A highly contagious respiratory virus known as human metapneumovirus (HMPV) is spreading rapidly across several western states, with Northern California showing especially high levels according to wastewater surveillance data. Communities including San Francisco, Marin, Vallejo, Napa, Novato, Santa Rosa, Sacramento, and Davis are reporting elevated viral activity. The virus peaked sharply in January and remains widespread in early March, though levels are beginning to taper as winter ends.
HMPV, first identified in 2001, is in the same viral family as RSV and spreads through close contact, respiratory droplets, and contaminated surfaces. Wastewater data also indicate rising levels in the Midwest and Northeast.
According to the CDC:…