Background: Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infection in children less than 5 years of age. The impact of non-RSV respiratory virus coinfection on the severity of RSV disease is unknown.
Methods: This hospital-based prospective study was conducted in Nagasaki, Japan, on all children less than 5 years of age with acute respiratory infection (ARI) who had undergone a rapid RSV diagnostic test between April 2009 and March 2010. Thirteen respiratory viruses were identified from nasopharyngeal swab samples using a multiplex polymerase chain reaction; polymerase chain reaction–positive samples were considered as confirmed respiratory virus infections. The cases were classified into 3 categories (pneumonia, moderate-to-severe nonpneumonic ARI and mild ARI) according to the findings of the chest radiograph and the hospitalization records.
Results: Among 384 cases enrolled, 371 were eligible for analysis, of whom 85 (23%) were classified as pneumonia cases; 137 (37%) as moderate-to-severe nonpneumonic ARI cases and 162 (40%) as mild ARI cases. RSV was detected in 172 cases (61.6%), and 31 cases (18.0%) had double or triple infections with other respiratory viruses. RSV infection was more frequently observed in pneumonia cases (odds ratio [OR]: 2.3; 95% confidence interval [CI]: 1.31–3.9) and moderate-to-severe nonpneumonic ARI cases (OR: 2.95; 95% CI: 1.82–4.78) than in mild ARI cases. The association with moderate-to-severe nonpneumonic ARI cases was stronger with RSV/non-RSV respiratory virus coinfection (adjusted OR: 4.91; 95% CI: 1.9–12.7) than with RSV single infection (adjusted OR: 2.77; 95% CI: 1.64–4.7).
Conclusions: Non-RSV respiratory virus coinfection is not uncommon in RSV-infected children and may increase the severity of RSV disease.
From the *Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Sakamoto; †Department of Pediatrics, Nagasaki Municipal Hospital, Shinchi; and ‡Department of Pediatrics, Nagasaki University School of Medicine, Sakamoto, Nagasaki, Japan.
This study was funded by the Japan Science and Technology Agency and the Grants-in-Aid for Scientific Research (Japan Society for the Promotion of Science). The funding sources did not have any role in conducting the study. The authors have no other funding or conflicts of interest to disclose.
Address for correspondence: Koya Ariyoshi, MD, PhD, Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Sakamoto 1-12-4, Nagasaki, 852–8523, Japan. E-mail: firstname.lastname@example.org.