HMPV cases are rising across Asia, but experts say not to panic

“The virus has circulated for at least 60 years, and genetic evolutionary studies suggest that it diverged from a bird virus between 200 to 400 years ago,” says John Williams, a pediatrician and infectious diseases professor at the University of Wisconsin–Madison, who has studied HMPV for more than 20 years. “HMPV causes regular annual seasonal epidemics, similar to the more widely recognized influenza virus and RSV. The typical HMPV season is late winter to early spring. So this isn’t totally unexpected.”