Multi-year study of human metapneumovirus infection at a large US Midwestern Medical Referral Center.

BACKGROUND: Because of its recent identification, few multi-year epidemiologic studies of hMPV infection have been reported. OBJECTIVE: We sought to retrospectively describe hMPV infections among patients evaluated by a large US Midwestern referral laboratory. STUDY DESIGN: Clinical specimens were submitted to a large US Midwest referral hospital from 1 October 2001 to 18 May 2004. RT-PCR was used to retrospectively screen the clinical specimens for human metapneumovirus. Demographic and clinical data were retrieved. RESULTS: 34 (2.6%) of 1294 specimens were hMPV positive. Among these, 21 (62%) were culture positive and available for genetic typing. A previously considered rare genotype of hMPV, B1, was the most common single genotype identified, comprising 9 (43%) of the 21 isolates. Multivariate logistic regression modeling identified patients aged 0.4-9 years (OR=8.9; 95% CI=2.0-38.5) and those under intensive care (OR=3.2; 95% CI=1.1-8.7) as more likely to have hMPV infection than their peers. CONCLUSION: In this large referral hospital viral assays more often had evidence of hMPV when they were collected from children receiving intensive care.