Original Article Clinical characteristics of influenza with or without Streptococcus pneumoniae co- infection in children Tzu-Yun Hsing a , Chun-Yi Lu a,b, *, Luan-Yin Chang a,b , Yun-Chung Liu a,b,c , Hsiao-Chi Lin a , Li-Lun Chen a , Yu-Cheng Liu a , Ting-Yu Yen a , Jong-Min Chen a , Ping-Ing Lee a,b , Li-Min Huang a,b , Fei-Pei Lai c,d,e a Division of Pediatric Infectious Diseases, Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan b College of Medicine, National Taiwan University, Taipei, Taiwan c Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan d Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan e Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan Received 15 March 2021; received in revised form 27 April 2021; accepted 7 July 2021 KEYWORDS Children; Co-infection; Influenza; Outcome; Streptococcus pneumoniae Background/purpose: Influenza is frequently complicated with bacterial co-infection. This study aimed to disclose the significance of Streptococcus pneumoniae co-infection in children with influenza. Methods: We retrospectively reviewed medical records of pediatric patients hospitalized for influenza with or without pneumococcal co-infection at the National Taiwan University Hospi- tal from 2007 to 2019. Clinical characteristics and outcomes were compared between patients with and without S. pneumoniae co-infection. Results: There were 558 children hospitalized for influenza: 494 had influenza alone whereas 64 had S. pneumoniae co-infection. Patients with S. pneumoniae co-infection had older ages, lower SpO 2 , higher C-Reactive Protein (CRP), lower serum sodium, lower platelet counts, more chest radiograph findings of patch and consolidation on admission, longer hospitalization, more intensive care, longer intensive care unit (ICU) stay, more mechanical ventilation, more ino- tropes/vasopressors use, more surgical interventions including video-assisted thoracoscopic surgery (VATS) and extracorporeal membrane oxygenation (ECMO), and higher case-fatality rate. * Corresponding author. Department of Pediatrics, National Taiwan University Hospital and College of Medicine, National Taiwan Uni- versity, No. 8, Chung Shan S. Rd., Taipei 10002, Taiwan. Fax: þ886 2 23147450. E-mail address: cylu@ntu.edu.tw (C.-Y. Lu). + MODEL Please cite this article as: T.-Y. Hsing, C.-Y. Lu, L.-Y. Chang et al., Clinical characteristics of influenza with or without Streptococcus pneumoniae co-infection in children, Journal of the Formosan Medical Association, https://doi.org/10.1016/j.jfma.2021.07.012 https://doi.org/10.1016/j.jfma.2021.07.012 0929-6646/Copyright ª 2021, Formosan Medical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.jfma-online.com Journal of the Formosan Medical Association xxx (xxxx) xxx