What to know about human metapneumovirus

It’s not COVID-19 or the flu, but a respiratory virus has been hammering Northern California cities including Sacramento and Davis, testing shows.

WastewaterSCAN data shows “high concentrations” of human metapneumovirus, or HMPV, in Sacramento and Davis, along with San Francisco, Marin, Vallejo, Napa, Novato and Santa Rosa.

The virus can “cause upper and lower respiratory illness in people of all ages, especially in young children, older adults, and people with weakened immune systems,” the U.S. Centers for Disease Control and Prevention said.

A spokesperson for the Sacramento County Department of Health, which does not track HMPV, said the agency could not comment on the findings.

Here’s what to know:

What is human metapneumovirus?

Human metapneumovirus, also called HMPV, is a virus that infects the nose, throat and lungs, according to the Mayo Clinic.

For most people, it feels like having the common cold, but it can lead to complications like croup and pneumonia.

Although the first case of HMPV in humans was confirmed in 2001, scientists say the virus has been spreading among humans for at least 50 years, the clinic said.

“HMPV is in the same family of viruses as respiratory syncytial virus, also called RSV,” reported the Mayo Clinic.

How common is human metapneumovirus?

The virus is extremely common, WebMD said. Most people are likely to have an infection at least once before age 5. And you can be infected multiple times in your life.

The virus makes up about 1 in 10 of all respiratory infections, and anyone can catch it.

Infections are most common during winter through spring, the CDC said, although HMPV infections can occur year-round.

What are the symptoms of human metapneumovirus?

The symptoms of HMPV are a lot like those of the flu or common cold — cough, fever, sore throat, runny or stuffy nose, body aches and headache, the World Health Organization said.

Less common symptoms can include voice changes, eye or ear infection and a rash that comes and goes, the Mayo Clinic said.

Symptoms usually go away in two to five days, WebMD said. If they last more than two weeks, contact your doctor.

What are the complications of human metapneumovirus?

While most people recover fairly quickly from HMPV, people with weakened immune system or other medical conditions, or who are very young or old, are more likely to suffer serious illness, the Mayo Clinic said.

Possible complications can include croup, pneumonia, asthma attacks, middle ear infections, bronchiolitis and fever, the CDC said.

How does human metapneumovirus spread?

The virus mainly spreads from contact with infected people, WebMD said.

You also can be exposed by touching contaminated surfaces, touching your nose, mouth or eyes after touching infected surfaces, droplets sprayed by coughs or sneezes from an infected person, or shaking hands or touching an infected person.

How can you prevent human metapneumovirus?

There is no vaccine for HMPV, the Mayo Clinic said, but you can take steps to try to avoid infections.

Wash your hands regularly, don’t touch your face, clean surfaces and avoid infected people, the site said.

How do you treat human metapneumovirus?

There are no antiviral treatments for HMPV, the CDC said.

The agency advises people with human metapneumovirus to drink plenty of liquids, stay home and rest.

How can you tell human metapneumovirus from other illnesses?

“It is hard to tell different respiratory illnesses apart as they have similar symptoms such as fever, cough, runny nose and congestion,“ the World Health Organization said.

But the treatment can differ, especially for people with the flu or COVID-19, which can be treated with antiviral medications. Doctors may rule out these diagnoses with tests.

This story was originally published March 3, 2026 at 11:11 AM.