Coronavirus Infections in Pediatric Outpatients with Febrile Respiratory Tract Infections in Hiroshima, Japan, over a 3-Year Period

Previously, we conducted a 3-year prospective study to determine the viral causes of acute respiratory tract infections among 495 febrile pediatric outpatients. We collected 495 nasopharyngeal aspirate specimens, and used both real-time PCR assays and viral culture to test each for respiratory viruses other than coronavirus. Here, we used real-time PCR to test the 495 archival specimens for four human coronavirus strains. We identified 15 coronavirus-positive specimens: eight with OC43, 5 with NL63, 2 with HKU1, and none with 229E. Of the 15 children (5 boys) infected with human coronavirus, the mean age was 3.5 years, and the age range was 1.1 to 5.8 years; one child was diagnosed with lower respiratory infection; the other 14 were diagnosed with upper respiratory infection. Of these 15 patients, none were hospitalized, 5 were infected with coronavirus alone, 8 were co-infected with another virus, and 2 were co-infected with 2 other viruses. The multi-virus infections involved 6 adenoviruses, 3 respiratory syncytial viruses, 2 parainfluenza viruses, and 1 rhinovirus. In conclusion, the burden of human coronaviruses was relatively light among this cohort of 495 pediatric outpatients, and the incidence of these infections was low.