Beijing is witnessing a significant increase in human metapneumovirus (HMPV) cases, particularly among children, attributed to seasonal factors. Experts clarify that while HMPV leads to mild respiratory infections for most, it poses greater risks to the very young and immunocompromised individuals. The virus, which has been known since 2001, typically peaks in cold weather. Increased cases are also reported across the northern hemisphere, although experts suggest this aligns with normal seasonal patterns rather than an impending pandemic.