Mystery virus as common as flu

A little-known, hard-to-identify virus is to blame for thousands of acute respiratory infections in children each year, a large US study finds.

The research found human metapneumovirus (HMPV) was detected in 6% of under-fives hospitalised for acute respiratory illness over six years — the same proportion as influenza and only slightly less than respiratory syncytial virus.

Extrapolating nationwide, the virus could be hospitalising 20,000 young children each year in the US alone, the researchers wrote