question: Objectives The aim of this study was to estimate the impact of the COVID-19 pandemic on the circulation of non-SARS-CoV-2 respiratory viruses and clinical characteristics of COVID-19 in hospitalized children. Methods 226 and 864 children admitted to Children's City Clinical Hospital with acute respiratory infection in September-November of 2018 and 2020 in Moscow were tested for respiratory viruses using multiplex PCR and Mycoplasma pneumoniae/Chlamydia pneumoniae using ELISA. Results The detection rate of non-SARS-CoV-2 viruses in 2020 was lower than in 2018, 16.9% vs 37.6%. An increase in the median age of children with the respiratory viruses was observed during the pandemic (3 years vs 1 year). There was no significant difference in the frequency of ICU admission among children with SARS-CoV-2 and other respiratory virus infections (2.7% vs 2.9%). SARS-CoV-2 and hRV, hMPV, hAdV showed significantly lower than expected co-detection rates during co-circulation. An increase in BMI or bacterial coinfections lead to an increased risk of ICU admission and a longer duration of COVID-19 in children. Conclusions The COVID-19 pandemic led to significant changes in the epidemiological characteristics of non-SARS-CoV-2 respiratory viruses during the autumn peak of the 2020 pandemic, compared to the same period in 2018.