1. 1. Wu X, Cai Y, Huang X, et al. Co-infection with SARS-CoV-2 and influenza A virus in patient with pneumonia, China. Emerg Infect Dis. 2020;26:1324-6.
2. 2. World Health Ordganization (WHO) Preparing GISRS for the upcoming influenza seasons during the COVID-19 pandemic – practical considerations. Interim guidance, 26 May 2020. Available at <https://apps.who.int/iris/bitstream/handle/10665/332198/WHO-2019-nCoV-Preparing_GISRS-2020.1-eng.pdf?ua=1>. Accessed January 29, 2021.
3. 3. Ministry of Health, Labour and Welfare. Measures promotion headquarters a guideline for novel coronavirus (COVID-19) pathogen testing. Available at <https://www.mhlw.go.jp/content/000678571.pdf>. Accessed October 22, 2021. Japanese.
4. 4. National Institute of Infectious Diseases Japan. Influenza. Available at <https://www.niid.go.jp/niid/ja/10/2096-weeklygraph/1644-01flu.html>. Accessed January 25, 2021. Japanese.
5. 5. WHO. Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected: interim guidance, 13 March 2020. Available at <https://apps.who.int/iris/handle/10665/331446>. Accessed January 29, 2021.