Little-known viruses causing spike in respiratory infections, including COVID-like strain.

The human metapneumovirus (HMPV), a little-known respiratory virus, caused a surge in hospitalizations and illnesses this spring, with cases surging about 36 percent in mid-March, according to the Centers for Disease Control and Prevention. HMPV causes symptoms similar to COVID-19 or RSV, but doctors don’t usually test for it outside of a hospital setting. The virus can lead to complications and intensive care for vulnerable patients, but in most cases, the symptoms will resolve without treatment after several days.