS-CoV-2.
The occurrence in this cluster of one 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 suspect Covid-19 cases.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2020 Apr 11 [Epub ahead of print]
Kostas Danis, Olivier Epaulard, Thomas Bénet, Alexandre Gaymard, Séphora Campoy, Elisabeth Bothelo-Nevers, Maude Bouscambert-Duchamp, Guillaume Spaccaferri, Florence Ader, Alexandra Mailles, Zoubida Boudalaa, Violaine Tolsma, Julien Berra, Sophie Vaux, Emmanuel Forestier, Caroline Landelle, Erica Fougere, Alexandra Thabuis, Philippe Berthelot, Raphael Veil, Daniel Levy-Bruhl, Christian Chidiac, Bruno Lina, Bruno Coignard, Christine Saura, Investigation Team
Santé Publique France (SpFrance), the French National Public Health Agency, Department of infectious diseases, Saint-Maurice, France., Infectious diseases department, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France., Santé Publique France (SpFrance), the French National Public Health Agency, Auvergne-Rhône-Alpes regional office, Lyon, France., Virology Department, Infective Agents Institute, National Reference Center for Respiratory Viruses, North Hospital Network, Lyon, France., Regional Health Agency of Auvergne Rhône Alpes, Lyon, France., Infectious Diseases department, University hospital of Saint-Etienne, France., Infectious and tropical disease department, Croix-Rousse hospital, University Hospital of Lyon., Infectious diseases unit, Centre Hospitalier Annecy Genevois, Annecy, France., Infectious Disease Department, Centre Hospitalier Metropole Savoie, Chambery, France., Service d'Hygiène Hospitalière et de Gestion des Risques, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France., Public Health Emergency Operations Center of the French Ministry of Health, Paris, France.