[Viral etiology of acute respiratory tract infection among pediatric inpatients and outpatients from 2010 to 2012 in Beijing, China].

Objective: Acute respiratory tract infections (ARI) are the leading cause of pediatric morbidity and mortality worldwide, particularly in developing countries. Viruses are the main pathogens of ARI in children. The purpose of the present study was to determine the epidemiologic features of respiratory viruses, including novel viruses, in outpatient and hospitalized children with ARI.

Method: From March 2010 to February 2012, 2066 children with ARI, including 1050 outpatients and 1016 inpatients, were involved in this study. One nasopharyngeal aspirate or throat swab specimen was collected from each patient. Reverse transcription (RT) PCRs were performed to detect common respiratory tract viruses including respiratory syncytial virus (RSV), human rhinovirus (HRV), influenza virus (IFV), parainfluenza virus (PIV) type 1-4, adenovirus (ADV), enterovirus (EV), human coronavirus (HCOV), human metapneumonia virus (HMPV) and human bocavirus (HBOV).

Result: At least one viral pathogen was identified in each of 1274 out of 2066 patients and the overall positive rate was 61.7%. The positive rate in inpatient (69.7%) was higher than that in outpatient (53.9%). The frequencies of detection of various viruses among in- and outpatients were different. RSV was the most prevalent virus detected among hospitalized children, followed by HRV and PIV, whereas IFV was the most frequently identified virus in the outpatient group, followed by ADV and PIV. Simultaneous detection of two or more viruses was found in 377 cases. Coinfection was more frequent in inpatients than in outpatients (30.1% vs. 6.8%, P < 0.001).

Conclusion: Respiratory viruses play an important role in children with ARI, especially in young children. RSV was the most prevalent virus detected among hospitalized children, whereas IFV was the most frequently identified virus in the outpatient group. Viral coinfections are frequently identified, particularly in hospitalized patients. Further studies are required to better understand the impact of coinfections in children with ARI.