Clinical Characterization and Outcomes of Human Clade IIb Mpox Virus Disease: A European Multicenter Mpox Observational Cohort Study (MOSAIC)
Elise Pesonel, Cédric Laouénan, Laetitia Guiraud, Josephine Bourner, Isabelle Hoffmann, Diana Molino, Coralie Tardivon, Delphine Bachelet, France Mentré, Alain Amstutz, Laura Merson, Amanda Rojek, Minerva Cervantes-Gonzalez, Andrea Antinori, Antonella Castagna, Silvia Nozza, Valérie Pourcher, Agnès Libois, Jake Dunning, Evelina Tacconelli, Maya Hites, Fernando Calle, Peter Horby, Yazdan Yazdanpanah, Alexandra Calmy, François-Xavier Lescure, Piero Olliaro, for the Mpox ObServAtIonal Cohort (MOSAIC) Study Group, Maya Hites, Leïla Belkhir, Marie‐Angélique De Scheerder, Jean‐Christophe Goffard, Agnès Libois, Zineb Khalil, Catherine Orban, Lucie Seyler, Clotilde Visée, Florence Ader, Antoine Bachelard, Yasmine Bouaraba, Jean-Marc Chapplain, Hugues Cordel, François Danion, Aurélien Dinh, Nikita Dobremel, Manuel Etienne, Pierre Frange, Karine Faure, François Goehringer, Karine Lacombe, François-Xavier Lescure, R. Manaquin, Guillaume Martin‐Blondel, Jean‐Michel Mansuy, Giovanny Gombert, Duc Thanh Nguyen, Romain Palich, Gilles Pialoux, Aoife G. Cotter, Virginie Gautier, Evelina Tacconelli, Oriana Awwad, Andrea Antinori, Antonella Castagna, Silvia Nozza, Angelo Roberto Raccagni, Elena Bruzzesi, Antonio Cascio, Anna Maria Cattelan, Maddalena Cordioli, Giulia De Luca, Lorenza Lambertenghi, Giulia Marchetti, Valentina Mazzotta, Emanuele Nicastri, Vincenzo Scaglione, Carlo Tascini, Jorge Machado, Lurdes Santos, Wong Chen Seong, Travis Ren Teen Chia, Wilnard Yeong Tze Tan, Fernando Calle, Vicente Estrada, Miguel Nicolás Navarrete Lorite, Alfredo Soler Carracedo, Maria Velasco Arribas, Dominique L. Braun, Alexandra Calmy, Matthias Cavassini, Lorenzo Ciullini, Stéphane Emonet, Chiara Fedeli, Yvan Gosmain, Laetitia Guiraud, Benjamin Hampel, Olivier Ségéral, Cornelia Staehelin, Marcel Stöckle, Alejandro Arenas‐Pinto
Abstract
BACKGROUND: The global mpox outbreak that started in May 2022 was caused by a novel clade IIb variant of the mpox virus (Orthopoxvirus monkeypox, MPXV). It differed from the traditional Western and Central Africa disease in transmission patterns and clinical presentation. METHODS: To address the need for detailed clinical and virologic data, we conducted an observational cohort study (MOSAIC) during May 2022-July 2023 in individuals with confirmed MPXV infection enrolled in 6 European countries. Case management decisions were left to the attending physician. Participants were monitored for up to 6 months for clinical signs/symptoms and clinical and virologic outcomes through hospital visits, phone interviews, and self-administered questionnaires. Outcomes included time to lesion resolution, clinical status, and virus clearance. RESULTS: The 518 participants not receiving any specific treatment ("untreated") were diagnosed a median 5 days from symptom onset; 90% were managed as outpatients. Lesions were mostly cutaneous (88%) and perigenital (74%). By day 14 from the first polymerase chain reaction (PCR)-positive sample, 39% had resolved lesions. Time to 95% unculturable virus was longest in cutaneous lesions (52 days). A putative systemic antiviral was available for 57 participants, 44% as inpatients; 34% and 58% had resolved lesions by day 14 from the first PCR-positive sample and from treatment start, respectively. Time to 95% unculturable virus was 60 days in skin and oropharynx. No death or recrudescence occurred by day 180. CONCLUSIONS: MOSAIC provides comprehensive insights into the clinical and virologic characteristics of mpox caused by the clade IIb variant. The study forms the basis of clinical characterization for ongoing mpox outbreaks.