Doctors say this is the most important virus you’ve never heard of

The past winter was a heavy one for respiratory viruses, dominated by surges of RSV, influenza and Covid-19. But just as it was winding down, a little-known virus that causes many of the same symptoms – a lower lung infection, hacking cough, runny nose, sore throat and fever – was just picking up steam.

Cases of human metapneumovirus, or HMPV, spiked this spring, according to US Centers for Disease Control and Prevention’s respiratory virus surveillance systems. It filled hospital intensive care units with young children and seniors who are the most vulnerable to these infections. At its peak in mid-March, nearly 11% of tested specimens were positive for HMPV, a number that’s about 36% higher than the average, pre-pandemic seasonal peak of 7% test positivity.

Most people who caught it probably didn’t even know they had it, however. Sick people aren’t usually tested for it outside of a hospital or ER. Unlike Covid-19 and the flu, there’s no vaccine for HMPV or antiviral drugs to treat it. Instead, doctors care for seriously ill people by tending to their symptoms.