Mysterious HMPV Virus Surges Across U.S., Sparking Health Alerts

Health officials are tracking a sharp rise in human metapneumovirus (HMPV) cases across the United States, with surges reported from Northern California to the West Coast as of March 2026. First identified in 2001, HMPV causes symptoms mimicking RSV, including cough, wheezing, pneumonia and bronchiolitis, and is spreading via respiratory droplets, close personal contact and fomites like contaminated surfaces.[1][2][4] The CDC's National Respiratory and Enteric Virus Surveillance System (NREVSS) confirms the seasonal spike, typically from late winter through spring in mild climates.[2][4] Young children under 2, older adults over 65, and those with weakened immune systems face the highest risks of severe illness requiring hospitalization. Infants born prematurely, cancer patients, organ transplant recipients and individuals with chronic lung conditions are particularly vulnerable, according to UC Davis pediatric infectious disease chief Dean Blumberg.[2] HMPV circulates alongside RSV and influenza, contributing to combined peak hospitalizations during the week ending January 3, 2026, which neared last season's levels.[3] No vaccine or specific treatment exists for HMPV, leaving supportive care—hydration, rest and over-the-counter symptom relief—as the mainstay, per CDC guidelines.[1][4] Diagnosis requires healthcare provider testing, and experts advise seeking medical attention for difficulty breathing, chest pain, persistent symptoms beyond 10 days or fever in infants under 3 months.[2] Northern California reports highlight a spring spike distinct from flu or COVID-19, with RSV activity also lingering unusually into April.[2][3] CDC data as of March 27, 2026, shows low overall acute respiratory illness levels, but HMPV's predictable pattern signals continued circulation into spring.[3][5] Officials emphasize prevention through handwashing, avoiding close contact with the ill and surface disinfection to curb transmission.[1][4] While most cases remain mild, the virus's contagiousness underscores the need for heightened awareness amid overlapping respiratory threats.