Impact of COVID‐19 on Respiratory Virus Infections in Children, Japan, 2018–2023

BACKGROUND: COVID-19, caused by SARS-CoV-2, was first documented in Japan in January 2020. We previously reported an increased risk of rhinovirus infections among children during the early phase of the COVID-19 pandemic. Here, we assessed the impact of COVID-19 on respiratory virus infections after SARS-CoV-2 spread nationwide. METHODS: We analyzed clinical specimens from 4012 patients with respiratory infections in Yokohama, Japan from January 2018 to April 2023. RESULTS: Among 15 representative respiratory viruses we detected (influenza virus, rhinovirus, coxsackievirus, echovirus, enterovirus, human coronavirus 229E, HKU1, NL63, and OC43, human metapneumovirus, human parainfluenza virus, human parechovirus, RSV, human adenovirus, human bocavirus, human parvovirus B19, herpes simplex virus type 1, and varicella-zoster virus), influenza was most affected by the COVID-19 pandemic, with no influenza viruses detected for nearly 3 years. CONCLUSIONS: The decrease in influenza infections following the emergence of SARS-CoV-2 may have contributed to the previously reported increase in rhinovirus infections. The rhinovirus outbreak, rather than SARS-CoV-2, may have contributed to the decrease in enveloped virus infections (RSV, parainfluenza viruses, metapneumovirus, and coronavirus 229E, HKU1, NL63, and OC43), possibly due to negative virus-virus interactions.