Respiratory Virus Without Vaccine Spreads Across US

HMPV cases rise among children and older adults in several states

Published on Mar. 8, 2026

Got story updates? Submit your updates here. ›

A respiratory virus known as human metapneumovirus (HMPV) that lacks a vaccine or specific treatment is spreading in parts of the United States, including California and New Jersey. HMPV can infect both the upper and lower respiratory tract, and care is limited to easing symptoms. While most people recover without medical intervention, the virus can lead to more serious cases requiring oxygen therapy, especially in children and adults 65 and older.

Why it matters

HMPV is a little-known virus that has the potential to cause significant illness, especially among vulnerable populations, in the absence of a vaccine or targeted treatment. Its spread highlights the ongoing challenges in managing emerging respiratory viruses and the importance of preventive measures.

The details

HMPV was first identified in 2001 and last saw a notable surge in the US in April 2025, when it accounted for over 7% of weekly positive respiratory virus tests. Cases have been increasing since October 2026, with elevated levels reported in the San Francisco Bay Area, Napa wine country, and the Northeast. Symptoms of HMPV include cough, stuffy nose, fever, and shortness of breath, which can sometimes progress to bronchitis or pneumonia.

  • HMPV was first identified in 2001.
  • HMPV last saw a notable US surge in April 2025, when it accounted for over 7% of weekly positive respiratory virus tests.
  • Cases have been increasing since October 2026.

The players

Centers for Disease Control and Prevention

The leading national public health institute in the United States.

Cleveland Clinic

A nonprofit academic medical center that provides clinical and hospital care.

Mayo Clinic

A nonprofit organization committed to clinical practice, education, and research.

Got photos? Submit your photos here. ›

The takeaway

The spread of HMPV, a respiratory virus without a vaccine or specific treatment, highlights the ongoing challenges in managing emerging infectious diseases and the importance of preventive measures, such as handwashing, avoiding contact with sick individuals, and improving indoor air quality, to protect vulnerable populations.