Clinical characteristics, co-detection patterns and prognostic risk factors of human metapneumovirus infection in children: a retrospective study.

Median age was 3.50 years (IQR 1.75-4.75).

Of 621 patients, 399 (64.3%) had Single-detection and 222 (35.7%) co-detection, with viral-viral co-detection dominant (68.9%) and rhinovirus the most common co-pathogen (39.6%).

Viral-bacterial co-detection was associated with longer hospitalization (median 6.5 days) and higher severe pneumonia rate (14.5%, both P<0.01).

Older age (3-5 years: aOR=0.20; >5 years: aOR=0.03) showed significant protective effects.