Epidemiology and seasonality of acute respiratory infections in hospitalized children over four consecutive years (2012–2016)

•The respiratory viral profile varied with age.•The distribution of viruses is variable over the year depending on the species.•Persistence of non-enveloped viruses throughout the year.•Atmospheric temperature was rarely a limiting factor in the circulation of viruses. Acute respiratory infections are a principal cause of illness and mortality especially in young children worldwide. To study the epidemiology and seasonality of viral respiratory infections in hospitalized children (under the age of 16) between September 2012 and August 2016. Nasopharyngeal swabs or aspirates were collected from 3199 symptomatic patients and then screened with a routine multiplex PCR assay. Respiratory viruses were detected for 1624 (50.8%) of the 3199 children in the study population. Of these, 210 (13.3%) were positive for two viruses, 28 (1.7%) were positive for three, and 3 (0.2%) were positive for four. The viral profile varied with age. Some viruses were significantly more frequent in children under the age of 1 month (such as human respiratory syncytial virus (p