[Sentinel Surveillance Results for Influenza and Acute Respiratory Infections during the Coronavirus Disease 2019 Pandemic].

As a result of sentinel surveillance for outpatients influenza-like illness (ILI), seasonal influenza activity remains below national baseline from 13 weeks of 2020 to 8 weeks of 2023 and Inpatient surveillance results for acute respiratory infections has decreased by less than half compared to pre-coronavirus disease 2019 (COVID-19) pandemic. In the 2022–2023 season, the weekly ILI rate was above the national baseline of 4.9 per 1,000 outpatients and flu activity increased early in the 37th week of 2022. The number of hospitalized patients for parainfluenza virus infection increased rapidly from August to October 2021 and for human metapneumovirus infection have been slightly increasing after October 2022. These unusual patterns of respiratory viruses are presumed to be due to the ease of COVID-19 related social distancing and control measures.