Human metapneumovirus (HMPV), a flu-like virus that poses risks to young children, older adults and those with weakened immune systems, has raised concerns, but health officials are urging calm amid speculation about another potential pandemic.

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.