A nosocomial outbreak caused by human rhinovirus species A type 61 in a welfare facility in Gunma Prefecture, Japan.

The human rhinovirus (HRV) is generally considered as the common cold and its mild symptoms' main cause. However, HRV are also implicated in severe respiratory infections. This study reports on a nosocomial outbreak of bronchitis and pneumonia caused by HRV in a hospital during the COVID-19 epidemic in September 2022 in Gunma Prefecture, Japan. Patients continued to become infected for 9 days. During this outbreak, all 15 residents had respiratory symptoms, and HRV-A was detected in 12 of the 12 samples and phylogenetic analysis showed that it was classified into HRV-A type 61. HRV and COVID-19 or other respiratory infections cannot be differentiated from clinical symptoms; therefore, a surveillance system to monitor them may be needed.