Detection of Respiratory Viruses during the Early Phase of the Coronavirus Disease 2019 Pandemic in Ibaraki and Gunma Prefectures, Japan

Respiratory infections are common, and the most common causative agent is a virus. Therefore, routine surveillance of respiratory viruses is useful in the case of novel viral diseases such as coronavirus disease 2019 (COVID-19). In this study, to clarify the kind of virus involved in suspected cases of COVID-19 in the early stages of the pandemic, we attempted to detect various respiratory viruses in 613 specimens that tested negative for severe acute respiratory syndrome coronavirus 2 using reverse transcription polymerase chain reaction. As a result, viruses were detected in 59 (9.6%) patients. In addition, human rhinovirus (HRV), human metapneumovirus (HMPV), human respiratory syncytial virus, and human parechovirus were detected in 29, 25, 3, and 2 patients, respectively. Although this study was conducted over a short period of time and not all specimens were tested, these results indicate that various respiratory viruses, especially HRV and HMPV, can be detected even during the early stages of the COVID-19 pandemic. Because various respiratory viruses maintain a constant effect during the outbreak of the newly emerged pandemic, systematic surveillance of respiratory viruses is needed during the normal period to make good use for clinical and public health.