Characteristics and forecasting of respiratory viral epidemics among children in west China.

We aimed to assess the respiratory virus characteristics and forecasts among young children with acute respiratory tract infection (ARTI) in west China.This retrospective study investigated the epidemic characteristics of respiratory viruses among 11,813 paediatric ARTI patient samples (mean age, 2.25 years) between March 2018 and March 2020.The ratio of boys to girls was 1.36. The 2 predominant viruses were influenza (Flu) A and respiratory syncytial virus (RSV) in both years, with Flu A accounting for 47.3% and 47.5% in the first and second years and RSV accounting for 32.7% and 24.7% of the positive samples in the first and second years, respectively. The Flu B positive rates were 10.9% and 13.1%, and those of the other 4 viruses were <7%. The most common virus was RSV in children below 5 years and Flu A in those between 5 and 10 years. Flu A and RSV demonstrated pronounced seasonality, and their infection rates increased from October. During the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, isolation measures led to a decline in the number of ARTI cases.This study provides surveillance data of the respiratory viruses in west China. It could guide medical staff in implementing necessary prevention and management strategies before future viral outbreaks.