In this study, we performed a single‐centred study of 307 SARS‐CoV‐2 infected patients. It was found that co‐infection of SARS‐CoV‐2 and influenza virus was common during COVID‐19 outbreak. And patients co‐infected with SARS‐CoV‐2 and influenza B virus have a higher risk of developing poor outcomes so a detection of both viruses was recommended during COVID‐19 outbreak. This article is protected by copyright. All rights reserved.