Background The clinical relevance of infections with the novel human coronavirus NL63 (HCoV-NL63) has not been investigated systematically. We therefore determined its association with disease in young children with lower respiratory tract infection (LRTI). Methods and Findings Nine hundred forty-nine samples of nasopharyngeal secretions from children under 3 y of age with LRTIs were analysed by a quantitative HCoV-NL63-specific real-time PCR. The samples had been collected from hospitalised patients and outpatients from December 1999 to October 2001 in four different regions in Germany as part of the prospective population-based PRI.DE study and analysed for RNA from respiratory viruses. Forty-nine samples (5.2%), mainly derived from the winter season, were positive for HCoV-NL63 RNA. The viral RNA was more prevalent in samples from outpatients (7.9%) than from hospitalised patients (3.2%, p = 0.003), and co-infection with either respiratory syncytial virus or parainfluenza virus 3 was observed frequently. Samples in which only HCoV-NL63 RNA could be detected had a significantly higher viral load than samples containing additional respiratory viruses (median 2.1 × 10 6 versus 2.7 × 10 2 copies/ml, p = 0.0006). A strong association with croup was apparent: 43% of the HCoV-NL63-positive patients with high HCoV-NL63 load and absence of co-infection suffered from croup, compared to 6% in the HCoV-NL63-negative group, p < 0.0001. A significantly higher fraction (17.4%) of samples from croup patients than from non-croup patients (4.2%) contained HCoV-NL63 RNA. Conclusion HCoV-NL63 infections occur frequently in young children with LRTI and show a strong association with croup, suggesting a causal relationship. The novel human coronavirus HCoV-NL63 shows a strong association with croup.
【초록키워드】 coronavirus, children, Infection, RNA, respiratory viruses, Region, Real-time PCR, Viral load, respiratory syncytial virus, Germany, Patient, Co-infection, age, NL63, Viral RNA, novel, disease, Quantitative, HCoV-NL63, association, Outpatient, Croup, Lower respiratory tract, fraction, finding, positive, prevalent, compared, detected, different, determined, collected, Sample, respiratory virus, investigated, analysed, median, absence, occur, suffered, nasopharyngeal secretion, parainfluenza virus 3, significantly higher, hospitalised patient,