Human coronavirus NL-63 infections in children: a 1-year study.

Human coronavirus NL63 (HCoV-NL63), a newly discovered coronavirus, has been associated with acute respiratory tract infections (ARI). Important questions pertaining to the contribution of HCoV-NL63 to ARI and its impact on public health remain. We reviewed HCoV-NL63 in specimens collected from 13 November 2002 to 31 December 2003 from the Stollery Children's Hospital on patients of <17 years of age to assess the role of this virus in ARI in children. Twenty-six of 1,240 specimens (2.1%) from seven outpatients and 19 inpatients aged 7 days to 9.5 years tested positive for HCoV-NL63 by reverse transcription-PCR. The majority of outpatients (86%) had upper respiratory tract infections, while the majority of inpatients (58%) had bronchiolitis. Peak HCoV-NL63 activity occurred in March. These results provide further evidence of the importance of HCoV-NL63 in ARI in children.