As China experiences a rise in respiratory infections this winter, one little-known virus has gotten a lot of attention – and some people may worry whether the rise in cases could be felt more broadly around the world.

China’s winter illness season is less severe compared to the year before, according to data from its health authority. But the proliferation of a long-standing though little-known pathogen called human metapneumovirus (hMPV) has been raising alarm both at home and in other countries.

Cases of human metapneumovirus (hMPV) have jumped in the UK amid speculation about an outbreak in China. Data shared by health authorities shows that infections have been going up during December and are expected to continue to rise in the coming weeks.