BACKGROUND: Viruses are the main infectious agents of acute respiratory infections in children. We aim to describe the epidemiological characteristics of viral pathogens of acute respiratory tract infections in outpatient children. METHODS: From April 2018 to March 2019, the results of viral detection using oral pharyngeal swabs from 103,210 children with acute respiratory tract infection in the outpatient department of the Children’s Hospital, Zhejiang University School of Medicine, were retrospectively analyzed. Viral antigens, including adenovirus (ADV), influenza A (FLUA), influenza B (FLUB) and respiratory syncytial virus (RSV), were detected by the colloidal gold method. RESULTS: At least one virus was detected in 38,355 cases; the positivity rate was 37.2%. A total of 1910 cases of mixed infection with two or more viruses were detected, and the positivity rate of multiple infection was 1.9%. The ADV positivity rate was highest in the 3–6-year-old group (18.7%), the FLUA positivity rate was highest in the > 6-year-old group (21.6%), the FLUB positivity rate was highest in the > 6-year-old group (6.6%), and the RSV positivity rate was highest in the < 1-year-old group (10.6%). There was a significant difference in the positivity rate of viral infection among different age groups (χ(2) = 1280.7, P < 0.001). The rate of positive viral infection was highest in winter (47.1%). The ADV infection rate was highest in spring (18.2%). The rates of FLUA and FLUB positivity were highest in winter (28.8% and 3.6%, respectively). The rate of RSV positivity was highest in autumn (17.4%). The rate of positive viral infection in different seasons was significantly different (χ(2) = 6459.1, P < 0.001). CONCLUSIONS: Viral infection rates in children differ for different ages and seasons. The positivity rate of ADV is highest in the preschool period and that of RSV is highest in infants; that of FLU increases with age. The total positive rate of viral infection in different seasons is highest in winter, as is the rate of FLU positivity.
Epidemiological characteristics of four common respiratory viral infections in children