Co-circulation of human metapneumovirus and SARS-associated coronavirus during a major nosocomial SARS outbreak in Hong Kong

Background: The clinico-epidemiological significance of human metapneumovirus (hMPV) detected during the SARS outbreak is unknown. Objectives: To characterize a nosocomial hMPV outbreak during the 2003 SARS epidemic. Study design and methods: All available nasopharyngeal aspirate (NPA) collected from confirmed patients during the first 8 weeks of the SARS outbreak in 2003 were tested for hMPV by a nested RT-PCR assay targeting the F-gene. Clinico-epidemiological information was used to analyze the relationship of hMPV co-infection to specific risk factors (demographics/symptoms/outcomes; status as health-care workers (HCWs)/patients; history of exposure/contact; ward location). Multivariate logistic regression analysis was performed to determine independent risk factors. Results: An hMPV outbreak occurred during 6-16 March 2003 (first week of the Hong Kong SARS epidemic). hMPV RNA was detected in 31 of 155 (20%) NPAs from SARS patients. HCW status (OR 2.72, 95% CI 1.11-6.68; p = 0.029) or epidemiological linkage to the SARS outbreak ward (OR 3.59, 95% CI 1.42-9.05; p = 0.007) were independent factors associated with hMPV infection. Symptoms of cough and coryza were more common in co-infected individuals (22.6% vs. 15.9%) but this was not statistically significant. Other clinical manifestations and outcomes were hot different in co-infected patients. Conclusions: A major nosocomial hMPV outbreak involving HCWs occurred during the early SARS epidemic. Patients with dual hMPV and SARS infection were not sicker than those with SARS infection only. (C) 2007 Elsevier B.V. All rights reserved.