Little-known virus with no vaccine is spreading in California — here’s what to know

A little-known virus that causes nasty flu-like symptoms is spreading in California — and it doesn’t have a vaccine.

Cases of human metapneumovirus (HMPV) have been steadily rising since winter began, but new data suggests the virus is surging in Northern California.

Wastewater monitoring has found high levels of HMPV in several Northern California communities, including San Francisco, Sacramento, Davis, and Vallejo, according to the San Francisco Chronicle.

Like the flu, HMPV is seasonal. Cases typically rise in January, peak in March and April, and then decline as temperatures warm in May.

Most people in the US may not know about HMPV, but experts say its symptoms can resemble those of a cold, the flu, or RSV.

For most people, HMPV causes mild illness that goes away in a few days. Symptoms can include cough, fever, stuffy nose, sore throat, wheezing, shortness of breath, and sometimes a rash.

However, in serious cases, HMPV can cause pneumonia, bronchitis, or ear infections. It may also trigger asthma attacks or make chronic lung problems like COPD worse.

Studies show that nearly everyone will get HMPV at least once in their life.

HMPV spreads through direct contact with an infected person or by touching contaminated surfaces.

The virus spreads most easily during the first few days of illness and usually remains contagious for 1 to 2 weeks. Symptoms usually appear 3 to 7 days after exposure, according to the Cleveland Clinic.

Those at higher risk include young children, older adults, and individuals with weakened immune systems.

To reduce the risk of spreading HMPV, the CDC recommends staying home when sick, washing hands regularly, and cleaning commonly touched surfaces.

A patient should see a doctor if they are experiencing trouble breathing, chest pain, trouble staying hydrated, symptoms that last more than 10 days, or if an infant under 3 months has a fever or seems unusually tired.

Currently, there is no vaccine to guard against HMPV and no specific treatment for those who become infected.