Epidemiology of Human Metapneumovirus Infection in a Community Setting, Seattle, Washington, USA

The clinical and genomic epidemiology of human metapneumovirus (hMPV) infections in community settings is not well understood.

From 2018 to 2022, individuals with respiratory symptoms were recruited and enrolled from the greater Seattle, Washington community in the United States. Residual clinical specimens from individuals presenting with respiratory symptoms were additionally collected. Specimens were tested for hMPV by reverse-transcription polymerase chain reaction, with whole genome sequencing performed on a subset (209/1002).

hMPV positivity was higher among clinical specimens (835/21 539 [3.9%]) compared to community specimens (167/28 348 [0.6%]). Children aged 0-4 years had the highest percent positivity across both clinical and community settings (497/10 213 [4.9%] and 28/1640 [1.7%], respectively). In multivariate analysis, a household income of ≤US$100 000 (adjusted odds ratio [aOR], 1.72 [95% confidence interval {CI}, 1.07-2.85]), and recent international travel (aOR, 6.51 [95% CI, 3.11-12.22]) were associated with hMPV positivity. A subset of 209 of 1002 samples (21%) was sequenced; the distribution of subtypes A2b, A2c, B1, and B2 were similar across both community and clinical settings, with an increase in the proportion of subtype B1 after the start of the pandemic.

Risk factors of testing positive for hMPV in a community setting included lower household income and recent international travel. Co-circulation of hMPV subtypes was observed across community and clinical settings.