While cases are climbing in China, the situation is very different from what it was when Covid-19 emerged five years ago, medical experts say. HMPV is common and decades old.

Professor Paul Hunter from the University of East Anglia notes that almost every child contracts HMPV by five years of age, with reinfections occurring throughout life. “HMPV typically causes cold-like symptoms that recover by themselves within 2 to 5 days. Severe cases are rare but can occur in vulnerable groups,” he says.

As cases of the HMPV virus continue to increase in the U.S. and in China, here's what you need to know about the virus.

The human metapneumovirus is reportedly surging in China, but should Americans be concerned? Here's what to know about HMPV symptoms and more.

Dr Andrew Catchpole, chief scientific officer at challenge trial and laboratory services company hVIVO, said rates of serious hMPV “may be higher in China than what we would expect in a normal year”. More information is needed to understand whether the circulating strain was different from previous ones he said, but there is no need to panic.