Respiratory Virus Surge: HMPV Spreads in California with No Vaccine Available

Got story updates? Submit your updates here. ›

Increased detection of Human Metapneumovirus (HMPV) has been observed in northern parts of California this winter. The lack of immunity built up during the COVID-19 pandemic has contributed to the vulnerability of certain groups and altered the typical dynamics of respiratory illnesses. HMPV is a common respiratory virus that can cause cold-like symptoms, but there is currently no approved vaccine or antiviral treatment specifically for it.

Why it matters

The re-emergence of normal routines after the pandemic has led to a shift in the timing and severity of viral illnesses, with record levels of childhood viral illnesses observed due to the lack of usual immunity from exposure. This has put a strain on the healthcare system, particularly for vulnerable populations.

The details

Between mid-December and late February, cities like Merced, Novato and Sunnyvale in California saw increases in HMPV levels in wastewater. In Los Angeles County, HMPV presence remains at low to moderate levels. Nationally, the peak positive test rate for HMPV reached 6.1% as of February 21st of this year, compared to 7.15% at the end of April last year and 11.7% at the end of March in 2022. HMPV was first identified in 2001 and spreads through close contact with infected individuals or by touching contaminated surfaces.

• Between mid-December and late February, cities like Merced, Novato and Sunnyvale in California saw increases in HMPV levels in wastewater.
• As of February 21st of this year, the national peak positive test rate for HMPV reached 6.1%, compared to 7.15% at the end of April last year and 11.7% at the end of March in 2022.